ZnO supported on zeolite pellets as efficient catalytic system for the removal of caffeine by adsorption and photocatalysis

Management of caffeine in wastewater using MOF and perovskite materials: optimization, kinetics, and adsorption isotherm modelling

Pharmaceuticals and personal care products (PPCPs) have been increasingly used all over the world and they have been reported on water cycle and cause contamination. Among these pharmaceuticals is caffeine (CAF). In this work, CAF removal from aqueous samples by metal-organic framework (UIO-66) and perovskite (La0.7Sr0.3FeO3) was achieved. Detailed studies on the preparation of MOFs and perovskite oxides compounds have been presented. Extensive characterizations such as X-Ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared spectra (FT-IR), N2 adsorption-desorption isotherms were also carried out to assure proper formation and to better understand the physico-chemical behavior of the synthesized samples before and after adsorption. Batch experiments of CAF adsorption onto both MOFs and perovskite were performed to compare the effectiveness of both materials on the removal competence of the CAF residue at different conditions including the effect of pH, initial concentration, and contact time. It was observed that the adsorption capacity of CAF by MOF increased with increasing acidity. On the other hand, the adsorption capacity of perovskite is stable in pH 4-10. The maximum adsorption capacities of UiO-66 and perovskite toward CAF are high as 62.5 mg g-1 and 35.25 mg g-1, respectively. Equilibrium isotherms were investigated by numerous models: Langmuir, Freundlich, Temkin, Redlich-Peterson, Sips, Langmuir-Freundlich, Toth, Kahn, Baudu, and Fritz Schlunder. Moreover, the kinetics of the CAF@MOF and CAF@Perovskite systems have been studied by five kinetic models (Pseudo-1st -order (PFO), Pseudo-2nd -order (PSO), Mixed 1st, 2nd-order, Intraparticle diffusion and Avrami). The best model described the adsorption of CAF onto both of MOF and perovskite was the mixed 1st, 2nd-order model. The metal-organic framework and perovskite were applied to quickly extract CAF from water samples successfully. The maximum removal percentage obtained for MOF and perovskite was 0.89% and 0.94% respectively within 30 min contact time which suggests that these materials are considered as promising adsorbents for CAF.

The potential of zeolite nanocomposites in removing microplastics, ammonia, and trace metals from wastewater and their role in phytoremediation

Nanocomposites are emerging as a new generation of materials that can be used to combat water pollution. Zeolite-based nanocomposites consisting of combinations of metals, metal oxides, carbon materials, and polymers are particularly effective for separating and adsorbing multiple contaminants from water. This review presents the potential of zeolite-based nanocomposites for eliminating a range of toxic organic and inorganic substances, dyes, heavy metals, microplastics, and ammonia from water. The review emphasizes that nanocomposites offer enhanced mechanical, catalytic, adsorptive, and porosity properties necessary for sustainable water purification techniques compared to individual composite materials. The adsorption potential of several zeolite-metal/metal oxide/polymer-based composites for heavy metals, anionic/cationic dyes, microplastics, ammonia, and other organic contaminants ranges between approximately 81 and over 99%. However, zeolite substrates or zeolite-amended soil have limited benefits for hyperaccumulators, which have been utilized for phytoremediation. Further research is needed to evaluate the potential of zeolite-based composites for phytoremediation. Additionally, the development of nanocomposites with enhanced adsorption capacity would be necessary for more effective removal of pollutants.

Preparation of food active packaging materials based on calcium hydroxide and modified porous medium for reducing carbon dioxide and kimchi odor

Carbon dioxide and kimchi odor compounds, formed during fermentation, negatively affect the long-distance distribution of commercial kimchi. To address these issues, in this study, we modified different porous media (activated carbon, bleaching earth, diatomite, and zeolite) using sodium bicarbonate and silver (Ag) ions. Functional sheets were prepared using linear low-density polyethylene, calcium hydroxide, a porous medium, and a blowing agent. Various prepared porous media and sheets were effective in removing acetic acid, sulfur compounds (allyl methyl sulfide, dimethyl disulfide, allyl methyl disulfide, and diallyl disulfide), and carbon dioxide. Porous media with micropores exhibited a sulfur compound removal efficiency of 43.5%-99.4%, while no effect was observed on acetic acid removal. However, porous media with mesopores showed an acetic acid removal efficiency of 42.3%-90.7%, with no reduction in sulfur compounds removal. The impregnation of porous materials with sodium bicarbonate significantly (p < 0.05) enhanced the acetic acid removal activity. Ag modification improved the sulfur compound removal of the mesoporous bleaching earth and diatomite statistically (p < 0.05). Additionally, the incorporation of sodium bicarbonate-impregnated mesoporous media significantly improved carbon dioxide removal, reducing concentrations from 25.97% to 14.27% with respect to the control group. Our functional food packaging materials can solve the current issues in kimchi distribution by removing carbon dioxide and kimchi odor without affecting its quality. PRACTICAL APPLICATION: Food active packaging materials containing calcium hydroxide and modified porous medium are effective in removing carbon dioxide and kimchi odor (acetic acid and sulfur compounds). The removal of carbon dioxide and kimchi odor, which adversely affect the distribution and sale of commercial kimchi, can help solve the current issues with kimchi distribution without affecting its quality.

Supercritical Phase Inversion to Produce Photocatalytic Active PVDF-coHFP_TiO2 Composites for the Degradation of Sudan Blue II Dye

TiO2-loaded poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-coHFP) membranes were produced by supercritical CO2-assisted phase inversion. Three different TiO2 loadings were tested: 10, 20, and 30 wt% with respect to the polymer. Increasing the TiO2 amount from 10 wt% to 20 wt% in the starting solution, the transition from leafy-like to leafy-cellular morphology was observed in the section of the membrane. When 30 wt% TiO2 was used, the entire membrane section showed agglomerates of TiO2 nanoparticles. These polymeric membranes were tested to remove Sudan Blue II (SB) dye from aqueous solutions. The adsorption/photocatalytic processes revealed that membrane morphology and TiO2 cluster size were the parameters that mainly affected the dye removal efficiency. Moreover, after five cycles of exposure of these membranes to UV light, SB removal was higher than 85%.

Comprehensive Review on Zeolite-Based Nanocomposites for Treatment of Effluents from Wastewater

All humans and animals need access to clean water in their daily lives. Unfortunately, we are facing water scarcity in several places around the world, and, intentionally or unintentionally, we are contaminating the water in a number of ways. The rise in population, globalization, and industrialization has simultaneously given rise to the generation of wastewater. The pollutants in wastewater, such as organic contaminants, heavy metals, agrochemicals, radioactive pollutants, etc., can cause various ailments as well as environmental damage. In addition to the existing pollutants, a number of new pollutants are now being produced by developing industries. To address this issue, we require some emerging tools and materials to remove effluents from wastewater. Zeolites are the porous aluminosilicates that have been used for the effective pollutant removal for a long time owing to their extraordinary adsorption and ion-exchange properties, which make them available for the removal of a variety of contaminants. However, zeolite alone shows much less photocatalytic efficiency, therefore, different photoactive materials are being doped with zeolites to enhance their photocatalytic efficiency. The fabrication of zeolite-based composites is emerging due to their powerful results as adsorbents, ion-exchangers, and additional benefits as good photocatalysts. This review highlights the types, synthesis and removal mechanisms of zeolite-based materials for wastewater treatment with the basic knowledge about zeolites and wastewater along with the research gaps, which gives a quality background of worldwide research on this topic for future developments.

Double Z-Scheme ZnCo2O4/MnO2/FeS2 photocatalyst with enhanced photodegradation of organic compound: Insights into mechanisms, kinetics, pathway and toxicity studies

The present work highlights the preparation of double Z-scheme ZnCo2O4/MnO2/FeS2 nanocomposite (NCs) and investigated its photocatalytic activity against methyl orange (MO) dye degradation under visible light. An array of techniques was carried out to characterize the nanoparticles (NPs) in order to evaluate their morphological, structural, optical, and photocatalytic properties using FE-SEM, TEM, XRD, N2 adsorption and desorption studies, PL, UV-visible spectrophotometer, XPS, Raman, and UV-vis DRS analysis. The degradation efficiency of NCs was tested along with different parameter studies such as different pH, NCs concentration, dye concentration, reusability and structural stability. The NCs exhibited complete photodegradation of MO dye under visible light within 80 min at pH 4. The structural and compositional stability of the prepared NCs over 6 consecutive cycles was tested via XRD and XPS analysis. The results of active species trapping experiments showed that O2-• and OH• are responsible for the degradation of MO dye. The TOC analysis showed 95% of mineralization by the prepared NCs. The MO dye degradation pathway was determined using GC-MS/MS analysis and drafted all the intermediates involved. End product toxicity via seed germination and intermediate toxicity study using ECOSAR software results in less toxicity of end product compared to parent compound. Finally, the genotoxicity of the prepared NCs was evaluated using Allium cepa and showed its no causes of cytotoxicity & genotoxicity by the prepared NCs. ZnCo2O4/MnO2/FeS2 NCs exhibited its high photocatalytic activity and the toxicity studies confirms that there is no cause of any environmental impact.

Green synthesis of P − ZrO2CeO2ZnO nanoparticles using leaf extracts of Flacourtia indica and their application for the photocatalytic degradation of a model toxic dye, Congo red

In the present work P−ZrO2CeO2ZnO nanoparticles were synthesised for the first time using phytochemical extracts from Flacourtia indica leaves and applied in the photocatalytic degradation of Congo Red in the presence of Light Emitting Diode warm white light. The photocatalytic degradation was optimized with respect to P−ZrO2CeO2ZnO nanoparticle dosage, initial Congo Red concentration, and degradation time. The optimum conditions for P−ZrO2CeO2ZnO nanoparticle synthesis was pH 9, leaves extracts of F. indica dosage 4 g 100 mL⁻¹, Zirconia, Cerium and Zinc metal ion concentration 0.05 mg/L and metal ion to plant volume ratio of 1:4. The leaves extract dosage, pH and metal concentration had the most significant effects on the synthesis of the nanoparticles. The nanoparticles followed type III physisorption adsorption isotherms with surface area of 0.4593 m³g⁻¹, pore size of 6.80 nm, pore volume 0.000734 cmg−13 and average nanoparticle size 0.255 nm. A degradation efficiency of 86% was achieved and the optimum degradation conditions were 0.05 g/L of P−ZrO2CeO2ZnO nanoparticle dosage, 10 mg/L initial Congo red concentration, and 250 minutes irradiation time. Data from kinetic studies showed that the degradation followed pseudo first order kinetics at low concentration, with a rate constant of 0.069 min⁻¹. The superoxide, h+ holes and light were the main determinants of the reaction mechanisms for the degradation of Congo Red. The investigation outcomes demonstrated that P−ZrO2CeO2ZnO nanoparticles offer a high potential for photocatalytic degradation of Congo Red.

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The most significant factors on P−ZrO2CeO2ZnO nanoparticles synthesis were plant leaves dosage, pH and initial metal concentration.

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The nanoparticles exhibited high catalytic activity towards photocatalytic degradation of Congo red.

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Superoxide, h+ holes and light were the main determinants of the photocatalytic degradation mechanisms.

Photocatalytic Degradation of Recalcitrant Pollutants of Greywater

These days, many countries have a water shortage and have limited access to clean water. To overcome this, a new treatment is emerging, namely, the photocatalytic processing of greywater. Photocatalytic processes to remove the organic matter from different greywater sources are critically reviewed. Their efficiency in degrading the organic matter in greywater is scrutinized along with factors that can affect the activity of photocatalysts. Modified TiO2, ZnO and TiO2 catalysts show great potential in degrading organic materials that are present in greywater. There are several methods that can be used to modify TiO2 by using sol-gel, microwave and ultrasonication. Overall, the photocatalytic approach alone is not efficient in mineralizing the organic compounds, but it works well when the photocatalysis is combined with oxidants and Fe3+. However, factors such as pH, concentration and catalyst-loading of organic compounds can significantly affect photocatalytic efficiency.

Synthesis of BiOI/Mordenite Composites for Photocatalytic Treatment of Organic Pollutants Present in Agro-Industrial Wastewater

Recently, bismuth oxyiodide (BiOI) is an attractive semiconductor to use in heterogeneous photocatalysis processes. Unfortunately, BiOI individually shows limited photocatalytic efficiency, instability, and a quick recombination of electron/holes. Considering the practical application of this semiconductor, some studies show that synthetic zeolites provide good support for this photocatalyst. This support material permits a better photocatalytic efficiency because it prevents the quick recombination of photogenerated pairs. However, the optimal conditions (time and temperature) to obtain composites (BiOI/ synthetic zeolite) with high photocatalytic efficiency using a coprecipitation-solvothermal growth method have not yet been reported. In this study, a response surface methodology (RSM) based on a central composite design (CCD) was applied to optimize the synthesis conditions of BiOI/mordenite composites. For this purpose, eleven BiOI/mordenite composites were synthesized using a combined coprecipitation-solvothermal method under different time and temperature conditions. The photocatalytic activities of the synthesized composites were evaluated after 20 min of photocatalytic oxidation of caffeic acid, a typical organic pollutant found in agro-industrial wastewater. Moreover, BiOI/mordenite composites with the highest and lowest photocatalytic activity were physically and chemically characterized using nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS). The optimal synthesis conditions prove to be 187 °C and 9 h. In addition, the changes applied to the experimental conditions led to surface property modifications that influenced the photocatalytic degradation efficiency of the BiOI/mordenite composite toward caffeic acid photodegradation.

Application of natural minerals in photocatalytic degradation of organic pollutants: A review

Photocatalysis is an effective, inexpensive and environmentally friendly technology for the decomposition of various aqueous organic pollutants and plays an increasingly critical role in the degradation of pollutants. Natural minerals are abundant natural resources on Earth and can be obtained directly from nature. Natural minerals are excellent photocatalyst carriers that are environmentally friendly, low in price, and will not cause secondary pollution to the environment. Natural minerals have the characteristics of a large specific surface area, providing more active centres, and adsorbing pollutants to concentrate catalysis. Natural minerals are also excellent photocatalysts, such as haematite and magnetite, which play a very good role in the degradation of water pollutants. Studies that make full use of natural minerals are of great significance. This review covers the latest research on natural minerals as photocatalytic composite materials to degrade organic pollutants in water, including three parts: the classification of natural minerals, the structural description of natural mineral composites, and the photocatalytic degradation of organic pollutants by natural mineral composites. In addition, the current limitations and opinions of natural mineral composites are discussed to achieve better results in applying natural minerals.

Process enhancing strategies for the reduction of Cr(VI) to Cr(III) via photocatalytic pathway

This discourse aimed at providing insight into the strategies that can be adopted to boost the process of photoreduction of Cr(VI) to Cr(III). Cr(VI) is amongst the highly detestable pollutants; thus, its removal or reduction to an innocuous and more tolerable Cr(III) has been the focus. The high promise of photocatalysis hinged on the sustainability, low cost, simplicity, and zero sludge generation. Consequently, the present dissertation provided a comprehensive review of the process enhancement procedures that have been reported for the photoreduction of Cr(VI) to Cr(III). Premised on the findings from experimental studies on Cr(VI) reductions, the factors that enhanced the process were identified, dilated, and interrogated. While the salient reaction conditions for the process optimization include the degree of ionization of reacting medium, available photogenerated electrons, reactor ambience, type of semiconductors, surface area of semiconductor, hole scavengers, quantum efficiency, and competing reactions, the relevant process variables are photocatalyst dosage, initial Cr(VI) concentration, interfering ion, and organic load. In addition, the practicability of photoreduction of Cr(VI) to Cr(III) was explored according to the potential for photocatalyst recovery, reactivation, and reuse reaction conditions and the process variables.

Photocatalytic degradation of hydroxychloroquine using ZnO supported on clinoptilolite zeolite

The objective of this work was to evaluate the photocatalytic activity of zinc oxide catalysts supported on natural zeolite clinoptilolite for photocatalytic degradation of the drug hydroxychloroquine, used in the treatment of malaria and which has been tested in the treatment of COVID-19. To synthesize 10%ZnOCP and 15%ZnOCP catalysts, the wet impregnation methodology was used. The raw and synthesized catalysts were characterized by XRD, SEM, XRF, BET, DRS, PCZ, FT-IR and PL. The degradation of hydroxychloroquine was calculated using UV-vis absorption from the samples before and after the photocatalytic process. The maximum percentage of degradation (96%) was obtained with the operational parameters of C₀ = 10 mg L^-1; C_cat = 2 g L^-1 of 15%ZnOCP; pH = 7.5; UV-A radiation. Ecotoxicological tests against the bioindicators Lactuca sativa and Artemia salina confirmed the reduction of effluent toxicity after treatment.

Removal of volatile organic compounds (VOCs) from waste air stream using ozone assisted zinc oxide (ZnO) nanoparticles coated on zeolite

The release of volatile organic compounds (VOCs) from stationary and mobile sources increases the concentration of these pollutants in the environment. These compounds have the potential to cause adverse effects on human health and the environment. The adoption of management and engineering procedures to control the emission of these pollutants to the air has become essential. The aim of this study was to use an advanced oxidation process namely the catalytic ozonation to reduce the concentration of these pollutants in industrial output. In this experimental study, the catalytic ozonation process in the presence of ZnO nanoparticles coated on zeolite media was used in a laboratory scale to treat the air contaminated with BTEX compounds as indicators of VOCs. For this purpose, First the nanocomposites were synthesized based on chemical co-precipitation method. SEM, XRD, BET and FT-IR analyses were performed to investigate the characteristics of nanocomposites. The variables including initial concentrations of BTEX (50-200 ppm), polluted air flow rate (5-20 l/h), humidity (0-75%) and ozone dose (0.25-1 g/h) were investigated. The concentration of BTEX compounds was measured by the Gas Chromatography (GC) technique according to the NIOSH 1501 manual. The results of SEM, XRD, BET and FT-IR analyses showed the proper synthesis of nanocomposites. According to the laboratory results, the optimal conditions of the process were found to be as follows: the initial concentration of pollutants equal to 50 ppm, inlet air flow rate of 5 l/h, relative air humidity of 25-35%, and inlet ozone concentration equal to 1 g/h. Under these conditions, the removal efficiency of the compounds: benzene, toluene, ethylbenzene and xylene were obtained 98, 96, 92 and 91%, respectively. Simple ozonation and adsorption processes were less efficient than catalytic ozonation. This process had the ability to reduce the concentration of BTEX compounds to standard level.

Continuous process applied to degradation of triclosan and 2.8-dichlorodibenzene-p-dioxin

This study describes the use of a prototype for the continuous photocatalytic reaction process using Fe/Nb₂O₅-immobilized catalyst for triclosan and 2.8-dichlorodibenzene-p-dioxin (2.8-DCDD)'s degradation. The experiments were carried out with different parameters and matrices in a steady state. In addition, photolysis and photocatalytic tests were performed. The results indicated that the generation of 2.8-DCDD was observed in matrices with Cl^-. The Fe/Nb₂O₅-immobilized catalysts were efficient in the degradation of triclosan and 2.8-dichlorodibenzene-p-dioxin. However, 2.8-DCDD formation was not observed in the ultra-pure water matrix, which indicated influence of ions. The photocatalysis was more efficient than the photolysis when comparing both matrices and radiation. Even with a radiation oscillation, the solar process showed positive results.

Photocatalysis for Organic Wastewater Treatment: From the Basis to Current Challenges for Society

Organic pollutants such as dyes, antibiotics, analgesics, herbicides, pesticides, and stimulants become major sources of water pollution. Several treatments such as absorptions, coagulation, filtration, and oxidations were introduced and experimentally carried out to overcome these problems. Nowadays, an advanced technique by photocatalytic degradation attracts the attention of most researchers due to its interesting and promising mechanism that allows spontaneous and non-spontaneous reactions as they utilized light energy to initiate the reaction. However, only a few numbers of photocatalysts reported were able to completely degrade organic pollutants. In the past decade, the number of preparation techniques of photocatalyst such as doping, morphology manipulation, metal loading, and coupling heterojunction were studied and tested. Thus, in this paper, we reviewed details on the fundamentals, common photocatalyst preparation for coupling heterojunction, morphological effect, and photocatalyst’s characterization techniques. The important variables such as catalyst dosage, pH, and initial concentration of sample pollution, irradiation time by light, temperature system, durability, and stability of the catalyst that potentially affect the efficiency of the process were also discussed. Overall, this paper offers an in-depth perspective of photocatalytic degradation of sample pollutions and its future direction.

Tricks and tracks in removal of emerging contaminants from the wastewater through hybrid treatment systems: A review

In recent years, many biological and physicochemical treatment technologies have been investigated for the removal of the emerging contaminants (ECs) from the wastewater matrix. However, due to the deficiency of these treatments to completely degrade the ECs in wastewater, hybrid systems were explored using the distinguishing removal potential of the different treatment processes. This review gives an insight on such hybrid systems combining several physical, chemical and biological treatments for the fast and eco-efficient removal of ECs from wastewater. Most of the hybrid systems have applied biological treatments first and then physical or chemical treatments. The hybrid system of membrane bioreactor (MBR) followed by membrane filtrations (RO/NF) effectively removed a suite of ECs such as pharmaceuticals, beta blockers, pesticides and EDCs. Some of the hybrid systems of constructed wetlands and waste stabilization ponds showed promising potential for the biosorptive removal of pharmaceuticals and some beta blockers. The hybrid systems combining activated sludge process and physical processes such as ultrafiltration (UF), reverse osmosis (RO) and gamma radiations are considered as the cost effective technologies and had better removal of trace organic pollutants. The hybrid system of MBR coupled with UV oxidation, activated carbon and ultrasound, and ozonation followed by ultrasounds, completely degraded some ECs and many pharmaceuticals. The review also synthesizes the trend followed by the hybrid system processes for the removal of various categories of ECs. The future research directions for the ECs removal utilizing hybrid nanocomposites and green sustainable technology have been suggested.

Elimination of basic blue 9 by electrocoagulation coupled with pelletized natural dead leaves (Sapindus mukorossi) biosorption

Elimination of basic blue 9 (BB-9), a cationic textile dye, by electrocoagulation coupled with biosorption exploiting pelletized natural dead leaves (PNDL) of Sapindus mukorossi, an economic alternative biosorbent, was investigated. The experimental runs were conducted in a laboratory-scale hybrid reactor loaded with Al electrodes, aeration spargers and PNDL packed twin suspended buckets. The pelletized adsorbents offer key advantages of good mechanical stability, lesser clogging risk, and easy disengagement as compared to powdered adsorbents. The parameters of current density, pH, PNDL dose, and initial dye concentration were studied for the decolorization and COD removal efficiency. The experimental results revealed that up to 99.9% decolorization and 90.01% COD removal efficiency achieved after 8 min at optimum condition of current density (j)=20.27 mA/cm², pH = 9, PNDL dose = 6 g/L, and initial dye concentration = 50 mg/L. The BB-9 elimination followed the first-order kinetics with K₁=0.318 min^-1 and R²=0.997. The results revealed the potential of PNDL as a feasible biosorbent with the effective performance of the coupled process.

Assessment comparison of commercial TiO2 and TiO2 sol-gel on the degradation of caffeine using artificial radiation

The presence of endocrine disrupting compounds in water receptor bodies, such as drugs, currently has in scientific field a great focus of studies focused on advanced water treatment techniques that enable the decontamination of water sources and public supply. In this context, this study focused on the characterization and evaluation of photocatalytic activity of catalysts calcined and uncalcined synthesized TiO₂ and the commercial sol-gel route from caffeine degradation. The photocatalysts were characterized by N₂ physisorption, X-ray diffraction, scanning electron microscopy (SEM/EDS), photoacoustic spectroscopy, and infrared spectroscopy (FTIR). They seek to evaluate the main textural, structural, chemical, and morphological differences that the method of synthesis can promote in obtaining a titanium oxide-based catalyst. Thus, the results of this study demonstrate that the synthesis method significantly influences the activity of the materials and that calcined TiO₂ catalyst prepared using the sol-gel method has promising photocatalytic capabilities for the elimination of drugs such as caffeine when present in wastewater.

Removal of caffeine, nicotine and amoxicillin from (waste)waters by various adsorbents. A review

The fast growth in the anthropogenic activities, that involve a wide use of pharmaceuticals, has led to the appearance of new toxic and hazardous chemical compounds, called "emerging pollutants", which could cause unpredictable consequences to the ecosystems. The current review is focused on emerging pollutants occurring in food or air and include caffeine and nicotine, as well as on pharmaceuticals, in particular amoxicillin, and the concerns caused by its wide usage for medical purposes. This review, for the first time, analyzes and discusses the potential risks and implications of caffeine, nicotine and amoxicillin as emerging environmental pollutants, a field that remains underrepresented to date. Both caffeine and nicotine belong to life style compounds, while pharmaceutical amoxicillin is one of the very popular β-lactam antibiotics used to take care of human and animal infections. The review covers the toxic effect caused by caffeine, nicotine and amoxicillin on humans and animals and describes some of the main adsorbents utilized for their removal (e.g., grape stalk, tea waste, wheat grains, bentonite, activated carbon, acid and base modified grape slurry wastes, graphene oxides, modified graphene oxides, zeolites, etc.). The isotherm and kinetic models for the analysis of caffeine, nicotine and amoxicillin adsorption by different adsorbents are presented. The impact of pH, temperature, adsorbent dosage and thermodynamic studies were deeply analyzed. The review also discusses the mechanism of adsorption for the above-mentioned emerging pollutants, which includes π-π interaction, cation-π bonding, electron-donor and electron-acceptor forces, van der Waals forces, electrostatic interactions, etc. The present review has a potential value for chemists, ecologists, toxicologists, environmental engineers, and other professionals that are involved in environmental protection.

Zinc Oxide for Functional Textile Coatings: Recent Advances

The use of ZnO for the functionalization of textile substrates is growing rapidly, since it can provide unique multifunctional properties, such as photocatalytic self-cleaning, antimicrobial activity, UV protection, flame retardancy, thermal insulation and moisture management, hydrophobicity, and electrical conductivity. This paper aims to review the recent progress in the fabrication of ZnO-functionalized textiles, with an emphasis on understanding the specificity and mechanisms of ZnO action that impart individual properties to the textile fibers. The most common synthesis and application processes of ZnO to textile substrates are summarized. The influence of ZnO concentration, particle size and shape on ZnO functionality is presented. The importance of doping and coupling procedures to enhance ZnO performance is highlighted. The need to use binding and seeding agents to increase the durability of ZnO coatings is expressed. In addition to functional properties, the cytotoxicity of ZnO coatings is also discussed. Future directions in the use of ZnO for textile functionalization are identified as well.

Packed Bed Photoreactor for the Removal of Water Pollutants Using Visible Light Emitting Diodes

A packed bed photoreactor was developed using a structured photocatalyst active under visible light. The packed bed reactor was irradiated by visible light-emitting diodes (LEDs) for the evaluation of photocatalytic activity in the removal of different types of water pollutants. By using a flexible LEDs strip as the external light source, it was possible to use a simple cylindrical geometry for the photoreactor, thereby enhancing the contact between the photocatalyst and the water to be treated. The visible light active structured photocatalyst was composed by N-doped TiO2 particles supported on polystyrene spheres. Photocatalytic results showed that the almost total methylene blue decolorization was achieved after 120 min of irradiation. Moreover, the developed packed bed photoreactor was effective in the removal of ceftriaxone, paracetamol, and caffeine, allowing it to reach the almost total degradation of the pollutants and a total organic carbon removal above 80% after 180 min of visible light irradiation.

Ternary semiconductor metal oxide blends grafted Ag@AgCl hybrid as dimensionally stable anode active layer for photoelectrochemical oxidation of organic compounds: Design strategies and photoelectric synergistic mechanism

The development of ultra-efficient, sustainable, and easily accessible anode with relative non-precious semiconducting metal oxides is highly significant for application in the practical treatment of organically polluted water. Herein, we report SnO₂, TiO₂, and Ag₂O ternary semiconductor metal oxide blend grafted Ag@AgCl hybrids, prepared with the one-step sol-gel method and applied as a dimensionally stable anode (DSA)-active layer on a SnO₂-Sb/Ti electrode. Factors affecting crystal formation, including the presence or absence of O₂ during calcination, the calcination temperature, and Ag@AgCl additive dosage were discussed. The micromorphology, phase composition, and photoelectrochemical activity of the newly designed anode were comprehensively characterized. The optimized preparation, which yielded a solid-solution structure with flat and smooth surface and well-crystallized lattice configuration, occurred in the absence of O₂ during calcination at 550 ℃ with an Ag@AgCl additive dosage of 0.2 g in the sol-gel precursor. The newly designed DSA displayed improved electrocatalysis (EC) and photoelectrical catalysis (PEC) capacity. The phenol and its TOC removal efficiency reached 90.65% and 58.17% for 10 mA/cm² current density with a metal halide lamp in 3 h. The lifespan was four times that of SnO₂-Sb/Ti electrode. This proposed DSA construction strategy may support improved EC and PEC reactivities toward the decomposition of organic pollutants.

Crystal violet and toxicity removal by adsorption and simultaneous photocatalysis in a continuous flow micro-reactor

A continuous flow micro-reactor irradiated by UV-LEDs was employed to treat coloured wastewater by adsorption and simultaneous photocatalysis. Zinc oxide (ZnO) immobilized on commercial zeolites pellets in spherical shape (ZEO) was used as catalytic material in a micro-reactor maximizing the photocatalyst exposition to light sources, irradiating uniformly the entire solution volume and improving the mass transfer phenomena. Experimental tests were carried out on crystal violet dye (CV) as one of the main dying agent present in textile wastewater. The comparison between adsorption and adsorption/photocatalytic tests showed that UV irradiation can achieve a steady state CV concentration value corresponding to an equilibrium condition between adsorption and photocatalytic oxidation. The higher removal efficiency (i.e. 93%) was observed with a liquid flow rate of 1.1 mL/min (contact time = 4.7 min; CV = 10 mg/L) under UV light irradiation. In the steady state, CV removal remained constant for the overall testing time. Bioassays evidenced that toxicity was not completely removed (i.e. final effluent ranked as "slight acute toxic") from wastewater suggesting its suitability for sewage collection discharge. A Dubinin Radushkevich (D-R) isotherm model was applied for studying the adsorption behaviour of ZnO/ZEO sample. CV adsorption constants were evaluated from experimental data carried out in dark conditions in a batch system. Kinetic expression of CV removal and the D-R adsorption were incorporated in the CV mass balance estimating the kinetic parameter. The model was validated comparing the calculated CV conversion with the experimental tests collected at different CV inlet concentration.