改性松针对水体中铅(II)的吸附

探讨了改性松针(GXLsp)作为吸附剂对水体中铅离子的吸附性能,考察了吸附时间、溶液pH值、吸附剂用量、盐离子浓度、Pb(II)初始浓度及温度对改性松针吸附Pb(II)的影响。利用Langmuir和Freundlich等温线模型对实验数据进行非线性拟合分析,结果表明,Freundlich等温线模型能很好地描述松针对Pb(II)的吸附过程。热力学参数表明吸附是一个自发的吸热过程。改性松针对铅的吸附行为符合拟二级动力学方程,表明吸附过程是以化学吸附为主。在293K时松针对Pb(II)的饱和吸附量为318.3 mg/g,因此,GXLsp可作为一种高效低值生物质吸附剂以去除水体中重金属Pb(II)的污染。

Adsorption of Pb(II) from aqueous solution by modified pine needles

Pine needles modified by gas-expanded liquids (GXLs) was used as low cost adsorbent for removal of Pb(II) from aqueous solution. Experiments were conducted to study the factors affecting the adsorption process, such as the contact time, solution pH, the dosage of adsorbent, salt ion concentration, initial Pb(II) concentration and temperature. According to the Langmuir and Freundlich isotherm models, the non-linear regressive analysis of the equilibrium adsorption data was conducted, respectively. The results show that the Freundlich model provides good correlations of the experimental data. The thermodynamics parameters of adsorption system indicated spontaneous and endothermic process. The dynamic data fitted the pseudo-second order model well which suggested that the adsorption might be a chemisorption process. The maximal equilibrium quantity of GXLsp from Langmuir model was 318.3 mg/g at 293 K. The present study suggested that GXLsp has high potential to be used as low-cost effective adsorbent for the removal of Pb (II) from aqueous solutions.