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对水热合成法制备的介孔材料麦羟硅钠石(magadiite)对重金属离子Pb~(2+)吸附性能进行了探索,考察了吸附过程中麦羟硅钠石的投加量、溶液pH值、吸附时间和Pb~(2+)初始浓度等因素对Pb~(2+)去除率和吸附量的影响,并运用BET法计算麦羟硅钠石的比表面积和平均孔径,对吸附剂吸附前后的结构进行表征,并分析了吸附行为和机理。结果表明:麦羟硅钠石的平均孔径为19 nm,平均孔容约为0.087 6 cm~3/g;麦羟硅钠石对Pb~(2+)的吸附量和去除率随着溶液pH值的增大而增大,当pH值大于5时,吸附量和去除率趋于稳定;在优化条件下,麦羟硅钠石对Pb~(2+)的最大去除率为93.2%。用准一级和准二级吸附动力学模型以及动边界模型拟合麦羟硅钠石吸附Pb~(2+)的吸附过程。结果表明:准二级动力学模型更适合描述其吸附过程,且膜扩散过程和颗粒扩散过程为吸附过程的速率控制步骤。另外,利用Langmuir和Freundlich等温线模型分析表明,Langmuir模型能很好地描述麦羟硅钠石对Pb~(2+)的吸附过程,由其获得的最大吸附量为54.26 mg/g,吸附机理兼有物理吸附和化学吸附,但以化学吸附为主。
The adsorption of heavy metal ions Pb 2+ by magadiite, a mesoporous material prepared by hydrothermal synthesis, was investigated. The effects of the addition amount of magadiite, the solution pH The adsorption time and the initial Pb2 + concentration on the removal rate of Pb2 + and the adsorption capacity of Pb2 + were studied. The BET surface area and average pore diameter were calculated by BET method. The structure before and after adsorption was characterized, and the adsorption behavior and mechanism were analyzed. The results showed that the average pore diameter of magadiite was 19 nm and the average pore volume was about 0.087 6 cm -3 / g. The adsorption amount and removal rate of magadiite to Pb 2+ increased with the increase of solution pH When the pH value is larger than 5, the adsorption amount and removal rate tend to be stable. Under the optimized conditions, the maximum removal rate of Pb ~ (2+) is 93.2%. The quasi-two-level adsorption kinetic model and the dynamic boundary model were used to fit the adsorption process of magadiite to Pb 2+. The results show that quasi-second-order kinetic model is more suitable for describing the adsorption process, and the membrane diffusion process and particle diffusion process are the rate control steps of the adsorption process. In addition, the Langmuir and Freundlich isotherm models show that the Langmuir model can well describe the adsorption process of magadiite to Pb 2+, and the maximum adsorption capacity is 54.26 mg / g. The adsorption mechanism Both physical adsorption and chemical adsorption, but mainly chemical adsorption.