玉米芯对磺胺甲恶唑和甲氧苄啶的吸附效果及机制

Adsorption effect and mechanism of sulfamethoxazole and trimethoprim on corncob

为探究农业废物是否能吸附去除抗生素以及不同抗生素之间是否存在相互作用,通过对玉米芯的理化特征分析、傅里叶红外光谱分析、吸附动力学和吸附等温线分析,研究了玉米芯对磺胺甲恶唑(SMX)和甲氧苄啶(TMP)的吸附效果及机制。结果表明:在只含有单一抗生素(初始浓度为10 mg/L)、温度为25℃、玉米芯浓度为25 g/L的体系中,玉米芯对SMX和TMP吸附量分别为131.18和358.75 mg/kg;在同时含有SMX和TMP的体系中(初始浓度均为10 mg/L),玉米芯对其的吸附量分别为131.02和358.74 mg/kg,SMX和TMP之间为非交互吸附过程。在2种体系中,SMX和TMP的吸附均较好地符合准二级反应动力学方程,Langmuir和Freundlich等温线较好地拟合了SMX的吸附过程,而Freundlich等温线对TMP的拟合效果较好。SMX吸附主要为静电作用、π-π堆积作用,且以静电作用为主;TMP吸附主要通过疏水分配、π-π堆积作用和氢键作用。

To explore whether agricultural wastes can adsorb antibiotics and whether there is an interaction between different antibiotics,the physicochemical characteristics analysis of corncob,Fourier Infrared Spectroscopy analysis,adsorption kinetics,and adsorption isotherms analysis were used to study the adsorption effect and mechanism of sulfamethoxazole(SMX)and trimethoprim(TMP)on corncob.The results showed that SMX and TMP adsorption capacities on corncob were 131.18 and 358.75 mg/kg in the system with single antibiotic(the initial concentration was 10 mg/L)at 25℃and corncob concentration of 25 g/L,and they were 131.02 and 358.74 mg/kg in the coexistence system with both SMX and TMP(the initial concentration both were 10 mg/L),respectively.There was non-interactive adsorption between SMX and TMP in the coexistence system.The adsorption kinetics of SMX and TMP were better represented by the pseudo-second-order kinetic model in the two systems.Both Langmuir and Freundlich isotherms were well fitted with the SMX adsorption process,and the adsorption of TMP was described well by the Freundlich isotherm.SMX was mainly adsorbed by electrostatic interaction andπ-πstacking mechanism,and the electrostatic interaction played the main role.The adsorption of TMP was mainly due to the hydrophobic distribution,π-πstacking,and hydrogen bonding.