Effective Sequestration of Phosphate and Ammonium Ions by the Bentonite/Zeolite Na-P Composite as a Simple Technique to Control the Eutrophication Phenomenon: Realistic Studies

Desalination RO reject brine as a novel-based porous geopolymer for phosphorus removal from contaminated media

Desalination reverse osmosis reject brine-based porous geopolymer (RO/GP) was produced and investigated as an improved adsorbent for phosphorus (P) removal from tainted seawater, brackish water, river water, and municipal wastewater effluent. The RO reject brine/geopolymer was produced by reacting metakaolin and fly ash with a Na-alkali activator and anhydrous RO brine as a sacrificial template. The influence of RO reject brine content on water absorption, porosity, mechanical, and structural properties were examined. The developed RO-based geopolymers exhibited the greatest porosity (58.3-84.2 % vol%), a significant ratio of open porosity to total porosity (67.7-92.1 %), and outstanding compression strength (3.6-10.4 MPa). The produced RO/GP structure has an adsorption capacity of 92.4 mg-P/g. The sequestration reaction of phosphorus by RO/GP is of pseudo-second-order kinetic behavior via Chi-squared (χ2), RMSE, and determination coefficient (R2) values. Regarding their agreement with Langmuir behavior, the phosphorus adsorption uptakes occur in homogeneous and monolayer states. The reaction is exothermic, spontaneous, and favorable. The RO/GP exhibits significant affinity for phosphorus co-existing with Cl-, Na+, SO42-, K+, HCO3-, and Ca2+. The RO/GP shows high safety during the adsorption investigation, with a total cost of 0.32 $/kg-P.

Exploring zeolite-based composites in adsorption and photocatalysis for toxic wastewater treatment: Preparation, mechanisms, and future perspectives

Water scarcity has become a critical global concern exacerbated by population growth, globalization, and industrial expansion, resulting in the production of wastewater containing a wide array of contaminants. Tackling this challenge necessitates the adoption of innovative materials and technologies for effective wastewater treatment. This review article provides a comprehensive exploration of the preparation, applications, mechanisms, and economic environmental analysis of zeolite-based composites in wastewater treatment. Zeolite, renowned for its versatility and porous nature, is of paramount importance due to its exceptional properties, including high surface area, ion exchange capability, and adsorption capacity. Various synthetic methods for zeolite-based composites are discussed. The utilization of zeolites in wastewater treatment, particularly in adsorption and photocatalysis, is thoroughly investigated. The significance of zeolite in adsorption and its role in the photocatalytic degradation of pollutants are examined, along with its applications in treating volatile organic compounds (VOCs), dye wastewater, oil-field wastewater, and radioactive waste. Mechanisms underlying zeolite-based adsorption and photocatalysis, including physical and chemical adsorption, ion exchange, and surface modification, are elucidated. Additionally, the role of micropores in the adsorption process is explored. Furthermore, the review delves into regeneration and desorption studies of zeolite-based composites, crucial for sustainable wastewater treatment practices. Economic and environmental analyses are conducted to assess the feasibility and sustainability of employing zeolite-based composites in wastewater treatment applications. Future recommendations are provided to guide further research and development in the field of zeolite-based composites, aiming to enhance wastewater treatment efficiency and environmental sustainability. By exploring the latest advancements and insights into zeolite-based nanocomposites, this paper aims to contribute to the development of more efficient and sustainable wastewater treatment strategies. The integration of zeolite-based materials in wastewater treatment processes shows promise for mitigating water pollution and addressing water scarcity challenges, ultimately contributing to environmental preservation and public health protection.

Preparation, Features, and Efficiency of Nanocomposite Fertilisers Based on Glauconite and Ammonium Dihydrogen Phosphate

This paper studies the chemical and mechanochemical preparation of glauconite with ammonium dihydrogen phosphate (ADP) nanocomposites with a ratio of 9:1 in the vol.% and wt.%, respectively. The methods include X-ray diffraction analysis, scanning electron microscope with energy-dispersive X-ray spectroscopy, transmission electron microscopy, infrared spectroscopy, and differential thermal analysis with a quadruple mass spectrometer. The manufactured nanocomposites keep the flaky glauconite structure. Some glauconite unit structures have been thickened due to minimal nitrogen (ammonium) intercalation into the interlayer space. The globular, granular, or pellet mineral particles of nanocomposites can be preserved via chemical techniques. Globular and micro-aggregate particles in nanocomposites comprise a thin film of adsorbed ADP. The two-step mechanochemical method makes it possible to slightly increase the proportion of adsorbed (up to 3.2%) and intercalated (up to 6.0%) nutrients versus chemical ways. Nanocomposites prepared via chemical methods consist of glauconite (90%), adsorbed (1.8-3.6%), and intercalated (3.0-3.7%) substances of ADP. Through the use of a potassium-containing clay mineral as an inhibitor, nitrogen, phosphorus, and potassium (NPK), nanocomposite fertilisers of controlled action were obtained. Targeted and controlled release of nutrients such as phosphate, ammonium, and potassium are expected due to various forms of nutrients on the surface, in the micropores, and in the interlayer space of glauconite. This is confirmed via the stepwise dynamics of the release of ammonium, nitrate, potassium, and phosphate from their created nanocomposites. These features of nanocomposites contribute to the stimulation of plant growth and development when fertilisers are applied to the soil.

Advancing our understanding of bioreactors for industrial-sized cell culture: health care and cellular agriculture implications

Bioreactors are advanced biomanufacturing tools that have been widely used to develop various applications in the fields of health care and cellular agriculture. In recent years, there has been a growing interest in the use of bioreactors to enhance the efficiency and scalability of these technologies. In cell therapy, bioreactors have been used to expand and differentiate cells into specialized cell types that can be used for transplantation or tissue regeneration. In cultured meat production, bioreactors offer a controlled and efficient means of producing meat without the need for animal farming. Bioreactors can support the growth of muscle cells by providing the necessary conditions for cell proliferation, differentiation, and maturation, including the provision of oxygen and nutrients. This review article aims to provide an overview of the current state of bioreactor technology in both cell therapy and cultured meat production. It will examine the various bioreactor types and their applications in these fields, highlighting their advantages and limitations. In addition, it will explore the future prospects and challenges of bioreactor technology in these emerging fields. Overall, this review will provide valuable insights for researchers and practitioners interested in using bioreactor technology to develop innovative solutions in the biomanufacturing of therapeutic cells and cultured meat.

Spectroscopic and Microestructural Evidence for T-2 Toxin Adsorption Mechanism by Natural Bentonite Modified with Organic Cations

Aluminosilicates are adsorbents able to bind mycotoxins, and their chemical modification increases their affinity to adsorb low-polarity mycotoxins. To further investigate if the inclusion of salts in bentonite modifies its adsorptive capacity, we studied T-2 toxin adsorption in natural bentonite (NB) and when modified with quaternary ammonium salts differing in polarity and chain length: myristyl trimethyl ammonium bromide (B14), cetyl trimethyl ammonium bromide (B16) and benzyl dimethyl stearyl ammonium chloride (B18). The results showed that quaternary salts made bentonite: displace monovalent (Na+1, K+1) and divalent (Mg+2, Ca+2) ions; reduce its porosity; change its compaction and structure, becoming more crystalline and ordered; and modify the charge balance of sheets. T-2 adsorption was higher in all modified materials compared to NB (p ≤ 0.0001), and B16 (42.96%) better adsorbed T-2 compared to B18 (35.80%; p = 0.0066). B14 (38.40%) showed no differences compared to B16 and B18 (p > 0.05). We described the T-2 adsorption mechanism in B16, in which hydrogen bond interactions, Van der Waals forces and the replacement of the salt by T-2 were found. Our results showed that interaction types due to the inclusion in B16 might be more important than the hydrocarbon chain length to improve the adsorptive capacity of bentonite.

Synthesis of zeolite/geopolymer composite for enhanced sequestration of phosphate (PO43-) and ammonium (NH4+) ions; equilibrium properties and realistic study

Zeolite impeded geopolymer (Z/G) was synthesized from natural kaolinite and diatomite. The structure (Z/G) was characterized as an enhanced adsorbent for PO₄^3- and NH₄⁺ ions from aqueous solutions, groundwater, and sewage water. The synthetic Z/G structure exhibits sequestration capacities of 206 mg/g and 140 mg/g for PO₄^3- and NH₄⁺, respectively which are higher values than the recognized results for the geopolymer and other adsorbents in literature. The sequestration reactions of PO₄^3- and NH₄⁺ by Z/G are of Pseudo-Second order kinetic behavior considering both the Chi-squared (χ²) and correlation coefficient (R²) values. The sequestration reactions occur in homogenous and monolayer forms considering their agreement with Langmuir behavior. The Gaussian energies (12.4 kJ/mol (PO₄^3-) and 10.47 kJ/mol (NH₄⁺)) demonstrate the operation of a chemical sequestration mechanism that might be involved zeolitic ion exchange process and chemical complexation. Additionally, these reactions are exothermic processes of spontaneous and favorable properties based on thermodynamic studies. The Z/G structure is of significant affinity for both PO₄^3- and NH₄⁺ even in the existence of other anions as Cl^-, HCO₃^-, SO₄^2-, and NO₃^-. Finally, the structure used effectively in the purification of groundwater and sewage water from PO₄^3- and NH₄⁺ in addition to nitrate, sulfate, and some metal ions.

Separation of pollutants from aqueous solution using nanoclay and its nanocomposites: A review

Wastewater is always composed of different pollutants, most of which are toxic to the living being. It is very tough to separate all those diverse groups of contaminants using a single process or single material. Rather a sustainable and environment friendly processes should be adapted to restrict the secondary pollution generation. Nanoclay and its nanocomposites are one of the most used adsorbents that have been modified and used for the separation of almost all types of pollutants, including dyes, heavy metals, fluoride, nitrate, ammonia, emerging pollutants and bacteria. They are relatively inexpensive, easy to exploit and relatively maintenance-free. Thus, recent research bloomed for developing suitable adsorbents, including clay nanocomposites. The advantages and drawbacks of all the clay nanocomposites-based processes have been discussed critically in this article. Nano-clays or other nanoparticles incorporated synthetic and natural polymers-based clay nanocomposites were synthesized, and it was found that they can remove dyes in the range between 48 mg/g and 1994 mg/g. Similarly, they separate a diverse group of heavy metal ions, including As, Cu, Co, Pd, Zn, Cr, Ni, Cd, and Hg, in the range of 0.073-1667 mg/g. The clay nanocomposites also showed fluoride removal efficacy in the range of 0.134-23 mg/g. They are also useful for the separation of emerging pollutants like pesticides, pharmaceuticals, personal care products, trace elements, and particulate matters in the range of 0.1-651 mg/g the clay nanocomposites showed considerable nitrate, ammonia and bacteria removal efficacy too. Though it seems promising, more investigations with real wastewater and pilot-scale studies are recommended to explore large-scale wastewater treatment capabilities.

Reusable Hyperbranched Polyethylenimine-Functionalized Ethyl Cellulose Film for the Removal of Phosphate with Easy Separation

The design of a reusable film adsorbent with easy solid-liquid separation for the removal of phosphate is necessary and significant but remains hugely challenging. Herein, the hyperbranched polyethylenimine-functionalized ethyl cellulose (HPEI-EC) film was successfully synthesized by a one-step solution-casting method. The structure and elemental composition of the HPEI-EC film were characterized by Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The phosphate adsorption capacity of the HPEI-EC film was 15.53 mg g-1, which is 12 times higher than that of EC. Significantly, the elongation at break of the HPEI-EC film was 13.43%, which is higher than that of the EC film (8.9%), and the HPEI-EC film had a considerable tensile strength of 13.21 MPa. Such good mechanical properties of the HPEI-EC film bring about the advantage of the saturated HPEI-EC film, allowing it to be easily taken out using a pair of tweezers, which significantly reduces the operation time and saves the cost in the application process. Furthermore, the HPEI-EC film possessed good reusability, and 71.6% of the original adsorption capacity of phosphate was retained even after five cycles. Moreover, the electrostatic interaction between protonated the amine group (-NH3 +) and the phosphate ion (PO4 3-) is mainly responsible for the adsorption process. This study presents a low-cost and reusable film adsorbent for the effective removal of phosphate from water and provides an easy solid-liquid separation method for use in the adsorption field.

Synthesis of layered double hydroxides with nitrate and its adsorption properties of phosphate

In the present study, different ratios of layered double hydroxides (LDHs) were synthesized via co-precipitation method. The synthesized LDHs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nitrogen adsorption-desorption analysis, point of zero charges (pH_pzc), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Phosphate adsorption performances were estimated by batch adsorption experiments; desorption hysteresis and adsorption mechanism were also investigated. The XRD, SEM and TEM results confirmed the multilayer structure of the synthesized LDHs. The pseudo-second-order kinetic model and the Freundlich model describe the adsorption behavior of LDHs best. The maximum adsorption capacity is 185.86 mg-KH₂PO₄/g for Mg₂Al-NO₃ LDH. When the dosage of LDHs was greater than 2 g/L, the phosphorus content in the solution decreased from 30 mg-P/L to 0.077 mg-P/L after adsorption by Mg₂Al-NO₃ LDH. All the results reveal that Mg₂Al-NO₃ LDH is a potential adsorbent for removing phosphate from aqueous solution.