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氢氧化钠改性沸石对水中Cu2+的吸附特性研究
Adsorption of Cu2+ in aqueous solution by sodium hydroxide modified zeolite
【摘要】 利用氢氧化钠对天然沸石进行改性,将天然沸石和改性沸石用于吸附去除水中的Cu2+,分析了p H、温度、Cu2+初始浓度、吸附时间对Cu2+吸附性能的影响,并对吸附过程的吸附等温模型及吸附动力学进行研究。结果表明,改性沸石对Cu2+的吸附性能明显优于天然沸石,当沸石投加量为10 g/L,Cu2+为200 mg/L,p H为6.67,温度为50℃时,天然沸石和改性沸石对Cu2+的吸附量分别为2.02、2.69 mg/g。Langmuir和Freundlich吸附等温模型均能较好地描述两种沸石对Cu2+的吸附过程。天然沸石对Cu2+的吸附行为更符合准一级动力学方程,而准二级动力学方程对改性沸石的吸附行为拟合度更好。两种沸石对Cu2+的吸附均为非均相吸附,且内扩散过程不是唯一的速控步骤。
【Abstract】 Natural zeolites and sodium hydroxide modified zeolites were used to remove Cu2+in aqueous solution. The effects of p H,temperature,Cu2+initial concentration and adsorption time on the Cu2+adsorption capacity of two zeolites were studied. The isotherm and kinetics of adsorption process were also studied. The results showed that modified zeolite had a better adsorption capacity than natural zeolite. When the zeolite dosage was 10 g/L,Cu2+was 200 mg/L,p H was 6. 67,and the temperature was 50 ℃,the Cu2+adsorption capacities of natural zeolites and modified zeolites were 2. 02,2. 69 mg/g,respectively. Both Langmuir and Freundlich isotherm could well fit the Cu2+adsorption process on natural and modified zeolites. Adsorption process of natural zeolite conformed to pseudo-first order kinetic equation,while pseudo-second order kinetic equation was better for fitting the adsorption process of modified zeolites. The adsorption of Cu2+on zeolites was heterogeneous adsorption and intraparticle diffusion was not the only rate-determining step for this adsorption prosess.
【Key words】 zeolite; Cu2+; adsorption isotherm model; adsorption kinetic equation;
- 【文献出处】 环境污染与防治 ,Environmental Pollution & Control , 编辑部邮箱 ,2017年03期
- 【分类号】X703
- 【被引频次】20
- 【下载频次】362