FeCl_(3)改性污泥生物炭对水中吡虫啉的吸附性能研究

Study on the adsorptive performance of imidacloprid from aqueous solution by FeCl_(3) modified biochar derived from sludge

以脱水污泥为原料,制备污泥生物炭(SBC)和FeCl_(3)改性污泥生物炭(Fe-SBC)处理低浓度吡虫啉(IMI)废水(浓度为10 mg·L^(-1)),考察SBC和Fe-SBC对IMI的吸附性能及影响因素,并探究其吸附机理.采用SEM、XRD、FTIR、BET及元素分析等探得污泥生物炭FeCl_(3)改性成功.Fe-SBC对IMI的最大吸附量为4.915 mg·g^(-1),是SBC的1.97倍,表现出更好的IMI吸附性能.pH和离子强度的变化对Fe-SBC的吸附性能影响较小,最大波动幅度分别为4.4%和7.8%.两种生物炭对IMI的吸附均符合准二级动力学模型,Freundlich模型可以更好地描述其等温吸附曲线.热力学研究表明,SBC吸附IMI是非自发吸附,而Fe-SBC是自发吸附.Fe-SBC对IMI的吸附机理包括静电作用力、氢键作用力及π-π键相互作用力.多次热解再生后的Fe-SBC对IMI的去除率仍可达93.088%.

Sludge biochar(SBC) and FeCl_(3) modified sludge biochar(Fe-SBC) were prepared by dewatered sludge to treat imidacloprid(IMI) containing wastewater(concentration 10 mg·L^(-1)). the adsorption performance, influencing factors and adsorption mechanism of SBC and Fe-SBC on IMI were investigated. With SEM, XRD, FTIR, BET and elemental analysis, sludge biochar was found to be successfully modified by FeCl_(3). Fe-SBC shows a better IMI adsorption performance with a maximum adsorption capacity of 4.915 mg·g^(-1) for IMI, 1.97 times higher than that of SBC. The varies of pH and ionic strength had little effect on the adsorption performance of Fe-SBC, with maximum fluctuations of 4.4% and 7.8%, respectively. Adsorption of IMI by SBC and Fe-SBC are both in accordance with quasi-second-order kinetic model. Freundlich model has a better description of the adsorption of IMI onto SBC and Fe-SBC. Thermodynamic calculations indicate that the adsorption of IMI onto SBC is a non-spontaneous process, while that onto Fe-SBC is a spontaneous one. The adsorption mechanism of Fe-SBC to absorb IMI includes electrostatic force, hydrogen bond force and π-π bond interaction force. After multiple pyrolysis regenerations, Fe-SBC can maintain IMI removal ratio of 93.088%.