Preparation of Novel H3PO4 Mixed Sludge‐Sunflower Seeds Husk Biochar and its Application in TC Removal

Abstract This study primarily focuses on creating a new biochar substance using a combination of sewage sludge and sunflower seed husk. The biochar shows significant efficacy in eliminating tetracycline (TC). The characteristics of biochar, such as SEM, XPS, FT‐IR, and BET, were investigated respectively. After H 3 PO 4 was added to change the surface, the novel biochar exhibited a porous and stiff surface, a larger specific surface area, and more carboxylic acid functional groups. Consequently, the activated biochar exhibited a higher adsorption capacity for TC than the pristine biochar, with values of 39.57 mg/g and 15.74 mg/g, respectively. The pseudo‐second‐order kinetics could describe the sorption of TC on PBCSS and BCSS well (R 2 for PBCSS and BCSS is 0.876 and 0.824, respectively). The adsorption process was described using the Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms. Chemical adsorption helps TC and biochar stick to each other. Donor‐acceptor interactions, hydrogen bonds, and electrostatic interactions all make this possible. The study showed that the new biochar has the potential to be an economical adsorbent for the removal of TC from wastewater.