皂化改性橘子皮生物吸附剂对重金属离子的吸附

Adsorption of heavy metal ions by saponified orange peel

以生物废料橘子皮(OP)为原料,经乙醇、氢氧化钠处理,得到改性橘子皮生物吸附剂SOP,将其用于对重金属离子Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的吸附。研究了溶液pH、吸附时间和重金属离子初始浓度对SOP吸附性能的影响。结果表明,重金属离子在生物吸附剂上的吸附速率快,符合准二级动力学方程。SOP对重金属离子的吸附等温线符合Lang-muir模型,根据Langmuir模型计算SOP对Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的饱和吸附量分别为56.82、152.4、66.27、33.90和23.02 mg/g,均高于改性前。常见阳离子的存在对重金属离子吸附的影响较小,改性后的橘子皮生物吸附剂可以再生重复使用4次以上,是性能良好的重金属离子吸附剂。

In this study,the biosorbent（SOP） was prepared by treating chemically orange peel（OP） with ethanol and sodium hydroxide and then used to adsorb heavy metal ions（Cu2＋,Pb2＋,Cd2＋,Zn2＋ and Ni2＋） from aqueous solution.Equilibrium isotherms and kinetics were obtained and the effect of solutions pH was studied in batch experiments.Equilibrium was well described by Langmuir isotherms and kinetics was found to fit pseudo-second order type adsorption kinetics.According to the Langmuir equation,the maximum adsorption capacities of SOP for Cu2＋,Pb2＋,Cd2＋,Zn2＋ and Ni2＋ were 56.82,152.4,66.27,33.90 and 23.02 mg/g,respectively,which were higher than for untreated OP.The existence of common cations such as K＋,Na＋,Ca2＋ and Mg2＋ in water interfered scarcely the adsorption of modified orange peel.The loaded biosorbent was regenerated using HCl solution and could be used repeatedly for four times with little loss of adsorption capacity.The results show that additional chemical treatments of the biosorbent by ethanol and sodium hydroxide increase the adsorption capacity.