柠檬酸修饰油菜秸秆对Pb^(2+)的吸附行为研究

Study of Adsorption Behavior for Pb^(2+) on Citric Acid-modified Rape Straw

选用柠檬酸对油菜秸秆进行化学修饰,制备了一种新型吸附剂,研究了该吸附剂对水溶液中Pb2+的吸附行为,并对吸附的最佳条件(吸附剂投加量、Pb2+溶液浓度、pH值、吸附时间、温度)进行了探讨:在吸附剂投加量为1.2g/L、Pb2+溶液浓度为200mg/L、pH值为5.3、吸附时间为4h的条件下,柠檬酸修饰油菜秸秆对Pb2+的吸附效率可达98%;温度对于修饰后秸秆对去除Pb2+无明显影响。吸附动力学研究表明,该吸附行为符合准二级动力学方程;吸附等温模型拟合结果显示,以单分子层吸附的Langmiur模型能更好地描述该吸附剂对Pb2+的吸附行为,最大吸附量qmax达到164mg/g。

In this paper,a novel adsorbent citric acid-modified rape straw is prepared,the adsorption behavior of Pb2+from aqueous solution on the novel adsorbent is studied and the optimal adsorption condition is discussed.The results show that the removal ratio can reach 98% when the concentration of the adsorbent dosage is 1.2g/L,Pb2+concentration is 200mg/L,pH is 5.3.Kinetic studies show that the adsorption on citric acid-modified rape straw isconsistant with pseudo second-order kinetic model.And the Langmuir isotherm which indicates the monolayer adsorption form can better describe the adsorption on citric acid-modified rape straw,The maximum adsorption capacity is 164mg/g.The result of temperature test shows the temperature has little influence on the Pb2+removal.