Photodegradation Performance Research Articles

The Zinc Ferrite Decorated Unexfoliated Graphitic Carbon Nitride for Effective Antibiotic Degradation under Visible Light

The antibiotic pollutant treatment in wastewater using conventional method remains a challenge. One of the most fluoroquinolone antibiotics family used by human and animal cure is ciprofloxacin (CIP). CIP has exhibited as a recalcitrant compound in nature with concentration from ng to mg. To overcome this issue, recent technologies have applied such as photocatalysis technology for water decontamination. Furthermore, photocatalyst materials that used in this research were zinc ferrite and graphitic carbon nitride. A simple hydrothermal-coprecipitation method has succeed to synthesis zinc ferrite. While, unexfoliated graphitic carbon nitride (ZFO@ue-CN) was synthesized by calcination at 550 °C for 4 h under air condition. A heterostructure approach combining zinc ferrite and unexfoliated graphitic carbon nitride (ZFO@ue-CN) has been investigated as a potential solution. In this study, a ZFO@ue-CN was constructed by calcination method under atmosphere condition at 400 °C for 2 h. The ZFO@ue-CN has been characterized involving structural, morphological, and optical. Furthermore, ZFO@ue-CN exhibited excellent degradation performance with over 88% removal of ciprofloxacin. The heterojunction formation of ZFO@ue-CN nanocomposite provide more efficient electron transfer compared to single material. Combination between metal oxide@ue-CN can open up the new platform for simple material preparation, nevertheless it can keep the photodegradation performance. This result also emphasizes that the ZFO@ue-CN nanocomposites has prominent application for wastewater treatment.

Tin(IV)Porphyrin-Based Porous Coordination Polymers as Efficient Visible Light Photocatalyst for Wastewater Remediation.

Two porphyrin-based polymeric frameworks, SnP-BTC and SnP-BTB, as visible light photocatalysts for wastewater remediation were prepared by the solvothermal reaction of trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(IV) (SnP) with 1,3,5-benzenetricarboxylic acid (H3BTC) and 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB), respectively. The strong bond between the carboxylic acid group of H3BTC and H3BTB with the axial hydroxyl moiety of SnP leads to the formation of highly stable polymeric architectures. Incorporating the carboxylic acid group onto the surface of SnP changes the conformational frameworks as well as produces rigid structural transformation that includes permanent porosity, good thermodynamic stability, interesting morphology, and excellent photocatalytic degradation activity against AM dye and TC antibiotic under visible light irradiation. The photocatalytic degradation activities of AM dye were found to be 95% by SnP-BTB and 87% by SnP-BTC within 80 min. Within 60 min of visible light exposure, the photocatalytic degradation activities of TC antibiotic were found to be 70% by SnP-BTB and 60% by SnP-BTC. The enhanced catalytic photodegradation performances of SnP-BTB and SnP-BTC were attributed to the synergistic effect between SnP and carboxylic acid groups. The carboxylic acid connectors strongly resist the separation of SnP from the surface of SnP-BTB and SnP-BTC during the photodegradation experiments. Therefore, the high degradation rate and low catalyst loading make SnP-BTB or SnP-BTC more efficient than other reported catalysts. Thus, the present investigations on the porphyrin-based photocatalysts hold great promise in tackling the treatment of dyeing wastewater.

Facile synthesis of CQD/g-C3N4 as a highly effective metal-free photocatalyst for the degradation of carmoisine and indigo carmine dye

The development of extensive dye pollution in the water ecosystem seriously endangers the health of the living organism. For effectively eradicating dyecontaminants from water bodies, photocatalysis is consideredan effective, energy-consumption, inexpensive disinfection technique. As an alternative to conventional metal-based catalysts, heterogeneous metal-free photocatalysts are more sustainable and kinder to the environment. Here, we reported the simplehydrothermalchemical production of Carbon Quantum dots (CQD)-doped graphitic carbon nitride(GCN). Analytical instruments such as XRD, SEM, FE-SEM, HR-TEM, EDX, FT-IR, thesurface area of BET analysis, photoluminescence, and UV–vis spectroscopy, zeta potentialwere used to characterize the as-prepared CQD doped GCN (CDCN). The degradation studies reveal that the CDCN catalyst displays the highest rate of degradation performance than pure GCN. Within 60 min, it shows 96 % degradation toward indigo Carmine (IC) and 93 % decomposition towards carmoisine dye (CM). Significant e−/h+ separation, an increased surface area, and a high redox potential capacity to induce charge bears may all contribute to the CDCN catalyst’s enhanced photocatalytic degradation efficiency. The efficiency of the photocatalytic process was optimized by studying and altering many variables. These include Dye concentration, catalyst concentration, and variation of the pH solution were some of these. The nanocomposite exhibited excellent stability after three successive runs of the photocatalytic procedure. According to the kinetics analysis results indicate that the photocatalytic decomposition of Indigo Carmine (IC) and carmoisine (CM) dye follows pseudo-first-order kinetics. For better photodegradation performance, a potential photocatalytic method employing several pairs of electron-hole acceptor scavengershas been put forth. Based on the positionsof the band gap and the result of the characterization, a feasible mechanismpathway for charge carriers was also presented.

Tailoring the coordination microenvironment of Zn(ii) in a light-responsive coordination polymer system for molecular sensing and photodegradation performance

Three semi-conductive CPs with skilfully tuned coordination surroundings exhibited highly efficient sensing of bilirubin and photodegradation of methylene blue due to the bandgap-dominated movements of the photogenerated charge carriers.

FACILE HYDROTHERMAL SYNTHESIS OF NIOBIUM PENTOXIDE SEMICONDUCTOR AND THEIR APPLICATION IN THE PHOTODEGRADATION OF DYES AND REDUCTION OF FREE FAT ACIDS IN WASTE OIL

We report a facile hydrothermal method for the synthesis of niobium pentoxide (Nb2O5) under two different temperatures, 120 °C (Nb2O5-120) and 150 °C (Nb2O5-150). The obtained materials were characterized by structural, optical and morphological techniques. Also, the photocatalytic properties of the Nb2O5 samples were evaluated in two reactions under ultraviolet (UVC) irradiation: degradation of methylene blue (MB) and indigo carmine (IC) dyes; and esterification of free fatty acids (FFA) present in waste cooking oil (WCO). The Nb2O5 was formed at different temperatures of synthesis, and the increase in temperature did not cause significant changes in the structural and optical characteristics, but resulted in an increased surface area of the synthesized materials. Both synthesized materials showed excellent efficiency for dye photodegradation. The sample Nb2O5-150 presented the best performance for the MB photodegradation, with almost 85% of the removal efficiency. In this case, the adsorption of MB molecules on the surface of the material was high due to the favorable electrostatic interaction and also because of its high surface area. For the IC photodegradation, the adsorption was insignificant, and both samples presented approximately 100% of the removal efficiency. These materials were also promising for the reduction of free fat acids in waste oil by photoesterification.

Insights on nitrogen/oxygen dual defects synergistic modulated charge transfer across the g-C3N4/TiO2-NTAs heterojunction enhanced photodegradation and gas-sensing performances

Insights on nitrogen/oxygen dual defects synergistic modulated charge transfer across the g-C3N4/TiO2-NTAs heterojunction enhanced photodegradation and gas-sensing performances

Stabilize the oxygen vacancies in 2D bipyramidal CoFe2O4 via altering local electronic structure by SnSe for boosted photocatalytic degradation of ciprofloxacin: Interfacial engineering, mechanism insight and toxicological evaluation of byproducts

Investigating a cost-effective, environmentally friendly, and improved photocatalysis system for ciprofloxacin (CIPRO) degradation presents a significant hurdle in environmental remediation. In this work, SnSe nanoparticles (NPs) were synthesized by hydrothermal approach leading to the successful formation of SnSe-CoFe2O4 nanocomposite (SCF NCs). It was achieved by decorating the surface of SnSe NPs with 2D bipyramidal oxygen-vacant (OV) CoFe2O4 NPs. This work aims to stabilize the OV in 2D bipyramidal CoFe2O4 by altering the local electronic structure through SnSe, enhancing the photocatalytic degradation of CIPRO. The NPs surface morphological features, high crystalline nature, and enhanced surface area properties are investigated using several characterization techniques. The X-ray photoelectron spectroscopy (XPS) reveals the oxygen defect site in CoFe2O4 and the interfacial electric field between SnSe and CoFe2O4 NPs, significantly improving the catalytic activity of SCF NCs. The degradation of CIPRO at the optimized concentration (50 mg/L – SCF NCs, 10 mg/L CIPRO, pH - 3) under visible light reached around 91.3%. The SCF NCs demonstrate superior photodegradation performance of 2.59 and 1.86 times greater activity compared to their individual counter parts, SnSe and CoFe2O4, respectively. Furthermore, the system accommodates a broad range of degradation concentrations of CIPRO from 5 – 25 mg/L, indicating promising potential for practical applications. Additionally, the intermediate compounds formed during the photodegradation process were analyzed using gas chromatography-mass spectrometry (GC-MS), and a possible degradation pathway was proposed. The toxicity levels of these intermediates were assessed in various aquatic organisms, including fish, daphnia, and green algae using the ecological structure activity relationship (ECOSAR) tools. This research presents a new perspective on the development of innovative materials for the removal of pollutants from water sources.

Modification of bismuth-rich to synthesize floral spherical Z-type heterojunction CoAl2O4/Bi4O5Br2 photocatalysts for photocatalytic degradation of tetracycline: DFT calculations, toxicity assessment

Strategies were employed to boost responsiveness to visible light to augment the elimination of water-borne organic contaminants and mitigate the recombination of electron-hole pairs. Herein, a floral spherical CoAl2O4/Bi4O5Br2 Z-scheme heterojunction was effectively produced through in-situ construction, followed by an evaluation of its photocatalytic activity against tetracycline hydrochloride. The best-prepared photocatalyst CoAl2O4/Bi4O5Br2 showed good photodegradation performance (91.5%) under visible light. In addition, it exhibits good removal efficiency for other antibiotics and dyes, and the prepared catalyst demonstrates favorable stability. The accomplishment of fabricating the CoAl2O4/Bi4O5Br2 heterojunction, along with the photogenerated carrier relay mechanism conforming to a Z-scheme process, was substantiated through a variety of analytical techniques and DFT calculations. Within the engineered Z-scheme heterojunction of CoAl2O4/Bi4O5Br2, an intrinsic electric field facilitates the direct shuttling of photo-induced charges from Bi4O5Br2's conduction band to CoAl2O4's valence band. Simultaneously, this electric field formation serves to diminish the recombination rate of electrons and holes. Finally, possible degradation pathways were proposed, and the intermediates were evaluated for toxicity. The results indicate that the construction of CoAl2O4/Bi4O5Br2 heterojunction is a feasible pathway for the effective degradation of antibiotics.

Construction of Anthracene‐based Metal–Organic Framework Exhibiting Enhanced Singlet Oxygen Storage and Release Capabilities for Efficient Photodegradation of Phenolic Pollutants

AbstractControlling the generation and release of singlet oxygen (1O2) with high oxidation activity and long lifetime properties holds significant potential for efficient oxidation of permanent organic pollutants, tumor eradication, and targeted molecular oxidation. However, the conditions for controlled generation and release of 1O2 remain unclear. Hence, the novel anthracene‐ligands based Zr‐MOFs which use acetic acid (HAc) are constructed to optimize the surface defects and specific surface area exhibit ultrafast saturation adsorption capacity (362.60 mg g−1 in 60 s) and deep photodegradation performance toward bisphenol A (BPA) in water (50 ppm in 20 min) via Zr‐DPA MOF‐1HAc. Mechanistic studies have shown that MOFs are capable of generating high concentrations of 1O2, while anthracene ligands can rapidly store 1O2 and form endoperoxides (EPOs), which can be rapidly released under external light, heat, or chemical triggering conditions. Thus, high concentration of 1O2 is always involved in the oxidation reaction throughout the whole photodegradation process and ultimately achieves the complete mineralization of target phenolic pollutant molecules. This innovative strategy has important implications for generating, storing and controlling the release of 1O2 in the field of environmental engineering and chemical synthesis.

Robustic and hybrid cobalt doped BaFe12O19 hexaferrites for the photocatalytic degradation of Congo Red for wastewater treatment

The industrial sector faces a significant challenge in finding the highly effective and efficient treatments for harmful dye-based color effluents. In this study, pure and cobalt doped barium hexaferrite of chemical formula, Ba1-xCoxFe12O19 (x = 0—0.06) are made via sol–gel auto-combustion (SC) methodology. These nano hexaferrite based catalysts are employed for the photodegradation of Congo Red (CR) pollutant. X-rays diffraction investigation confirms the creation of pristine M-type with a hexagonal structure for the prepared hexaferrites. Field emission scanning electron microscopy analysis shows the existence of the hexagonal-shaped grains with well-defined grain boundaries. The reduction in the band gap of prepared hexaferrites are observed with the cobalt doping which is helpful in enhancing the photocatalytic performance. The X-ray photoelectron spectroscopy examination verifies the oxidation states of all elements found in the fabricated specimens. From the photocatalytic measurements, it is observed that the CR dye attains the removal percentage of 87.90%, 90.73%, 91.86% and 94.88% for the BaFe12O19 (x = 0.00), Ba0.08Co0.02Fe12O19 (x = 0.02), Ba0.06Co0.04Fe12O19 (x = 0.04), and Ba0.04Co0.06Fe12O19 (x = 0.06) hexaferrites under the natural sunlight of two hours. In addition, the reusability potential of prepared hexaferrites is also studied over the six consecutive experimental cycles. The excellent photodegradation performance of the Co- doped barium M-type hexaferrites for the removal of CR dye makes them highly useful for the wastewater remediation.

Energy-efficient Carbon-doped TiO2 for Visible Light Degradation of Methyl Orange: Preparation, Performance, and Mechanism

Water pollution caused by textile dyes has become a serious issue, making the treatment of sewage urgent. Carbon-doped TiO2 (C-doped TiO2), using alkanes and polyols as carbon sources, has been found to be light-responsive in degrading dyes. However, there is a lack of studies on the interfacial interaction between carboxylic acids and TiO2. Therefore, citric acid, a triprotic, hexadentate carboxylic acid, was used to dope TiO2 through solvothermal-calcination. The effects of carbon content and calcination temperature on the photodegradation performance of C-doped TiO2 were investigated. The band gap energy of C-doped TiO2 was found to be narrower (2.67 eV) than that of undoped TiO2 (2.88 eV). After carbon doping, the absorption band extended from the UV to the visible regions, lowering the energy required for electron excitation. The functional groups present on C-doped TiO2 assisted in the adsorption of methyl orange (MO), assisting in photodegradation. Only the anatase phase of TiO2 was observed at calcination temperatures between 250 and 400 °C. Photoluminescence analysis revealed that a lower carbon content and slightly higher calcination temperature resulted in better interfacial charge separation and transfer efficiency. The 10 wt% C-doped TiO2 calcined at 300 °C demonstrated the best MO photodegradation efficiency of 62.1% under visible light illumination. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Preparation and properties of high-efficiency lignin-carbon based photocatalytic composites for the degradation of dye wastewater under visible light

Lignin-based carbon/cadmium sulfide (LCS) composite photocatalytic materials with excellent porous structures were prepared by simple carbonization and in situ precipitation using lignin from a wide range of sources as a carbon source. The CdS nanoparticles were uniformly fixed in LC, which improved the sunlight absorption ability and good stability of the photocatalyst. The effect of different factors on the pore structure of composite photocatalytic materials was investigated. The results showed that the obtained LCS composites had the maximum specific surface area (334.841 m2·g−1) and porosity (0.4406 mL·g−1) when the mass ratio (the lignin: the templating agent) was 2:1 and the carbonization was carried out at 600 °C for 1.5 h (LCS-600-1.5-2). Compared with pure CdS, the photodegradation performance of the prepared LCS under simulated sunlight (500 W Xe lamp) irradiation was significantly improved. The degradation rate of methylene blue (MB) and methyl orange/methylene blue (MO/MB) by LCS reached 91.7% and 90.8% in 2 h, respectively. The material stability test of LCS showed that LCS has good acid–base stability, and the degradation rate of MB remained above 80% after 5 cycles. The LCS prepared from lignin biomass, improved the dispersion uniformity of cadmium sulfide, reduced the recombination of photogenic electron hole, enhanced the photocatalytic performance under visible light, which greatly expanded the application of photocatalytic material.

Density Functional Theory Insight in Photocatalytic Degradation of Dichlorvos Using Covalent Triazine Frameworks Modified by Various Oxygen-Containing Acid Groups.

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is a highly toxic organophosphorus insecticide, and its persistence in air, water, and soil poses potential threats to human health and ecosystems. Covalent triazine frameworks (CTFs), with their sufficient visible-light harvesting capacity, ameliorated charge separation, and exceptional redox ability, have emerged as promising candidates for the photocatalytic degradation of DDVP. Nevertheless, pure CTFs lack effective oxidative active sites, resulting in elevated reaction energy barriers during the photodegradation of DDVP. In this work, density functional theory (DFT) calculations were employed to investigate the impact of various oxygen-containing acid groups (-COOH, -HSO3, -H2PO3) on DDVP photodegradation performance. First, simulations of the structure and optical properties of modified CTFs reveal that oxygen-containing acid groups induce surface distortion and result in a redshift in the absorption edge. Subsequently, analysis of the density of states, frontier molecular orbitals, surface electrostatic potential, work function, and dipole moment demonstrates that oxygen-containing acid groups enhance CTF polarization, facilitate charge separation, and ameliorate their oxidative capability. Additionally, the free-energy diagram of DDVP degradation uncovers that oxygen-containing acid groups lower the energy barrier by elevating the adsorption and activation capability of DDVP. Notably, -H2PO3 presents optimal potential for the photodegradation of DDVP by unique electronic structure and activation capability. This work offers a valuable reference for the development of oxygen-containing acid CTF-based photocatalysts applied in degrading toxic organophosphate pesticides.

Green Synthesis of Zinc Oxide Particles using Banana Peels and Tea Leaves Extracts for Rhodamine B Photodegradation

Rhodamine B is a widely used dye in the textile sector. However, the wastewater produced during the dyeing process presents a notable source of pollution, contaminating water and posing a threat to aquatic ecosystems due to its presence in liquid waste. Photocatalysis is a technique for breaking down toxic textile dye waste a semiconductor as a catalyst, valued for its high sensitivity and eco-friendly nature. In this research, zinc oxide particles were synthesized via a green synthesis approach using precipitation, employing natural capping agents from banana peel and tea leaf to degrade the synthetic dye of rhodamine B. The catalyst material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and ultraviolet-visible diffuse reflectance (UV-DRS). The photodegradation performance of rhodamine B was determined under UV light exposure for 3 hours. The XRD spectra of ZnO show the specific peaks of 2θ at 31.8°, 34.5°, and 36.3° with a crystallinity value of around 79.50%. The SEM result shows that the morphology of ZnO is in cotton-like form with a minimum band gap of 3.17 eV. The cotton-like ZnO particles demonstrated superior photodegradation efficiency for Rhodamine B, achieving 61.8%, compared to 47.9% with pure ZnO. It suggests that synthesizing ZnO particles with banana peels and tea leaf extracts boosts photodegradation efficiency by up to 20% compared to pure ZnO. This research highlights the potential of utilizing eco-friendly and sustainable methods as a greener approach for reducing waste in environmental applications.

Thermal kinetics and photodegradation performance towards methylene blue of melt-quenched Se70Te30 glass

Abstract This paper reports the structure, basic characteristics, photocatalytic performance, and crystallization kinetics of the Se70Te30 glass. The Se70Te30 glass was synthesized using the melt-quenching method. The crystallization kinetics were investigated under non-isothermal condition via the differential scanning calorimetry (DSC) technique. For example, the glass transition activation energy, the thermal stability, and the Avrami index have been determined and discussed. It was found that thermal stability and glass-forming ability influence the crystallization rate. Furthermore, the activation energy needed for the amorphous-crystalline transition of the Se70Te30 glass was obtained using conventional methods. The thermal kinetic parameters were analyzed using various conventional approaches and were revealed to be influenced by the heating rate (β). The photocatalytic activity of the Se70Te30 glass towards methylene blue (MB) was examined and compared to the literature. The UV-visible irradiation time affects the photodegradation of MB and reaches 72.13% under the UV-visible irradiation for 70 min. A hypothesized mechanism for the degradation of the MB dye by Se70Te30 catalysts is described. The study employed Langmuir–Hinshelwood kinetics to ascertain the rate constant of 2.1 × 10–2 min–1 towards MB dye degradation and to assess the photo-reactivity of the Se70Te30 glass under investigation using quantitative analysis. The synthesized Se70Te30 glass could be helpful for purifying wastewater and degrading other organic dyes, in addition to its benefits for phase change memory applications.

Synthesis of silver-decorated titanium dioxide nanostructured films for enhanced visible light photocatalysis

Titanium dioxide (TiO2) has been extensively investigated for applications in photocatalysis due to its stability, nontoxicity, and robust photocatalytic properties. Although thin films of TiO2 are effective in wastewater treatment, their dense structure limits surface accessibility. The oblique angle deposition (OAD) technique can be used to create high surface area nanostructured thin films essential for photocatalytic applications. In this study, OAD was used to grow TiO2 thin films. To extend the activity to the visible light region, plasma-reduced silver (Ag) particles were coupled to the TiO2 surface. The Ag-decorated TiO2 (Ag-TiO2) nanostructured films were fabricated using a custom-built magnetron sputter deposition system with OAD technique capability. Different substrate angles of 0°, 35°, and 70° with respect to the target normal were used. The films were characterized for their structural, compositional, and optical properties. The photodegradation performance was evaluated using methylene blue (MB) as the test analyte under visible light irradiation. The results showed a significant improvement in degradation efficiency using plasma-reduced Ag-TiO2. Substrates tilted at 70° achieved the highest MB degradation efficiency of 89.84% after 5 h exposure. This tilt angle also revealed high surface roughness and high surface area. By tilting the substrate with respect to the target, high surface area thin films can be fabricated. This technique is ideal for applications that depend on the area of contact, such as photocatalysis.

Machine learning predictive model to estimate the photo-degradation performance of stannates and hydroxystannates photocatalysts on a variety of waterborne contaminants

In this work, a comprehensive machine learning (ML) methodology was used to predict the degradation efficiency of different stannate and hydroxystannate photocatalysts on a wide range of waterborne pollutants. The structural, atomic features along with molecular fingerprints (MF) were used as descriptors of the crystalline phase of the photocatalysts and the organic compounds, respectively. The encoded features of the photocatalysts and contaminants along with the experimental variables of the degradation process are input to two ML models, named as RF (random forest) and KNN (K nearest neighbor). The RF model has achieved a very good prediction of the photocatalytic degradation efficiency (%) by different photocatalysts over a wide range of organic contaminants. The RF model performance was investigated by applying two different training strategies. The effects of different factors on photocatalytic degradation performance are further evaluated by feature importance analyses. Two illustrative applications on the use of the ML model for optimal photocatalyst selection and for assessing other types of photocatalysts for different environmental applications were provided.

Preparation of Biochar-Loaded Er3+-Doped BiOCl Ultrathin Nanosheets Composite Photocatalysts and Their Photodegradation Performance of TC-HCl

In this study, biochar-loaded E3+:BiOCl (C/3E3+:BiOCl) was synthesized with varying levels of E3+ doping using a one-step solvothermal method and used for tetracycline hydrochloride (TC-HCl) degradation. Their structure, shape and morphology were not only characterized by power X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) but also by UV-vis diffuse reflectance spectra and upconversion (UC). The results indicated a significant enhancement in the photocatalytic activity of the catalyst following the introduction of Er3+. The composite material C/3E3+:BiOCl, with a doping concentration of 3 mol%, demonstrated the highest photocatalytic activity, achieving an impressive visible light degradation efficiency of 89.2% for TC HCl within 90 min. This marks an increase of 33.5% compared to the BiOCl monomer and 17.4% compared to C/BiOCl. Additionally, when exposed to light with wavelengths exceeding 600 nm, C/3E3+:BiOCl maintained a photodegradation efficiency of 44.3%, while BiOCl and C/BiOCl showed no photocatalytic activity under the same conditions. This finding highlights the effectiveness of BiOCl as a doping matrix, which enhances the photocatalytic performance of BiOCl through the upconversion effect of E3+ and the electron transfer mechanisms associated with biochar.

Ibuprofen photodegradation promoted by ZnO and TiO2-P25 nanoparticles: A comprehensive kinetic, reaction mechanisms, and thermodynamic investigation

Photocatalytic activity, reaction kinetics, modeling, and thermodynamics of commercial TiO2-P25 and ZnO nanoparticles (NPs) for ibuprofen (IBU) photodegradation were investigated. Photodegradation experiments were performed in a batch reactor under UV irradiation. The photodegradation performances of TiO2-P25 and ZnO NPs were further studied and modeled under different operation conditions, by varying the reaction temperature, catalyst bulk density, and the initial concentration of the IBU solution. The descriptive kinetic models for the experimental data were tested, through the estimated kinetic parameters, together with the statistical information, revealing that the reaction rate in the case of TiO2-P25 is of first order while the ZnO NPs follow second-order kinetics with respect to IBU. The photodegradation mechanisms for both TiO2-P25 and ZnO NPs were determined to be Langmuir-Hinshelwood and Eley-Rideal, respectively. Thermodynamic parameters were assessed, particularly, changes in Gibbs free energy, enthalpy, and entropy indicating the efficient photodegradation performance of these NPs.

Elaboration and Characterization of Different Zirconium Modified ETS Photocatalysts for the Degradation of Crystal Violet and Methylene Blue.

In this study, Zirconium-modified Engelhard Titanium Silicate 4 (Na-K-ETS-4/xZr) catalysts were synthesized and evaluated for their photocatalytic efficiency in degrading crystal violet (CV) and methylene blue (MB) in aqueous solutions. The catalysts were characterized using XRD, FTIR, SEM, WDXRF, and nitrogen adsorption/desorption isotherms. The results confirmed the successful incorporation of Zr into the ETS-4 framework, with the highest Zr content reaching 9.2 wt %. The photocatalytic performance under visible light irradiation was studied at varying pH levels. The Na-K-ETS-4/6.3Zr catalyst exhibited the highest photodegradation efficiency for CV (76.6 %), while Na-K-ETS-4/8.9Zr achieved 86.6 % efficiency for MB. A combination of Engelhard Titanium Silicate 10, Na-K-ETS-10/6.3Zr and Na-K-ETS-4/8.9Zr significantly enhanced dye degradation, achieving up to 96.5 % efficiency for MB. Kinetic studies indicated that the degradation process follows a non-linear pseudo-first-order model. The catalysts also demonstrated excellent reusability, with minimal efficiency loss after five cycles, and full recovery after an ethanol wash. These findings suggest that Na-K-ETS-4/xZr is a promising candidate for environmental water treatment applications due to its efficient photodegradation performance and stability.