The photocatalytic process in the treatment of polluted water

Toxicity of individual and mixture of organic compounds to P. Phosphoreum and S. Capricornutum using interpretable simple structural parameters

Human and environmental ecosystem beings are exposed to multicomponent compound mixtures but the toxicity nature of compound mixtures is not alike to the individual chemicals. This work introduces four models for the prediction of the negative logarithm of median effective concentration (pEC50) of individual chemicals to marine bacteria Photobacterium Phosphoreum (P. Phosphoreum) and algal test species Selenastrum Capricornutum (S. Capricornutum) as well as their mixtures to P. Phosphoreum, and S. Capricornutum. These models provide the simplest approaches for the forecast of pEC50 of some classes of organic compounds from their interpretable structural parameters. Due to the lack of adequate toxicity data for chemical mixtures, the largest available experimental data of individual chemicals (55 data) and their mixtures (99 data) are used to derive the new correlations. The models of individual chemicals are based on two simple structural parameters but chemical mixture models require further interaction terms. The new model's results are compared with the outputs of the best accessible quantitative structure-activity relationships (QSARs) models. Various statistical parameters are done on the new and comparative complex QSAR models, which confirm the higher reliability and simplicity of the new correlations.

TiO2 nanorod decorated with MoS2 nanospheres: An efficient dual-functional photocatalyst for antibiotic degradation and hydrogen production

The design and preparation of dual-functional photocatalysts for simultaneously realizing photocatalytic wastewater purification and hydrogen energy generation pose significant challenges. This article presents the engineering of a binary heterostructured photocatalyst by combining TiO2 (nanorods) and MoS2 nanosphere using a straightforward solvothermal method and the assessment of the phase structures, morphologies, and optical properties of the resulting nanocomposites using diverse analytical techniques. The TiO2(Rod)/MoS2 composite exhibits remarkable efficacy in degrading ciprofloxacin, achieving 93% removal rate within 1 h, which is four times higher than that of bare TiO2. Moreover, the optimized TiO2(Rod)/MoS2 presents an outstanding hydrogen production rate of 7415 μmol g-1, which is ∼24 times higher than that of pristine TiO2. Under UV-visible light irradiation, the TiO2(Rod)/MoS2 heterojunction displays an exceptional photocatalytic performance in terms of both photodegradation and hydrogen production, surpassing the performance of TiO2 particle/MoS2. The study findings demonstrate that TiO2(Rod)/MoS2 nanocomposites exhibit considerably improved photocatalytic degradation and hydrogen generation activities. Based on the experimental results, a possible mechanism is proposed for the transfer and separation of charge carriers in Z-scheme heterojunctions.

Recent progresses in synthesis and modification of g-C3N4 for improving visible-light-driven photocatalytic degradation of antibiotics

Graphitic carbon nitride (g-C3N4) is a widely studied visible-light-active photocatalyst for low cost, non-toxicity, and facile synthesis. Nonetheless, its photocatalytic efficiency is below par, due to fast recombination of charge carriers, low surface area, and insufficient visible light absorption. Thus, the research on the modification of g-C3N4 targeting at enhanced photocatalytic performance has attracted extensive interest. A considerable amount of review articles have been published on the modification of g-C3N4 for applications. However, limited effort has been specially contributed to providing an overview and comparison on available modification strategies for improved photocatalytic activity of g-C3N4-based catalysts in antibiotics removal. There has been no attempt on the comparison of photocatalytic performances in antibiotics removal between modified g-C3N4 and other known catalysts. To address these, our study reviewed strategies that have been reported to modify g-C3N4, including metal/non-metal doping, defect tuning, structural engineering, heterostructure formation, etc. as well as compared their performances for antibiotics removal. The heterostructure formation was the most widely studied and promising route to modify g-C3N4 with superior activity. As compared to other known photocatalysts, the heterojunction g-C3N4 showed competitive performances in degradation of selected antibiotics. Related mechanisms were discussed, and finally, we revealed current challenges in practical application.

Facile Synthesis of Band Gap-Tunable Kappa-Carrageenan-Mediated C,S-Doped TiO2 Nanoparticles for Enhanced Dye Degradation

Semiconducting nanoparticles (SNPs) have garnered significant attention for their role in photocatalysis technology, offering a cost-effective and highly efficient method for breaking down organic dyes. Of particular significance within SNP-based photocatalysis are tunable band gap TiO2 nanoparticles (NPs), which demonstrate remarkable enhancement in photocatalytic efficiency. In the present work, we introduce an approach for the synthesis of TiO2 NPs using kappa-carrageenan (κ-carrageenan), not just as a reducing and stabilizing agent but as a dopant for the resulting TiO2 NPs. During the synthesis of TiO2 NPs in the presence of sulfate-rich carrageenan, the process predominantly leaves residual sulfur and carbon. The presence of residual carbon, in conjunction with sulfur doping, as indicated by fast FTIR spectra, XPS, and EDX, leads to a significant reduction in the band gap of the resulting composite to 2.71 eV. The reduction of composite band gap yields remarkable degradation of methylene blue (99.97%) and methyl orange (97.84%). This work presents an eco-friendly and highly effective solution for the swift removal of environmentally harmful organic dyes.

Advanced cellulose-based hydrogel TiO2 catalyst composites for efficient photocatalytic degradation of organic dye methylene blue

Sustainable cellulose-based hydrogels are used in medicine and environmental science. Hydrogels' porosity makes them excellent adsorbents and stable substrates for immobilizing photocatalysts to remove organic dyes. Despite their potential, the implementation of hydrogels for this purpose is still limited due to their high synthesis temperature and low cellulose content. To overcome these challenges, this study develops cellulose-based hydrogels, which have a high cellulose content and can be easily synthesized under ambient conditions. Containing a higher cellulose concentration than previous hydrogels, the synthesized hydrogels are more stable and can be reused numerous times in treatment operations. The hydrogel properties were investigated using Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. Scanning electronic microscopy revealed that TiO2 nanoparticles were homogeneously distributed throughout the hydrogel's matrices. In addition, transparent hydrogels allow light to pass through, making them suitable substrates to remove organic dye. The results showed that the hydrogel with TiO2 was able to degrade nearly 90% of organic dye within 180 min. Furthermore, the hydrogel with the embedded catalyst exhibits the potential for reusability with a regeneration efficiency of 80.01% after five runs. These findings suggest that this novel hydrogel is a promising candidate for water pollution remediation.

Nickel-doped magnetic carbon aerogel derived from xanthan gum: a competent catalyst for the degradation of single and binary dye-based water pollutants

Toxic organic dyes (colorants) are one of the main causes of water pollution that releases destructive effluents in the environment. To overcome this issue, a fundamental need to produce a novel, efficient catalyst for the degradation and mineralization of dye mixtures has arisen. The objective of this research is to develop an eminent Ni-doped magnetic carbon aerogel (Ni-MCA) catalyst using graft co-polymerization method having xanthan gum as backbone doped with Ni-magnetic nanoparticles (Ni-MNPs), that do not show agglomeration and easy to separate. The examination revealed that Ni-MCA provided exceptional magnetic characteristics (Ms = 52.75 emu/g) and potent catalytic activity for the degradation of mono- as well as binary-dye solutions of Congo red (CR) and methyl green (MG) dyes. The formation was verified by various characterization techniques such as FTIR, VSM, XRD, XPS, SEM, TEM, and EDX mapping. Interestingly, Ni-MCA shows faster result on anionic dye CR up to 97% with degradation rate of 5.647 × 10-1 min-1, and MG dye shows degradation of 95.7% with the degradation rate of 2.169 × 10-1 min-1, while dye mixture is showing 90% degradation with rate of 2.159 × 10-1 min-1.

Photocatalytic activity enhancement of two-step and one-pot synthesis of Pd/ZnO nanocomposites: an experimental and DFT study

Pd/ZnO nanocomposites were successfully synthesized by means of one and two pot synthesis and applied in the photodegradation of Rh6G. The nanocomposites were characterized by XRD, SEM, TEM, FTIR and micro-Raman spectroscopies. It was found the presence of PdZn2, PdO and agglomerated particles in the support surface for the Palladium-based nanocomposites fabricated by one-pot route; the two-step method allowed the formation of spherical Pd nanoparticles, with homogeneous distribution in the nanocomposite matrix, with an average size of 2.16 nm. The results show higher photocatalytic efficiency for the samples fabricated under the two-step approach compared to the one-pot synthesis. Based on experimental results, density functional theory (DFT) calculations were carried out to understand the enhancement photocatalytic of Pd/ZnO nanocomposites. To achieve it, the ZnO (001) and (101) surfaces were built and decorated by different Pd coverages. The theoretical results indicated two different photocatalytic mechanisms. In ZnO (001) case, the electrons flowed from surface to Pd, generating the superoxide radical anion (⋅O2-). Furthermore, the density of states of the ZnO (001) surface was modified by impurity Pd-d states at proximity to the conduction states, which may work as electron acceptors states. On the other hand, we found that the electrons flow from Pd to ZnO (101) surface, inducing the formation of ⋅OH and ⋅O2- for the degradation of Rh6G. The density of states of the ZnO (101) revealed a reduction in its bandgap, due to Pd-d states localized above valence states. Hence, our theoretical results suggest that the Pd-d states may facilitate the mobility of electrons and holes in (001) and (101) surfaces, respectively, reducing the rate of charge recombination.

Rational design of CdS-enwrapped polypyrrole nanoparticles for wastewater treatment: removal of hazardous pollutants in aqueous solutions

The modern world requires a chemical industry that can run at low production costs while producing high-quality products with minimal environmental impact. The development of environmentally friendly, cost-effective, and efficient wastewater treatment materials remains a major problem for the sustainable approach. We prepared nanoscale cadmium sulfide (CdS)-enwrapped polypyrrole (PPy) polymer composites for degradation of organic pollutants. The prepared CdS@PPy nanocomposites were characterized by powder X-ray diffraction, scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible (UV) absorption spectroscopy, indicating proper intercalation between CdS and PPy. Consequently, the catalytic efficiency of the synthesized hybrid nanocomposites was analyzed through the degradation of methylene blue (MB) and rhodamine B (Rh B) under visible light irradiation. The measured degradation efficiency of the dye solutions under the photolysis process is about 18% and 23% for MB and Rh B dye, respectively. Furthermore, the recycle test result concludes that the CdS@PPy composite exhibits 91% and 89% of MB and Rh B dye degradation efficiency even at the 4th cycle, respectively. The positive synergistic impact of CdS and PPy may be the result of effective photocatalytic degradation of MB and RhB.

Fabrication of samarium doped MOF-808 as an efficient photocatalyst for the removal of the drug cefaclor from water

MOFs are emerging photocatalysts designed by tuning organic ligands and metal centers for optimal efficiency. In this study, a samarium decorated MOF-808(Ce) metal organic framework was fabricated by facile hydrothermal synthesis. The synthesized samarium decorated MOF-808(Ce) was characterized by using analytical techniques such as SEM, EDX, XRD and TGA to study its morphological, thermal and structural properties. SEM images showed that MOF-808(Ce) comprised of truncated octahedrons. The morphology of the material was changed upon Sm incorporation. Sm/MOF-808(Ce) exhibited better UV-vis light absorption properties than MOF-808(Ce) as evidenced by its slightly higher band gap value. This material was exploited for the degradation of the drug cefaclor from water. Cefaclor removal followed double a first order in parallel model (DFOP). Under UV light, 97.7% of the cefaclor was removed in only 20 minutes and after 60 minutes this removal efficiency was increased to 99.25%. These features exhibited that samarium decorated MOF has immense potential for the photocatalytic degradation of cefaclor as it generates e- and h+ to enhance the photocatalytic efficiency and it is a promising candidate to treat wastewater without formation of harmful byproducts.

One-pot synthesis optimization of thiol-capped SnS and SnS/ZnS QDs for photocatalytic degradation of Rhodamine 6G

Interest in SnS-based quantum dots (QDs) has increased due to their low toxicity, widespread natural availability, and superior electro-optical characteristics suitable for photodegradation applications. Herein, we report the synthesis of SnS-based QDs using thiourea and tin (II)chloride as salt precursors. The study explored the impact of various synthetic parameters such as pH, capping ligand, Sn:S ratio, reaction solvent, and ZnS shell on the optical characteristics of the synthesized QDs. The optimal QDs properties were observed at pH = 3 and Sn:S ratio = 1:1. Transmission electron microscopy analysis showed spherical nanoparticles, while the Fourier Transform Infrared spectroscopy revealed QDs with thiol capping. Time-dependent studies revealed that when the QDs were synthesized using propylene glycol, the ultraviolet-visibile (UV-vis) spectrum exhibited an increase in absorbance over time and improved stability compared to aqueous synthesized QDs. SnS/ZnS QDs capped with 3-mercaptopropanoic acid exhibited improved photoluminscence (PL) emissions, stability, and aqueous dispersion compared to glutathione and l-Cysteine as thiol-capping agents. The photocatalytic activity of SnS/ZnS QDs was assessed against Rhodamine 6G and increased to 65 % when passivated with ZnS compared to 31 % for the core SnS QDs. With the given findings, this study supports the stability and effectiveness of the SnS/ZnS QDs as a viable dye degradant.

Highly efficient ZnO/WO3 nanocomposites towards photocatalytic gold recovery from industrial cyanide-based gold plating wastewater

Discharging the gold-contained wastewater is an economic loss. In this work, a set of ZnO/WO3 was facile synthesized by hydrothermal method in order to recover gold from the industrial cyanide-based gold plating wastewater by photocatalytic process. Effect of ZnO contents coupled with WO3 was first explored. Then, effects of operating condition including initial pH of wastewater, type of hole scavenger, concentration of the best hole scavenger and photocatalyst dose were explored. A series of experimental results demonstrated that the ZnO/WO3 nanocomposite with 5 wt% ZnO (Z5.0/WO3) depicted the highest photocatalytic activity for gold recovery due to the synergetic effect of oxygen vacancies, a well-constructed ZnO/WO3 heterostructure and an appropriate band position alignment with respect to the redox potentials of [Au(CN)2]- and hole scavengers. Via this ZnO/WO3 nanocomposite, approximately 99.5% of gold ions was recovered within 5 h using light intensity of 3.57 mW/cm2, catalyst dose of 2.0 g/L, ethanol concentration of 20 vol% and initial pH of wastewater of 11.2. In addition, high stability and reusability were observed with the best nanocomposite even at the 5th reuse. This work provides the guidance and pave the way for designing the ZnO/WO3 nanocomposite for precious metal recovery from a real industrial wastewater.

Luminescence and photocatalytic degradation of indigo carmine in the presence of Sm3+doped ZnS nanoparticles

Industrial wastewater discharge is well acknowledged to constitute a significant environmental and public health risk. In addition, synthetic dyes used in the textile sector are major culprits in water pollution. The amount of water polluted by these dyes is simply staggering. We urgently address this issue to protect our planet and health. The degradation of indigo carmine dye in the presence of Sm3+-doped ZnS nanoparticles is reported in this study and characterized by XRD, FTIR, SEM, EDX, TEM, BET, PL, UV, etc. The particle size calculated from the Scherrer equation was 3-12 nm. When excited at 395 nm, Sm3+ undergoes f-f transitions, which are visible as prominent peaks in the photoluminescence spectrum at 559, 595, and 642 nm wavelengths. The catalyst showed vigorous catalytic activity for dye degradation, with a 93% degradation rate when used at 15 mg/L catalyst within 210 min. The reaction was found to have pseudo-first-order kinetics. After applying the Freundlich and Langmuir data, the Langmuir isotherm offered the best fit. The findings indicate that the Sm3+-doped ZnS catalyst might be successfully used in the degradation of dyes present in the environment. Doping with Sm3+ ions can significantly change the photocatalytic breakdown of indigo carmine and the luminescence characteristics of ZnS.

An advanced photo-oxidation process for pharmaceuticals using plasmon-assisted Ag-CoFe2O4 photocatalysts

The discharge of amoxicillin (AMX) from pharmaceutical intermediates has adverse effects on aquatic ecosystems. The elimination of AMX requires advanced oxidation processes (AOPs) that utilize high-performance photocatalysts. Furthermore, the design of highly visible light photocatalysts for AOPs demands both cost-effectiveness and efficiency. In this work, a plasmon-assisted visible light photocatalyst of 2D Ag-CoFe2O4 nanohybrids was successfully synthesized and characterized with several analytical tools to degrade AMX in aqueous solutions through advanced AOPs. The results showed that the Ag-CoFe2O4 nanohybrids had excellent photocatalytic activity and stability, which could efficiently reduce the AMX concentration by 99% within 70 min under visible light irradiation. In particular, CoFe2O4 and Ag have an interfacial contact that prevents electron-hole pair recombination more effectively than pure CoFe2O4, which results in electrons in its conduction band (CB) migrating to metallic Ag sites. Thus, charge transfers between the two materials are more efficient, leading to higher photocatalytic oxidation of AMX. Furthermore, the surface plasmon of Ag nanoparticles are excited by their plasmonic resonance, which increases the absorption of visible light. The plasmon-assisted visible light photocatalyst could replace expensive and energy-intensive advanced oxidation processes (AOPs). AOPs pathways associated with AMX have been discussed in detail. The HPLC chromatogram clearly showed AMX was oxidized by four-membered B-lactam ring opening and hydroxylation with •OH. 2D Ag-CoFe2O4 heterostructure was found to be efficient, selective, and cost-effective for the degradation of several pharmaceutical compounds. Additionally, it was found to be eco-friendly and sustainable, making it a viable alternative to AOPs.

Recent Advances in Metal-Organic Framework (MOF)-Based Photocatalysts: Design Strategies and Applications in Heavy Metal Control

The heavy metal contamination of water systems has become a major environmental concern worldwide. Photocatalysis using metal-organic frameworks (MOFs) has emerged as a promising approach for heavy metal remediation, owing to the ability of MOFs to fully degrade contaminants through redox reactions that are driven by photogenerated charge carriers. This review provides a comprehensive analysis of recent developments in MOF-based photocatalysts for removing and decontaminating heavy metals from water. The tunable nature of MOFs allows the rational design of composition and features to enhance light harvesting, charge separation, pollutant absorptivity, and photocatalytic activities. Key strategies employed include metal coordination tuning, organic ligand functionalization, heteroatom doping, plasmonic nanoparticle incorporation, defect engineering, and morphology control. The mechanisms involved in the interactions between MOF photocatalysts and heavy metal contaminants are discussed, including light absorption, charge carrier separation, metal ion adsorption, and photocatalytic redox reactions. The review highlights diverse applications of MOF photocatalysts in treating heavy metals such as lead, mercury, chromium, cadmium, silver, arsenic, nickel, etc. in water remediation. Kinetic modeling provides vital insights into the complex interplay between coupled processes such as adsorption and photocatalytic degradation that influence treatment efficiency. Life cycle assessment (LCA) is also crucial for evaluating the sustainability of MOF-based technologies. By elucidating the latest advances, current challenges, and future opportunities, this review provides insights into the potential of MOF-based photocatalysts as a sustainable technology for addressing the critical issue of heavy metal pollution in water systems. Ongoing efforts are needed to address the issues of stability, recyclability, scalable synthesis, and practical reactor engineering.

Development of hierarchical copper sulfide-carbon nanotube (CuS-CNT) composites and utilization of their superior carrier mobility in efficient charge transport towards photodegradation of Rhodamine B under visible light

In this work, the synthesis of visible light sensitive copper sulfide (CuS) nanoparticles and their composites with carbon nanotubes (T-CuS) via a solvothermal technique is reported. The synthesized nanoparticles (NPs) and their composites were significantly characterized by powder X-ray diffraction (PXRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, photoluminescence (PL) spectroscopy and thermogravimetric analysis (TGA). The effect of carbon nanotubes (CNTs) on the crystallinity, microstructures, photo-absorption, photo-excitation, thermal stability and surface area of CuS was investigated. The current-voltage (I vs. V) characteristics of both CuS and T-CuS based Schottky diodes were measured to determine the charge transport parameters like photosensitivity, conductivity, mobility of charge carriers, and transit time. The photocatalytic performance of bare CuS and T-CuS in the decomposition of Rhodamine B dye was studied using a solar simulator. The T-CuS composite showed higher photocatalytic activity (94%) compared to bare CuS (58%). The significance of charge carrier mobility in transferring photo-induced charges (holes and electrons) through complex networks of composites and facilitating the photodegradation process is explained. Finally, the reactive species responsible for the Rhodamine B degradation were also identified.

Highly effective Fe-doped TiO2nanoparticles for removal of toxic organic dyes under visible light illumination

This article addresses the synthesis of Fe³⁺doped TiO₂nanoparticles with variations of molar concentrations of Fe³⁺and their adequate use as potential photocatalysts for Photocatalysis applications. Synthesized photocatalysts were characterized thoroughly by different analytical techniques in terms of morphological, chemical, structural, crystalline, optical, electronic structure, surface area etc properties. The occurrence of red shift phenomenon of the energy band gap attributes to the transfer of charges and transition between the d electrons of dopant and conduction band (CB) or valence band (VB) of TiO₂. The doping of Fe³⁺ions generates more trap sites for charge carriers with the surface trap sites. Thorough experimental conclusions revealed that the Fe³⁺ions necessarily regulate the catalytic property of TiO₂nanomaterial. The obtained total degradation efficiency rate of Methylene Blue (MB) was 93.3% in the presence of 0.1 M Fe³⁺in the host material and for Malachite Green Oxalate the efficiency was 100% in the presence of 0.05 M and 0.1 M Fe³⁺in the host material. In both the cases the total visible light irradiation time was 90 min. The adsorption properties of the photocatalysts have been also performed in a dark for 90 min in the presence of MB dye. However, till now there are hardly reported photocatalysts which shows complete degradation of these toxic organic dyes by visible light driven photocatalysis. of potential values of valence and conduction band shows the production of active oxidizing species for hydrogen yield and the possible mechanism of the Schottky barrier has been proposed. A schematic diagram of visible light driven Photocatalysis has been pictured showing degradation activity of Fe³⁺-TiO₂catalysts sample.

Ternary nanocomposites of CdS/WO3/g-C3N4 for hydrogen production

The sustainable rise in global warming and the consumption of fossil fuels considerably contribute to energy and environmental issues. To address these issues, semiconductor heterostructures can be used to generate clean energy sources as alternative energy sources and to reduce environmental impacts. Herein, we report the synthesis of a ternary semiconductor of the CdS/WO₃/g-C₃N₄ (i.e. C-CNW) nanostructured composite for hydrogen production and dye degradation under visible-light irradiation. The structural properties of the prepared materials were studied using a series of investigational analyses. The 3C-CNW nanostructure photocatalyst exhibited faster malachite green (MG) dye photodegradation within 105 min and the highest hydrogen production rate is 868.23 μmol g^-1 h^-1 under visible light illumination. Moreover, the photocatalytic hydrogen production of the 3C-CNW nanostructure photocatalyst with various scavengers was analyzed. Its higher photocatalytic activity is ascribed to the Z-scheme mechanism, which induces rapid diffusion of photoinduced charges within the ternary photocatalyst with its optical bandgap. This proposed strategy is useful to improve photocatalysts that play a role in mitigating energy and environmental issues.

Cobalt-Phosphate (Co-Pi)-Modified WO3 Photoanodes for Performance-Enhanced Photoelectrochemical Wastewater Degradation

Photocatalytic technology, with features of wide applicability, mild reaction conditions and sunlight availability, satisfies the requirements of "green chemistry". As the star photoanode material for photoelectrochemical catalysis, WO₃ has a suitable band gap of 2.8 eV and a strong oxidation capacity, as well as displaying great potential in organic wastewater degradation. However, its performance is usually hindered by competition with water oxidation to generate peroxides, rapid charge complexation caused by surface defect sites, and so on. Herein, WO₃ films modified with cobalt-phosphate (Co-Pi/WO₃) film were prepared and involved in photocatalytic organic wastewater degradation. A degradation rate constant of 0.63311 h^-1 was obtained for Co-Pi/WO₃, which was much higher than that of WO₃, 10.23 times that of direct photocatalysis (DP) and 23.99 times that of electrocatalysis (EC). After three cycles of degradation, the film can maintain a relatively good level of stability and a degradation efficiency of 93.79%.

Catalytic Photodegradation of Cyclic Sulfur Compounds in a Model Fuel Using a Bench-scale Falling-film Reactor Irradiated by a Visible Light

A homemade N doped-TiO2 nanoparticle were used to degrade dibenzothiophene (DBT) in a model fuel flowing on a bench-scale glass-made falling film reactor irradiated by a xenon lamp that emitted visible light. The photocatalyst was immobilized on the glass sheet. EDS, SEM, and FT-IR techniques were utilized to identify the morphology of the N doped-TiO2 nanoparticles. Different operating parameters (e.g., N loading (0, 4, 5, and 6 wt%), light intensity (20, 40, and 60 W/m2), and pH (4, 7, and 10)) were investigated for their effect on the DBT degradation.  The effect of the N loading on the wettability of the nano-TiO2 particles was also investigated. Experimental results revealed that the N loading did not affect the wettability characteristics of the nano TiO2 particles. Moreover, results showed that DBT conversion positively depends on N loading, light intensity (hv), and pH increase. The estimated optimal operating parameters were 5 wt% N loading, pH = 10, and hv = 40 W/m2 to ensure the best photo-oxidation efficiency of 91.4% after 120 min of operation. The outcomes of the present work confirmed the effective efficiency of the N-doped TiO2 nanoparticles irradiated by visible light for DBT degradation. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

A Brief Review of Photocatalytic Reactors Used for Persistent Pesticides Degradation

Pesticide pollution is a major issue, given their intensive use in the 20th century, which led to their accumulation in the environment. At the international level, strict regulations are imposed on the use of pesticides, simultaneously with the increasing interest of researchers from all over the world to find methods of neutralizing them. Photocatalytic degradation is an intensively studied method to be applied for the degradation of pesticides, especially through the use of solar energy. The mechanisms of photocatalysis are studied and implemented in pilot and semi-pilot installations on experimental platforms, in order to be able to make this method more efficient and to identify the equipment that can achieve the photodegradation of pesticides with the highest possible yields. This paper proposes a brief review of the impact of pesticides on the environment and some techniques for their degradation, with the main emphasis on different photoreactor configurations, using slurry or immobilized photocatalysts. This review highlights the efforts of researchers to harmonize the main elements of photocatalysis: choice of the photocatalyst, and the way of photocatalyst integration within photoreaction configuration, in order to make the transfer of momentum, mass, and energy as efficient as possible for optimal excitation of the photocatalyst.