High performance removal of sulfamethoxazole using large specific area of biochar derived from corncob xylose residue

To remove antibiotics from waste water, an alkali active porous biochar, 850BC, was prepared from corncob xylose residue. In preparation, NaOH dipping was used for silicon removal and KOH activation was operated at 850℃. Further characterization containing BET, SEM, and FTIR were confirmed. 850BC possessed a huge specific surface area of 3043 m 2 ·g −1 , developed pore structure and abundant oxygen functional groups. The adsorption performance of sulfamethoxazole on 850BC was quick and efficient, and the adsorption capacity reached 1429 mg·g −1 , which was significantly higher than other adsorbents reported previously. While pseudo-second-order kinetic model and Langmuir model could better describe the adsorption, chemisorption dominated the SMX adsorption onto 850BC. In virtue of pore-filling and π–π interaction as major mechanism, a large surface area and rich oxygen-containing functional groups led to an excellent adsorption performance. Thus, this preparation method provided a biochar-based adsorbent with enhanced specific surface for efficient removal of antibiotic pollutants. Graphical Abstract Highlights Corncob xylose residue biochar was modified by KOH with huge surface area. Biochar product possessed excellent absorption quantity of SMX of 1429 mg·g −1 . The SMX on biochar adsorption was mainly attributed to pore filling effect, π–π interactions, and hydrogen bonding.