提高有机膨润土对Cr(Ⅵ)吸附能力的方法及机理分析  

The Methods to Improve Adsorption of Cr(Ⅵ) onto Organic Bentonite and its Mechanism

作　　者：郝建朝[1,2] 连宾[2] 侯莉蓉[1] 云坤[1] 刘惠芬[1] 石利军[1] 徐晓燕[1] 尹祚莹[3] 

机构地区：[1]天津农学院农学系,天津300384 [2]南京师范大学生命科学学院,江苏省功能微生物与功能基因组学重点实验室,江苏省微生物工程技术研究中心,南京210023 [3]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550002

出　　处：《地球与环境》2013年第4期460-467,共8页Earth and Environment

基　　金：国家自然科学基金委创优群体项目(41021062);天津市自然科学基金项目(10JCYBJC05400);环境地球化学国家重点实验室科研专项(SKLEG2013407)及开放课题(SKLEG2013816)

摘　　要：六价铬Cr(Ⅵ)是工业废水排放中受严格控制的污染物之一,Cr(Ⅵ)污染废水的治理受到广泛关注。本文采用三氯化铁(FeCl3)改性有机膨润土(organic bentonite modified by ferric trichloride,OBF),并研究它与微生物絮凝剂(microbial flocculant,MBF)混合对Cr(Ⅵ)的吸附作用及作用机理,为MBF与水解盐改性材料混合使用提供理论依据。OBF是在有机膨润土与FeCl3·6H2O质量比为10∶1的条件下制得,0.1g OBF对Cr(Ⅵ)溶液(20mg/L,50mL)去除率可达97.15%。采用此OBF和MBF混合对模拟Cr(Ⅵ)废水进行处理,测定处理后溶液的Cr(Ⅵ)浓度,分析其去除效果和作用机理。OBF对Cr(Ⅵ)去除率随着[OH1-]/[1/3Fe3+]摩尔比增加而降低;用MBF与OBF混合去除Cr(Ⅵ),形成的絮凝体密实稳定,易于沉淀分离;MBF与OBF混合对Cr(Ⅵ)的去除率随着MBF加入量增加呈线性递减关系,其线性方程为y=-0.0404x+0.936(R2=0.9678),OBF对Cr(Ⅵ)吸附动力学符合伪二级动力学方程:t/qt=0.1355t-0.0831(R2=0.9979);选择在添加OBF之前先加MBF和FeCl3,结果既能增加对Cr(Ⅵ)的吸附,还有利于分离沉降。FeCl3水解形成羟基铁离子可以置换有机膨润土中的一些阳离子,使有机膨润土表面带正电,增加改性有机膨润土对Cr(Ⅵ)的吸附能力。MBF利用其本身所带官能团和黏滞性可对吸附了Cr(Ⅵ)的OBF凝聚沉降,易于固液分离。此研究结果将为低浓度Cr(Ⅵ)废水治理提供技术支持和理论依据。There is an increasing concern with Cr（VI） control due to the fact that it is the most strict control pollutant in indus- trial wastewater. Organic bentonite was modified by ferric trichloride （OBF） and the adsorption mechanism of Cr（VI ） was studied by microbial flocculant（MBF） and OBF. This research will provide the basis for the application of microbial flocculant and some materials modified by hydrolysis salts in practice. The aim of this paper is to analyze the adsorption mechanism of Cr （ VI ） from simulated wastewater by using OBF and MBF together. The results showed that the optimum quality ratio of organic bentonite and six water ferric trichlorides was 10 ： 1, the removal rate of Cr（VI） was 97. 15% when 0. lg OBF was added in 50mL Cr（VI） solution（2Omg/L） ; the Cr （VI） removal of modified bentonite decreased with increasing [＇OH^1-]/[1/3Fe3＋] （mole/mole） ; the floc was easily separated from the solution because it was dense and stable, but microbial flocculant colud not improve Cr （VI） removat of OBF and result in the dcrease of removal; the inhibition of microbial flocculant increased with the duration of exposure and showed a strong linear relationship between them： y=-0. 0404xq-0. 936（R2 =0. 9678）, the adsorp- tion kinetics of Cr （VI） by OBF and MBF together followed the pseudo-second kinetics equation： t/q, =0. 1355t-0. 0831（Rz = 0, 9979） ; adding the solution of FeCI3 and MBF before adding OBF could improve Cr（VD removal. Hydroxyl iron from hydrol- ysis of FeC13 can replace some cations in the organic bentonite which would cause the surface of organic bentonite to be charged positively, thus increasing the adsorption of Cr（VI）. MBF can aggregate OBF which has adsorbed Cr（VI） through functional groups and viscosity. This study will provide the technological support to and the theoretical basis for treatment of low concen- tration solution of Cr（VI）.

关 键 词：微生物絮凝剂 CR(VI) 吸附 有机膨润土 改性 

分 类 号：X52[环境科学与工程—环境工程]