Cost-effective micro/mesoporous biochar derived from soda residue-assisted hydrocarbonization and activation of crop waste for sulfamethoxazole removal from water environments.

The low-cost transformation of agricultural biowaste into high-value biochar materials presents substantial technological and economic challenges. In this study, we report for the first time that soda residue can effectively substitute for chemical activation agents to produce micro/mesoporous biochars (MMBs) with a well-developed specific surface area (473.73 m g) and pore volume (0.55 cm g). These MMBs exhibit exceptional sorption capacity for the antibiotic sulfamethoxazole in aqueous solutions, reaching a maximum sorption capacity of 92.97 mg g. The sorption mechanism is governed by multiple interactions, including pore filling, hydrogen bonding, partitioning, electrostatic interactions, and π-π stacking. MMBs demonstrate superior stability, excellent reusability, cost-effectiveness, environmental compatibility, and strong anti-interference capability, rendering them highly suitable for practical applications. This study opens new avenues for the sustainable recycling of soda residue and biowaste and the fabrication of high-performance porous biochars while also providing an efficient and eco-friendly sorbent for environmental remediation.