碱改性泡桐树叶粉末对水中Pb^(2+)的吸附特性

The Adsorbability of Alkali-modified Paulownia Leaf Powder on Pb^(2+) in Aqueous Solution

生物吸附剂的改性方法不同,影响吸附剂性能和其对重金属离子的去除效果.本研究采用泡桐树叶粉末经Ca(OH)2改性后,吸附废水中Pb2+,并探讨了反应时间、吸附剂浓度、p H这三个因素对吸附效果的影响.结果表明,吸附剂浓度0.8 g/L,溶液p H为5,吸附60 min即可达到平衡,此时吸附量为60.43 mg/g,去除率为95.61%,吸附过程可用准二级吸附动力学模型描述.通过扫描电镜(SEM)发现泡桐树叶粉末经改性,表面变得松散粗糙;能谱分析(XPS)发现,吸附过程中发生了阳离子交换,Pb2+被吸附到泡桐粉末表面,而Ca2+被释放到溶液中.Ca(OH)2改性泡桐树叶粉末对Pb2+具有良好的吸附性能,可以用于重金属污染废水的处理.

Different bio- adsorbent modification methods will exert different influences on its adsorbability andheavy metal ion removal efficiency. In this work,Paulownia leaves were modified by Ca（OH）2to absorb Pb^2＋inwastewater. Further,the effects of reaction terms,sorption agent concentration and p H value on the absorption wereevaluated. The results showed that the sorption agent concentration of 0.8 g/L,pH of 5 and reaction time of 60 minwere favor for the adsorption equilibrium. The maximal adsorption was 60.43 mg/g and the Pb^2＋removal rate was95.61%,and the process was agree with Quasi-two adsorption kinetics model. The scanning electron microscopy（SEM）showed that the surface of Paulownia leaf powder becomes rough and loose. Spectroscopy（XPS）showedthat the cation exchange occured during adsorption,Pb^2＋is adsorbed onto the surface of Paulownia leaves powder,and Ca^2＋is released into the solution. Paulownia leaves powder modified by Ca（OH）2presented good Pb^2＋adsorption properties,and could be used for treatment heavy metal contaminated wastewater.