Search Results (4)

Peroxynitrite-based advanced oxidation technology has gradually become a research hotspot for degrading dye wastewater due to its high efficiency and environmentally friendly features. Transition metal elements, which are commonly used as catalysts for the activation of persulfates, suffer from problems such as easy deactivation and leaching of metal ions, which limit their practical application. In this study, Co₇₈Si₈B₁₄/g-C₃N₄ composite catalysts were prepared by wet milling and ball milling methods to investigate their degradation of Orange II dyes by assisting the activation of peroxynitrite under visible light, and the effects of the catalyst ratio, light intensity, and the dosage of catalysts on the degradation performance were investigated. It was shown that the optimum ratio of Co₇₈Si₈B₁₄ to g-C₃N₄ was 1:3, and the reaction rate constants for the degradation of orange dye by Co₇₈Si₈B₁₄/g-C₃N₄ + PMS + VIS were 4.3 and 5.37 times higher than those of single g-C₃N₄ + PMS and Co₇₈Si₈B₁₄ + PMS, respectively. Meanwhile, the composite catalyst also showed good degradation performance for rhodamine B, methyl orange, and methylene blue dyes, and the degradation effect could reach more than 75%. Cyclic stability tests showed that the catalyst maintained a high degradation efficiency of more than 94% over multiple cycles with low ion dissolution concentration. Its high catalytic activity is attributed to the lowest adsorption energy of the composite catalyst to PMS (E_ads = −1.97 eV), which facilitates the degradation reaction, while the synergistic effect of g-C₃N₄ and Co₇₈Si₈B₁₄ promotes the production of ·SO₄, ·OH, and ·O²⁻. This study provides new ideas for the development of stable and efficient catalysts to expand the synergy between PMS-based and other advanced oxidation technologies. Full article

Defects and heteroatom doping are two refined microstructural factors that significantly affect the performance of photocatalytic materials. Coupling defect and doping engineering is a powerful approach for designing efficient photocatalysts. In this research, we successfully construct dual defect-engineered BiVO₄ nanosheets (BVO-N-OV) by introducing N doping and oxygen vacancies through ammonium oxalate-assisted thermal treatment of BiVO₄ nanosheets. Due to the combined enhancement of band structure and surface properties from N doping and oxygen vacancies, the obtained BVO-N-OV nanosheets demonstrate improved visible light absorption, effective charge transfer efficiency, and increased active sites. As a result, the constructed BVO-N-OV/PMS system demonstrates significantly enhanced ciprofloxacin (CIP) removal performance under visible light illumination. The highest rate constant for CIP degradation over BVO-N-OV/PMS system is 7.9, 1.9, and 6.6 times greater than pristine BiVO₄ (BVO), oxygen vacancy-enriched BiVO₄ (BVO-OV), and N-doped BiVO₄ (BVO-N), respectively. Even in a broad pH range (3.0–11.0) with various anions, the BVO-N-OV/PMS/Vis system still demonstrates stable and excellent CIP removal performance. This study seeks to provide valuable insights into the interaction between defect and doping engineering in photocatalytic activation of PMS, thereby proposing new strategies for designing effective photocatalyst/PMS systems for wastewater treatment. Full article

In this work, the heterojunctions of CuInS₂ embedded in the g-C₃N₄ materials (xCuInS₂/g-C₃N₄, abbreviated as xCIS/GCN) was successfully prepared for peroxymonosulfate (PMS) activation under visible light. The catalysts are characterized by different techniques, such as XRD, FTIR, SEM, TEM, and UV-vis. The unique heterojunction composites can suppress the recombination of photogenerated pairs. The catalytic results showed that the 3CIS/GCN exhibited excellent catalytic levofloxacin (LVF) degradation efficiency, while more than 98.9% of LVF was removed in 60 min over a wide pH range. SO₄^•−, O₂^•−, OH^•, and ¹O₂ were verified as the main reactive species for LVF degradation via the quenching experiments and electron paramagnetic resonance technology (EPR). The synergetic effect of xCIS/GCN, PMS, and visible light irradiation was discussed. The possible LVF degradation pathway was proposed through byproducts analysis (LC-MS). Moreover, the 3CIS/GCN/vis-PMS system has very low metal leaching. Owing to xCIS/GCN having good properties for PMS activation, it has potential applications for LVF or other hazardous pollutants degradation. Full article

Zn_1−xCd_xS catalysts with Zeolitic Imidazolate Framework-8 (ZIF-8) as the precursor were successfully prepared by ion exchange method, and the ability and electrochemical properties of a series of ZIF-8, ZnS and Zn_1−xCd_xS catalysts in photocatalytic degradation of 2-CP and TC were investigated. Doping of Cd ions was able to modulate the ZnS band gap width and improve the utilization of visible light by the photocatalyst. The nanocage catalysts with hollow structure of Zn_1−xCd_xS have better photocatalytic response. The removal of photocatalytic pollutants was up to 90% under optimal conditions. Using a Peroxymonosulfate (PMS)-assisted system to improve the degradation efficiency of 2-chlorophenol and tetracycline hydrochloride under visible light, we present a possible mechanism of Zn_1−xCd_xS as a photocatalyst for degradation in persistent pollutants and in PMS-assisted photocatalysis. Four active species, O₂⁻, h⁺, -OH, and SO₄•⁻, can be generated to degrade 2-chlorophenol and tetracycline hydrochloride under PMS-assisted activation. Zn_1−xCd_xS nanocage with high activity and stability provides a feasible approach to catalytically remove persistent pollutants from aqueous solutions under visible light conditions. Full article