水葫芦对水溶液中Cu^(2+)和Pb^(2+)的吸附研究

ADSORPTION OF Cu^(2+) AND Pb^(2+) FROM AQUEOUS SOLUTION WITH WATER HYACINTH

采用水葫芦作为生物吸附剂去除溶液中的Cu2+和Pb2+,针对pH、吸附剂投加量、重金属初始含量、温度及吸附时间等影响吸附的主要因素进行了实验研究,探讨了等温吸附、吸附热力学及动力学。结果表明,pH是影响吸附效果的重要因素,在pH为2~6时,随着pH的增加,重金属离子的去除率也相应的升高。水葫芦对Cu2+和Pb2+的吸附速度很快,80min左右即可达到平衡,吸附过程符合准2级动力学模型;利用Langmuir等温方程拟合得到水葫芦对Cu2+和Pb2+的最大吸附量分别为26.39、81.63mg/g;吸附热力学参数ΔG、ΔH均小于0,表明吸附是一个自发放热的过程。经3次解吸后,水葫芦仍然保持着较高的吸附性能,在重金属废水处理方面有很好的应用前景。

Water＇hyacinth was used as a biosorbent to remove Cu^2＋ and Pb^2＋ from aqueous solution. The effect of solution pH, adsorbent dosage, initial concent and initial temperature of heavy metal and adsorption time on the adsorption process was investigated. And the isothermal adsorption, adsorption thermodynamics and kinetics were discussed. Results showed that the metal removal was strongly dependent on solution pH and the adsorption capacity increased with the increase of solution pH in the range of 2-6. The velocity of adsorption to Cu^2＋ and Pb^2＋ was quick and reached to adsorption equilibrium around 80 rain. The adsorption process fitted well with pseudo-second-order kinetic models. The maximal adsorption capacities of the biomass to Cu^2＋, Pb^2＋, calculated from Langmuir isotherm equation, which were 26.39 mg/g and 81.63 mg/g respectively. Both thermodynamic parameters AG and AH below zero indicated that the adsorption was a spontaneous exothermic process. The adsorbent water hyacinth still maintained a high adsorption performance after three desorption, therefore water hyacinth showed good application prospects in the treatment of heavy metal wastewater.