Photodegradation Of Pollutants Research Articles

Enhanced pollutant photodegradation activity of graphitic carbon nitride on via bismuth oxyhalide graphene hybridization and the mechanism study

Addressing the degradation of persistent organic pollutants like Bisphenol A (BPA) and Rhodamine B (RhB) with a photocatalyst that is both cost-effective and environmentally friendly is a notable challenge. This...

Graphene oxide decorated BiOI/CdS nanocomposite: An efficient ternary heterostructure for photodegradation and adsorption study of organic pollutants

This study presents a ternary heterostructure comprising graphene oxide (GO) decorated BiOI/CdS, as a highly effective candidate for both the photodegradation and adsorption of organic pollutants. The composite materials were synthesized through a facile solvothermal method. The structural and morphological characteristics of the synthesized materials were thoroughly analyzed using various analytical techniques. Photoluminescence (PL) spectral analysis of the photocatalysts emphasises the strong charge-carrier separations in ternary composites, which is the main requirement for enhancing degradation performances. The photocatalysts were utilized to remove the methylene blue (MB) and doxycycline (DC) from aqueous suspensions. The most effective ternary composite (GO/BiOI/CdS-x, x = 0.4 mmol CdS) resulted in 99.2% degradation of MB within 25 min and 83.7 % degradation of DC within 150 min of light exposure. Trapping experiments identified O2•- and h+ as the most active species in pollutant degradation. A Z-scheme mechanism, supported by Mott-Schottky plots, VB-XPS spectra, and active species observations, was proposed to elucidate degradation processes. Additionally, the GO/BiOI/CdS-0.4 ternary composite demonstrated impressive adsorption ability for MB, indicating its robust pollutant removal capability. The composite also demonstrated remarkable stability and an impressive ability to be reused, positioning it as a highly promising material for use in wastewater treatment.

Insights into the photocatalytic role of glycine-assisted sol-gel auto-combustion synthesized (Co, Mn)(Co, Mn)2O4 nanostructures for efficient visible light-driven degradation of methyl orange

Research on the use of new materials and the improvement of existing fast ways for removal of water pollutants is still challenging. This work documented rational fabrication of (Co, Mn)(Co, Mn)2O4 nanoparticles as nano-photocatalyst materials with improved charge carrier separation and strong redox potential for efficient degradation of methyl orange (MO) in wastewater. This investigation illustrated that the Co/Mn molar ratio can greatly affect the textural and structural properties. From the point of view of size and shape, the optimum product with 1:3 M ratio of Co to Mn precursors was selected as a catalyst in the photocatalysis process. The prepared highly crystallized phase of tetragonal (Co, Mn)(Co, Mn)2O4 describe an optical band gap of 1.7 eV, according to the DRS data, which make them as efficient visible driven photocatalysts. The photodegradation experiments of spinel mixed structures were assessed by investigation of photocatalyst dosages and initial MO concentrations to unravel how these operational parameters affect Co-Mn-O photocatalysis. A remarkable discoloration capability of 68.07 % could result from the catalyst dosage of 0.04 g and dye concentration of 15 mg/L after 120 min of visible light. The kinetics survey further unveiled the maximum rate constant of 0.0080 min−1 for the MO degradation. In the scavenger trials, singlet oxygen (1O2) and superoxide (●O2−) radicals were principal reactive oxygen species (ROS) responsible for pollutant photodegradation in the presence of pure (Co, Mn)(Co, Mn)2O4 structures. In addition, the cyclic performance of catalyst depicted a removal efficiency of 60.1 % over 5 runs.

Synthesis of novel g-C3N4/CaTiO3/CQDs heterojunction photocatalyst with enhanced visible light photocatalytic performance

In this paper, a high-efficient visible light responsive g-C3N4/CaTiO3/CQDs Z-type heterojunction photocatalyst was successfully prepared by a two-step method for the photodegradation of organic pollutants in water. The combination of g-C3N4, CaTiO3 and CQDs could produce synergistic effect, which facilitated the separation of carriers, thereby enhancing photocatalytic activity. The photocatalytic kinetic removal rate of g-C3N4/CaTiO3/CQDs for methylene blue could reach about 8 times of g-C3N4 and 5.5 times higher than that of CaTiO3. The effects of co-existing ions, initial pH, water source, and humic acid on meloxicam degradation were examined. Repeatability experiments indicated that the composite had good reusability and stability with 81.1 % removal for meloxicam after four cycles. The main active substances of g-C3N4/CaTiO3/CQDs in free radical capture experiment was ⋅O2−. Possible degradation pathways of meloxicam were also analyzed. The results highlight the g-C3N4/CaTiO3/CQDs Z-type heterojunction is a desirable photocatalyst for removing organic pollutants in water.

Designing step-scheme AgI decorated Ta2O5-x heterojunctions for boosted photodegradation of organic pollutants

Step-scheme (S-scheme) AgI decorated Ta2O5-x heterojunctions have been designed and synthesized via a combination of solvothermal and chemical deposition methods for enhanced visible-light harvesting and high-performance photocatalysis. The AgI nanoparticles showed great influences on the visible-light absorption and charge separation between AgI and Ta2O5-x microspheres. The experimental results indicated that the as-prepare AgI/Ta2O5-x composites achieved enhanced photocatalytic performance towards tetracycline degradation under visible light, and the AgI/Ta2O5-x-11 sample displayed the highest photocatalytic performance and the maximum rate constant of approximately 0.09483 min−1, which was 7.22 times that of Ta2O5-x microspheres and 2.56 times that of AgI, respectively. The highly enhanced photocatalytic performance was mainly attributed to the construction of S-scheme heterostructure and formation of oxygen vacancies in Ta2O5-x microspheres. In addition, the trapping experimental and DMPO spin-trapping ESR spectra confirmed the ⸱O2− and ⸱OH species as the main radicals during tetracycline degradation. Current work indicates an S-scheme tantalum-based composites for high-performance environmental photocatalysis.

Facile preparation of ZnO/TiO2 nanocomposite photocatalysts and study of their photocatalytic performance

Due to its strong photocatalytic activity, chemical stability, resistance to chemical and optical corrosion, and non-toxic qualities, TiO2 has received a lot of attention as a significant semiconductor material. One of the main areas of research in the field of photocatalysis has always been the system made of ZnO, another significant semiconductor, which has stronger physical and chemical characteristics and photocatalytic activity than TiO2 and ZnO alone.The performance of the photocatalysts can be optimized by adjusting the ratio of the components in the complexes. It was found that the catalytic activity of the particulate ZnO nano photocatalysts could be improved by trace TiO2 addition and high TiO2 concentration in the complex, with higher degradation efficiency for methyl orange under simulated solar illumination. The enhanced performance was attributed to the high photogenerated electron-hole separation rate caused by the increased surface oxygen vacancy defects and the enhanced interfacial charge transfer of the pluralistic heterojunction structure. In addition, there is a certain selectivity of ZnO and TiO2 for the photocatalytic degradation of methylene blue and methyl orange, which is related to the charged nature of the catalyst surface and the ionic nature of the pollutant molecules. The inhibitor studies revealed that the degradation reactions of methylene blue and methyl orange involved the active species hydroxyl radicals, superoxide radicals, and photogenerated holes formed on the catalyst surface, with superoxide radicals dominating the methyl orange reaction. The produced photocatalysts' great stability was validated by cycling experiments. Further research on the impact of catalyst dosage and pH of the contaminant solution on the photocatalytic performance of the catalysts revealed that an increase in catalyst dosage resulted in a greater number of active sites for contaminant molecules and incident light, which increased the efficiency of contaminant degradation. In an alkaline environment, the efficiency of the catalyst for photodegradation of pollutants was significantly increased due to the high concentration of strongly oxidizing hydroxyl radicals contained in the alkaline solution.

Croton macrostachyus Leaf Extract-Mediated Green Synthesis of ZnO Nanoparticles and ZnO/CuO Nanocomposites for the Enhanced Photodegradation of Methylene Blue Dye with the COMSOL Simulation Model.

The photodegradation of organic pollutants using metal oxide-based catalysts has drawn great attention as an effective method for wastewater treatment. In this study, zinc oxide nanoparticles (ZnO NPs) and zinc oxide/copper oxide nanocomposites (ZnO/CuO NCs) were fabricated using the leaf extract of Croton macrostachyus as a nontoxic, natural reducing and stabilizing agent. The synthesized samples were characterized by employing X-ray diffraction, microscopic, spectroscopic, and electrochemical methods. The results confirmed the successful synthesis of ZnO NPs and ZnO/CuO NCs with well-defined crystalline structures and morphologies. The prepared samples were tested for the photodegradation of methylene blue (MB) dye under visible light irradiation. Compared to ZnO NPs, ZnO/CuO NCs showed greatly improved photocatalytic performances, particularly with the sample prepared with the 20 mol % Cu precursor (97.02%). The enhancement could be related to the formed p-n heterojunction, which can suppress the recombination of charge carriers and extend the photoresponsive range. A theoretical study of the photocatalytic activity of ZnO/CuO NCs against MB dye degradation was also conducted by using COMSOL Multiphysics software. The results of the simulation are in reasonable agreement with those of the experiment. This study contributes to the development of sustainable and effective photocatalytic materials that are suitable for application in environmental remediation, particularly in the treatment of wastewater.

Distinguishable photocatalytic activity of nano polyaniline with quantum dots metal oxide as photocatalysts for photodegradation of Dianix blue dye and different industrial pollutants

Nanopolyaniline (PAN) polymers have recently been under active investigation as promising photocatalysts. In this work, a simple modified sol–gel method is used to make nano PAN polymers, and a chemical polymerization method is used to make nano polyaniline titanium dioxide quantum dots (PAN-TiQD) polymers as an active photocatalyst during the photodegradation of Dianix blue dye as an organic pollutant under xenon light. The traditional colloidal sol–gel method and the microwave-assisted hydrothermal method were used to make TiQD, which was then mixed with nanoPAN to make PAN-5 % TiQD (W/W) nanocomposites. Characterizations like XRD, FTIR, UV and visible diffuse reflectance spectra, TGA, surface area, EDX, and TEM were used to characterize the nanoPAN and PAN-TiQD that were made. Also, the photocatalytic activity of all synthesized polymers was investigated by the photodegradation process of Dianix blue dye as an organic hazardous pollutant in aqueous medium using a xenon photoreactor with an initial power of 75 W/Cm2. The effects of irradiation time and photocatalyst type on the photodegradation process efficiency of Dianix blue dye were examined. After 3 h of photodegradation processes, the photodegradation efficiency of PAN-TiQD reached 69 % compared to 36 % of nanoPAN due to the fact that it contains 5 % TiQD as a highly active catalyst, which reached 91 %. As an added value for this study, a significant contribution is the examination of eight hazardous industrial wastewater samples, which were assessed under direct sunlight and were in accordance with the KSA environmental permissible limit of 1000 ppm.Finally, the recycling processes in the presence of all synthesized catalysts were investigated and evaluated six times. The photodegradation rate of the recycling processes of Dianix blue dye was highly decreased in the presence of nano PAN than PAN-TiQD, while it had a low decreasing percentage in the case of TiQD. The recycling process using sunlight for industrial pollution samples was investigated at one of the KSA textile plants by using six synthetic catalysts and assessing COD and TOC values.

Interfacial and Electronic Modulation of M-Bridged Heterostructures with L-Tryptophan and Transition Metallic Oxides: Enhancing Corrosion Resistance and Photocatalytic Activity.

Despite remarkable advancements in multilayer composite materials, achieving controlled growth on stationary platforms for optimal corrosion protection and photocatalytic capabilities remains a challenge. In this study, we introduce an innovative approach by integrating bifunctional metal-organic frameworks (MOFs) into plasma-electrolyzed layers made on AZ31 Mg alloy. Metallic oxides of Zr, Ti, and W serve as new pivotal centers for MOF formation, while L-tryptophan (Trp) acts as an organic linker. This innovative approach establishes an efficient electron transport system that acts as a functional pathway for creating highly effective and versatile materials. The tunable structure of the MOF/plasma electrolyzed layer enables it to concurrently display electrochemical stability and photocatalytic activity for the photodegradation of organic pollutants. Remarkably, the WOF complex emerges as a standout performer, effectively shielding the substrate from corrosive anion attacks. This sample showcases exceptional photocatalytic efficiency of 99.61% for crystal violet solution, with sustained performance after five cycles and a 72 h corrosion test (96.55% and 98.39% degradation, respectively). Moreover, DFT calculations elucidate the fundamental bonding modes between MOFs and inorganic constituents, delivering comprehensive insights into their structural formation. Our research addresses the critical challenge of achieving controlled growth for enhanced corrosion resistance and photocatalytic activity, demonstrating a novel pathway for creating multifunctional materials with practical applications across various fields.

Four-in-one strategy to boost the performance of 3-dimensional MoS2 nanostructures for industrial effluent treatment and hydrogen evolution reactions

Two-dimensional (2D) molybdenum disulfide (MoS2) has gained enormous attention as a photocatalytic material due to its extraordinary optical, electrical, and chemical properties which are highly tunable by engineered control of its 2D layers orientation. However, high carrier recombination rates in pristine MoS2 nanostructures hinder their practical applications as an efficient catalyst. There is an upsurge of research on developing new strategies to improving its photocatalytic actions for environmental remediation. One approach is to design MoS2 nanostructures with vertically aligned layer-structures or cross-linking 3-dimensional flower-like morphologies, which exhibit ultrahigh-density 2D edge sites that offer tremendous chemical reactivity. Another challenge is to obtain its highly active metallic 1 T phase by functional design of intrinsic structures without sacrificing its ambient stability. Herein, we reported highly active and mix-phased 1 T/2 H MoS2 nanostructures through elegant synthesis management. By regulating reaction kinetics with the assimilation of NH4+ ions and water molecules, tunable surface morphology from nano wrinkles to nanoflowers was achieved. The morphology regulations induced modifications in the surface areas of final products which were calculated as 64.3 m2g−1, 114.3 m2g−1, and 219.7 m2g−1, respectively. Moreover, the bandgaps were significantly lowered from 2.13 eV to 1.93 eV and 1.85 eV. This four-in-one strategy efficiently boosted photodegradation of organic pollutants up to 94% in less than 20 min with excellent cyclic reproducibility for seven cycles. In addition, exceptional hydrogen evolution reaction (HER) performance with a very low overpotential of 145 mV and Tafel slope of 81.4 mV/dec was recorded. The results obtained in this work demonstrated excellent suitability of these materials as catalysts in environment related applications such as organic dye removal and for efficient hydrogen production.

Insight into enhanced photogeneration mechanism of reactive intermediates from dissolved black carbon by co-pyrolysis of plastics and biomass

The dissolved black carbon (DBC) derived from co-pyrolysis of plastic and biomass be released into aquatic environment. DBC was an important photoactive constituent, however, the photochemical activity of DBC from the co-pyrolysis plastic and biomass remains unclear. Herein three popular plastic wastes (polystyrene, PS; polylactic acid, PLA; plastic mulch film, PMF) and pine needle biomass prepared co-pyrolysis biochar, and effects of co-pyrolysis plastics on DBC’s photogeneration ability of reactive intermediates, affecting pollutant photodegradation, were investigated. In comparison to individual DBC, the mixed DBC from co-pyrolysis biochar had a lower molecular weight and more oxygen-containing groups. Quantum yields of singlet oxygen (1O2) and triplet state DBC (3DBC*) from mixed DBC were higher, especially PMF-DBC since its lower aromaticity and molecular weight connected with its higher E2/E3 and lower SUVA254 values. Steady-state photochemical experiment demonstrated 3DBC* formation rates for mixed DBC were lower than individual DBC, while the second-order reaction rate constants of 3DBC* with 2,4,6-trimethylphenol for mixed DBC were higher than that of individual DBC. Quenching experiment by sorbic acid to distinguish high/low-energy triplets revealed that contributions of low-energy triplets to 3DBC* and 1O2 generation decreased relative to individual DBC, indicating the transformation of reductive groups to oxidative groups, which was supported by the phototransformation kinetics. Quantum yields of 3DBC* and 1O2 were positively linear correlations with E2/E3 using twenty DBC samples. These findings are helpful in understanding DBC’s photochemical activity from co-pyrolysis of plastics and biomass, especially in aquatic environments adjacent to soil amended by biochar.

Assessing the efficacy of iron (II, III) oxide nanocomposite for the photodegradation of organic dye pollutants and textile wastewater under UV–visible irradiation

Assessing the efficacy of iron (II, III) oxide nanocomposite for the photodegradation of organic dye pollutants and textile wastewater under UV–visible irradiation

Ferroelectric‐Photocatalysts for Degradation of Phthalate: Doped BiFeO3‐Graphene Oxide Nanocomposites

AbstractA complete photocatalytic degradation of dibutyl phthalate (DBP) using ferroelectric doped‐bismuth ferrite‐ (BiFeO3; BFO) graphene oxide (GO) nanocomposites is achieved. The local ferroelectric properties of doped BFO photocatalysts supported onto GO is well‐utilized for photodegradation of pollutant. A complete photodegradation of DBP under ultraviolet light irradiation is achieved within 2.5 h, traced by gas chromatography. The best photocatalytic activity of Bi0.95Ag0.05Fe0.95Mn0.05O3‐GO (ABMGO) nanocomposite is attributed to its large intrinsic local ferroelectric polarization, which suppresses the recombination of photoinduced charge carriers and the presence of Ag+ and Mn4+ as new active sites on the large surface of ABMGO speeds up the photodegradation of DBP. The possible mechanism of photodegradation of DBP is presented using mass spectrometry includes several intermediate products; phthalic acid, benzoic acid, benzaldehyde, and hydroquinone and 3‐methyl butyric acid which are harmless for the environment compared to DBP.

Magnetic perovskite nanohybrid based on g-C3N4 nanosheets for photodegradation of toxic environmental pollutants under short-time visible irradiation

In this study, a magnetic perovskite nanohybrid based on g-C3N4 (gCN) nanosheets was synthesized and developed for the efficient photodegradation of toxic environmental pollutants under short-time visible irradiation. The synthesis of this nanohybrid involved the incorporation of SrTiO3:N (STO:N) and ZnFe2O4 (ZnF) onto the g-C3N4 nanosheets through a simple reflux method. Our investigation encompassed a comprehensive suite of analytical techniques, including BET, TGA, TEM, SEM, EDX, DRS, VSM, XRD, photocurrent, and FT-IR, to elucidate the physicochemical characteristics of this nanocomposite in the context of its application in photodegradation processes. The nanohybrid displayed significantly enhanced photocatalytic activity compared to its individual components, achieving a degradation efficiency of over 90% for various pollutants, including organic dyes like Rhodamine B (Rh-B), within a short irradiation time. This enhanced activity can be attributed to the synergistic effect between gCN, STO:N, and ZnF, which promotes the generation of reactive oxygen species and facilitates the degradation process. Notably, the nanocomposite containing 20 wt% STO:N perovskite and 20 wt% ZnF demonstrated the highest Rh-B degradation rate under visible light irradiation within just 30 min. Furthermore, the nanohybrid displayed excellent stability and reusability over seven consecutive runs, retaining its high photocatalytic activity even after multiple cycles of degradation. This remarkable performance can be attributed to the strong interaction between the gCN nanosheets and the magnetic perovskite components, which prevents their aggregation and ensures their efficient utilization. Additionally, the nanohybrid exhibited excellent visible light absorption, enabling the utilization of a wider range of light for degradation. This feature is particularly advantageous, as visible light is more abundant in sunlight compared to UV light, rendering the nanohybrid suitable for practical applications under natural sunlight. In conclusion, the ternary gCN-STO:N@ZnF nanocomposite represents a promising candidate for the treatment of organic pollutants in aqueous environments, offering a versatile and efficient solution.

Assembling ZnMnFe2O4@Ag-AgVO3 nanostructure heterojunctions for photocatalytically degrading RhB and Pseudomonas aeruginosa bacteria under visible irradiation

Improving the separation of photocarriers is a vital approach to create highly effective heterojunction photocatalysts for the photodegradation of environmental pollutants. In this work, coprecipitation and hydrothermal methods were employed to develop a new heterojunction of Zn0.5Mn0.5Fe2O4@Ag-AgVO3 magnetic nanocomposite as photocatalysts for the photodegradation of Rhodamine B (RhB) and bacterial inactivation of Pseudomonas aeruginosa (P. aeruginosa) when exposed to illumination of visible light. FESEM, EDX, UV–vis reflectance spectroscopy (DRS), N2 adsorption/desorption, TEM, PL, Brunauer-Emmett-Teller (BET) surface area, Vibrating Sample Magnetometer (VSM), and XRD techniques were used to investigate the structural and optical properties of synthesized materials. The Zn0.5Mn0.5Fe2O4@Ag-AgVO3 photocatalyst demonstrated noticeably higher photocatalytic activity for RhB degradation when compared to the pure constituents AgVO3, Ag-AgVO3, and Zn0.5Mn0.5Fe2O4 samples. The results revealed that when RhB was used at a concentration of 20 ppm, the Zn0.5Mn0.5Fe2O4@Ag-AgVO3 possessed a high degradation rate (93.43 % within 180 min), and this was sufficient to get the highest total organic carbons (TOC) removal (90 %). Besides, Zn0.5Mn0.5Fe2O4@Ag-AgVO3 possesses complete inactivation efficiency (log(CFU) decreased from 6.5 to 0.00001) toward P. aeruginosa in 120 min of visible illumination. The photodegradation mechanism was explained by the surface plasmonic resonance Z-type heterostructure, and tested by trapping experiments. It can beinferredthat the Zn0.5Mn0.5Fe2O4@Ag-AgVO3 photocatalyst was very stable and efficient in removing different organic pollutants and pathogenic bacteria from wastewater.

Synthesis of novel maghemite (γ-Fe2O3)-decorated g-C3N4 nano-tubes (g-C3N4 NTs/γ-Fe2O3) photocatalytic nano-composite for ultrafast degradation of organics in wastewater: Insight into the mechanism of photoexcited charge separation

In this study, to enhance the photodegradation of organic pollutants including Methyl blue (MB) and Methyl orange (MO), mesoporous tubular g-C3N4/γ-Fe2O3 (FCN) nano-composite synthesized via facile procedures. FT-IR and XRD data proved the existence of maghemite (γ-Fe2O3) nanoparticles on the g-C3N4 nano-tubes. Experimental data showed that among fabricated photocatalysts, FCN exhibited the highest activity rate toward the photodegradation of MB (%96.1/60 min) and MO (%98.3/120 min) with an excellent kinetic rate of 0.0509 min−1 (MB) and 0.0352 min−1 (MO) under visible light and considerable photocatalytic stability after six cycles. In addition, the visible light-harvesting-capability of FCN enhanced compared to unequipped forms of g-C3N4 (BCN and CNNTs), surprisingly functioning under irradiation of photons greater than 900 nm, proving the synergistic role of γ-Fe2O3 nanoparticles not only in harvesting visible light but also in hindering electron-hole recombination. BET analysis showed mesoporous structure, the highest SSA and pore volume (55.623 m2/g, 0.1699 cm3/g) for FCN, indicating more active sites and enhanced target molecules adsorption, then augmented photocatalytic performance in comparison to the rest of the samples. Finally, FCN generated an excellent photocurrent density (3.76 μA/cm2) with the least arc radius, introducing a high-potential hybrid photocatalyst to the research field.

Concave microlens arrays with tunable curvature for enhanced photodegradation of organic pollutants in water: A non‐contact approach

AbstractSolar‐driven photodegradation for water treatment faces challenges such as low energy conversion rates, high maintenance costs, and over‐sensitivity to the environment. In this study, we develop reusable concave microlens arrays (MLAs) for more efficient solar photodegradation by optimizing light distribution. Concave MLAs with the base radius of μm are fabricated by imprinting convex MLAs to polydimethylsiloxane elastomers. Concave MLAs possess a non‐contact reactor configuration, preventing MLAs from detaching or being contaminated. By precisely controlling the solvent exchange, concave MLAs are fabricated with well‐defined curvature and adjustable volume on femtoliter scale. The focusing effects of MLAs are examined, and good agreement is presented between experiments and simulations. The photodegradation efficiency of organic pollutants in water is significantly enhanced by 5.1‐fold, attributed to higher intensity at focal points of concave MLAs. Furthermore, enhanced photodegradation by concave MLAs is demonstrated under low light irradiation, applicable to real river water and highly turbid water.image

Inorganic–organic hybrid quantum dots for AOP-mediated photodegradation of ofloxacin and para-nitrophenol in diverse water matrices

Due to concerns about the accessibility of clean water and the quality of treated wastewater, developing a suitable solution to enhance the water quality is critical. Thus, the current study focused on the synthesis of cadmium-doped CdIn2S4 incorporated in chitosan, forming Cd/CdIn2S4@Ch quantum dots using a solvothermal technique for the efficient photodegradation of hazardous pollutants like ofloxacin and para-nitrophenol through H2O2-mediated AOP. Cd/CdIn2S4@Ch quantum dots were characterized by several advanced methods, including XRD, PL, UV-DRS, FTIR, SEM, HR-TEM, XPS, DSC, TGA, EDX, and Elemental mapping analysis. The influence of varying reaction parameters, such as the effect of organic compounds, inorganic ions, and water matrices, was also investigated. The prepared composite showed outstanding photodegradation efficiency of 85.51 ± 1.35% and 96.70 ± 1.31%, with a rate constant of 0.02334 and 0.15134 min−1, which is about 1.24 and 2.07 times higher than pristine CdIn2S4 for ofloxacin and para-nitrophenol, respectively. The COD values were reduced to 80.67 ± 1.67% for ofloxacin and 88.36 ± 1.43% for para-nitrophenol, whereas the TOC values reduced to 73.49% and 86.34%, respectively, from their initial values. The improved performance is ascribed to the encapsulation of CdIn2S4 by chitosan, leading to the self-doping of cadmium into the photocatalyst, as the incorporated cadmium doping site can generate a local electron accumulation point, improving the charge separation efficacy and surface charge mitigation capability of chitosan nanosheets even further. The scavenger experiments showed that hydroxyl and superoxide radicals played a significant part in the photodegradation of contaminants. Additionally, the quantum dots showed excellent constancy and were recyclable up to six times, suggesting exceptional stability and reusability of the manufactured photocatalyst. The fabricated Cd/CdIn2S4@Ch quantum dots could be an excellent photocatalyst for removing organic pollutants from wastewater in the near future.

Rational design of coaxial CdS@ZnO nanowire array for efficient photodegradation of organic pollutants

Herein, a novel coaxial CdS@ZnO nanowire array catalyst was synthesized by magnetron sputtering and hydrothermal method. The optimum photocatalytic composite was obtained by controlling the ratio of CdS and ZnO. Take methylene blue (MB) as the model, the CdS@ZnO nanowire array (CdS@ZnO-10) exhibited strong photocatalytic solid activity, and the highest adsorption and photodegradation rate of MB reached 90.38 % in 50 min and 99.13 % in 120 min under simulated sunlight illumination. The mechanism of the heterojunction interface affecting photocatalytic performance was studied. Therefore, the synthesis approach could offer new design and controllable construction of coaxial structure for organic dye pollutant degradation.

Fabrication of Co3O4/CdO/clinoptilolite nanocomposite heterojunction with synergistically enhanced catalytic performance for photodegradation of pharmaceutical pollutants

Environmental protection has become a global priority with the increasing use of renewable energy sources. Solar-light photocatalytic processes have attracted significant attention due to the highly effective degradation of organic pollutants and the use of renewable resources and. In this research, a green approach was employed to fabricate a Co3O4/CdO/clinoptilolite (CCC) heterojunction nanocomposite as an effective S-scheme photocatalyst for the photodegradation of levofloxacin under sunlight. As compared to single semiconductors, the CCC revealed the best performance in degradation of levofloxacin, indicating a great synergy effect between Co3O4 and CdO nanoparticles. Almost complete degradation of levofloxacin was attained by the CCC system with a reaction rate constant of 0.041212 min−1 under optimal conditions (neutral pH, catalyst dose= 2 g/L, and initial concentration of the pollutant= 10 mg/L). CCC heterojunction photocatalyst exhibited excellent stability and recyclability with minimal leaching of metal ions. In addition, CCC displayed antimicrobial activity against Gram-positive and - negative bacteria. Also, the results of planting experiments exhibited the possibility of discharging the treated levofloxacin solutions to irrigate green space. The results of this study provide new insight into the fabrication of unique ternary nanocomposites with diverse applications and excellent photocatalytic performance.