壳聚糖/木质素磺酸钠吸附剂的制备及其除Pb^(2+)和Cd^(2+)

Preparation of chitosan/sodium lignosulfonate adsorbent and its removal of Pb^(2+)and Cd^(2+)

工业废水给水体和土壤带来巨大的灾害,严重影响农作物的生长。为了获得洁净水,须制备一种稳定、有效、可持续的处理剂来控制水污染。使用木质素磺酸钠和壳聚糖,以自由基聚合法在聚丙烯酸上制备木质素基水凝胶吸附剂,并将其应用于除去Pd^(2+)和Cd^(2+)。采用正交法对木质素磺酸钠、壳聚糖、交联剂以及引发剂的含量进行优化。分别利用傅里叶红外光谱仪、扫描电镜图、热分析仪以及Zeta电位仪对吸附剂进行表征。探究不同条件对木质素基水凝胶吸附Pb^(2+)和Cd^(2+)的影响,在此基础上建立动力学和等温线模型。结果表明:在吸附剂为0.015 g、重金属离子浓度为100 mg·L^(-1)、pH值为7时,对Pd^(2+)的吸附容量为367 mg·g^(-1),对Cd^(2+)的吸附容量为296 mg·g^(-1)。同时,揭示木质素基水凝胶剂的吸附过程是一种以静电吸附为辅、化学吸附为主的吸附模式。

Industrial wastewater has brought huge disasters to water bodies and soil,and seriously affected the growth of crops.In order to obtain clean water,a stable,effective and sustainable treatment agent must be prepared to control water pollution.The lignin-based hydrogel adsorbent was prepared on polyacrylic acid by free radical polymerization of sodium lignosulfonate and chitosan,which was applied to remove Pd^(2+)and Cd^(2+).The orthogonal method was used to optimize the content of sodium lignosulfonate,chitosan,cross-linking agent and initiator.Fourier infrared spectrometer,scanning electron micrograph,thermal analyzer and Zeta potentiometer were used to characterize the adsorbent.The effects of different conditions on the adsorption of Pb^(2+)and Cd^(2+)by lignin-based hydrogels were discussed,and the kinetics and isotherm models on the basis were established.The results show that when the adsorbent is 0.015 g,the concentration of heavy metal ions is 100 mg·L^(-1),and the pH value is 7,the adsorption capacity for Pd^(2+)is 367 mg·g^(-1) and the adsorption capacity for Cd^(2+)is 296 mg·g^(-1).Simultaneously,it is revealed that the adsorption process of lignin-based hydrogels is an adsorption mode in which electrostatic adsorption is supplemented by chemical adsorption.