Synthesis of hydrochar-based AgBr/Bi2WO6 heterojunction photocatalyst using dopant element and its loading on PVDF membrane: Study on degradation of sulfadiazine

[Display omitted] •Br- doping in Bi2WO6 was reused to form tightly bound heterojunction;•Ag/AgBr/Bi2WO6/CHC (AABC) could degrade 97.58% sulfadiazine (SD) within 90 min;•Polyfuran structure in hydrochar might promote photogenerated carrier separation;•Hydroxyl and carboxyl groups on hydrochar had a positive effect on ⋅O2– production;•PVDF/AABC membrane could degrade 90.03% SD within 200 min. Environmentally friendly bismuth-based photocatalysts and biomass carbon materials are attractive in photocatalysis but also face the problem of fast photogenerated carrier complexation. To cope with this problem and forming tighter heterojunctions, this manuscript presented the synthesis of Bi2WO6/AgBr heterojunction photocatalyst loaded with Ag nanoparticles (Ag NPs) supported by hydrochar, which was synthesized by using Br- doped in Bi2WO6, resulting in an excellent photocatalytic effect. The heterojunction, the Ag NPs, and the abundance of oxygenated functional groups (OFGs) of hydrochar (CHC) all served to enhance the photogenerated carrier separation performance of Ag/AgBr/Bi2WO6/CHC (AABC). Furthermore, the polyfuran structure presented in CHC might accelerate the generation of photogenerated carriers, thus also promoting the ability of AABC to separate photogenerated carriers. This enabled AABC to degrade 97.58% of sulfadiazine (SD) in 90 min while exhibiting a pseudo-first-order kinetic constant more than 12 times that of pure Bi2WO6. Remarkably, AABC exhibited extraordinary reusability, environmental adaptability, and generalizability to different types of organic pollutants. After five cycles, the SD removal was maintained at 94.62% and the total organic carbon (TOC) removal rate of 78.27% was achieved in 150 min. The PVDF/AABC membrane, prepared by loading AABC, was observed to degrade 90.03% of SD within 200 min of visible light irradiation. This work enabled the utilization of the dopant Br- in Bi2WO6, providing new ideas for the design of efficient photocatalysts and their application in antibiotic water treatment, as well as new insights into the reuse of waste biomass.