Free Radical Trapping Research Articles

Dye-sensitized n-n heterojunction {001}TiO2@NH2-MIL-101(Fe) for degradation of rhodamine B under visible light

The {001}TiO2@NH2-MIL-101(Fe) heterojunctions (MT-x) crafted by the fusion of components {001}TiO2 and NH2-MIL-101(Fe) possesses an optimally positioned conduction band. Consequently, MT-x is capable of sensitizing Rhodamine B (RhB) and effectuating its degradation via a photocatalytic mechanism that is driven by visible light irradiation. Specifically, the n-n heterojunction designated as MT-3 achieved a RhB removal rate of 94.45 % within a 3-hour period, which corresponds to a 5.4-fold and 2.2-fold enhancement over the degradation rates observed for {001}TiO2 and NH2-MIL-101(Fe), respectively. Photo-electrocatalytic performance analyses showed that the n-n heterojunction MT-3 effectively inhibited electron-hole pair recombination. Moreover, the intimate interfacial contact between monomer materials enhanced the separation and transfer of photogenerated carriers, which indicates that MT-3 has excellent photocatalytic performance. The free radical trapping and EPR results indicated that ·O2- plays a major role in the photocatalytic degradation of RhB by MT-3, followed by h+ and ·OH. Furthermore, high-resolution liquid chromatography-mass spectrometry was employed to investigate photodegradation intermediates. The destruction of the RhB structure significantly reduced the environmental pollution associated with organic dye. The MT-x heterojunction exhibits remarkable potential for practical applications in organic contaminants removal.

Antibacterial Properties and Application of Bi2Sn2O7/ZnO Composite Photocatalytic Materials.

In this experiment, Bi2Sn2O7/ZnO composite photocatalytic materials were synthesized by a hydrothermal method and characterized by XRD, SEM, and EDS, etc. The prepared Bi2Sn2O7/ZnO has a nanorod structure and high phase purity. The photocatalytic antimicrobial performance of Bi2Sn2O7/ZnO against bacteria and fungi under visible light was significantly better than that of single Bi2Sn2O7 and ZnO. In particular, 1000 mg/L 1 : 3 Bi2Sn2O7/ZnO showed an antimicrobial rate of more than 97 % against Escherichia coli, Staphylococcus aureus, and Candida albicans, which are widely present in the nature. The free radical trapping experiments were selected and the antimicrobial mechanism was investigated, and the results showed that the antimicrobial process of the Bi2Sn2O7/ZnO system was regulated by the free radicals such as ⋅OH, h+, and e-, which were generated by its unique photocatalytic activity. Finally, MTT cytotoxicity experiments demonstrated that the Bi₂Sn₂O₇/ZnO composite was not toxic to cells. In addition, the antimicrobial performance of Bi2Sn2O7/ZnO on real livestock wastewater and the real-life application of the prepared Bi2Sn2O7/ZnO PCL composite antibiotic film for antimicrobial treatment of freshly cut fruits' surfaces under visible light were experimentally investigated. This study provides a new idea for Bi2Sn2O7/ZnO as a photocatalytic antimicrobial agent.

Fabrication of α-Fe2O3/TiO2 heterojunction for photocatalytic degradation of doxycycline hydrochloride

In this work, flower-like TiO2 (TiO2-F) was first prepared by modulating the morphology of TiO2, and then, α-Fe2O3 was loaded onto TiO2-F to successfully prepare α-Fe2O3/TiO2-F heterojunction materials. The material showed excellent degradation properties of doxycycline hydrochloride under visible light. The photocatalytic degradation efficiency of α-Fe2O3/TiO2-F2 for doxycycline hydrochloride under visible light reached 95.76 % in 120 min, and its pseudo-first-order degradation rate constant was 0.02647 min−1, which was 3.68 and 2.01 times higher than those of α-Fe2O3 and TiO2 alone, respectively. This good photocatalytic performance is attributed mainly to the introduction of α-Fe2O3 to form a Type II heterojunction with floral TiO2 (TiO2-F), which is capable of promoting the separation of electron–hole pairs of photocatalysts and exhibiting a stronger redox capacity. The material exhibits notable stability and maintains high degradation efficiency even after undergoing multiple cycles. Furthermore, free radical trapping experiments and electron spin resonance (ESR) characterization revealed that hydroxyl radicals play a dominant role in this system. Finally, the degradation pathways were analyzed, and relevant toxicological analyses were performed, indicating that the toxicity of doxycycline hydrochloride gradually decreased during the photocatalytic degradation process.

Photoelectrocatalytic activated persulfate degradation of organic contaminants by Ag3PO4/NiFe@Ni electrode

Ag3PO4/NiFe@Ni composites were obtained by depositing silver phosphate on nickel–iron layered double hydroxide (NiFe-LDH), is based on nickel flakes via two distinct methods: hydrothermal and successive ionic layer adsorption (SILAR). The electrode was used as a photoanode to remove Escherichia coli (E. coli) from wastewater and to facilitate the photoelectrocatalytic (PEC) breakdown of organic pollutants. In addition, the degrading efficiency of Tetracycline (TC) and rhodamine B was further enhanced by activating persulfate (PMS) during the PEC process. The Ag3PO4/NiFe@Ni electrode’s effective catalytic activity is mostly ascribed to Ag3PO4’s visible light activity as well as the construction of a Z-scheme heterojunction, it enhances the efficiency of e− and h+ (holes) separation and speeds up electron transport. The free radical trapping process revealed that multiple free radicals combined to achieve an efficient degradation of the pollutants. The PEC process activated PMS degraded 92 % of TC within 60 min, in which the oxidation of h+ was critically important. This study provides insights to design of multifunctional low-cost Z-scheme heterojunctions and broadens the application scope of photoelectrocatalytic technology.

Enhanced photocatalytic performance of SnS2/ZnO Z-scheme composite photocatalysts for efficient environmental remediation

Photocatalysts based on zinc oxide (ZnO) are promising for environmental applications, but their weak photoresponse and low photocarrier separation efficiency limit their practical use. To tackle this issue, we constructed Z-scheme composite photocatalysts of ZnO to boost its photocatalytic performance. We achieved the Z-scheme structure by hydrothermal modification of SnS2 nanoparticles onto ZnO microspheres. Its photocatalytic performance was evaluated through the degradation of Rhodamine B (RhB) under visible light with the assistance of magnetic stirring. The composite photocatalyst exhibited superior performance compared to individual ZnO and SnS2, achieving an optimal degradation rate of 0.0706 min⁻¹. This rate was 15.08 times higher than that of individual ZnO and 10.51 times higher than individual SnS2. Free radical trapping experiments showed that ·O2⁻ and ·OH radicals played a key role in RhB degradation. The Z-scheme composite structure established novel charge transport pathways, guided the migration of photogenerated carriers, and improved spatial separation, thereby enhancing photocatalytic performance. This study provides valuable insights into the design of highly efficient photocatalysts for environmental remediation, offering a promising solution for addressing challenges in pollution control and wastewater treatment.

Efficient photocatalytic degradation of tetracycline hydrochloride by Fe-TiO2/MIL-101(Cr) nanocomposites under visible light

The misuse of antibiotics, including tetracycline hydrochloride (TCH), can easily lead to drug resistance and the decline of human immunity, which is extremely harmful to human health. In this paper, TiO2 was modified using two different techniques: semiconductor composite and metal ion doping. Fe-TiO2/MIL-101 (Cr) nanocomposite photocatalyst (FTM-x) was effectively prepared by solvothermal method and used for the degradation of TCH in water under visible light. The performance of ternary composite materials, in comparison to single or binary compounds, are improved by using an easy and convenient hydrothermal technique. Among them, FTM-2 showed efficient photodegradation and structural stability. After 120 min in visible light, FTM-2 removed 95.5 % of TCH, and the removal was maintained at 85 % after 4 cycles. The composite FTM-x was characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman, which proved the successful synthesis of the composite. Photoelectrochemical and photoluminescence (PL) analyses were used to examine the photoelectric properties of the prepared photocatalysts. The results suggested that optimizing the composites' photoresponse and electron-hole separation could be linked to improving the photocatalytic performance. The photocatalytic activity of superoxide radicals (O2−) and hydroxyl radicals (OH) was demonstrated to be mediated by free radical trapping investigations, which were utilized to determine the active components of the process.

Fire safety and high mechanical strength epoxy resin enabled by a bis-benzimidazole-primed phenyl phosphonic acid

Preparation of fire safety and high mechanical strength epoxy resin (EP) has become a hot topic for its valuable applications in construction and other fields. Here, bis-2-aminobenzimidazole-modified phenyl phosphonates (PP-BMI) with symmetric structures were synthesized by a simple chemical modification strategy, and its fine structure and composition have been thoroughly characterized. Due to the multifaceted functions of PP-BMI in both gaseous and condensed phases, EP composite with 5 wt% PP-BMI reached a UL-94 V-0 rating and high LOI of 34.3 %. The excellent fire safety of EP/5PP-BMI was further verified with a significant reduction of 57 %, 52 % and 46 % in peak heat release rate (PHRR), total heat release (THR) and peak CO production (P-COP), respectively, compared to the original EP. The flame retardancy of PP-BMI on EP can be attributed to the dilution of non-combustion gases, free radical trapping and catalytic charring functions. More importantly, PP-BMI can further enhance the mechanical properties of EP, which is closely related to the interaction between PP-BMI and EP matrix. Furthermore, EP/PP-BMI composites have good resistance to acids and alkalis, ensuring long-lasting flame retardancy and mechanical properties. This work provides a new strategy for realizing epoxy composites with high fire safety and excellent mechanical properties in construction and multifaceted areas.

A fully bio-based intumescent flame retardant for enhancing the flame retardancy and smoke suppression properties of wood flour polypropylene composites

In this study, a fully bio-based intumescent flame retardant, phytic acid vanillin arginine salt (VR-PA), was designed and synthesized by l-arginine (AR) and vanillin (VA) via a Schiff base reaction, followed by the introduction of phytic acid (PA) using electrostatic ionic interactions. The intumescent flame retardant, VR-PA, was incorporated into wood flour polypropylene composites (WFPP) to enhance their flame retardant and smoke suppression properties. Compared to pure WF, the limiting oxygen index (LOI) of WFPP with 20 wt% VR-PA increased to 28.2 %, while the peak heat release rate and total heat release were reduced by 35.4 % and 20.6 %, respectively. Additionally, the WF with 15 wt% VR-PA exhibited the greatest reduction in total smoke production, with a significant decrease of 42.1 %. The improved flame retardant and smoke suppression performance of the WF is attributed to the free radical trapping effect of VR-PA in the gas phase during the combustion process, as well as the formation of an expanded and continuous carbon layer during in the condensed phase. This study provides a green method to enhance the flame retardancy and smoke suppression of WFPP composites.

Establishing robust ZnO-sodium alginate nanocomposite for dye wastewater treatment: characterization, RSM methodology, and mechanism evaluation.

In today's world, water is a highly valued resource, and enhancing the quality of this natural endowment is a significant concern and a worldwide endeavor. This study sought to purify real wastewater and water tainted with methylene blue (MB) by immobilizing ZnO nanoparticles onto an alginate matrix using a straightforward approach and a three-dimensional structure. After analyzing the impact of , it was determined that 93.84% of MB was successfully removed (time = 120 min, dye concentration = 15 mg/L, catalyst amount = 2.5 g). The effects of inorganic ions and water types were investigated to simulate real wastewater conditions, and the catalyst performed satisfactorily. Alginate played a significant role in selectively removing dye, and the catalyst effectively removed 80.36% of MB and, in contrast, 20% of methyl orange (MO). The practical application of the catalyst was evaluated in textile wastewater treatment, and the catalyst showed satisfactory performance. An average 2.49% reduction in dye removal was observed after five stages of using the catalyst, demonstrating the beads' excellent stability. The composites were subjected to free radical trapping experiments to ascertain the active species. According to the results, and acted as the main reaction species in the degradation of MB. At the end, the synergistic mechanism of adsorption and degradation in MB removal was presented.

A P,N flame retardant containing flexible chain segments, imparting excellent toughness and flame retardancy to epoxy resins

AbstractIn order to enhance the flame retardancy of epoxy resin (EP) without affecting its mechanical properties, a phosphorus‐nitrogen synergistic flame retardant (MPCD) was synthesized in this paper by using melamine, paraformaldehyde, 9,10‐dihydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (DOPO) and cashew phenol as the raw materials, which was applied to the Ep in order to improve its flame retardancy and toughness. Experiments have shown that only 5% content of MPCD added into the EPs could achieve a significant LOI of 35.8% and successfully obtained a V‐0 rating in UL‐94 testing. In contrast, the PHRR with 5% additional MPCD was 456.4 kW/m2 and the THR was 80.2 MJ/m2, which were 52.6% and 29.4% lower than that of pure EPs, respectively. The PHRR of pure EPs was 963.1 kW/m2 and THR was 113.6 MJ/m2, which indicated that the addition of MPCD improved the EP system's flame retardant performance. The impact strength of pure EPs was 13.5 KJ/m2, and 5% addition of MPCD resulted in a 99% increase in the impact strength of EP/MPCD cured samples up to 26.9 KJ/m2, which was explained by the cashew phenol moiety's flexible chain segments. Furthermore, it is discovered by researching its flame‐retardant mechanism that the addition of MPCD may significantly improve the carbon layer's capacity to form char and maintain thermal stability. It can also efficiently trap free radicals and dilute the combustible gases produced during combustion. The flame retardant can increase the overall safety of the EP system by acting as a biphasic flame retardant in both the gas and the solidified phases at the same time.

Efficient photocatalytic degradation of tetracycline and its derivatives by green recyclable PAN/Bi2WO6/Cu2O nanofiber membrane

The use of tetracycline antibiotics in industry, healthcare, animal husbandry, agriculture, and aquaculture has resulted in excessive concentrations in a variety of aquatic environments. In this work, PAN/Bi2WO6/Cu2O nanofibrous membranes (PBC ENMs) with photocatalytic degradation performance were successfully prepared using electrostatic spinning technique, and the morphology of catalysts and PBC ENMs were characterised by SEM, BET and UV–Vis. The results demonstrated that the prepared nanofibrous membranes could achieve 97.05 % photocatalytic degradation of TC under visible light, and the degradation efficiencies of its derivatives, chlortetracycline (CTC) and oxytetracycline (OTC), reached 90.87 % and 85.12 %, respectively. Free radical trapping experiments and mechanistic analyses showed that·O2– is the main active factor in the degradation process. The highest degradation rate of 97.05 % was achieved at initial pH = 7.2.PBC ENMs adsorbed above 87.5 % after six cycles of the experiment. The highest degradation rate of 97.05 % was achieved at initial pH = 7.2 PBC ENMs adsorbed above 87.5 % after six cycles of the experiment. Based on the above advantages, the preparation process of PBC ENMs is simple, low-cost and has good catalytic effect, which provides a simple and efficient treatment means for the treatment of TC wastewater and has a broad application prospect.

Rape straw biochar-assisted preparation of flower-like BiOCl with enriched oxygen vacancies for efficient photocatalytic CO2 reduction and pollutants degradation

Utilizing photocatalytic technology to transform CO2 into high added value chemical products has represented an effective strategy for alleviating the climate problems that have arisen due to excessive CO2 emissions. As a typical bismuth-based photocatalyst, BiOCl has garnered widespread attention due to its unique layered structure and low toxicity. However, the low light utilization efficiency and the rapid recombination of e−/h+ pairs severely hinder the practical application of BiOCl. Introducing oxygen vacancies (OVs) into BiOCl has been demonstrated to be one of the effective strategies for enhancing the photocatalytic performance of BiOCl. However, introduction of OVs through a mild and cost-effective approach remains a significant challenge. In this work, we developed a strategy for introducing OVs on BiOCl, which indues the growth of BiOCl into flower-like spherical structures and introduction of abundant OVs through addition of rape straw biochar (RC) under hydrothermal conditions. The synergistic interaction of RC and OVs endows with BiOCl more active sites as well as higher photogenerated carriers (e−/h+) separation efficiency. When the mass ratio of RC to BiOCl is 0.5 % (RC-0.5), the sample demonstrates the best performance, conversion of CO2 to CO on the sample is 4.0 μmol g−1 h−1, which is 3.08 times higher than that on the reference BiOCl. Additionally, versatility of the photocatalysts was further evaluated through photocatalytic degradation of rhodamine B (RhB) and perfluorooctanoic acid (PFOA). The degradation rate constant of RhB and PFOA on the RC-0.5 sample is 0.0642 min−1 and 0.00566 min−1, respectively, which is 2.26 times and 0.43 times higher than that on the reference BiOCl. Total organic carbon (TOC) experiments demonstrate that RhB can be effectively mineralized into CO2, H2O and small molecules on the photocatalyst. The main reactive species involved in the photocatalytic degradation process were investigated through active free radical trapping experiments and electron paramagnetic resonance (EPR). This work provides a viable strategy for the development of high-performance BiOCl photocatalysts for environmental applications.

Enhancing Microplastic Degradation through Synergistic Photocatalytic and Pretreatment Approaches.

Microplastics (MPs) pollution has emerged as a pressing environmental concern in recent years. Owing to their minute dimensions, conventional plastic remediation approaches are inadequate for addressing the challenges posed by MPs. Herein, spherical (BOC-S) and nanosheet (BOC-N) BiOCl photocatalysts were prepared and applied to the degradation of poly(ethylene terephthalate) (PET) MPs after hydrothermal pretreatment. The results indicated that the degradation efficiency of pretreated PET MPs using BOC-S and BOC-N photocatalysts was 8.8 and 6.9 times that of the unpretreated MPs under the same conditions. Comparative experiments confirmed the excellent performance of the photocatalysis-pretreatment system. The creation of pores on the surface of pretreated PET MPs facilitates the entry of active substances into the interior to cause damage, while the enhancement of hydrophilicity and specific surface area facilitates the contact between the catalyst and PET MPs, thus increasing the degradation efficiency. Free radical trapping experiments revealed that hydroxyl radicals (·OH) produced by photocatalysis had the greatest influence on the degradation performance of pretreated PET MPs. Finally, a possible photocatalytic degradation mechanism for PET MPs was proposed. This research offers a novel perspective on MPs degradation, providing valuable insights for advancing the efficacy of the process.

Novel biomass carbon dots/chitosan hydrogel-modified TiO2: An effective reduction of Cr(VI) in various wastewater under sunlight

Hexavalent chromium (Cr(VI)) poses a serious threat to the environment and human health owing to its inherent toxicity. Photocatalysis technology has garnered widespread attention owing to its efficiency and environmental friendliness. However, existing photocatalysts are constrained by light conditions, low reduction rates, and lack of studies in real wastewater. In this study, biomass carbon dots (P-CDs) were synthesized from peanut shell powder, then combined with chitosan (CS) and TiO2 to create a novel photocatalyst (9:1 1 % P-CDs/TiO2@CS). The photocatalyst exhibited a smaller band gap and a broader light absorption range than TiO2, while the porous structure of the hydrogel increased the contact area between P-CDs/TiO2@CS and Cr(VI), thereby enhancing its photocatalytic performance. Our study demonstrates that under simulated sunlight using a xenon lamp, 0.2 g of 9:1 1 % P-CDs/TiO2@CS reduced 50 mg/L Cr(VI) at a rate of 99.64 % in 30 min (pH 7). The photocatalyst also exhibited excellent reduction capabilities for Cr(VI) across a pH range (pH 2–9), at different concentrations (10, 20, 30, 40, 50, and 60 mg/L), and in various real wastewater samples (influent, effluent, and electroplating wastewater). After five cycles, the reduction rate was still maintained at 90.38 %. Experiments conducted under natural sunlight and ion interference further confirmed its outstanding photocatalytic performance and stability in real-world applications. Free radical trapping experiments indicated that electrons (e-) and holes (h+) were the primary active species. Additionally, antibacterial experiments showed that the reactive oxygen species generated by the photocatalyst under light irradiation effectively inhibited the proliferation ofEscherichia coli. Thus, P-CDs/TiO2@CS holds significant potential for practical application in environmental wastewater treatment.

Synthesis of ZnPc/BiVO4 Z-Scheme Heterojunction for Enhanced Photocatalytic Degradation of Tetracycline Under Visible Light Irradiation

The construction of semiconductor heterojunctions is an effective strategy to improve the photocatalytic degradation efficiency of organic pollutants. Herein, ZnPc/BiVO4 Z-scheme heterojunction was synthesized via a physical mixing method and was used for the photocatalytic degradation of tetracycline (TC) under visible light irradiation. Compared with BiVO4 and ZnPc, the 15ZnPc/BiVO4 sample exhibited improved light absorption capacity, and the electron-hole separation efficiency and redox capacity were enhanced due to the formation of the Z-scheme heterojunction. The 15ZnPc/BiVO4 composite exhibited an optimal TC degradation rate of 83.1% within 120 min. Additionally, 15ZnPc/BiVO4 exhibited excellent stability in cycling experiments, which maintained a high TC degradation rate of 79.5% after four cycles. Free radical trapping experiments indicated that superoxide radicals (O2−) were the main active substances in the photocatalytic degradation of TC.

Construction of Co-CN as a high-performance catalyst for photocatalytic tetracycline degradation and mechanism study

Constructing highly efficient and stable catalysts for tetracycline degradation is very important in avoiding harm to human and ecosystem health. Herein, we doped Co-MOF into carbon nitride (CN) and synthesized successfully a copolymer Co-CN with heterojunctions structure simple intramolecular doping. Various characterization results demonstrate that Co2+ cations are highly dispersed on the CN support. The Co-CN catalyst exhibited outstanding degradation efficiency and recycle stability for tetracycline (TC) degradation, demonstrates a degradation efficiency of 85.2% under benign conditions. Various characterization results revealed the pathway and mechanism of TC degradation. An intramolecular heterojunction structures in Co-CN copolymers promote charge separation and transport efficiency, which make a variety of active species to be generated in the reaction system. Free radical trapping experiment results show that four active species including h+, 1O2, ·O2− and ·OH synergistically catalyze to activate the substrate to achieve degradation of TC molecules.

ZIF-8-CdS photonic crystal beads for slow photon effect induced enhanced photocatalysts

The unique periodic structure of photonic crystals demonstrates an effective slow photon effect that enhances the interaction between light and matter. This study designed and prepared MOF photonic crystal beads, and significantly improved the photocatalytic efficiency by utilizing the slow light effect. Utilizing microfluidic technology, ZIF-8 was self-assembled to form photonic crystal beads (PCB-Z) to enhance adsorption properties and light absorption. The surface of PCB-Z is modified with CdS to form a heterostructure (PCB-ZC), which widens the absorption spectrum, reduces the carrier recombination rate, and increases the specific surface area, while the photocurrent intensity of PCB-ZC is about 1.8 and 29 times that of CdS and PCB-Z. Under the combined effect of photonic crystal structure, ZIF-8/CdS heterojunction and slow photon effect, the degradation rate of Rhodamine B by PCB-ZC was 15.22 times higher than the disordered ZIF-8 powder, and the photocatalytic performance was significantly improved. The dominant role of holes in Rhodamine B degradation was confirmed by free radical trapping experiments and EPR tests. This research confirms that MOF-based photonic crystals can be assembled into periodic structures to enhance adsorption properties and light absorption, which provides a new paradigm for the development of MOF-based photocatalysts.

A novel metal-free nanomaterial P-CN/BC/NCDs preparation and its performance of photocatalytic degradation

The development of photocatalysts with high charge separation and migration efficiencies for environmental remediation using sunlight had been a research priority. In this study, a ternary composite photocatalyst, P-CN/BC/NCDs, was successfully synthesized by thermal condensation and hydrothermal methods, incorporating graphitic carbon nitride (P-CN), biochar (BC), and nitrogen-doped carbon quantum dots (NCDs). Alizarin red S (ARS) was selected as the model pollutant to evaluate the photocatalytic degradation performance. P-CN/BC/NCDs exhibited enhanced photocatalytic degradation performance under visible light irradiation, with a 4.5-fold improvement compared to P-CN alone. The optimally NCDs-loaded P-CN/BC nanocomposites exhibited high visible light absorption and high specific surface area. The increased photocatalytic activity was further confirmed by the increase in photocurrent intensity and the decrease in fluorescence intensity and resistance. XPS and FT-IR tests showed that NCDs, as co-catalysts of P-CN/BC, effectively promoted charge separation through ether bonds and electrostatic interactions. It was experimentally verified by free radical trapping experiments and EPR tests that •O2− was the primary active species in the photocatalytic process, while •OH served as an auxiliary site during the degradation process. Cyclic experiments demonstrated high reusability and excellent stability, with an activity exceeding 93.8 %. Decomposition intermediates and reaction pathways were identified by liquid-quality analysis. Photocatalyst pervasiveness was evaluated by using different pollutants including methyl orange (MO), rhodamine B (Rh B) under similar conditions. This design concept of functional synergistic modification of P-CN materials holds promise for application in various fields.

Synthesis of a novel NiCo-LDH/Bi2WO6 Z-scheme heterojunction composite for photocatalytic degradation of tetracycline

This article aims at preparing of Z-scheme heterojunction NiCo-LDH/Bi2WO6 (LDH: layered double hydroxides) via a solvothermal technique, addressing the rapid recombination of electron-hole pairs caused by the narrow bandgap of Bi2WO6. Successful loading of NiCo-LDH onto Bi2WO6 was confirmed through various characterization techniques, assessing the composite's crystal structure, morphological traits, and performance. Notably, the NiCo-LDH/Bi2WO6 composite exhibited excellent photocatalytic performance in the degradation of tetracycline (TC), achieving an optimal reaction rate of 0.03 min−1, which is 4.8 times faster than that of Bi2WO6 alone. The findings demonstrate that the formation of the heterojunction structure facilitated the separation of photogenerated electron-hole pairs by reducing recombination in monomers. Free radical trapping experiments showcased that the decomposition of TC is primarily driven by h+ and ∙O2−. Additionally, liquid chromatography-mass spectrometry analysis identified the degradation products of TC and suggested two potential degradation pathways. The present research provides a novel approach for preparing LDH photocatalytic materials using NiCo-LDH/Bi2WO6.

Synthesis of novel Ag-doped ZnFe based-oxides nanocomposite for wastewater treatment, self-cleaning, and corrosion resistance

To tackle the critical environmental and industrial challenges, this research endeavors to develop nanomaterial with enhanced photocatalytic function, corrosion resistance, self-cleaning capabilities, and optimal effluent treatment. This research successfully synthesized Ag@ZnFe2O4 nanocomposite to activate peroxymonosulfate (PMS) for the removal of Congo red from water. The structural composition and morphology of the materials were examined by the utilization of XRD, FTIR, XPS, SEM with EDS and TEM. The study examined the impacts of catalyst dosage, concentrations of PMS, pH, and simultaneous ions on the experiment, as well as the ability of the nanocomposites to be reused and their stability. The photocatalytic degradation process was hypothesized to operate using free radical trapping tests. Results indicated that the heterostructure junction flanked by ZnFe2O4 nanoparticles and Ag promoted charge transfer, reducing electron-hole recombination. By adding 5 mg of Ag@ZnFe₂O₄ nanocomposite, Congo red degradation was optimized at 98.7 % due to the huge surface area of Ag microflowers, which boosted active sites and CR elimination. Due to nanoparticle surface charge, PMS speciation, and radical interactions, CR degradation was most efficient at pH 7.3 and less efficient at pH 9.5. CR degradation rates rose with PMS concentration, reaching 34.7 %, 67.9 %, and 97.9 % at 0.3, 0.6, and 1 mM, respectively. The order of the inhibitory action was CO32− > H2PO4− > Cl− > NO3−. Free radical entrapment experiments show that hydroxyl (•OH) and sulfate radicals (•SO₄⁻) are key in CR photodegradation, with h+ and •O₂ being the main active species. ESR tests revealed radicals, while electron transfer between ZnFe₂O₄ and Ag boosted carrier migration, driving redox cycles and CR breakdown into stable byproducts like CO₂ and H₂O. Light-induced reaction eliminated 45.8 % of TOC, indicating CR partial mineralization. Mechanism of PMS-based photodegradation of CR removal was proposed. This study underscores the promising potential of Ag@ZnFe2O4/nanocomposites for PMS activation in degrading Congo red-contaminated wastewater. Electrochemical impedance spectroscopy (EIS) showed that a polymeric nanocomposite coating greatly improves the ability to resist corrosion in steel substrates when exposed to a 3.5 % NaCl solution. This is achieved by reducing the corrosion current density and boosting corrosion resistance. Superhydrophobic nanocomposite coatings repel water and pollutants, safeguarding various substrates from soil residues.