After modification with sulfuric acid, glycyrrhiza residue was used as biosorbent for Pb2+ ion. The physical structure and chemical properties of the glycyrrhiza residue before and after modification were characterized using a variety of analytical instruments and methods, such as scanning electron microscopy (SEM), FT-IR and the surface functional group titration. The effects of initial Pb2+ concentration, adsorption time and solution pH on a high efficiency of the studied biosorbent for Pb2+ were also investigated. The results indicate that after modification, the surface structure of glycyrrhiza residue is changed and the number of surface active groups also increases accordingly. When the solution pH is 5.5 and the initial concentration of Pb2+ ion is 1 mmol?L?1, a high percentage is 97.43% after 90 min adsorption. Equilibrium can be well described by Langmuir isotherms and adsorption can be fitted by a fit pseudo-second order kinetic model. According to the Langmuir equation, the maximum adsorption capacities of modified products for Pb2+is 1.2 mmol?g?1, which is higher than that of haven't modified glycyrrhiza residue (0.08 mmol?g?1). The modified products were regenerated using HCl solution and could be used repeatedly for five times with little loss of adsorption capacity.%以甘草废渣为原料,经硫酸处理得到了改性甘草废渣生物吸附剂,并将其用于对水溶液中重金属离子Pb 2+的吸附.通过扫描电镜、红外光谱、比表面积和表面官能团的测定等方法对改性前后甘草废渣进行了表征.采用静态吸附实验,考察了Pb2+初始浓度、吸附时间、溶液pH值及投入量对吸附剂吸附性能的影响.经硫酸改性后,甘草废渣表面结构发生了变化,表面活性基团的数目增加.在pH = 5.5,对浓度为1 mmol?L?1的含Pb2+离子溶液,经90 min吸附后,吸附率达97.43%.等温吸附符合Langmuir模式,根据Langmuir方程计算,25℃时饱和吸附量为1.12 mmol?L?1,高于改性前(0.8 mmol?L?1).甘草废渣吸附剂对Pb2+离子的吸附符合二级动力学方程.解吸再生实验表明改性后的甘草废渣吸附剂可以再生重复使用5次以上,是性能良好的重金属离子吸附剂.
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