Oviposition-Deterrent Effect of a High-Quality Natural Zeolite on the Olive Fruit Fly Bactrocera oleae, under Different Conditions of Temperature and Relative Humidity

In recent years, the number of available chemical pesticides has been dramatically reduced, urging the need for the discovery of alternatives to chemical pesticide products such as, among others, natural zeolites (zeolitic rocks). We determined the mineralogical and chemical composition of a specific and continuous layer of zeolitic rock sample (ZeotP) from Petrota, Evros, Greece, and evaluated its oviposition-deterrent effect on the olive fruit fly Bactrocera oleae Gmelin (Diptera: Terphritidae). The tested natural zeolite contained 70 wt. % clinoptilolite, 18 wt. % amorphous material, 7 wt. % feldspars, 4 wt. % cristobalite, and 1 wt. % quartz. We tested the oviposition-deterrent effect of ZeotP mixed or not with an emulsifier adjuvant, NU-FILM-P®, in water and applied it to the surface of olive fruits. The ZeotP oviposition-deterrent effect on the olive fly was very high under a series of tested temperatures (17 °C, 20 °C, 25 °C, and 30 °C) and RHs (23%, 33%, 55%, 75%, and 94%). In addition, the ZeotP residual deterrent effect after equable water spraying was high, like the respective effect of the pyrethroid insecticide Decis® (deltamethrin). Our results may contribute to the effective control of the olive fruit fly using an alternative to chemical pesticides: natural zeolite (zeolitic rocks) products.

Aluminosilicates as a Double-Edged Sword: Adsorption of Aflatoxin B1 and Sequestration of Essential Trace Minerals in an In Vitro Gastrointestinal Poultry Model

Aflatoxins can cause intoxication and poisoning in animals and humans. Among these molecules, aflatoxin B1 (AFB1) is the most dangerous because of its carcinogenic and mutagenic properties. To mitigate these effects, clay adsorbents are commonly included in the diet of animals to adsorb the carcinogens and prevent their absorption in the gastrointestinal tract. In this study, four clays, three smectites (C-1, C-2, and C-3), and one zeolite (C-4), were compared as adsorbents of AFB1 and trace inorganic nutrients using an in vitro gastrointestinal model for poultry. Characterization of the clays using Fourier transform infrared spectroscopy revealed characteristic bands of smectites in C-1, C-2, and C-3 (stretching vibrations of Si-O, Al-O-Si, and Si-O-Si). The C-4 presented bands related to the bending vibration of structural units (Si-O-Si and Al-O-Si). X-ray diffraction analysis showed that C-1 is a montmorillonite, C-2 is a beidellite, C-3 is a beidellite-Ca-montmorillonite, and C-4 is a clinoptilolite. The elemental compositions of the clays showed alumina, silica, iron, calcium, and sodium contents. The cation exchange capacity was higher in C-3 clay (60.2 cmol(+)/kg) in contrast with the other clays. The AFB1 adsorption of C-1 was the highest (98%; p ˂ 0.001), followed by C-2 (94%). However, all the clays also sequestered trace inorganic nutrients (Fe, Mn, Zn, and Se). Both smectites, montmorillonite and beidellite, were the most suitable for use as adsorbents of AFB1.

Photocatalytic Degradation of Xylene by Carbon Quantum Dots/Clinoptilolite Composites

In this work, a series of clinoptilolite composites decorated with carbon quantum dots (CQDs/clinoptilolite) with hierarchical pore structures was demonstrated that exhibits good photocatalytic performance for the removal of xylene. The technique for the attachment of carbon quantum dots to clinoptilolite was prepared by a hydrothermal method in this study. The structural features were confirmed by SEM, TEM, EDS, XRD, BET, XPS, and solid diffuse reflection measurements, while the degradation mechanism was investigated by adding a trapping agent into the nanocomposites. The introduction of CQDs promoted the separation of photogenerated electrons and holes as well as the generation of reactive radicals, which effectively improved the light utilization and even increased the degradation rate of xylene by 73% at the optimal state. The photocatalytic test was conducted under a different dwell time, catalyst dosage, initial concentration, and illumination intensity. The results showed that the degradation rate of xylene by the CQDs/clinoptilolite catalyst reached 97.4% under the optimal reaction conditions (the catalyst was Catalyst No. 2, the residence time was 90 s, the initial concentration was 2.5 g/m3, the light intensity was three lamps for irradiation, and the catalyst dosage was 0.05 g). In addition, the degradation efficiency of the CQDs/clinoptilolite photocatalyst still reached 78% after eight consecutive catalytic regeneration cycles. This work sheds new light on the degradation of xylene.

Using Natural Zeolite as a Feed Additive in Broilers' Diets for Enhancing Growth Performance, Carcass Characteristics, and Meat Quality Traits

BACKGROUND

Using natural zeolites as a food additive in poultry diets offers an intriguing perspective. The objective of this study was to investigate the effects of zeolite addition and particle size on broiler performance, carcass characteristics, meat quality, moisture of excreta and litter, and intestinal measurements during 35 days.

METHODS

A total of 560 1-day-old female Ross-308 broilers were divided into five treatment levels (0, 5, 10, 15, and 20 g zeolite/kg diet) (n = 16 replicates/treatment, n = 8 replicates /particle size of each treatment). Performance was calculated weekly. Carcass characteristics, meat quality, small intestine (SI) measurements, litter pH, and moisture content were determined on day 35.

RESULTS

Litter pH, breast redness, cooking loss, chewiness, total weight, and SI length were all affected by zeolite treatments (p < 0.05). Particle size had an impact on the gastric pH and texture analysis. Their interaction had an effect on color redness, litter pH, and cooking loss. Performance was unaffected by either the main or interaction effects.

CONCLUSION

Zeolite as a feed additive may be useful in broiler diets, particularly large particles. The performance and production efficiency factor improved numerically (p > 0.05) with increasing zeolite doses up to 10 g zeolite/kg diet.

Constructing Randomly Lamellar HKUST-1@Clinoptilolite through Polyethylene Glycol-Assisted Hydrothermal Method and Coordinated Complexation for Enhanced Adsorptive Separation for CO2 and CH4

Clinoptilolite (CP) was successfully synthesized via a hydrothermal route in the presence of polyethylene glycol (PEG), and it was then delaminated by washing using Zn²⁺ containing acid. HKUST-1, as one kind of the Cu-based MOFs, showed a high CO₂ adsorption capacity owing to its large pore volume and specific surface area. In the present work, we selected one of the most efficient ways for preparing the HKUST-1@CP compounds via coordination between exchanged Cu²⁺ and ligand (trimesic acid). Their structural and textural properties were characterized by XRD, SAXS, N₂ sorption isotherms, SEM, and TG-DSC profiles. Particularly, the effect of the additive PEG (average molecular weight of 600) on the induction (nucleation) periods and growth behaviors were detailed and investigated in the hydrothermal crystallization procedures of synthetic CPs. The corresponding activation energies of induction (E_n) and growth (E_g) periods during crystallization intervals were calculated. Meanwhile, the pore size of the inter-particles of HKUST-1@CP was 14.16 nm, and the BET specific area and pore volume were 55.2 m²/g and 0.20 cm³/g, respectively. Their CO₂ and CH₄ adsorption capacities and selectivity were preliminarily explored, showing 0.93 mmol/g for HKUST-1@CP at 298 K with the highest selective factor of 5.87 for CO₂/CH₄, and the dynamic separation performance was evaluated in column breakthrough experiments. These results suggested an efficient way of preparing zeolites and MOFs composites that is conducive to being a promising adsorbent for applications in gas separation.

Removal of Cesium and Strontium Ions from Aqueous Solutions by Thermally Treated Natural Zeolite

The radionuclides of cesium (Cs) and strontium (Sr) are dangerous products of nuclear fission that can be accidentally released into wastewater. In the present work, the capacity of thermally treated natural zeolite (NZ) from Macicasu (Romania) to remove Cs⁺ and Sr²⁺ ions from aqueous solutions in batch mode was investigated by contacting different zeolite quantities (0.5, 1, and 2 g) of 0.5-1.25 mm (NZ1) and 0.1-0.5 mm (NZ2) particle size fractions with 50 mL working solutions of Cs⁺ and Sr²⁺ (10, 50, and 100 mg L^-1 initial concentrations) for 180 min. The concentration of Cs in the aqueous solutions was determined by inductively coupled plasma mass spectrometry (ICP-MS), whereas the Sr concentration was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The removal efficiency of Cs⁺ varied between 62.8 and 99.3%, whereas Sr²⁺ ranged between 51.3 and 94.5%, depending on the initial concentrations, the contact time, the amount, and particle size of the adsorbent material. The sorption of Cs⁺ and Sr²⁺ was analyzed using the nonlinear form of Langmuir and Freundlich isotherm models and pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The results indicated that the sorption kinetics of Cs⁺ and Sr²⁺ on thermally treated natural zeolite was described by the PSO kinetic model. Chemisorption dominates the retention of both Cs⁺ and Sr²⁺ by strong coordinate bonds with an aluminosilicate zeolite skeleton.

Structure Features and Physicochemical Performances of Fe-Contained Clinoptilolites Obtained via the Aqueous Exchange of the Balanced Cations and Isomorphs Substitution of the Heulandite Skeletons for Electrocatalytic Activity of Oxygen Evolution Reaction and Adsorptive Performance of CO2

Fe(III)-modified clinoptilolites (Fe-CPs) were prepared by hydrothermal treatment. The collapse of the heulandite skeletons was avoided by adjusting the pH value using HCl solution, showing the maximum relative crystallinity of the Fe-CPs at an optimal pH of 1.3. The competitive exchange performances between Fe³⁺ ions and H⁺ with Na⁺ (and K⁺) suggested that the exchange sites were more easily occupied by H⁺. Various characterizations verified that the hydrothermal treatments had a strong influence on the dispersion and morphology of the isolated and clustered Fe species. The high catalytic activity of the oxygen evolution reaction indicated the insertion of Fe³⁺ into the skeletons and the occurrences of isomorphic substitution. The fractal evolutions revealed that hydrothermal treatments with the increase of Fe content strongly affected the morphologies of Fe species with rough and disordered surfaces. Meanwhile, the Fe(III)-modified performances of the CPs were systematically investigated, showing that the maximum Fe-exchange capacity was up to 10.6 mg/g. Their thermodynamic parameters and kinetic performances suggested that the Fe(III)-modified procedures belonged to spontaneous, endothermic, and entropy-increasing behaviors. Finally, their adsorption capacities of CO₂ at 273 and 298 K were preliminarily evaluated, showing high CO₂ adsorption capacity (up to 1.67 mmol/g at 273 K).

Preparation, Characterization, and Performance of Natural Zeolites as Alternative Materials for Beer Filtration

The clarity of the beer is essential to its marketability and good consumer approval. Moreover, the beer filtration aims to remove the unwanted constituents that cause beer haze formation. Natural zeolite, an inexpensive and widespread material, was tested as a substitute filter media for diatomaceous earth in removing the haze constituents in beer. The zeolitic tuff samples were collected from two quarries in Northern Romania: Chilioara, in which the zeolitic tuff has a clinoptilolite content of about 65%, and the Valea Pomilor quarry, containing zeolitic tuff with a clinoptilolite content of about 40%. Two-grain sizes, <40 and <100 µm, from each quarry were prepared and thermally treated at 450 °C in order to improve their adsorption properties and remove organic compounds and for physico-chemical characterization. The prepared zeolites were used for beer filtration in different mixtures with commercial filter aids (DIF BO and CBL3) in laboratory-scale experiments, and the filtered beer was characterized in terms of pH, turbidity, color, taste, flavor, and concentrations of the major and trace elements. The results showed that the taste, flavor, and pH of the filtered beer were generally not affected by filtration, while turbidity and color decreased with an increase in the zeolite content used in the filtration. The concentrations of Na and Mg in the beer were not significantly altered by filtration; Ca and K slowly increased, while Cd and Co were below the limits of quantification. Our results show that natural zeolites are promising aids for beer filtration and can be readily substituted for diatomaceous earth without significant changes in brewery industry process equipment and protocols for preparation.

Optimization of Ciprofloxacin Adsorption on Clinoptilolite-Based Adsorbents Using Response Surface Methodology

The adsorption of the antibiotic ciprofloxacin (CIP) from water solution by natural zeolite-clinoptilolite (CLI), magnetic clinoptilolite (MAG-CLI), and graphene oxide coated magnetic clinoptilolite (GO-MAG-CLI) was investigated. The novel approach of an environmentally friendly and cost-effective microwave-assisted method was applied for the magnetic composite synthesis. Detailed characterization of the prepared composites was achieved. In order to investigate the effect of the initial CIP concentration, pH, temperature, contact time, and type of adsorbent on the adsorption efficiency of CIP, and to obtain the optimal conditions for CIP removal, the response surface methodology central composite factorial design (RSM-CCF) was applied. The results obtained by the RSM-CCF showed that among the studied adsorbents, GO-MAG-CLI had the highest adsorption capacity for CIP, achieved for the initial concentration of 48.47 mg dm^-3 at a pH of 5 and 24.78 °C after 19.20 min of contact time. The adsorption kinetics studied for the initial CIP concentration range of 15-50 mg dm^-3 followed Lagergren's pseudo-second-order model, and the Langmuir isotherm was the most suitable one to describe the CIP adsorption onto GO-MAG-CLI.

Influence of Acid-Modified Clinoptilolite on the Self-Adhesive Properties of Silicone Pressure-Sensitive Adhesives

The preparation of a new "eternally alive adhesive" based on silicone pressure-sensitive adhesives with clinoptilolite is presented. Neat and acid-modified (i.e., treated with sulfuric acid (VI)) clinoptilolite was used. The effect of clinoptilolite acid treatment on the adhesive properties of pressure-sensitive adhesive tapes was tested. The obtained tapes exhibited increased thermal resistance when compared to the reference tapes. Despite introducing the filler, the pressure-sensitive adhesive tapes maintained good functional properties. The new self-adhesive materials show promising implementation potential where increased thermal resistance is required.

The Impact of Long-Term Clinoptilolite Administration on the Concentration Profile of Metals in Rodent Organisms

Heavy metals are dangerous systemic toxicants that can induce multiple organ damage, primarily by inducing oxidative stress and mitochondrial damage. Clinoptilolite is a highly porous natural mineral with a magnificent capacity to eliminate metals from living organisms, mainly by ion-exchange and adsorption, thus providing detoxifying, antioxidant and anti-inflammatory medicinal effects. The in vivo efficiency and safety of the oral administration of clinoptilolite in its activated forms, tribomechanically activated zeolite (TMAZ) and Panaceo-Micro-Activated (PMA) zeolite, as well as the impact on the metallic biodistribution, was examined in healthy female rats. Concentration profiles of Al, As, Cd, Co, Pb, Ni and Sr were measured in rat blood, serum, femur, liver, kidney, small and large intestine, and brain using inductively coupled plasma mass spectrometry (ICP-MS) after a 12-week administration period. Our results point to a beneficial effect of clinoptilolite materials on the concentration profile of metals in female rats supplemented with the corresponding natural clinoptilolite materials, TMAZ and PMA zeolite. The observed decrease of measured toxicants in the kidney, femur, and small and large intestine after three months of oral intake occurred concomitantly with their most likely transient release into the bloodstream (serum) indicative of a detoxification process.

Effects of clinoptilolite on heavy metal levels in milk, proinflammatory cytokine responses (IL-1β and IL-6) and oxidative stress in dairy cows

The effects of clinoptilolite on milk copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd) and iron (Fe) concentrations, proinflammatory cytokine responses, oxidative stress status, whole blood cell counts and liver and kidney functions were investigated in dairy cows exhibiting no signs of any kind of toxicity. Clinoptilolite was added to the feed at a dose of 200 mg kg-1 body weight in the clinoptilolite-treated group (n = 14), but was not added to the feed in the control group (n = 7). In the milk samples (n = 21) collected before the experiment, the Cu, Pb, Zn, Cd and Fe values were 0.021 ± 0.020, 0.104 ± 0.01, 3.42 ± 0.32, <0.000, 0.56 ± 0.34 ppm, respectively. At the end of the experiment (30th day), among the elements measured in milk samples collected from the clinoptilolite-treated group, only the Pb value (0.076 ± 0.01) was lower than the 0-day value of the clinoptilolite-treated group (0.104 ± 0.01) and the 30th-day value of the control group (0.105 ± 0.01) was found to be statistically lower. Changes determined at the end of clinoptilolite application in serum superoxide dismutase (SOD), malondialdehyde (MDA), albumin, glucose, urea and urine creatinine/urine total protein (uCr/uTP) values, which were interpreted as the effect of lead exposure before the trial, were evaluated as the positive effect of clinoptilolite. It was concluded that the addition of clinoptilolite to the feed in dairy cows caused a significant decrease in the amount of Pb in milk, and positive changes in the parameters related to oxidative stress in serum and in parameters related to renal function.

Utilisation of waste Cu-, Mn- and Fe-loaded zeolites generated after wastewater treatment as catalysts for air treatment

Disposal of copper, manganese and iron is particularly problematic in wastewater of metallurgical and galvanization plants, the electronics industry and agriculture. On the other hand, volatile organic compounds (VOCs), emitted from industrial processes, transportation and consumer products are the main class of air pollutants. The study revealed the potential of waste metal-loaded zeolite, generated through wastewater treatment procedures, to be utilised as an effective VOC removal catalyst for air treatment. In the first step, we have evaluated the sorption performance of natural zeolite clinoptilolite (HEU type), and synthetic zeolite 4A (LTA type) for the simultaneous removal of Cu2+, Mn2+ and Fe3+ species from aqueous solution. By a detailed sorption study, we determined the optimum sorption conditions and maximum metal concentrations in wastewater that can be after treatment disposed of in rivers or municipal plants. The efficiency of both zeolites for metal immobilization was demonstrated for concentrations up to 5 mg metals/1 g zeolite. These waste Cu-, Mn- and Fe-loaded zeolites were thermally treated at 540 °C before the second step, where we evaluated their catalytic performance in removing VOC. The thermally treated waste Cu-, Mn- and Fe-loaded natural zeolite clinoptilolite showed good catalytic performance in total toluene oxidation as a model VOC (conversion rate up to 96% at 510°C) and cycling stability (less than 15% drop in conversion rate in 4 h). In contrast, this is not the case for thermally treated waste Cu-, Mn- and Fe-loaded synthetic zeolite 4A.

Water-Holding Properties of Clinoptilolite/Sodium Polyacrylate-Modified Compacted Clay Cover of Tailing Pond

Clinoptilolite and sodium polyacrylate (Na-PAA) were used as water-retaining agents to improve the water-holding capacity of compacted clay cover (CCC). The optimum moisture content and Atterberg limits of the CCC modified by clinoptilolite and Na-PAA were studied. The soil-water characteristic curve (SWCC) of the CCC modified by clinoptilolite and Na-PAA was studied. The mesostructure of the CCC was analyzed by polarized light microscopy. The test results show that: (1) the optimum moisture content and liquid limit of the CCC modified by clinoptilolite and Na-PAA increased, while the maximum dry density decreased; (2) the SWCC of the CCC modified by clinoptilolite and Na-PAA shifts to the upper right, and the volume moisture content of modified CCC is higher than that of unmodified CCC under the same matrix suction; (3) compared with the unmodified CCC, the air-entry value (AEV) of the clinoptilolite-modified CCC increased by 65.18% at most, and the AEV of the further modified CCC with Na-PAA in-creased by about two times; and (4) the flocculation structure and porosity of modified CCC decreased, and the porosity was distributed uniformly.

Hydrotalcite-Modified Clinoptilolite as the Catalyst for Selective Catalytic Reduction of NO with Ammonia (NH3-SCR)

A series of clinoptilolite-supported catalysts, modified with hydrotalcite-like phase (HT) by co-precipitation, were prepared and tested in NH₃-SCR reactions. It was found that deposition of HT on clinoptilolite increased conversion of NO within 250-450 °C, and that the positive impact on the catalytic activity was independent of HT loading. The promoting effect of clinoptilolite was attributed to Brönsted acid sites present in the zeolite, which facilitated adsorption and accumulation of ammonia during the catalytic process. Concentration of N₂O in the post-reaction gas mixture reached its maximum at 300 °C and the by-product was most likely formed as a consequence of NH₄NO₃ decomposition or side reaction of NH₃ oxidation in the high-temperature region. The gradual elimination of nitrous oxide, noticed as the material with the highest concentration of hydrotalcite phase, was attributed to the abundance of oligomeric iron species and the superior textural parameters of the material. UV-Vis experiments performed on the calcined samples indicated that Fe sites of higher nuclearity were generated by thermal decomposition of the hydrotalcite phase during the catalytic reaction. Therefore, calcination of the materials prior to the catalytic tests was not required to obtain satisfactory overall catalytic performance in NO reductions.

Modification of Clinoptilolite as a Robust Adsorbent for Highly-Efficient Removal of Thorium (IV) from Aqueous Solutions

The natural zeolite has been modified with sulphate and phosphate. The adsorption of thorium from the aqueous solutions by using the natural and modified zeolites has been investigated via a batch method. The adsorbent samples were characterized by X-ray Diffraction (XRD), N₂ adsorption-desorption (BET), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). Modification of natural zeolite with sulphate and phosphate was found to increase its adsorption capacity of thorium but reduced its specific surface area (S_BET). The adsorption experiments were expressed by Langmuir, Freundlich and Dubinin-Radushkevitch (D-R) isotherm models and the results of adsorption demonstrated that the adsorption of thorium onto the natural and modified zeolites correlated better with the Langmuir isotherm model than with the Freundlich isotherm model. The maximum adsorption capacity (Qo) was determined using the Langmuir isotherm model at 25 °C and was found to be 17.27, 13.83, and 10.21 mg/g for phosphate-modified zeolite, sulfate-modified zeolite, and natural zeolite, respectively. The findings of this study indicate that phosphate-modified zeolite can be utilized as an effective and low-cost adsorbent material for the removal of thorium from aqueous solutions.

Use of Natural Zeolite and Glass Powder Mixture as Partial Replacement of Portland Cement: The Effect on Hydration, Properties and Porosity

The study investigates effect of the additive consisting of natural zeolite (clinoptilolite) and soda lime glass powder on the hydration, mechanical properties and porosity of Portland cement concrete. The effect of mineral additive on the technological, physical-mechanical properties and porosity of the mortar was investigated by increasing the content of natural zeolite and glass powder added to the mortar up to 20% by weight of cement in increments of 5% and different particles size of natural zeolite. The mixes with the best technological and mechanical properties were identified and further studies were conducted by replacing 10% and 15% of cement with natural zeolite and soda lime glass with an average grain size of 59.3 μm, 29.0 μm or 3.6 μm of zeolite, and 29.6 μm of glass powder. The hydration process and microstructure of hardened cement paste modified with the aforementioned mineral additives was analysed by microcalorimetry, X-ray diffraction tests and thermogravimetric analysis. The optimal composition of cement paste and particle size distribution of natural zeolite were determined to achieve the higher flexural and compressive strength and lower open porosity. The mixture of mineral additives has the highest effect in terms of flexural and compressive strength and open porosity when added at the proportion 75:15:10 (cement:natural zeolite:soda lime glass) and when zeolite with an average particle size of about 3.6 μm is used

Waste-derived volatile fatty acid production and ammonium removal from it by ion exchange process with natural zeolite

Volatile fatty acids (VFAs) produced during anaerobic digestion (AD) of organic waste are a promising alternative carbon source for various biological processes; however, their applications are limited due to the presence of impurities such as ammonium (NH₄⁺). This study investigates the potential for removal of ammonium using a naturally occurring zeolite (clinoptilolite) from chicken manure (CKM) derived VFA effluent recovered from an anaerobic membrane bioreactor (MBR). Experiments were conducted for both synthetic and actual VFA (AD-VFA) solutions, and the effects of different parameters were investigated with batch and continuous studies. It was observed that the Langmuir-type isotherm provided the best fit to the equilibrium data in the isotherm investigations carried out with the AD-VFA solution. The maximum adsorption capacity (q_m) was found as 15.7 mg NH₄⁺/g clinoptilolite. The effect of some operational parameters on process performance such as pH, initial NH₄⁺ loading and potassium ion (K⁺) concentration was investigated. The pH had a negligible effect on ammonium removal for a pH range of 3-7, while the removal efficiency of ammonium decreased with the increase of initial NH₄⁺ loading and K⁺ concentration. At the optimum conditions determined in batch experiments, the ammonium removal from synthetic and AD-VFA solutions were compared and average ammonium removal efficiencies of 93 and 94% were found in 12 h equilibrium time for synthetic and AD-VFA solutions, respectively. Overall findings indicated that clinoptilolite has excellent potential for ion exchange when combined with biological processes such as acidogenic fermentation of VFAs to purify the solution from high-ammonium content.

Characteristics of Volcanic Tuff from Macicasu (Romania) and Its Capacity to Remove Ammonia from Contaminated Air

In the present work, the capability of the volcanic tuff from Macicasu (Romania) to remove ammonia (NH₃) from air with different contamination levels during 24 h of adsorption experiments was investigated. The natural zeolitic volcanic tuff was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), the Brunauer–Emmett–Teller (BET) method, inductively coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA). The adsorption capacities varied between 0.022 mg NH₃ g⁻¹ zeolite and 0.282 mg NH₃ g⁻¹ zeolite, depending on the NH₃ concentrations in the air and at the contact time. The nonlinear forms of the Langmuir and Freundlich isotherm models were used to fit the experimental data. Additionally, the adsorption of NH₃ was studied using nonlinear pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich kinetic model. Based on the total volume of pores of used volcanic tuff, the NH₃ was removed from the air both due to the physical adsorption of NH₃ gas and the ion exchange of NH₄⁺ (resulted from a reaction between NH₃ and H₂O adsorbed by the zeolite). Depending on the initial NH₃ concentration and the amount of volcanic tuff, the NH₃ concentrations can be reduced below the threshold of this contaminant in the air. The adsorption capacity of NH₃ per unit of zeolite (1 g) varied in the range of 0.022–0.282 mg NH₃ g⁻¹ depending on the NH₃ concentration in the air.

Clinical Evaluation of a Defined Zeolite-Clinoptilolite Supplementation Effect on the Selected Blood Parameters of Patients

The natural clinoptilolite material is an inorganic crystal mineral called zeolite. It has been extensively studied and used in industrial applications and veterinary and human medicine due to positive effects on health. Limited data is available in the scientific literature about its effects on the levels of physiologically relevant minerals in the human organism. Accordingly, we performed a comprehensive and controlled monitoring of the relevant mineral and contaminants levels in human subjects supplemented with a certified clinoptilolite material within three clinical trials with different supplementation regimens. Effects of a registered and certified clinoptilolite material PMA-zeolite on selected mineral and metal levels were determined by standard biochemical methods and inductively coupled plasma mass spectrometry (ICP-MS) in the blood of subjects enrolled in three clinical trials: short-term (28 days, Mineral Metabolism and selected Blood Parameters study MMBP), medium-term (12 weeks, Morbus Crohn study), and long-term (4 years, Osteoporosis TOP study) supplementation. Lower concentrations were observed for copper (Cu) in patients with osteoporosis, which normalized again in the long-term supplementation trial, whereas sodium (Na) and calcium (Ca) levels diminished below the reference values in patients with osteoporosis. In the short- and long-term supplementation trials, increased levels of lead (Pb) were observed in PMA-zeolite-supplemented subjects, which decreased in the continued long-term supplementation trial. Increased levels of aluminum (Al) or Pb attributable to eventual leakage from the material into the bloodstream were not detected 1 h after intake in the short-term supplementation trial. Nickel (Ni) and Al were statistically significantly decreased upon long-term 4-year supplementation within the long-term supplementation trial, and arsenic (As) was statistically significantly decreased upon 12-weeks supplementation in the medium-term trial. Alterations in the measured levels for Na and Ca, as well as for Pb, in the long-term trial are probably attributable to the bone remodeling process. Checking the balance of the minerals Cu, Ca, and Na after 1 year of supplementation might be prescribed for PMA-supplemented patients with osteoporosis.

Clinical Trial Registration

[https://clinicaltrials.gov], identifiers [NCT03901989, NCT05178719, NCT04370535, NCT04607018].

Purified Clinoptilolite-Tuff as an Efficient Sorbent for Gluten Derived from Food

Various gluten-related diseases (celiac disease, wheat allergy, gluten sensitivity) are known and their incidence is growing. Gluten is a specific type of plant storage protein that can impair the health of gluten-prone persons following consumption, depending on the origin. The most severe effects are induced by wheat, barley, and rye. The only treatment is based on the absolute avoidance of those foods, as even traces might have severe effects on human well-being. With the goal of binding gluten impurities after ingestion, an in vitro setting was created. A special processed kind of zeolite, purified clinoptilolite-tuff (PCT), was implemented as an adsorber of gluten derived from different origins. Zeolites are known for their excellent sorption capacities and their applications in humans and animals have been studied for a long time. Tests were also performed in artificial gastric and intestinal fluids, and the adsorption capacity was determined via a certified validated method (ELISA). Depending on the kind of gluten source, 80–130 µg/mg of gluten were bound onto PCT. Hence, purified clinoptilolite-tuff, which was successfully tested for wheat, barley, and rye, proved to be suitable for the adsorption of gluten originating from different kinds of crops. This result might form the basis for an expedient human study in the future.

Thermal Properties of Illite-Zeolite Mixtures up to 1100 °C

Illitic clays are the commonly used material in building ceramics. Zeolites are microporous, hydrated crystalline aluminosilicates, they are widely used due to their structure and absorption properties. In this study, illitic clay (Füzérradvány, Hungary) was mixed with natural zeolite (Nižný Hrabovec, Slovakia) with up to 50 wt.% of zeolite content. The samples were submitted to thermal analyses, such as differential thermal analysis, differential scanning calorimetry, thermogravimetry, and dilatometry. In addition, the evolution of thermal diffusivity, thermal conductivity, and specific heat capacity in the heating stage of firing were measured and discussed. The amount of the physically bound water in the samples increased along with the amount of zeolite. The temperature of the illite dehydroxylation (peak temperature) was slightly shifted to lower temperatures, from 609 °C to 575 °C (for sample IZ50). On the other hand, the mass loss and the shrinkage of the samples significantly increased with the zeolite content in the samples. Sample IZ50 reached 10.8% shrinkage, while the sample prepared only from the illitic clay contracted by 5.8%. Nevertheless, the temperature of the beginning of the sintering (taken from the dilatometric curves) decreased from 1021 °C (for illitic clay) to 1005 °C (for IZ50). The thermal diffusivity and thermal conductivity values decreased as the amount of zeolite increased in the samples, thus showing promising thermal insulating properties.

Explorations on Thermodynamic and Kinetic Performances of Various Cationic Exchange Durations for Synthetic Clinoptilolite

Various cation–exchanged clinoptilolites (M–CPs, M = Li⁺, Cs⁺, Ca²⁺, Sr²⁺) were prepared, and their exchanged thermodynamic (and kinetic) properties and adsorption performances for CH₄, N₂, and CO₂ were investigated. The results demonstrated that the relative crystallinity of M–CP_S decreased with the increase of exchange times. Their chemisorbed water weight loss gradually increased with the increasing exchange times, except that of Cs–x–CP. The Δ_rGmθ values of exchange process of Li⁺, Cs⁺, Ca²⁺, or Sr² presented the increased trend with the enhanced exchange times, but they decreased as the temperature increased. The negative Δ_rGmθ values and the positive Δ_rHmθ and Δ_rSmθ values suggested that the exchanged procedure belonged to spontaneous, endothermic, and entropy-increasing behaviors; their kinetic performances followed a pseudo–second–order model. However, the calculated E_a values of exchange process showed the increased tendencies with the enhanced exchange times, indicating that the exchange process became more difficult. Finally, the preliminary adsorption results indicated that the maximum adsorption amount at 273 K and 1 bar was 0.51 mmol/g of CH₄ and 0.38 mmol/g of N₂ by (Na, K)–CP, and 2.32 mmol/g of CO₂ by Li–6–CP.

Fixed-Bed Modification of Zeolitic Tuffs and Their Application for Cr(VI) Removal

Natural clinoptilolite tuff (CL) and chabazite-clinoptilolite tuff (CH) were modified in fixed-bed column by immobilization of hexadecyltrimethylammonium bromide (HDTMA-Br), then investigated as a sorbent for inorganic anions of Cr(VI). The proposed modification technique combined with surfactant solution batching allows minimizing the surfactant loses through foaming and crystallization and creation of stable organic coverage. The HDTMA loading depended on the mineral composition of the zeolitic tuff, the topology of its external surface, and process conditions. The maximum surface coverage was obtained by gradually dosing surfactant solution in the smallest volume of batches and corresponded up to 100% and 182% of external cation exchange capacity (ECEC) for mono and double layer coverage, respectively. In case of mono layer coverage, modification proceeds until the exhaustion of surfactant in supply solution, while in the double layer one, until equilibrium of HDTMA concentration in both zeolitic and liquid phases was established. The efficiency of Cr(VI) uptake by prepared surface modified zeolites (SMZs) increased with increasing of HDTMA loading. In the case of mono layer SMZs, the capacities of CH-HDTMA and CL-HDTMA were 10.3 and 5.4 mg/g, respectively, while in the case of double layer SMZs, the amount of Cr uptake on CH-HDTMA and CL-HDTMA were 16.8 and 15 mg/g, respectively. Ion exchange is the predominant mechanism of Cr(VI) sorption but it takes place only if modification resulted in at least partial double layer coverage. The XPS analysis reveals Cr(VI) reduction to a less-toxic Cr(III) by the electron donating N-containing groups and by reaction with Fe⁺² ions on the zeolite external surface.

Construction of BiOCl/Clinoptilolite Composite Photocatalyst for Boosting Formaldehyde Removal

Binary composite was synthesized via coupling BiOCl with alkali leached natural clinoptilolite (40B0/CN), which showed retarded recombination of photo-generated carriers. The clinoptilolite was pretreated with alkali leaching, resulting in a larger pore size and high cation exchange capacity. The modified clinoptilolite was more feasible for the growth of BiOCl and to promote the adsorption ability for formaldehyde (HCHO). In addition, the cation exchange capacity was conducive to anchor Bi³⁺, further leading to the reduction of the particle size of BiOCl. The carrier effect of alkali leached natural clinoptilolite promoted the amorphous transformation of BiOCl at low temperature, which simultaneously produced more distortions and defects in the BiOCl lattice. The 40B0/CN composite exhibited the superior light absorption ability with a narrower band gap. The photocatalytic degradation rate for HCHO of 40B0/CN under solar light reached 87.7%, and the reaction rate constant was 0.0166 min⁻¹, which was 1.6 times higher than that of BiOCl. This paper gave a deep insight into photocatalytic technology to efficiently degrade formaldehyde.

Effects of Zeolite as a Drug Delivery System on Cancer Therapy: A Systematic Review

Zeolites and zeolitic imidazolate frameworks (ZIFs) are widely studied as drug carrying nanoplatforms to enhance the specificity and efficacy of traditional anticancer drugs. At present, there is no other systematic review that assesses the potency of zeolites/ZIFs as anticancer drug carriers. Due to the porous nature and inherent pH-sensitive properties of zeolites/ZIFs, the compounds can entrap and selectively release anticancer drugs into the acidic tumor microenvironment. Therefore, it is valuable to provide a comprehensive overview of available evidence on the topic to identify the benefits of the compound as well as potential gaps in knowledge. The purpose of this study was to evaluate the potential therapeutic applications of zeolites/ZIFs as drug delivery systems delivering doxorubicin (DOX), 5-fluorouracil (5-FU), curcumin, cisplatin, and miR-34a. Following PRISMA guidelines, an exhaustive search of PubMed, Scopus, Embase, and Web of Science was conducted. No language or time limitations were used up to 25th August 2021. Only full text articles were selected that pertained to the usage of zeolites/ZIFs in delivering anticancer drugs. Initially, 1279 studies were identified, of which 572 duplicate records were excluded. After screening for the title, abstract, and full texts, 53 articles remained and were included in the qualitative synthesis. An Inter-Rater Reliability (IRR) test, which included a percent user agreement and reliability percent, was conducted for the 53 articles. The included studies suggest that anticancer drug-incorporated zeolites/ZIFs can be used as alternative treatment options to enhance the efficacy of cancer treatment by mitigating the drawbacks of drugs under conventional treatment.

Nutrients Recovery from Dairy Wastewater by Struvite Precipitation Combined with Ammonium Sorption on Clinoptilolite

Struvite precipitation from Wastewater involves an excess of ammonium to create a supersaturated initial solution. The remaining fraction can be a threat to the environment. This work combined struvite precipitation and ammonium sorption using natural zeolite to decrease the ammonium level in the effluent. Two approaches of estimation of feed sample doses were used. One consisted of gradient experiments for ammonium precipitation to the asymptotic level and was combined with clinoptilolite to lower the ammonium level in the effluent. This approach used doses of 0.05:1.51:0.61:1 of Ca:Mg:NH₄⁺:PO₄³⁻ mole ratios, respectively. In contrast, three level design with narrowed NH₄⁺:PO₄³⁻ range reached 0.25:1.51:0.8:1 for Ca:Mg:NH₄⁺:PO₄³⁻ mole ratios. The addition of zeolite decreased effluent ammonium concentration. In both ways, the P and N recoveries were higher than 94% and 72%, respectively. The complexity of the precipitation mixture decreased the ammonium sorption capacity (Q_e) of clinoptilolite from Q_e of 0.52 to 0.10 meq∙g⁻¹ in single and complex solutions, respectively. Thermodynamically, the addition of 1.5 % of clinoptilolite changed the struvite precipitation spontaneity from ∆G of −5.87 to −5.42 kJ·mol⁻¹ and from 9.66 to 9.56 kJ·mol⁻¹ for gradient and three level experimental procedures, respectively. Thus, clinoptilolite demonstrated a positive effect on the struvite precipitation process and its environmental impact.

Characterizing laboratory-scale clinoptilolite bio-columns for removal and nitrification of ammoniacal nitrogen in simulated stormwater

Due to the diverse speciation and biochemical characteristics of nitrogen in urban runoff, excess nitrogen continues to be a major source of eutrophication in receiving waters. The performance of a nitrifying-sorptive Clinoptilolite (ZT) was examined for use in a media-based stormwater control measure (SCM) for ammonium removal. Results suggested that columns operated under continuous feed showed more nitrification as the media approached ammonium exhaustion. Influent concentrations of 2.5 and 5 mg NH₄ ⁺ -N/L tested under continuous flow regimes both showed steady-state operation after media exhaustion, with the average effluent [NO₃ ^- N] of 1.2 and 1.7 mg/L, respectively. The performance of the media under intermittent flow regime showed lower effluent ammonium, nitrification between simulated saturated periods, and could treat an additional 70 bed volumes of simulated runoff when compared to a column receiving identical continuous feed. However, nitrification was not sufficient to prevent desorption of ammonium during drops in influent NH₄ ⁺ -N concentrations. Use of Clinoptilolite for ammonium sorption/nitrification is a systematic approach for capture and transformation of incoming/mineralized ammonium to nitrate prior to reaching an anoxic/denitrifying zone within SCMs. PRACTITIONER POINTS: Clinoptilolite can accumulate stormwater ammonium, allowing it to be nitrified. Ammonium nitrification will regenerate exchange sites on the clinoptilolite. Intermittent flow conditions allowed more nitrification between stormwater events.

Clinoptilolite and iron sorption/desorption under multiple pH conditions: Testing a substrate for passive treatment of acidic, iron-rich solutions

Equilibrium sorption and desorption experiments were conducted with clinoptilolite to evaluate the potential sorption/desorption of iron during different pH conditions. Sorption experiments indicated a partitioning of 0% to 17% of the iron in solution given pH of 2 to 4. The pH 2 solution was able to desorb 70% of the iron that was captured from a pH 3 solution. The largest desorption and sorption of iron and corresponding pH represent the end points of iron capture primarily by sorption/exchange. These endpoints are the estimated pH_pzc of 2.5 and the initial precipitation point of iron(II) at pH ~3.5. This acidity range is where clinoptilolite is able to capture iron without precipitation or the occurrence of full surface protonation. The inability of the highest acidity to remove all sorbed iron represents the greater bound iron that will not readily desorb with a change in pH. This retained iron creates a metastable state of the clinoptilolite that has a lower sorption capacity but reflects the ability of clinoptilolite to retain a sorbed transition metal with changes in pH. As pH varies, clinoptilolite may evolve in a sequence of metastable states reflective of its ability to capture or retain metals. PRACTITIONER POINTS: Clinoptilolite is a capable reactive substrate, but its sorption/exchange effectiveness at low and variable pH and ability to retain captured metals was unknown. Clinoptilolite retains its metal capture properties to a pH of 2.5 where surface protonation and mineral degradation likely occurs. The ability of clinoptilolite to retain captured iron under greater acidity reflects an evolution of its sorption/retention capacity.

Effect of Exchangeable Ions in Natural and Modified Zeolites on Ag Content, Ag Nanoparticle Formation and Their Antibacterial Activity

To broaden the application of silver nanoparticles (AgNPs), which are well-known antibacterial agents, they are supported on different substrates to prevent aggregation, increase their surface area and antibacterial efficiency, and to be separated from the system more effectively at the end of treatment. To produce nanocomposites that consist of silver nanoparticles on natural and modified zeolites, silver ions (Ag⁺) were loaded onto zeolite (natural, Na-modified, H-modified) and then thermally reduced to AgNPs. The effect of the exchangeable cations in zeolite on Ag⁺ uptake, AgNPs formation, size and morphology was investigated by the TEM, SEM, EDX, XPS, UV-vis, XRD and BET methods. The silver amount in the nanocomposites decreased in the following order Na-modified zeolite > natural zeolite > H-modified zeolite. Microscopic techniques showed formation of AgNPs of 1–14 nm on natural and Na-modified zeolite, while the diameter of metal particles on H-modified zeolite was 12–42 nm. Diffuse reflectance UV-vis and XPS methods revealed the presence of both silver ions and AgNPs in the materials indicating that partial reduction of Ag⁺ ions took place upon heating at 400 °C in air. Additionally, antibacterial properties of the nanocomposites were tested against Escherichia coli, and it was found that Ag–containing composites originating from the Na-modified zeolite demonstrated the highest activity.

Investigation of a Novel Multicomponent Mycotoxin Detoxifying Agent in Amelioration of Mycotoxicosis Induced by Aflatoxin-B1 and Ochratoxin A in Broiler Chicks

The present study was designed to determine the efficacy of a novel multicomponent mycotoxin detoxifying agent (MMDA) containing modified zeolite (Clinoptilolite), Bacillus subtilis, B. licheniformis, Saccharomyces cerevisiae cell walls and silymarin against the deleterious effects of Aflatoxin B₁ (AFB₁) and Ochratoxin A (OTA) in broiler chicks. A total of 160 one-day-old Ross 308^® broiler chicks were randomly allocated in four treatment groups, with four replicates, according to the following experimental design for 42 days. Group A received a basal diet; Group B received a basal diet contaminated with AFB₁ and OTA at 0.1 mg/kg and 1 mg/kg, respectively; Group C received a basal diet contaminated with AFB₁ and OTA and MMDA at 1 g/kg feed, and Group D received a basal diet contaminated with AFB₁ and OTA and MMDA at 3 g/kg feed. Results showed that ingested mycotoxins led to significant (p ≤ 0.05) reduction in body weight and feed conversion from 25 days of age, induced histopathological changes, increased the pH of the intestinal content, and altered the biochemical profile of birds with significantly (p ≤ 0.05) increased aspartate aminotransferase (AST) values (p ≤ 0.05). On the other hand, the supplementation of MMDA significantly (p ≤ 0.05) improved the feed conversion ratio (FCR) during the second part of the study, diminished biochemical alterations, reduced pH in jejunal and ileal content, and E. coli counts in the caeca of birds (p ≤ 0.05). It may be concluded that the dietary supplementation of the MMDA partially ameliorated the adverse effects of AFB₁ and OTA in broilers and could be an efficient tool in a mycotoxin control program.

Effect of Low Zeolite Doses on Plants and Soil Physicochemical Properties

Thousands of tons of zeolitic materials are used yearly as soil conditioners and components of slow-release fertilizers. A positive influence of application of zeolites on plant growth has been frequently observed. Because zeolites have extremely large cation exchange capacity, surface area, porosity and water holding capacity, a paradigm has aroused that increasing plant growth is caused by a long-lasting improvement of soil physicochemical properties by zeolites. In the first year of our field experiment performed on a poor soil with zeolite rates from 1 to 8 t/ha and N fertilization, an increase in spring wheat yield was observed. Any effect on soil cation exchange capacity (CEC), surface area (S), pH-dependent surface charge (Qv), mesoporosity, water holding capacity and plant available water (PAW) was noted. This positive effect of zeolite on plants could be due to extra nutrients supplied by the mineral (primarily potassium—1 ton of the studied zeolite contained around 15 kg of exchangeable potassium). In the second year of the experiment (NPK treatment on previously zeolitized soil), the zeolite presence did not impact plant yield. No long-term effect of the zeolite on plants was observed in the third year after soil zeolitization, when, as in the first year, only N fertilization was applied. That there were no significant changes in the above-mentioned physicochemical properties of the field soil after the addition of zeolite was most likely due to high dilution of the mineral in the soil (8 t/ha zeolite is only ~0.35% of the soil mass in the root zone). To determine how much zeolite is needed to improve soil physicochemical properties, much higher zeolite rates than those applied in the field were studied in the laboratory. The latter studies showed that CEC and S increased proportionally to the zeolite percentage in the soil. The Qv of the zeolite was lower than that of the soil, so a decrease in soil variable charge was observed due to zeolite addition. Surprisingly, a slight increase in PAW, even at the largest zeolite dose (from 9.5% for the control soil to 13% for a mixture of 40 g zeolite and 100 g soil), was observed. It resulted from small alterations of the soil macrostructure: although the input of small zeolite pores was seen in pore size distributions, the larger pores responsible for the storage of PAW were almost not affected by the zeolite addition.

The adsorption of fluoride from aqueous solutions by Fe, Mn, and Fe/Mn modified natural clinoptilolite and optimization using response surface methodology

Natural clinoptilolite was modified using iron, manganese, or iron-manganese for adsorption of fluoride from aqueous solutions. Natural and modified clinoptilolite samples were characterized by X-ray fluorescence spectrometry, scanning electron microscope, X-ray diffraction, and Brunauer-Emmett-Teller. For all modified clinoptilolite samples, the time required to reach equilibrium was determined as 5 hr. The effects of adsorbent dose, pH, and initial fluoride concentration for fluoride adsorption were determined using the Box-Behnken Design. Maximum fluoride removal efficiency was 80.23% at the solution pH of 11, iron-modified clinoptilolite amount of 1.08 g/50 ml and at the initial fluoride concentration of 2 mg/L. Fluoride adsorption on iron-modified clinoptilolite showed good compatibility with the Freundlich isotherm and the pseudo-second-order kinetic model. The adsorption capacity of iron-modified clinoptilolite was found to be 1.72 mg/g for the initial fluoride concentration of 50 mg/L. This study has shown that BBD is an effective and dependable method in determining the optimum conditions for fluoride adsorption. PRACTITIONER POINTS: Response surface methodology is effective in determining the optimum conditions for fluoride adsorption using modified clinoptilolite. Fluoride adsorption on iron-modified clinoptilolite is well described Freundlich isotherm and follows pseudo-second-order kinetic model. Fluoride removal percentage not only depends on the adsorbent dose, but also depends on the initial fluoride concentrations. Regeneration process using acid solution is not very effective for desorption of iron-modified zeolite. The natural clinoptilolite is an effective and economical adsorbent for adsorption of fluoride.

Graphene oxide-iron modified clinoptilolite based composites for adsorption of arsenate and optimization using response surface methodology

In this study, graphene oxide and composites of graphene oxide-iron modified clinoptilolite were synthesized and used for arsenate removal from aqueous solution. All adsorbents were characterized using X-ray diffraction and specific surface area analysis. The specific surface areas of composites were found to be less than the iron modified clinoptilolite. The time required to reach equilibrium was determined as 3 hours for all adsorbents. The Box-Behnken statistical experiment design method was used to determine the effects of initial arsenate concentration, pH and the amount of adsorbent on the percent arsenate removal. Graphene oxide was not as effective as composites for arsenate adsorption from water. Arsenate adsorption on composites was showed good compatibility with the Freundlich isotherm. The maximum arsenate uptake was realized at pH 4 for graphene oxide and at pH 7 for composites. The maximum adsorption capacities obtained at the optimum points determined by using the Box-Behnken design method were calculated as 39.49, 117.98 and 124.64 µg.g^-1 for graphene oxide and composites, respectively.

Synthetic Zeolite Supplementation as a Potential Candidate for the Therapy of Diabetic Syndrome

<b>Background and Objective:</b> Natural and Synthetic Zeolite (SZ) is potentially useful for biopharmaceuticals and bio tools due to its unique and outstanding physical and chemical properties. Thus, the present study aimed to evaluate the possible effect of synthetic zeolite in (STZ)-induced diabetic rats. <b>Materials and Methods:</b> About 4 groups of rats were used, (I) normal control, (II) SZ group, (300 mg/kg/day), (III) STZ group, diabetic rats acted as positive control and (IV) STZ+SZ group, included diabetic rats treated with synthetic zeolite (300 mg/kg/day), statistical analysis comparisons between means were carried out using one-way analysis of variance (ANOVA) followed by a post hock (Tukey) multiple comparisons test at p<u>></u>0.05. <b>Results:</b> After six weeks, treatment of diabetic animals with synthetic zeolite markedly exhibited a significant reduction in glucose, lipids, DNA fragmentation, Alanine Aminotransferase (ALAT), Aspartate Aminotransferase (ASAT), urea, creatinine, Malondialdehyde (MDA) and Nitric Oxide (NO) levels concomitant with a significant rise in insulin, Glutathione (GSH), Superoxide Dismutase (SOD) and Catalase (CAT) values close to the corresponding values of healthy ones. <b>Conclusion:</b> In conclusion, synthetic zeolite exhibits multi-health benefits with promising potentials against STZ-induced diabetes, this behaviour may be attributed to its antioxidant and free radical scavenging mechanisms.

Synergistic Effects of Catalyst Mixtures on Biomass Catalytic Pyrolysis

This paper studied the synergistic effects of catalyst mixtures on biomass catalytic pyrolysis in comparison with the single catalyst in a microwave reactor and a TGA. In general, positive synergistic effects were identified based on increased mass loss rate, reduced activation energy, and improved bio-oil quality compared to the case with a single catalyst at higher catalyst loads. 10KP/10Bento (a mixture of 10% K₃PO₄ and 10% bentonite) increased the mass loss rate by 85 and 45% at heating rates of 100 and 25°C/min, respectively, compared to switchgrass without catalyst. The activation energy for 10KP/10Bento and 10KP/10Clino (a mixture of 10% K₃PO₄ and 10% clinoptilolite) was slightly lower or similar to other catalysts at 30 wt.% load. The reduction in the activation energy by the catalyst mixture was higher at 100°C/min than 25°C/min due to the improved catalytic activity at higher heating rates. Synergistic effects are also reflected in the improved properties of bio-oil, as acids, aldehydes, and anhydrosugars were significantly decreased, whereas phenol and aromatic compounds were substantially increased. 30KP (30% K₃PO₄) and 10KP/10Bento increased the content of alkylated phenols by 341 and 207%, respectively, in comparison with switchgrass without catalyst. Finally, the use of catalyst mixtures improved the catalytic performance markedly, which shows the potential to reduce the production cost of bio-oil and biochar from microwave catalytic pyrolysis.

The Use of Activated Micronized Zeolite Clinoptilolite as a Possible Alternative to Antibiotics and Chestnut Extract for the Control of Undifferentiated Calf Diarrhea: An In Vitro and In Vivo Study

Simple Summary

Today, zeolite has appeared as an interesting alternative for the symptomatic treatment of acute diarrhea. Therefore, this study aimed to investigate the properties of activated micronized (five microns) zeolite clinoptilolite (MZC) from Transylvania, Romania, first by testing it in vitro and then in vivo on calves with diarrhea. To assess the toxic potential of MZC, we performed a cell cytotoxicity assay on cells of bovine origin, while its antimicrobial activity was investigated on Escherichia coli. The uncontrolled in vivo study was carried out over 8 days on a fattening farm, with some 650 calves. Selected calves were randomly assigned to 4 groups of 20 individuals. Several combinations between activated MZC, chestnut extract, and oxytetracycline were tested. At the beginning of the study, all calves had diarrhea, while at the end of the study, the prevalence of diarrhea was significantly lower in all four groups (p < 0.001), including the ones treated with MZC. Due to its low cytotoxicity on the intestinal cells and with regards to the results we obtained in vivo, MZC could represent an alternative method to reducing the amount of antimicrobials needed for the symptomatic treatment of diarrhea in calves, therefore contributing to the reduction of the antimicrobial resistance phenomenon.

Abstract

Today, zeolite appears as an interesting alternative for the symptomatic treatment of acute diarrhea. Therefore, this study aimed to investigate the properties of activated micronized (5 microns) zeolite clinoptilolite (MZC) from Transylvania, Romania, first by testing it in vitro and then in vivo on calves with diarrhea. To assess the toxic potential of the MZC, we performed a cell cytotoxicity assay using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) technique on primary bovine intestinal epithelial cells (BIECs). The antimicrobial activity of MZC was investigated by measuring the minimal inhibitory concentration (MIC) on Escherichia coli (ATCC 25922). The uncontrolled in vivo study was carried out over 8 days on a fattening farm, with some 650 calves. Selected calves were randomly assigned to four groups of 20 individuals. Several combinations between MZC, chestnut extract, and oxytetracycline were tested. At the beginning of the study, all calves had diarrhea, while at the end of the study, the prevalence of diarrhea was significantly lower in all four groups (p < 0.001), including the ones treated with MZC. Due to its low cytotoxicity on the intestinal cells and with regards to the results we obtained in vivo, MZC may be considered an alternative for the symptomatic treatment of undifferentiated diarrhea in calves.

Characterization of Modified Natural Minerals and Rocks for Possible Adsorption and Catalytic Use

This study focused on natural materials such as clinoptilolite (CLI), metakaolin (MK), marlstone (MRL) and phonolite (PH). Clinoptilolite is one of the most known and common natural minerals (zeolites) with a unique porous structure, metakaolin is calcined kaolin clay, marlstone is a sedimentary rock and phonolite is an igneous rock composed of alkali feldspar and other minerals. These natural materials are mainly used in the building industry (additions for concrete mixtures, production of paving, gravels) or for water purification, but the modification of their chemical, textural and mechanical properties makes these materials potentially usable in other industries, especially in the chemical industry. The modification of these natural materials and rocks was carried out by leaching using 0.1 M HCl (D1 samples) and then using 3 M HCl (D2 samples). This treatment could be an effective tool to modify the structure and composition of these materials. Properties of modified materials were determined by N₂ physisorption, Hg porosimetry, temperature programmed desorption of ammonia (NH₃-TPD), X-ray fluorescence (XRF), X-ray powder diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) and CO₂ adsorption using thermogravimetric analysis (TGA). The results of N₂ physisorption measurements showed that that the largest increase of specific surface area was for clinoptilolite leached using 3M HCl. There was also a significant increase of the micropore volume in the D2 samples. The only exception was marlstone, where the volume of micropores was zero even in the leached sample. Clinoptilolite had the highest acidity and sorption capacity of CO₂. TGA showed that the amount of CO₂ adsorbed was not significantly related to the increase in specific surface area and the opening of micropores. Hg porosimetry showed that acid leaching using 0.1 M HCl and 3 M HCl resulted in a significant increase in the macropore volume in phonolite, and during leaching using 3M HCl there was an increase of the mesopore volume. From the better properties, cost-efficient and environmental points of view, the use of these materials could be an interesting solution for catalytic and sorption applications.

The Efficiency of the Removal of Naphthalene from Aqueous Solutions by Different Adsorbents

The paper presents the results of laboratory tests on possibilities to utilize active carbons produced in Poland (AG-5 and DTO) and clinoptilolite for removing naphthalene from a water solution in the adsorption process. The concentration of naphthalene in the model solution was 20 mg/dm³. The effects of pH, dose and adsorption time were determined under static conditions. Adsorption kinetics were consistent with the pseudo-second-order model (PSO). Among the applied models, the best fit was obtained using the Langmuir isotherms. The maximum adsorption capacity for the activated carbons (AG-5 and DTO) equaled 24.57 and 30.28 mg/g, respectively. For clinoptilolite, all the analyzed models of adsorption poorly described the adsorption process. The flow conditions were realized by filtration method. On the basis of the obtained results, the breakthrough curves, so-called isoplanes, were prepared and served in turn to determine the adsorption capacities in flow conditions. The total adsorption capacities determined under dynamic conditions of the AG-5 and DTO activated carbons were 85.63 and 94.54 mg/g, respectively, and only 2.72 mg/g for clinoptilolite. The exit curves (isoplanes) were also utilized to determine the mass penetration zone (the adsorption front height), as well as to calculate the rate of mass-exchange zone advance.

Effects of Thermal Treatment on Natural Clinoptilolite-Rich Zeolite Behavior in Simulated Biological Fluids

This study presents the effect of thermal treatment (450, 500, 600, 750, and 800 °C) on a Romanian clinoptilolite-rich natural zeolite, along with the interaction of raw and thermally treated zeolites with simulated gastric fluid (SGF, pH = 1.20) at different zeolite to SGF ratios and exposure times. The zeolites were characterized using gravimetric analysis, X-ray fluorescence, powder X-ray diffraction (pXRD), and Fourier transform infrared (FT-IR) spectroscopy. The chemical composition of the zeolite subjected to thermal treatment did not change significantly with the increase of temperature. Structural changes were not detectable by pXRD and FT-IR analyses in the zeolites thermally treated up to 500 °C, while above 600 °C a gradual structural breakdown of zeolite was noticed. At high temperatures, the broad, low-intensity peaks in pXRD patterns indicated the partial amorphization of the crystalline structure. The pXRD and FT-IR analyses showed that the crystalline structure of zeolites remains unaffected after their exposure to SGF. The results revealed that the amounts of Fe, Na, Mg, K, Ca, Al, and Si released depends mainly on the zeolite to SGF ratio, and to a lower extent on the thermal treatment temperature, while the exposure time of 1 to 7 days does not have a significant impact on the elements released in SGF.

Pd (II) Immobilized on Clinoptilolite as a Highly Active Heterogeneous Catalyst for Ullmann Coupling-type S-arylation of Thiols with Aryl Halides

BACKGROUND

There are a number of protocols for Ullmann coupling-type S-arylation reactions, many of them suffer from the use of homogenous and often corrosive catalyst, cumbersome workup procedures, and long reaction times. Besides, many of these reagents are expensive and non-recoverable, leading to the generation of a large amount of toxic waste particularly when large-scale applications are considered.

OBJECTIVE

The aim of this study was to prepare a new Pd catalyst bonded on the surface of zeolite as a heterogeneous catalyst.

METHODS

A heterogeneous palladium catalyst has been prepared by immobilizing Pd ions on Clinoptilolite. This novel developed heterogeneous catalyst was thoroughly examined for Ullmann coupling-type S-arylation reaction using different bases, solvents and 0.003 mg of the catalyst. The structural and morphological characterizations of the catalyst were carried out using XRD, TGA, BET and TEM techniques.

RESULTS

Highly efficient heterogeneous palladium catalyst has been developed by immobilizing Pd ions on Clinoptilolite, as one of the most abundant naturally occurring zeolites for Ullmann Sarylation. By using this method, we provide an efficient way to a wide variety of substituted thiolic compounds. Moreover, the catalyst is easily recovered using simple filtration and reused for 5 consecutive runs.

CONCLUSION

In this effort, we developed a new Pd catalyst bonded on the surface of zeolite as a substrate to prepare the heterogeneous catalyst. We demonstrate that this novel catalyst offers reliable and convincing data that may offer a valuable application in further developing the science and technology of Ullmann reaction protocols and allied industries. Additionally, the catalyst was reusable and kept its high activities over a number of cycles.

Effects of Dietary Vibroactivated Clinoptilolite Supplementation on the Intramammary Microbiological Findings in Dairy Cows

Simple Summary

This study aimed to determine the effects of dietary vibroactivated clinoptilolite supplementation on the intramammary microbiological findings in dairy cows, causative agents of intramammary infection, and their sensitivity to antibiotics. The cows (n = 78) were randomly divided into two groups: the clinoptilolite (CPL)-treated group that received 100 g of clinoptilolite (CPL) in-feed (n = 38) from the seventh month of pregnancy to 75 days after calving and the control group (CON) of untreated cows (n = 40). Milk samples were taken from each cow on days 7, 25, 45, and 75 postpartum. Different causative pathogens were isolated in 86 udder quarters (7.07%), in 3.87% environmental microflora, and 89.06% were bacteriologically negative. The most effective antibiotics were cefoperazone and amoxicillin-clavulanic acid, while cloxacillin and tetracycline were the least effective. In the CPL group (14 cows), nine pathogens were isolated in 27 quarters, while in the control (CON) group (24 cows), 13 pathogens in 59 quarters. Cows from the CON group had a 1.96 times higher risk of intramammary infection than cows from the CPL group.

Abstract

The aim of this study was to determine the effects of dietary vibroactivated clinoptilolite supplementation on the intramammary microbiological findings in dairy cows, causative agents of potential intramammary infection, and their sensitivity to antibiotics. Cows (n = 78) were randomly divided into two groups: CPL-treated group that received clinoptilolite (CPL) in-feed (n = 38), i.e., 50 g natural powdered zeolite CPL, twice daily from the seventh month of pregnancy to 75 days after calving, and the control group (CON) of untreated cows (n = 40). Milk samples were taken from each cow on days 7, 25, 45, and 75 postpartum. The following causative pathogens were isolated in 86 udder quarters: Staphylococcus aureus in 5.81% of positive samples, Staphylococcus spp. 9.32%, coagulase-negative Staphylococcus (CNS) 22.09%, Streptococcus uberis 13.95%, Streptococcus agalactiae 1.16%, Streptococcus sp. 3.49%, Escherichia coli 8.13%, Enterococcus spp. 6.98%, Corynebacterium spp. 11.63%, Pasteurella sp. 10.47%, Serratia spp. 2.33%, and Arcanobacterium pyogenes, Citrobacter sp., Prototheca sp., and yeasts each in 1.16% of samples. Additionally, 3.87% of environmental microflora samples (n = 47) and 89.06% of udder samples (n = 1083) were bacteriologically negative. The most effective antibiotics were cefoperazone and amoxicillin-clavulanic acid, while cloxacillin and tetracycline were the least effective antibiotics in both groups. In the clinoptilolite supplemented (CPL) group (n = 38) of 14 cows, nine causative agents of mastitis were isolated in 27 quarters, while in the control (CON) group (n = 40) of 24 cows, 13 causative agents of mastitis were isolated in 59 quarters. Cows from the CON group had a 1.96 times higher risk of intramammary infection than cows from the CPL group during the observation period (odds ratio = 1.96, p = 0.0031; 95% CI = 1.2570–3.0770).

Application of Zeolite Tuffs as Mineral Filler in Warm Mix Asphalt

Zeolite materials are used in the warm mix asphalt technology as an asphalt foaming additive, which partially replaces the filler. This article analyzes the influence of the zeolite and other fillers addition on the properties of mastic asphalt. In the research, 35/50 penetration grade asphalt and three types of fillers were used: lime filler (L), zeolite tuff (clinoptilolite) (C), hydrated lime (H) and their mixed combinations (C:L in 1:1 and 1:3 proportions as well as C:L:H in 2:2:1 ratio). The characteristics of the materials included: chemical analysis, phase composition and particle size distribution. The following properties were determined on the asphalt mastic samples: penetration, softening point, penetration index, dynamic viscosity and stiffening measured by softening point increase. It was found that clinoptilolite could partially replace the traditional lime filler, without a negative impact on the asphalt mastic properties. Additionally, the hydrated lime inclusion should have a positive effect on the frost resistance of an asphalt mix.

Design and fabrication of clinoptilolite-nanohydroxyapatite/chitosan-gelatin composite scaffold and evaluation of its effects on bone tissue engineering

The aim of this study was to synthesize an innovative composite scaffold, which structured of clinoptilolite-nanohydroxyapatite/chitosan-gelatin (CLN-nHA/CS-G) with enhanced attributes for utilization in the bone tissue engineering. This composite scaffold was prepared by blending the CLN, nHA, chitosan, and gelatin solution followed by a freeze-drying step. The fabricated composite scaffolds were studied using BET, FTIR, XRD, and SEM techniques. The highly porous composite scaffolds with a pore size of 200 ± 100 μm were synthesized. Moreover, the effects of CLN and nHA on the physicochemical features of the scaffold such as density, swelling ratio, biomineralization, biodegradation, and mechanical behavior were studied. Compared with CS-G scaffold, the presence of CLN and nHA leads to an increased surface area, increased biomineralization, and low rate of degradation in simulated body fluid solution (SBF) and mechanical strength. Cytotoxicity of the CLN-nHA/CS-G scaffold was studied by MTT assay on human dental pulp stem cells (h-DPSCs). The biological response of h-DPSCs showed no toxicity and studied cells proliferated and attached on the pore surfaces of the scaffold. Results indicated that introducing CLN and nHA to composite improves the scaffold characteristics in a way that makes it suitable for bone tissue engineering.

Environmental-Friendly Modifications of Zeolite to Increase Its Sorption and Anion Exchange Properties, Physicochemical Studies of the Modified Materials

Zeolites, naturally possessing a high negative surface charge and large specific surface, are used in agriculture as cationic fertilizers, water holders, heavy metals, and organic pollutants sorbents. Since some nutrients occur in anionic forms, there is a need to modify the zeolite surface to hold anions. In this study, hydrogen (hydrochloric acid), iron (Fe²⁺ and Fe³⁺), and aluminum cations as well as the influence of sodium hydroxide modifiers on the specific surface area, water vapor, adsorption energy, fractal dimension, mesopore volumes and radii, electrokinetic (zeta) potential, and isoelectric point were investigated. The use of alkali solution did not affect the zeolite properties significantly, whereas hydrogen, iron, and treatments with aluminum cations resulted in an increase in the specific surface area, mesopore volumes, and radii, and a decrease in the water-binding forces. Aluminum cations were the most effective in recharging the zeolite surface from negative to positive, shifting the isoelectric point toward the highest values. Calcination enlarged the negative surface charge and mesopore radius, and diminished the surface area and mesopore volume. The modified zeolites are promising carriers of anionic nutrients, large surface area sorbents, and suppliers of water for plant roots in soil.

Ion exchange nutrient recovery from anaerobic membrane bioreactor permeate

Nutrient recovery from municipal wastewater was evaluated using anion exchange media loaded with hydrated ferric oxide (HFO) and copper (Cu²⁺ ) (Dow-HFO-Cu resin) to selectively capture phosphate, followed by clinoptilolite for ammonium removal and recovery. Nutrients were concentrated in the regenerants and recovered as precipitated struvite. Media exchange capacity after multiple ion exchange cycles was determined using permeate from an anaerobic membrane bioreactor (AnMBR) treating synthetic or actual municipal wastewater from a full-scale water reclamation facility. Regeneration through five ion exchange cycles using relatively low concentration regenerant solution (2% NaCl and 0.5% NaOH) resulted in the highest phosphate exchange capacity and phosphate recovery. This regenerant also provided the most consistent ammonium recovery. Column tests treating AnMBR permeate were performed over five ion exchange cycles; Dow-HFO-Cu resin exchange capacities ranged from 1.6 to 2.8 mg PO₄ -P/g dry media. A maximum of 94% of the removed phosphate was recovered during regeneration. The rate and extent of regeneration was insensitive to regenerant salt concentrations in the range investigated. Precipitation using a mixture of the spent regeneration brines from the Dow-HFO-Cu resin and clinoptilolite columns produced low molar ratios of Mg:NH₄ :PO₄ , suggesting that the recovered product was not pure struvite. PRACTITIONER POINTS: Ion exchange-precipitation for the removal and recovery of PO 4 3 - and NH₄ ⁺ from AnMBR permeate is a promising technology. 2% NaCl + 0.5% NaOH regeneration solution provided the most consistent exchange performance for both phosphate and ammonium recovery. Regenerated Dow-HFO-Cu resin exchange capacity was consistently less than the virgin resin, likely due to copper leaching during regeneration. Molar ratios in the precipitates suggested that the precipitated material was not pure struvite.

Zeolites as Carriers of Antitumor Ribonuclease Binase

Natural and synthetic zeolites have many applications in biomedicine and nutrition. Due to its properties, zeolites can absorb therapeutically active proteins and release them under physiological conditions. In this study we tested the clinoptilolite, chabazite, and natrolite ability to be loaded by antitumor ribonuclease binase and the cytotoxicity of the obtained complexes. We found the optimal conditions for binase loading into zeolites and established the dynamic of its release. Cytotoxic effects of zeolite-binase complexes toward colorectal cancer Caco2 cells were characterized after 24 and 48 h of incubation with cells using MTT-test. Zeolites were toxic by itselfs and reduced cells viability by 30% (clinoptilolite), 40% (chabazite), and 70% (natrolite) after 48 h of incubation. Binase complexes with clinoptilolite as well as chabazite always demonstrated enhanced toxicity (up to 57 and 60% for clinoptilolite and chabazite, respectively) in comparison with binase and zeolites separately. Our results contribute to the perspective development of binase-based complexes for therapy of colorectal cancer for or the treatment of malignant skin neoplasms where the complexes can be used in pasty form.

Separation of CH4/N2 of Low Concentrations From Coal Bed Gas by Sodium-Modified Clinoptilolite

Clinoptilolite is a widely distributed tectosilicate, mainly composed of Al₂O₃, SiO₂ with exchangeable cations such as Ca, K, Mg, and Na. In this research, raw clinoptilolite was ground, gravimetrically concentrated and ion-exchanged using different concentrations of NaCl solution. Then the modified clinoptilolite powder was formulated into particles as adsorbents. The adsorbents were applied to CH₄ separation in coal bed gas. The raw and modified clinoptilolites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), atomic emission spectrometer (ICP-AES), Fourier transform infrared spectrometer (FTIR), and Brunauer Emmett Teller (BET) specific surface area. The CH₄ absorptivity by raw and modified clinoptilolites was evaluated using pressure swing adsorption (PSA) to assess the CH₄ separation ability. The results indicated that the ion-exchanged clinoptilolite using 0.2 mol/L NaCl solution was found to be promising for the kinetic PSA separation of CH₄/N₂, giving a better absorptivity for CH₄ separation under different influence factors. Based on the simulated static experiments, it was indicated that both CH₄ and N₂ were capable of diffusing into clinoptilolite while N₂ adsorption by clinoptilolite was excellent. The experiment results also indicated that ion-exchanged clinoptilolite using a 0.2 mol/L NaCl solution was the optimal adsorbent for separating CH₄/N₂ at the low pressure condition. From the simulated dynamic experiments, the ion-exchanged clinoptilolite using a 0.2 mol/L NaCl solution as a potential sorbent in kinetic PSA processes for N₂/CH₄ separation, exhibited the best performance at 648 K under 0.2 MPa within 28 min, in comparison to the raw clinoptilolite and clinoptilolite under other modification conditions. In the next phase of research, the modified clinoptilolite will be tested for CH₄ separation in real coal bed gas.

Critical Review on Zeolite Clinoptilolite Safety and Medical Applications in vivo

Unique and outstanding physical and chemical properties of zeolite materials make them extremely useful in a variety of applications including agronomy, ecology, manufacturing, and industrial processes. Recently, a more specific application of one naturally occurring zeolite material, clinoptilolite, has been widely studied in veterinary and human medicine. Due to a number of positive effects on health, including detoxification properties, the usage of clinoptilolite-based products in vivo has increased enormously. However, concerns have been raised in the public about the safety of clinoptilolite materials for in vivo applications. Here, we review the scientific literature on the health effects and safety in medical applications of different clinoptilolite-based materials and propose some comprehensive, scientifically-based hypotheses on possible biological mechanisms underlying the observed effects on the health and body homeostasis. We focus on the safety of the clinoptilolite material and the positive medical effects related to detoxification, immune response, and the general health status.

Effect of Natural Zeolite (Clinoptilolite) on in vitro Biogenic Amine Production by Gram Positive and Gram Negative Pathogens

The effect of two levels of clinoptilolite (1 and 5%) on the production of biogenic amines (BA) and ammonia (AMN) by Gram positive (Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes) and Gram negative bacteria (Aeromonas hydrophila, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella Parathypi A), in tyrosine decarboxylase broth (TDB) was studied. A. hydrophila and E. coli produced the highest amounts of amines which were 1223.06 and 2627.90 mg/l, respectively. All strains were able to decarboxylate tyrosine to tyramine (TYR) with E. coli being the highest (1657.19 mg/l). A. hydrophila formed >50 mg/l histamine (HIS) while the other strains produced none or very low concentrations (<4 mg/l). Among Gram-positive pathogens, E. faecalis was characterized as the main amine producer (478.23 mg/l). Although dependent on bacterial strain and level used, the natural zeolite clinoptilolite can be used to decrease BA and AMN production by bacterial strains that are of health concern. Practical Applications: Uses of natural prodcuts for biogenic amines inhibition. Clinoptilolite was used to reduce the amounts of amines such as spermine, putrescine, and dopamine produced by pathogenic and spoilage bacteria.