Structure-phase transformation of bismuth oxide to BiOCl/Bi24O31Cl10 shoulder-by-shoulder heterojunctions for efficient photocatalytic removal of antibiotic.

Developing heterojunction photocatalyst with well-matched interfaces and multiple charge transfer paths is vital to boost carrier separation efficiency for photocatalytic antibiotics removal, but still remains a great challenge. In present work, a new strategy of chloride anion intercalation in Bi2O3 via one-pot hydrothermal process is proposed. The as-prepared Ta-BiOCl/Bi24O31Cl10 (TBB) heterojunctions are featured with Ta-Bi24O31Cl10 and Ta-BiOCl lined shoulder-by-shouleder via semi-coherent interfaces. In this TBB heterojunctions, the well-matched semi-coherent interfaces and shoulder-by-shoulder structures provide fast electron transfer and multiple transfer paths, respectively, leading to enhanced visible light response and improved photogenerated charge separation. Meanwhile, a type-II heterojunction for photocharge separation has been obtained, in which photogenerated electrons are drove from the CB (conduction band) of Ta-Bi24O31Cl10 to the both of bilateral empty CB of Ta-BiOCl and gathered on the CB of Ta-BiOCl, while the photogenerated holes are left on the VB (valence band) of Ta-Bi24O31Cl10, effectively hindering the recombination of photogenerated electron-hole pairs. Furthermore, the separated electrons can effectively activate dissolved oxygen for the generation of reactive oxygen species (·O2-). Such TBB heterojunctions exhibit remarkably superior photocatalytic degradation activity for tetracycline hydrochloride (TCH) solution to Bi2O3, Ta-BiOCl and Ta-Bi24O31Cl10. This work not only proposes a Ta-BiOCl/Bi24O31Cl10 shoulder-by-shoulder micro-ribbon architectures with semi-coherent interfaces and successive type-II heterojunction for highly efficient photocatalytic activity, but offers a new insight into the design of highly efficient heterojunction through phase-structure synergistic transformation strategy.

Mn/S diatomic sites in C3N4 to enhance O2 activation for photocatalytic elimination of emerging pollutants.

Oxygen activation leading to the generation of reactive oxygen species (ROS) is essential for photocatalytic environmental remediation. The limited efficiency of O2 adsorption and reductive activation significantly limits the production of ROS when employing C3N4 for the degradation of emerging pollutants. Doping with metal single atoms may lead to unsatisfactory efficiency, due to the recombination of photogenerated electron-hole pairs. Here, Mn and S single atoms were introduced into C3N4, resulting in the excellent photocatalytic performances. Mn/S-C3N4 achieved 100% removal of bisphenol A, with a rate constant 11 times that of pristine C3N4. According to the experimental results and theoretical simulations, S-atoms restrict holes, facilitating the photo-generated carriers' separation. Single-atom Mn acts as the O2 adsorption site, enhancing the adsorption and activation of O2, resulting the generation of ROS. This study presents a novel approach for developing highly effective photocatalysts that follows a new mechanism to eliminate organic pollutants from water.

Synergistic mechanisms of carbon-based materials for VOCs photocatalytic degradation: A critical review.

With the rapid expansion of human activities, there has been a significant increase in the release of volatile organic compounds (VOCs) from factories and interior decoration materials, posing a substantial risk to the surrounding ecosystem and human health. Photocatalysis technology based on semiconductors has emerged as a promising solution for mitigating atmospheric pollution and indoor air quality concerns. However, single semiconductors encounter several challenges when it comes to VOC photodegradation, including issues like the weak adsorption capacity for VOC molecules, insufficient surface-active sites, and limited light utilization. In recent decades, carbon-based materials have gained considerable interest in photodegrading VOCs owing to their strong adsorption capacity, electrical conductivity, broad light absorption range, and tunable surface characteristics. The incorporation of carbon materials can enhance the photodegradation efficiency of VOCs by facilitating the transfer of VOCs from the ambient air to the surface of the photocatalysts, increasing the number of active surface sites, expanding the light absorption region, and promoting the separation of charge carriers. This review provides a comprehensive overview of the applications of carbon materials with different dimensions in enhancing the performance of semiconductors for the photocatalytic degradation of VOCs. Based on the fundamental principles of photocatalytic VOC degradation, this review explores the factors influencing the degradation performance of catalysts and elucidates the degradation mechanisms. Moreover, it summarizes a range of synthesis approaches for carbon-based photocatalysts, discussing the multiple roles played by carbon materials in these processes. In conclusion, the review offers insights into the current state of carbon-based photocatalysts and outlines the existing challenges. It also provides a perspective on the future development of these materials, highlighting the need for continued research and innovation in this field.

Synergistic photocatalytic degradation of ciprofloxacin under natural sunlight using hot dip galvanization and medical incineration waste residues.

To improve the photodegradation capacity, for the first time, a simple yet efficient photocatalyst was prepared by solely employing hot dip galvanization waste (GW) and fly ash (FA) disposed from medical waste incinerators. Impressively, the as-synthesized photocatalyst (GW-FA) in the ratio 3:1 displayed an outstanding ciprofloxacin degradation efficiency of 98.3% under natural sunlight within 60 min and possessed superior reusability. Herein, adjusting the amount of GW evidenced effective tuning of the electronic band structure and increased active sites. Detailed microscopic morphology, chemical structure, magnetic, and optical properties of GW-FA were studied by UV-DRS, FESEM-EDX, HRTEM, XRD, XPS, ESR, VSM, and AFM, which confirmed the successful fabrication of GW-FA and their outstanding ability to reduce the recombination rate. Besides, the effects of crucial experimental parameters (concentration, pH, and photocatalyst loading) on ciprofloxacin degradation were examined using RSM-BBD. Further, OH• was manifested to be the main active species for the photodegradation of ciprofloxacin. Eventually, GC-MS analysis was employed to deduce plausible photodegradation pathways, and ICP-AES analysis proved that the concentration of leached heavy metals was lower than that of the standard limits for irrigation water. This work establishes a new route for effectively reutilizing waste generated from medical waste incinerators and galvanization industries as a photocatalyst, which otherwise would be disposed in landfills.

Small-molecule intercalation induces defective generation of bromine-doped bismuth oxychloride to enhance photocatalytic degradation and detoxification of tetracycline.

Photocatalysts are one of the effective methods to degrade antibiotic contamination, but the efficiency is low and the toxicity is not well recognized. Deep lattice doping to induce defect generation is an effective way to improve the performance of photocatalysts. Here, defect-rich bromine-doped BiOCl-XBr photocatalysts were constructed with the help of small molecules inserted into the interlayer. The photocatalytic degradation performance of BiOCl-XBr was significantly enhanced, and its degradation rate was up to about 12 times that of BiOCl monomer. The main reasons for the stronger photocatalytic performance of BiOCl-XBr include Br doping to enhance visible light absorption, surface defects, and Bi valence changes to improve charge transport. The degradation of tetracycline (TC) produced more toxic intermediates, and the biotoxicity experiments also confirmed that the toxicity showed a trend of increasing and then decreasing, indicating that the more toxic intermediates were also mineralized during the degradation process. However, the mortality and hatching rate of zebrafish in the exposed group after degradation recovered but changed their activity pattern under light and dark conditions. This further warns us to focus on the toxicity changes after antibiotic degradation. Finally, based on the free radical analysis, the mechanism of photocatalytic degradation and detoxification of TC by BiOCl-XBr was proposed.

A novel Bi12O17Cl2/GO/Co3O4 Z-type heterojunction photocatalyst with ZIF-67 derivative modified for highly efficient degradation of antibiotics under visible light.

Levofloxacin (LVX) is difficult to be naturally degraded by microorganisms in water, and its residues in water will pose significant risks to human health and ecological environment. In this study, Bi12O17Cl2 was used as the main body, Bi12O17Cl2/GO/Co3O4 composite photocatalyst was prepared by pyrolysis of zeolitic imidazolate framework-67 (ZIF-67) combined with in-situ precipitation method and used to degrade LVX. A sequence of characterizations shows that addition of Co3O4 and graphene oxide (GO) increases the visible light response range, improves the separation efficiency of photogenerated electrons and holes (e--h+) of photocatalyst, and thus improves the degradation efficiency of LVX. Under the optimal reaction conditions, the LVX degradation rate of Bi12O17Cl2/1.5GO/7.5Co3O4 can reach 91.2 % at 120 min, and its reaction rate constant is the largest (0.0151 min-1), which is 2.17, 13.14 and 1.53 times that of Bi12O17Cl2, Co3O4 and Bi12O17Cl2/7.5Co3O4, respectively, showing better photocatalytic performance. Simultaneously, the recycling stability of Bi12O17Cl2/1.5GO/7.5Co3O4 was also verified. The capture experiments and electron EPR test results showed that superoxide radicals (•O2-) and photogenerated holes (h+) were the primary active substances in the reaction process. Finally, combined with HPLC-MS results, the photocatalytic degradation pathway of LVX was derived. This work will provide a theoretical basis for the design of Metal Organic Frameworks (MOFs)-derivative modified Bi12O17Cl2-based photocatalysts.

Zirconium and cerium dioxide fabricated activated carbon-based nanocomposites for enhanced adsorption and photocatalytic removal of methylene blue and tetracycline hydrochloride.

Activated carbon (AC) is a porous, amorphous form of carbon known for its strong adsorption capacity, making it highly effective for use in wastewater treatment. In this investigation, AC-based nanocomposites (NCs) loaded with zirconium dioxide and cerium dioxide nanoparticles (ZrO2/CeO2 NPs) were successfully synthesized for the effective elimination of methylene blue (MB) and tetracycline hydrochloride (TCH). The AC-ZrO2/CeO2 NCs have a size of 231.83 nm, a zeta potential of -20.07 mV, and a PDI value of 0.160. The adsorption capacities of AC-ZrO2/CeO2 NCs for MB and TCH were proved in agreement with the Langmuir isotherm and pseudo 1st order kinetic model, respectively. The maximum adsorption capacities were determined to be 75.54 mg/g for MB and 26.75 mg/g for TCH. Notably, AC-ZrO2/CeO2 NCs exhibited superior photocatalytic degradation efficiency for MB and TCH under sunlight irradiation with removal efficiencies reaching up to 97.91% and 82.40% within 90 min, respectively. The t1/2 for the photo-degradation process of MB and TCH were 11.55 min and 44.37 min. Analysis of active species trapping confirmed the involvement of hole (h+), superoxide anion (•O2-), and hydroxyl radical (•OH) in the degradation mechanism. Furthermore, the residual solution post-contaminant removal exhibited minimal toxicity towards Artemia salina and NIH3T3 cells. Importantly, the NCs did not exhibit antibacterial activity against tested pathogens post-absorption/degradation of TCH. Thus, AC-ZrO2/CeO2 NCs could be a promising nanomaterial for wastewater treatment applications.

Enhanced photocatalytic property of Cu doped Ce2Zr2O7 toward photodegradation of methylene blue under visible light.

Widespread ecosystem degradation from noxious substances like industrial waste, toxic dyes, pesticides, and herbicides poses serious environmental risks. For remediation of these hazardous problems, present study introduces an innovative Cu-doped Ce2Zr2O7 nano-photocatalyst, fabricated via a simple, eco-friendly hydrothermal method, designed to degrade toxic textile dye methylene blue. Harnessing Cu doping for pyrochlore Ce2Zr2O7, structure engineering carried out through a hydrothermal synthesis method to achieve superior photocatalytic performance, addressing limitations of rapid charge carrier recombination in existing photocatalysts. Photoluminescence analysis showed that doped pyrochlore slows charge carrier recombination, boosting dye degradation efficiency. UV-Visible analysis demonstrated an impressive 96 % degradation of methylene blue by Cu-doped Ce2Zr2O7 within 50 min, far exceeding the performance of pristine materials. Trapping experiments clarified the charge transfer mechanism, deepening our understanding of the photocatalytic process. These findings highlight the potential for developing innovative, highly efficient photocatalysts for environmental remediation, offering sustainable solutions to combat pollution. This study not only addresses the limitations of existing photocatalysts but also opens new avenues for enhancing photocatalytic performance through strategic material design.

Bioinspired copper oxide nanocomposites: harnessing plant extracts for enhanced photocatalytic performance.

This study focuses on developing copper oxide-based nanocomposites using plant extracts for photocatalytic applications. Curcuma amada leaf and Alysicarpus vaginalis leaf extracts were utilized alongside recycled copper precursors to synthesize photocatalysts via a green synthesis approach. Structural characterization through X-ray diffraction confirmed the formation of monoclinic CuO with reduced crystallite sizes due to plant extract incorporation. Fourier-transform infrared spectroscopy identified additional functional groups from the plant extracts, enhancing the material's properties. UV-Vis spectroscopy demonstrated increased light absorption and narrowed bandgaps in the nanocomposites, crucial for efficient photocatalysis under visible light. Morphological studies using FESEM revealed unique leaf-like structures in nanocomposites, indicative of the plant extract's influence on morphology. Photocatalytic degradation of methylene blue, rhodamine B, Congo red, and reactive blue 171 dyes showed enhanced performance of plant extract-modified CuO compared to without plant extract mediated CuO, attributed to improved charge carrier separation and extended lifetime. The effects of pH, catalyst dosage, and dye concentration on degradation efficiency were systematically investigated, highlighting optimal conditions for each dye type. Radical scavenger studies confirmed the roles of holes and hydroxyl radicals in the degradation process. Kinetic analysis revealed pseudo-second-order kinetics for dye degradation, underscoring the effectiveness of the nanocomposites. Overall, this research provides insights into sustainable photocatalytic materials using plant extracts and recycled copper, showcasing their potential for environmental remediation applications.

Adsorption and photocatalytic degradation of 2,4-dicholrophenol using surgical mask derived SMAC-Fe2O3 composite; adsorption isotherms, kinetics, thermodynamics.

Hybrid material of surgical mask activated carbon (SMAC) and Fe2O3 (SMAC-Fe2O3) composite was prepared by simple co-precipitation method and used as potential material for the remediation of 2,4-dicholrophenol (2,4-DCP). The XRD patterns exhibited the presence of SMAC and Fe2O3, FTIR spectrum showed the FeO-carbon stretching at the wavenumber from 400 to 550 cm-1. UV-Vis DRS results showed the band gap was 1.97 eV and 2.05 eV for SMAC-Fe2O3 and Fe2O3, respectively. The SEM images revealed that the Fe2O3 doped onto the fiber morphology of SMAC. The outcomes of the BET examination exhibited a surface area of 195 m2/g and a pore volume of 0.2062 cm3/g for the SMAC/Fe2O3 composite. The batch mode study shows the maximum adsorption and photocatalytic degradation efficacies which were 97% and 78%, respectively. The experimental data was studied with both linear and nonlinear adsorption isotherm and kinetics models. The nonlinear Langmuir isotherm and pseudo-second-order kinetics (PSOK) models have well fit compared with other models. The Langmuir maximum adsorption capacity (qmax) was found 161.60 mg/g. Thermodynamic analysis shows that the 2,4-DCP adsorption onto SMAC-Fe2O3 was a spontaneous and exothermic process. The PSOK assumes that the adsorption process was chemisorption. The photocatalytic degradation rate constant of 2,4-DCP was calculated using pseudo-first-order kinetics (PFOK) and the rate constant for SMAC-Fe2O3 and Fe2O3 were 0.859 × 10-2 min-1 and 0.616 × 10-2 min-1, correspondingly. In addition, the obtained composite exhibited good reusability after a few cycles. These results confirmed that SMAC-Fe2O3 composite is an effective adsorbent and photocatalyst for removing 2,4-DCP pollutants.

Unveiling Ru(bpy)3 2+-Encapsulated Zeolite Y as Photocatalyst: Harnessing Photocatalytic Singlet Oxygen Generation for Mustard Gas Simulant Detoxification.

This study explores the encapsulation of Ru(bpy)3 2+ within Zeolite Y (ZY) to improve photocatalytic singlet oxygen generation for the degradation of a mustard gas simulant, namely 2-chloroethyl ethyl sulfide (CEES). Mustard gas simulants are known to disrupt several biological processes; thus, their effective degradation is essential. Zeolite Y, with its hierarchical structure and adjustable Si/Al ratios, is an ideal host for Ru(bpy)3 2+, significantly improving its photocatalytic efficiency and stability. It is demonstrated through XRD and spectroscopic analyses that encapsulated Ru(bpy)3 2+ maintains its structural and photophysical properties, which are essential for generating singlet oxygen. Ru(bpy)3(1.0) loaded ZY(15) (where 1.0 and 15 represent the encapsulated amount of Ru(bpy)3 2+ and Si/Al ratio, respectively) outperforms other investigated photocatalytic systems in the oxidation of CEES, demonstrating high conversion rates and selectivity toward nontoxic sulfoxide products. Immobilization of Ru(bpy)3 2+-encapsulated zeolite Y onto cotton fabric results in effective degradation of CEES. The experimental results, validated by theoretical calculations, indicate an improved oxygen affinity and accessibility in zeolites with higher Si/Al ratios. This study advances the design of photocatalytic materials for environmental and defense applications, providing sustainable solutions for hazardous chemical degradation.

Synthesis, characterization and photocatalytic activity of alginate based hybrid material for efficient degradation of organic pollutants under UV light and sunlight irradiation.

This study reports the development of alginate based hybrid material (Alg/CuO-gC3N4) with copper oxide (CuO) and graphitic carbon nitride (gC3N4). The Alg/CuO-gC3N4 hydrogel bead was prepared by two step process is as follows: formation of CuO-gC3N4 by co-precipitation method and incorporation of CuO-gC3N4 in the calcium alginate (Alg) by ionotropic gelation method. The structural and morphological features of the Alg/CuO-gC3N4 was characterized using different techniques namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), UV Diffuse Reflectance spectroscopy (UV-DRS) and Scanning electron microscopy (SEM). The photocatalytic activity of the Alg/CuO-gC3N4 was extensively evaluated by degrading methylene blue (MB) under UV-vis and sunlight irradiation. The influence of various parameters like pollutant type, initial dye concentration, catalyst dosage, effect of pH, light intensity and reusability was investigated. The Alg/CuO-gC3N4 achieved a maximum degradation efficiency of 86.26 % and 85.15 % for MB at a dye concentration of 1 × 10-5 M under UV-vis and sunlight irradiation respectively, within 60 min using 0.3 wt% of catalyst dosage. The Alg/CuO-gC3N4 exhibited excellent stability and reusability over multiple cycles. Additionally, the incorporation of CuO-gC3N4 in alginate facilitates in reducing the bandgap (2.54 to 2.28 eV) for efficient charge separation, further enhancing the overall photocatalytic activity.

Illuminating the Power of V2O5 Nanoparticles: Efficient Photocatalytic Degradation of Organic Dyes under Visible Light.

This research explores the synthesis, characterization, and application of Vanadium Pentoxide nanoparticles (V2O5 NPs), focusing on their efficacy in the photocatalytic degradation of organic dyes under visible light. Utilizing a co-precipitation method, we synthesized V2O5 NPs characterized by an orthorhombic crystal structure with a consistent average particle size of 28 nm. The optical properties of V2O5 NPs, including their band gap, were thoroughly investigated to understand their light absorption capabilities, which are crucial for photocatalytic activity. In our study, Methyl Violet (MV) dye was employed as a model organic pollutant to assess the photocatalytic performance of the nanoparticles. Under visible light irradiation, the V2O5 nanoparticles demonstrated an exceptional photocatalytic degradation efficiency, achieving up to 85% degradation of the MV dye within 100 min. This high level of efficiency is attributed to the nanoparticles' ability to effectively absorb visible light and generate electron-hole pairs, thereby facilitating a robust degradation process. Further analysis revealed that the photocatalytic activity led to the generation of reactive oxygen species (ROS) such as superoxide and hydroxyl radicals, which are integral to the dye degradation mechanism. These ROS play a critical role in breaking down the dye molecules, significantly contributing to the overall effectiveness of the photocatalytic process. The results of this study highlight the potential of V2O5 nanoparticles as a sustainable and effective photocatalytic material for environmental remediation applications, particularly in the treatment of wastewater containing organic dyes. This research not only advances our understanding of the photocatalytic properties of V2O5 nanoparticles but also demonstrates their practical application in addressing environmental pollution through innovative and efficient degradation of hazardous substances.

Stable loading of MOF-derived carbon skeleton encapsulated Ni and BiOBr on carbonized cellulose fibers for fabricating high-performance and recyclable photocatalytic paper.

The highly dispersed small-size metal co-catalysts can effectively improve the photocatalytic efficiency of semiconductor photocatalysts by separating photogenerated electrons and enriching active sites. However, this system tends to aggregate in the absence of carrier, resulting in the decrease of active sites. Here, MOF-derived carbon skeleton (MDCS) encapsulated Ni nanoparticles (Ni@MDCS) and BiOBr was loaded onto carbonized cellulose fibers (CCF) with the help of polydopamine (PDA) to construct high-performance and recyclable photocatalytic paper for photocatalytic degradation of organic dyes in water. The characterization results showed that MDCS promoted good dispersion of Ni nanoparticles and provided sufficient active sites. And Ni@MDCS as a co-catalyst accelerated the separation of photogenerated carriers in BiOBr. The PDA improved the loading state of Ni@MDCS on CCF and converted into N-doped C in the carbonization process for further increasing the transfer efficiency of photogenerated electrons. In the composite paper, the stable loading of Ni@MDCS/BiOBr hybrid on CCF improved the dispersion and reusability of photocatalyst. The degradation rate of rhodamine B on CCF/PDA-C/Ni@MDCS/BiOBr paper was as high as 94.6 % after 60 min visible light irradiation, which was about 2.5 times higher than that of CCF/BiOBr paper. During 10 cycles, CCF/PDA-C/Ni@MDCS/BiOBr paper maintained high photocatalytic efficiency and good structural stability. This study provides a new way for developing high-performance and recyclable photocatalytic paper.

Kinetics and thermodynamics studies of nickel manganite nanoparticle as photocatalyst and fuel additive.

In this study, nickel manganite (NiMn2O4) nanoparticles were prepared using a hydrothermal method and examined its potential as a photocatalyst for the Acid Green 25 (AG-25) dye degradation. The nanoparticles were subjected to structural analysis using X-ray diffraction (XRD) and morphological analysis using scanning electron microscopy (SEM). The study examined the kinetics and thermodynamics of degradation processes that are catalyzed by photocatalysis. To ascertain their effect on dye degradation, several parameters, such as catalyst dose, H2O2 concentration, and temperature, were investigated. With a temperature of 315 K in a pseudo-first-order kinetic reaction, a 0.3 M H2O2 concentration, 0.05 mg/mL catalyst dose, and a promising removal efficiency of 96 % was achieved by the NiMn2O4 NPs in 40 min. Thermodynamic analysis revealed the spontaneous and entropy-driven nature of catalytic degradation, progressing favorably at elevated temperatures. Additionally, the NiMn2O4 NPs were applied as a fuel additive to analyze its influence on combustion and the physical characteristics of the modified fuel. The modified fuel demonstrated exceptional catalytic efficiency, emphasizing the potential of the NiMn2O4 NPs as an effective additive.

Ionic Crosslinked Hydrogel Films for Immediate Decontamination of Chemical Warfare Agents.

This study describes the development of hydrogel formulations with ionic crosslinking capacity and photocatalytic characteristics. The objective of this research is to provide an effective, accessible, "green", and facile route for the decontamination of chemical warfare agents (CWAs, namely the blistering agent-mustard gas/sulfur mustard (HD)) from contaminated surfaces, by decomposition and entrapment of CWAs and their degradation products inside the hydrogel films generated "on-site". The decontamination of the notorious warfare agent HD was successfully achieved through a dual hydrolytic-photocatalytic degradation process. Subsequently, the post-decontamination residues were encapsulated within a hydrogel membrane film produced via an ionic crosslinking mechanism. Polyvinyl alcohol (PVA) and sodium alginate (ALG) are the primary constituents of the decontaminating formulations. These polymeric components were chosen for this application due to their cost-effectiveness, versatility, and their ability to form hydrogen bonds, facilitating hydrogel formation. In the presence of divalent metallic ions, ALG undergoes ionic crosslinking, resulting in rapid gelation. This facilitated prompt PVA-ALG film curing and allowed for immediate decontamination of targeted surfaces. Additionally, bentonite nanoclay, titanium nanoparticles, and a tetrasulfonated nickel phthalocyanine (NiPc) derivative were incorporated into the formulations to enhance absorption capacity, improve mechanical properties, and confer photocatalytic activity to the hydrogels obtained via Zn2+-mediated ionic crosslinking. The resulting hydrogels underwent characterization using a variety of analytical techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscometry, and mechanical analysis (shear, tensile, and compression tests), as well as swelling investigations, to establish the optimal formulations for CWA decontamination applications. The introduction of the fillers led to an increase in the maximum strain up to 0.14 MPa (maximum tensile resistance) and 0.39 MPa (maximum compressive stress). The UV-Vis characterization of the hydrogels allowed the determination of the band-gap value and absorption domain. A gas chromatography-mass spectrometry assay was employed to evaluate the decontamination efficacy for a chemical warfare agent (sulfur mustard-HD) and confirmed that the ionic crosslinked hydrogel films achieved decontamination efficiencies of up to 92.3%. Furthermore, the presence of the photocatalytic species can facilitate the degradation of up to 90% of the HD removed from the surface and entrapped inside the hydrogel matrix, which renders the post-decontamination residue significantly less dangerous.

Effects of Cation Exchange in Rhodamine B Photocatalytic Degradation Using Peroxo-Titanate Nanotubes.

Lepidocrocite-type layered sodium titanate (NaxH2-xTi2O5) is widely used in environmental remediation because of its large specific surface area, formed by anisotropic crystal growth, and its ability to store and exchange cations between layers. Additionally, peroxo-titanate nanotubes (PTNTs), which are tubular titanates with peroxy groups, exhibit visible-light absorption capabilities, rendering them suitable for photocatalytic applications under visible light irradiation. However, because of cation exchange reactions, the Na+ concentration and pH of the solution can fluctuate under aqueous conditions, affecting the photocatalytic performance of the PTNTs. Herein, we evaluated the impact of cation exchange reactions on the photocatalytic degradation of Rhodamine B (Rh B) by PTNTs at controlled Na+ ratios. The observed pH of Rh B solutions increases due to the cation exchange reaction with Na+ and H3O+, leading to the formation of zwitter-ionic Rh B molecules, eventually weakening their adsorption and photodegradation performance. Moreover, the results indicate that inhibiting the pH increase of the Rh B solution can prevent the weakening of both the adsorption and photodegradation performance of PTNTs. This study highlights the significance of regulating the sodium ion content in layered titanate materials, emphasizing their importance in optimizing these materials' photocatalytic efficacy for environmental purification applications.

In-Situ Hydrothermal Fabrication of ZnO-Loaded GAC Nanocomposite for Efficient Rhodamine B Dye Removal via Synergistic Photocatalytic and Adsorptive Performance.

In this work, zinc oxide (ZnO)/granular activated carbon (GAC) composites at different ZnO concentrations (0.25M-ZnO@GAC, 0.5M-ZnO@GAC, and 0.75M-ZnO@GAC) were prepared by an in-situ hydrothermal method and demonstrated synergistic photocatalytic degradation and adsorption of rhodamine B (RhB). The thermal stability, morphological structure, elemental composition, crystallographic structure, and textural properties of developed catalysts were characterized by thermal gravimetric analysis (TGA/DTG), scanning electron microscopy equipped with energy dispersive-x-ray (SEM-EDS), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The successful loading of ZnO onto GAC was confirmed by SEM-EDS and XRD analysis. The BET surface areas of GAC, 0.25M-ZnO@GAC, 0.5M-ZnO@GAC, and 0.75M-ZnO@GAC were 474 m2/g, 450 m2/g, 453 m2/g, and 421 m2/g, respectively. The decrease in GAC could be attributed to the successful loading of ZnO on the GAC surface. Notably, 0.5M-ZnO@GAC exhibited the best photocatalytic degradation efficiency of 82% and 97% under UV-A and UV-C light over 120 min, attributed to improved crystallinity and visible light absorption. The photocatalytic degradation parameters revealed that lowering the RhB concentration and raising the catalyst dosage and pH beyond the point of zero charge (PZC) would favor the RhB degradation. Photocatalytic reusability was demonstrated over five cycles. Scavenger tests revealed that the hydroxyl radicals (•OH), superoxide radicals (O2-•), and photoinduced hole (h+) radicals play a major role during the RhB degradation process. Based on the TOC results, the RhB mineralization efficiency of 79.1% was achieved by 0.5M-ZnO@GAC. Additionally, GAC exhibited a strong adsorptive performance towards RhB, with adsorption capacity and the RhB removal of 487.1 mg/g and 99.5% achieved within 90 min of equilibrium time. The adsorption characteristics were best described by pseudo-second-order kinetics, suggesting chemical adsorption. This research offers a new strategy for the development of effective photocatalyst materials with potential for wider wastewater treatment applications.

Photocatalytic Degradation of Organic Dyes by Magnetite Nanoparticles Prepared by Co-Precipitation.

Iron oxide nanoparticles were synthesized by co-precipitation using three different iron salt stoichiometric mole ratios. Powder X-ray diffraction patterns revealed the inverse cubic spinel structure of magnetite iron oxide. Transmission electron microscopic images showed Fe3O4 nanoparticles with different shapes and average particle sizes of 5.48 nm for Fe3O4-1:2, 6.02 nm for Fe3O4-1.5:2, and 6.98 nm for Fe3O4-2:3 with an energy bandgap of 3.27 to 3.53 eV. The as-prepared Fe3O4 nanoparticles were used as photocatalysts to degrade brilliant green (BG), rhodamine B (RhB), indigo carmine (IC), and methyl red (MR) under visible light irradiation. The photocatalytic degradation efficiency of 80.4% was obtained from Fe3O4-1:2 for brilliant green, 61.5% from Fe3O4-1.5:2 for rhodamine B, and 77.9% and 73.9% from Fe3O4-2:3 for both indigo carmine and methyl red. This indicates that Fe3O4-2:3 is more efficient in the degradation of more than one dye. This study shows that brilliant green degrades most effectively at pH 9, rhodamine B degrades best at pH 6.5, and indigo carmine and methyl red degrade most efficiently at pH 3. Recyclability experiments showed that the Fe3O4 photocatalysts can be recycled four times and are photostable.

Construction of a Wood Nanofiber-Bismuth Halide Photocatalyst and Catalytic Degradation Performance of Tetracycline from Aqueous Solutions.

Nanostructured bismuth oxide bromide (BiOBr) has attracted considerable attention as a visible light catalyst. However, its photocatalytic degradation efficiency is limited by its low specific surface area. In this study, a solvothermal approach was employed to synthesize BiOBr, which was subsequently loaded onto cellulose nanofibers (CNFs) to obtain a bismuth halide composite catalyst. The performance of this catalyst in the removal of refractory organic pollutants such as tetracycline (TC) from solutions under visible light excitation was examined. Our results indicate that BiOBr/CNF effectively removes TC from the solution under light conditions. At a catalyst dosage of 100 mg/L, the removal efficiency for TC (with an initial concentration of 100 mg/L) was 94.2%. This study elucidates the relationship between the microstructure of BiOBr/CNF composite catalysts and their improved photocatalytic activity, offering a new method for effectively removing pollutants from water.