Pyrolysis temperature effect on biochar-derived cow manure: Physicochemical properties and adsorption behavior toward organic dyes

Background: This study investigates the synthesis of biochar from cow manure at various pyrolysis temperatures and its effectiveness in dye adsorption, focusing on how temperature influences the adsorption capacities of biochar towards MB and MO. Methods: Biochar was produced at four pyrolysis temperatures (300, 500, 700, and 900 degrees C), labeled CMBC-x. Adsorption capacities for MB and MO were tested. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) identified functional groups involved in dye adsorption. Findings: Biochar produced at 900 degrees C (CMBC900) showed the highest adsorption capacities: 200 mg g-1 for MB and 147 mg g-1 for MO. For a dye mixture, CMBC900 adsorbed 104.5 mg g-1 of MB and 98.7 mg g-1 of MO, indicating efficient separation. CMBC900 maintained high efficiency after ten cycles, with 97.5 % for MB and 90.5 % for MO. These findings highlight the robustness and long-term potential of CMBC900 as an adsorbent. Converting agricultural waste into biochar offers an economically viable solution for waste management and environmental protection by removing harmful dyes from wastewater.