草酸改性膨润土对亚甲基蓝吸附性能的研究

Research on the adsorption behavior of oxalic acid modified bentonite with methylene blue

采用有机酸草酸改性天然膨润土(RB),制备了草酸膨润土(OAB),同时考察了膨润土与草酸质量之比、OAB投加量、溶液初始pH值、亚甲基蓝(MB)初始浓度、吸附时间对OAB去除MB的影响。结果显示,在膨润土与草酸质量比为1:1,OAB投加量为2g/L,溶液初始pH值为6%8,MB初始浓度为200mg/L,吸附2h能达到最佳去处效果,饱和吸附量为96. 9mg/g。进一步研究了OAB吸附MB的吸附动力学和吸附等温模型,结果表明,拟二级动力学和Langmuir模型能更好地描述OAB吸附MB。此外,还采用SEM观察了OAB吸附亚甲基蓝前后的表面微观形貌特征,采用FTIR对吸附前后的OAB进行表征,均表现出了关联性。

The modified bentonite(OAB)was prepared using natural bentonite(RB)modified with oxalic acid,and at the same time the effects of the ratio of the mass of bentonite and oxalic acid,OAB dosage,initial pH value,methylene blue(MB)initial concentration,adsorption time on MB adsorption have been studied.The results show that the better MB adsorption effect can be obtained when the ratio of the mass of bentonite and oxalic acid is 1:1,OAB dosage is 2g/L,initial pH value is 6-8,initial concentration is 200mg/L,adsorption time is 2h and the saturated adsorption capacity is 96.9mg/g.The dynamics and isotherm model of MB on OAB have been further studied.The results prove that the adsorption dynamic model of MB on OAB fits with psendo-second-order dynamic model,and the adsorption fits with Langmuir isothermal adsorption models.In addition,SEM was used to observe the surface micro-morphology of adsorbed methylene blue before and after OAB,and OAB before and after adsorption was characterized by FTIR.In addition,SEM was used to observe the surface micro-morphology of adsorbed methylene blue before and after OAB,and FTIR was used to characterize the OAB before and after adsorption.