MOF-modified Enteromorpha prolifera biochar for efficient removal of enrofloxacin from mariculture wastewater

MIL-101(Fe)-modified E. prolifera biochar (MIL-BC) was successfully synthesized. • MIL-BC showed 89.14% enrofloxacin removal in mariculture wastewater. • MIL-BC showed over 86% removal efficiency at pH 3–5 and salinity 15–35‰. • Adsorption followed pseudo-second-order and Freundlich models. • Experimental and DFT results unraveled synergistic adsorption mechanisms. In this study, a metal-organic framework (MOF)-modified biochar (MIL-BC) was synthesized by decorating Enteromorpha prolifera -derived pristine biochar (BC) with MIL-101(Fe). Compared to BC, the adsorption performance of MIL-BC for enrofloxacin (ENR) in mariculture wastewater was significantly enhanced to 89.14%, and it maintained a high adsorption efficiency under varying solution pH and salinity conditions. Notably, this high adsorption efficiency remained practically stable across varying solution pH and salinity levels. Under acidic pH conditions, MIL-BC exhibited both acid resistance and high adsorption efficiency, achieving a peak adsorption removal of 97.77%. The adsorption kinetics and isotherms were well described by the pseudo-second-order and Freundlich models, respectively, indicating a heterogeneous multilayer adsorption process. The adsorption mechanisms primarily involved a synergistic combination of pore filling, π-π interactions, hydrogen bonding, complexation, electrostatic interactions, and hydrophobic interactions. Furthermore, density functional theory (DFT) calculations corroborated that the higher adsorption energy of MIL-BC fundamentally contributes to its enhanced adsorption performance. In the treatment of real seawater aquaculture wastewater, MIL-BC demonstrated exceptional adsorption performance, validating its tremendous potential as a high-performance adsorbent. Maintaining a removal efficiency of over 70% after five cycles. Consequently, this study offers a viable and highly promising technical pathway for the efficient removal of antibiotics from seawater aquaculture effluents. Download: Download high-res image (182KB) Download: Download full-size image