壳聚糖聚多巴胺改性水凝胶对双氯芬酸钠的吸附实验研究

Experimental study on adsorption of diclofenac sodium by polydopamine modified chitosan hydrogel

双氯芬酸钠是水体中广泛分布的新型污染物之一,关于其去除的研究备受关注。为提高水体中双氯芬酸钠的去除效率,获得经济高效、对环境友好的吸附剂,以壳聚糖为原料,通过光催化法在壳聚糖上引入聚多巴胺进行改性,制备新型壳聚糖聚多巴胺改性水凝胶(CS-PDA),研究该材料对双氯芬酸钠的吸附性能。通过SEM、FTIR、XPS和BET测试对CS-PDA进行表征,材料呈网状结构,疏松多孔,比表面积达22.46 m^(2)/g;探究时间、温度、初始浓度、pH值对吸附效果的影响。结果表明:pH值为4.3时CS-PDA对双氯芬酸钠的吸附容量最大;吸附动力学符合拟二级动力学模型,在240 min时达到吸附饱和;吸附等温线符合Langmuir等温线模型,在25℃时双氯芬酸钠的Langmuir理论最大吸附容量为333.2 mg/g。CS-PDA对双氯芬酸钠的吸附容量经历7个再生循环后仍大于70 mg/g。

Diclofenac sodium is one of the new pollutants widely distributed in water,and its removal has attracted much attention.In order to improve the removal efficiency of diclofenac sodium and obtain cost-effective and environmentally-friendly adsorbents,the chitosan polydopamine modified hydrogel(CS-PDA)was prepared from chitosan by introducing polydopamine onto chitosan by photocatalytic method.The adsorption properties of diclofenac sodium were studied.The CS-PDA was characterized by SEM,FTIR,XPS and BET.The results showed that the CS-PDA had a network structure,porous structure and a specific surface area of 22.46 m^(2)·g^(-1).Explored the effects of time,temperature,initial concentration and pH value on the adsorption effect,the results showed that the adsorption capacity of CS-PDA was the largest at pH=4.3,the adsorption kinetics of CS-PDA for diclofenac sodium was in accordance with the pseudo second order kinetic model,and reached the adsorption saturation at 240 minutes.The adsorption isotherm was in line with the Langmuir isotherm model and the Langmuir theoretical maximum adsorption capacity of diclofenac sodium at 25℃was 333.2 mg/g.The adsorption capacity of diclofenac sodium by CS-PDA was higher than 70 mg/g after 7 regeneration cycles.