Relationship of the physicochemical properties of novel ZnO/biochar composites to their efficiencies in the degradation of sulfamethoxazole and methyl orange

Three different composites were produced, based on zinc oxide and biochar (ZnO/biochar), varying the type of biomass (Salvinia molesta: SM; exhausted husk of black wattle: EH; and sugarcane bagasse: SB), with pyrolysis under mild conditions at 350 and 450 degrees C. Evaluation was made of the capacities of the composites for photocatalytic degradation of sulfamethoxazole antibiotic (SMX) andmethyl orange dye (MO). The properties of the prepared compositeswere influenced by the biomass source, with larger crystallite size (SB), lower band gap energy (SM), higher specific surface area (SB), and larger pore size (SM) resulting in higher photocatalytic efficiency. Good degradation results were obtained using these innovative photocatalysts prepared at low temperatures, when compared to ZnO/biocharmaterials reported in previous studies. The best degradation capacities were obtained for the composites produced at 450 degrees C from SB and SM, with 99.3 and 97% degradation of SMX after 45 min, and 90.8 and 88.3% degradation of MO after 120 min, respectively. (C) 2020 Elsevier B.V. All rights reserved.