霉菌/膨润土复合吸附剂对Cr^(6+)的吸附研究  

Study on the adsorption of mold/bentonite composite adsorbent on Cr^(6+) ions in wastewater

作　　者：刘桂萍[1] 祝杏[1] 赵琪锐 

机构地区：[1]沈阳化工大学环境与生物工程学院,沈阳110142

出　　处：《安全与环境学报》2014年第1期198-201,共4页Journal of Safety and Environment

基　　金：辽宁省教育厅科研项目(L2012144)

摘　　要：用霉菌/膨润土复合吸附剂吸附Cr6+,通过单因素试验探讨复合吸附剂对Cr6+的吸附条件,并对其吸附机理进行了研究。结果表明,在pH值为5、吸附剂投加量为0.9 g(即18 g/L)、搅拌时间为20min、静置时间为1 h的条件下,对Cr6+的去除率达93%以上。霉菌/膨润土复合吸附剂对Cr6+的吸附特性较好地符合Langmuir等温吸附模型,吸附剂对Cr6+的吸附过程容易进行,属于单分子层吸附,且吸附动力学数据符合准二级动力学模型。This study intends to explore the application of treating heavy metal （Cr6＋ ions） solution with an inexpensive adsorbent com- pounded with Mold/Bentonite. In this paper, it discussed the adsorp- tion conditions and mechanism of Cr^6＋ ions through single factor ex-periments （including dosage, initial concentration, and pH, stirring time and standing time） . It a/so studied the adsorption kinetics and adsorption thermodynamies of this system. The equilibrium data for Cr^6＋ ions on Mold^Bentonite were modeled with the Langmuir and Freundlich models. While the applicability of the pseudo-first order pseudo-second-order and intrapartiele diffusion models was tested for the adsorption of Cr^6＋ ions onto Mold/Bentonite too. The best-fit model was selected based on the linear regression correlation coeffi- cient, R2, values. The more the Rz, the better the model matched. The results showed that the removing rate was above 93 % , when the dosage of composite absorbent was 0.9 g（18 g/L）, pH was 5.0, stirring time was 20 min and standing time was 1 h. The Cr^6＋ ions system accorded with Langmuir thermostatic adsorption equation better than Freundlieh absorption model. And the saturated adsorption ca- pacity 1.569 4 mg/g is close to 1.034 mg/g obtained from experi- ments. The sorption parameters showed that the adsorption of compos- ite absorbent on Cr6 ＋ ions was easy, the system was monolayer ad- sorption. The correlation eoeffieients R2 of the adsorption kinetics were 0.987 5, 0.998 4, 0.999 0 respectively. The adsorption kinet- ic of Cr6＋ ions system fitted second-order kinetics with 0.989 mg/g saturated adsorption capacity of Cr6＋ ions. When pseudo-seeond order model is matehed, equation eoeffieient of correlation income R2 I〉 0.9990, it can well describe the adsorption dynamics behavior of Cr6＋ ions. This shows that composite adsorbent to Cr6 ＋ ions adsorp- tion dynamics is mainly affected by chemical action control, and not be material transmission step eontrol.

关 键 词：环境工程学 膨润土 霉菌 吸附热力学 吸附动力学 

分 类 号：X754[环境科学与工程—环境工程]