Pyrolytic conversion of cattle manure into value-added products and application of biochar for adsorption of sulfamethoxazole.

This study investigated the thermochemical conversion of cattle manure (CM) to propose a sustainable platform for its valorization, and explored the applicability of CM-derived biochar (CMB) as an environmental medium for the adsorptive removal of sulfamethoxazole (SMZ). CM pyrolysis was conducted under two atmospheric conditions (N and CO), and the pyrogenic products were quantified and characterized. Real-time syngas monitoring revealed that CO enhanced CO generation from the CM, leading to the formation of a highly porous carbon structure in the produced biochar (CMBCO). The adsorptive removal of SMZ by CMBCO was highly dependent on the pH conditions. The adsorption kinetics of SMZ onto CMBCO reached equilibrium within 540 min, following a pseudo-second-order model. The SMZ adsorption isotherms fit the Langmuir-Freundlich model, highlighting the importance of chemisorption in the adsorption process. X-ray photoelectron spectroscopy revealed that SMZ was adsorbed by non-electrostatic mechanisms, including hydrogen bonding, Lewis acid-base interactions, surface complexation, and π-π electron-donor acceptor interactions. This study presents an exemplary strategy for converting livestock waste into valuable resources, enabling the harvesting of energy resources and the production of treatment media for environmental remediation.