磷酸改性稻秆和稻叶对Pb2+的静态吸附研究

Static Adsorption of Pb2+ Using Phosphoric Acid Modified Rice Straw and Rice Leaf

本研究以农业废弃物稻秆和稻叶为原料,以尿素为催化剂,采用一步法制备了磷酸改性的稻秆和稻叶生物吸附剂,并利用SEM、EDS和Zeta电势等手段对改性前后的稻秆和稻叶进行表征。结果表明,磷酸基团被成功地修饰在稻秆和稻叶表面。在静态实验条件下,探究了磷酸改性稻秆和稻叶对Pb^2+初始浓度、吸附时间、酸度及双组份体系中Cd^2+、Zn^2+、Cu^2+、Ca^2+等干扰共存离子及其初始浓度对Pb^2+吸附的影响。结果表明,改性后的稻秆和稻叶对Pb^2+的吸附量分别提高了3.6倍和4.5倍,对Pb^2+的吸附可在30 min达到平衡,吸附最佳适用pH范围均在4.0-5.5,共存离子实验结果表明,Cd^2+、Zn^2+和Cu^2+对铅离子吸附的干扰不大,Ca^2+的干扰较小,改性吸附剂可望用于含铅废水的处理中。

In this study, phosphoric acid modified rice straw and rice leaf adsorbent were prepared by one-step method using urea as catalyst,and SEM, EDS and Zeta potential were used to characterize and test rice straw and rice leaf before and after modification. Results showed that phosphate groups were successfully modified on the surface of rice straw and rice leaf. Under static experimental conditions, the effects of phosphoric acid modified rice straw and rice leaf on the initial concentration, adsorption time, acidity and the interference of Cd^2+, Zn^2+, Cu^2+ and Ca^2+ coexisting ions in the two-component system and their initial concentration on Pb^2+ adsorption were investigated. Results showed that the adsorption capacity of modified rice straw and rice leaf on Pb^2+ increased by 3.6 times and 4.5 times, respectively. Pb^2+ adsorption reached equilibrium in 30 min, and the optimal pH range of adsorption were 4.0~5.5. Co-ions experiment results showed Cd^2+, Zn^2+ and Cu^2+ had a little influence on the adsorption of Pb^2+, while Ca^2+ almostnot, the as-prepared sorbent had great potential in waste water treatment.