Catalytic fixation of hydrogen sulfide over CuO-CaCO3 co-impregnated tea stalk-derived biochar

Effective treatment of hydrogen sulfide (H 2 S) is crucial for minimizing nuisance odors from intensive livestock and poultry operations. The development of high-performance desulfurizers holds practical significance in this context. Herein, a novel CuO-CaCO 3 co-impregnated biochar desulfurizer (Cu x Ca y /BC T ) was synthesized by impregnation-pyrolysis method, using waste tea stalks and metal salts as raw materials, and it is intended for the treatment of H 2 S at room temperature. The optimized Cu 0.75 Ca 0.25 /BC 800 shows an excellent H 2 S removal capacity of 182.67 mg/g, which is 31 times and 5.6 times that of inactivated biochar (BC 800 ) and copper-oxide-impregnated biochar (Cu 0.75 /BC 800 ). The desulfurization mechanism of Cu 0.75 Ca 0.25 /BC 800 involves synergistic effect of reactive adsorption and catalytic oxidation . CaCO 3 ’s alkaline adsorption sites and copper-mediated activation of superoxide radicals (∙O 2 - ) were critical in this reaction. Besides, Cu 0.75 Ca 0.25 /BC 800 demonstrated excellent reusability, retaining approximately 85 % of its initial H 2 S removal capacity after seven cycles of desulfurization and regeneration. This study aims to develop a metal oxide- and carbonate-impregnated biochar-based desulfurizer, with the goal of advancing the technology for catalytic removal of H 2 S in a more environmentally friendly and effective manner.