Coadsorption of Tetracycline and Copper(II) by KOH-Modified biomass and biochar Derived from Corn Straw in aqueous Solution.

The coexistence of antibiotics and heavy metals in water environments always results in greater toxicity compared to the single pollution. Consequently, the development of efficient and economical technologies for the removal of antibiotics and heavy metals is essential. This study prepared KOH-modified biomass (KCS) and KOH-modified biochar (KCSB) for the coadsorption of tetracycline (TC) and Cu(II) in an aqueous solution. The removal performance and mechanism of TC and Cu(II) are to be explored through single-system and binary-system studies, adsorption isotherms, and kinetic models. The results indicate a synergistic effect between TC and Cu(II); the maximum adsorption capacity of KCS for TC and Cu(II) is 107.97 mg/g and 58.44 mg/g, respectively. Meanwhile, KCSB exhibits a maximum adsorption capacity of 109.32 mg/g for TC and 116.61 mg/g for Cu(II). The synergistic removal mechanism of TC and Cu(II) involved pore filling, hydrogen bonding, surface complexation, π–π interaction, ion exchange, and precipitation. Among them, KCS and KCSB have stronger π–π interactions with TC than ion exchange with Cu(II), while KCSB has stronger surface complexation and ion exchange with Cu(II) than KCS. This study provides a more cost-effective biomass adsorbent material for simultaneous removal of TC and Cu(II). [ABSTRACT FROM AUTHOR]