RESUMO
3DOMLaFeO3 was prepared by template method combined with sol-gel method using monodisperse polystyrene (PS) microspheres as template, and Ag/3DOMLaFeO3 perovskite catalyst was prepared by impregnation method combined with sodium borohydride reduction method. The catalysts were characterised by means of TG, XRD, SEM, BET, XPS, UV-vis DRS, etc. The photo-Fenton catalytic performance, stability and catalytic reaction mechanism of Ag/3DOMLaFeO3 were studied with penicillin G potassium (PEN G) as the model pollutant. The results indicated that the as-prepared Ag/3DOMLaFeO3 exhibited a three-dimensional ordered macroporous (3DOM) structure, and the light capture and mass transfer were enhanced through abundant pores and large specific surface area. Based on the surface plasmon resonance effect (SPR), Ag loading enhanced the absorption of the material in the visible light region, and inhibited the recombination of photogenerated carriers, which improved the photocatalytic performance of 3DOMLaFeO3 under visible light. Under the conditions of hydrogen peroxide dosage of 1.5â mL·L-1, initial pH of 5, PEN G initial concentration of 100â mg·L-1, catalyst dosage of 300â mg·L-1, xenon lamp irradiation, the degration ratio of PEN G and the removal rate of TOC reached 99.99% and 85.45% within 120â min, respectively. In addition, it had a wide range of pH application, excellent stability and practical application value. The quenching experiment and ESR test showed that ·OH and ·O2- were the reasons for high catalytic degradation. The least square method was used to fit the experimental data, and the results displayed that the degradation of PEN G was approximately in line with the first-order kinetic reaction.
RESUMO
A PVA aerogel/TiO2/MoS2/Au catalyst formed gradually using a hydrothermal method is used to degrade Rhodamine B. SEM and TEM results show that the composite presents a uniform and well-structured porous network structure, high specific surface area and large pore diameter were proved by the results of nitrogen adsorption measurement. UV-vis DRS and PL results indicate that the composite has a high absorption rate in the visible light range, and the recombination of photogenerated electron-hole pairs can be effectively inhibited because the composite material forms a heterojunction. In the photocatalytic degradation experiment of Rhodamine B, the composite material shows high photocatalytic performance, which can reach 86% in two hours of light. The photocatalysts supported by PVA are easy to recover and have high catalytic performance even after five recycles. The study shows that PVA/TiO2/MoS2/Au composite material has great potential to be used for the degradation of dye wastewater.
RESUMO
A composite consisting of reduced graphene oxide aerogel/titanium dioxide/molybdenum disulfide (abbreviated as RGO aerogel/TiO2/MoS2) was developed for the removal of organic dyes from solution cooperatively by adsorption and photocatalytic degradation mechanisms. The composite was successfully synthesized by stepwise layered assembly integration, including sol-gel and physical vapor deposition (PVD) methods. The resulting multi-component composite material featured a high specific surface area (255.441 m2/g) containing a myriad of negatively charged carboxylate functional groups on the surface of the composite, which enabled the composite material to demonstrate a high removal efficiency of cationic dyes, such as rhodamine B, from solution. In addition, the composite featured optimal optical and photocatalytic properties for facilitating efficient photodegradation of the dye molecules, including a large absorbance in the visible light region and a fast transfer of photogenerated electron-hole pairs. Moreover, electron paramagnetic resonance (EPR) analysis and reactive oxygen species scavenging experiments confirmed that superoxide radicals (O2â¢-), holes (h+), and hydroxyl radicals (â¢OH) were involved in photocatalytic degradation of the organic dyes.