Surface modified natural zeolites (SMNZs) as nanocomposite versatile materials for health and environment

Removal and elimination of pharmaceuticals in water using zeolites in diverse adsorption processes and catalytic advanced oxidation technologies-a critical review

Water pollution by pharmaceuticals is a current worrying environmental problem. Adsorption and catalytic processes using zeolites have been employed in several studies to remove/degrade pharmaceuticals from water. The interest of researchers in these two strategies based on the utilization of zeolites (i.e., adsorption and advanced oxidation technologies, AOT) is continuously growing. Then, this work presents a literature review, considering the origin of the zeolites (natural vs. synthetic) and the modifications of zeolites (e.g., the addition of surfactants) for the adsorption of diverse pharmaceuticals. The role of zeolites in catalytic ozonation, Fenton-based systems, and activation of peroxymonosulfate and peroxydisulfate is detailed. Also, the primary transformations of pharmaceuticals induced by these AOTs were examined. Moreover, the gaps regarding biodegradability and toxicity of the transformation products coming from the degradation of pharmaceuticals by the zeolites-based processes were discussed. To overcome the scarcity of information regarding the biodegradability and toxicity of the primary transformation products observed in the revised works, an initial approach to these topics, using a predictive tool, was made. Finally, from the present review, it was evidenced the need for future works involving zeolites that provide results about the simultaneous removal/elimination of multiple pharmaceuticals in complex matrices (e.g., hospital wastewater or municipal wastewater), new information about biodegradability and toxicity plus the development of combination or coupling of processes with other AOTs (e.g., sonochemistry) or classical systems (e.g., biological process).

Zeolites as Ingredients of Medicinal Products

Development of new medicinal products for particular therapeutic treatment or for better manipulations with better quality and less side effects are possible as a result of advanced inorganic and organic materials application, among which zeolites, due to their properties and versatility, have been gaining attention. This paper is an overview of the development in the use of zeolite materials and their composites and modifications as medicinal products for several purposes such as active agents, carriers, for topical treatments, oral formulations, anticancer, the composition of theragnostic systems, vaccines, parenteral dosage forms, tissue engineering, etc. The objective of this review is to explore the main properties of zeolites and associate them with their drug interaction, mainly addressing the advances and studies related to the use of zeolites for different types of treatments due to their zeolite characteristics such as molecule storage capacity, physical and chemical stability, cation exchange capacity, and possibility of functionalization. The use of computational tools to predict the drug-zeolite interaction is also explored. As conclusion was possible to realize the possibilities and versatility of zeolite applications as being able to act in several aspects of medicinal products.

Influence of the Type and the Amount of Surfactant in Phillipsite on Adsorption of Diclofenac Sodium

Modified phillipsite samples were prepared with two different amounts (monolayer and bilayer coverage) of surfactants octadecyldimethylbenzylammonium chloride (O) and dodecylamine (D). Composites were characterized by Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR–ATR), thermal analysis and determination of zeta potential, and subsequently tested for removal of diclofenac sodium (DCF). Drug adsorption experiments were performed under different initial DCF concentrations and different contact times. In order to investigate the influence of the chemical structure of surfactants used for modification of phillipsite on the preparation and properties of composites and DCF adsorption, experimental data were compared with previously published results on DCF adsorption by composites containing phillipsite and the same amounts of surfactants cetylpyridinium chloride (C) and Arquad®2HT-75 (A). DCF adsorption isotherms for O and D composites showed a better fit with the Langmuir model with maximum adsorption capacities between 12.3 and 38.4 mg/g and are similar to those for C and A composites, while kinetics run followed a pseudo-second-order model. Composites containing either benzyl or pyridine functional groups showed higher adsorption of DCF, implying that surfactant structure has a significant impact on drug adsorption. Drug adsorption onto O, D, C and A composites was also confirmed by FTIR–ATR spectroscopy and zeta potential measurements.

Chabazite from Campanian Ignimbrite Tuff as a Potential and Sustainable Remediation Agent for the Removal of Emerging Contaminants from Water

The technological performance of a chabazite-rich rock belonging to the Campanian Ignimbrite formation, outcropping in the nearby of San Mango sul Calore (southern Italy), has been evaluated for the sorption and release of ibuprofen sodium salt after a surface modification of the starting geomaterial using two different chlorinated surfactants. Equilibrium sorption isotherms and in vitro loading tests demonstrated that the maximum sorption capacities of this geomaterial reach up to 24.5 and 13.5 mg/g, respectively, for zeolite modified with cetylpyridinium and benzalkonium. These results, obtained by non-linear mathematical modeling of the experimental curves, are definitely compatible with the concentrations of the most common non-steroidal anti-inflammatory drugs (such as ibuprofen) in wastewaters, which have been recently considered as contaminants of emerging concern. This investigation also encourages a new possible sustainable exploitation of the lithified yellow facies of Campanian Ignimbrite, although future developments will be focused on using more stable and eco-friendlier two-tailed surfactants.

Application of Surfactant Modified Natural Zeolites for the Removal of Salicylic Acid-A Contaminant of Emerging Concern

This work aimed to test composites (surfactant modified zeolites prepared by treatment of natural zeolites—clinoptilolite (IZ CLI) and/or phillipsite (PHIL75)-rich tuffs with two different amounts of cationic surfactants: cetylpyridinium chloride (CPyCl) and Arquad^® 2HT-75 (ARQ)) for the adsorption of salicylic acid (SA)—a common contaminant of emerging concern. Adsorption of SA was studied at different initial drug concentrations (in the range of 2–100 mg/L) in water solution. The Langmuir isotherm model showed the highest adsorption was achieved by bilayer composite of IZ CLI and CPyCl—around 11 mg/g. Kinetic runs were performed by using the initial drug concentration of 20 mg/L in the time interval from 0 to 75 min and pseudo-second order had good correlation with experimental data. The influence of the four different temperatures on the SA adsorption was also investigated and thermodynamic parameters suggested that the adsorption drug onto composites is an exothermic and nonspontaneous process, followed by the decrease of randomness at the solid/liquid interface during the adsorption. Zeta potential and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) had been performed for the characterization of composites after adsorption of SA confirming the presence of the drug at composite surfaces.

Removal of non-steroidal anti-inflammatory drugs from water by zeolite-rich composites: The interference of inorganic anions on the ibuprofen and naproxen adsorption

Composites of two natural zeolites - clinoptilolite and phillipsite, and cationic surfactants (cetylpyridinium chloride and Arquad® 2HT-75) were tested for the removal of two emerging contaminants - ibuprofen and naproxen. For each zeolite-rich rock, two different modifications of the zeolitic surfaces were prepared (monolayer and bilayer surfactant coverage). The influence of the initial drug concentrations and contact time on adsorption of these drugs was followed in buffer solution. The Langmuir model showed the highest adsorption capacity for the composite characterized by a bilayered surfactant at the clinoptilolite surface: 19.7 mg/g and 16.1 mg/g for ibuprofen and naproxen, respectively. Also, to simulate real systems, drug adsorption isotherms were conducted in natural water (Grindstone creek water - Columbia, Missouri, USA) by using the best performing adsorbent; in this case, a slight decrease of drug adsorption was recorded. Kinetic runs were performed in distilled water as well as in the presence of ions such as sulfates and bicarbonates; also, in this case, the interfering agents defined an adsorption decrease for bilayer composites.

Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

The present work aimed at assessing the pharmaceutical tableting properties of some Egyptian kaolin samples belong to the Abu Zenima kaolin deposits (estimated at 120 million tons). Four representative samples were selected based on kaolinite richness and their structural order-disorder degree, and after purification, they were dried at 70 °C and heated from room temperature up to 400 °C (10 °C/min). Mineralogy, micromorphology, microtexture, granulometry, porosimetry, moisture content, bulk and tapped density, direct and indirect flowability, and tableting characteristics are studied. Results indicated that purified kaolin samples were made up of 95–99% kaolinite, <3% illite, 1% quartz and 1% anatase. The powder showed mesoporous character (pore diameters from 2 to 38 nm and total pore volume from 0.064 to 0.136 cm3/g) with dominance of fine nanosized particles (<1 μm–10 nm). The powder flow characteristics of both the ordered (Hinckley Index HI > 0.7, crystallite size D001 > 30 nm) and disordered (HI < 0.7, D001 < 30 nm) kaolinite-rich samples have been improved (Hausner ratio between 1.24 and 1.09) as their densities were influenced by thermal treatment (with some observed changes in the kaolinite XRD reflection profiles) and by moisture content (variable between 2.98% and 5.82%). The obtained tablets exhibited hardness between 33 and 44 N only from the dehydrated powders at 400 °C, with elastic recovery (ER) between 21.74% and 25.61%, ejection stress (ES) between 7.85 and 11.45 MPa and tensile fracture stress (TFS) between 1.85 and 2.32 MPa, which are strongly correlated with crystallinity (HI) and flowability (HR) parameters. These findings on quality indicators showed the promising pharmaceutical tabletability of the studied Egyptian kaolin powders and the optimization factors for their manufacturability and compactability.