铁观音茶梗对废水中Cr(Ⅵ)的还原吸附  

Reduction and adsorption of Cr(Ⅵ) in wastewater by Tieguanyin tea stalk

作　　者：向文英[1,2] 谢冰冰 胡军涛 张强[1] XlANG Wenying;XIE Bin ing;HU Juntao;ZHANG Qiang(Key Laboratory of Three Gorges Reservoir Region＇s Eeo-Environment,Ministry of Edueation;National Centre for International Research of Low-carbon and Green Buildings,Chongqing University,Chongqing 400045,P.R.China)

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400045 [2]重庆大学低碳绿色建筑国际联合研究中心,重庆400045

出　　处：《重庆大学学报（自然科学版）》2018年第10期103-116,共14页Journal of Chongqing University

基　　金：高等学校学科创新引智计划(B13041)~~

摘　　要：通过单因素实验,研究了铁观音茶梗作为一种新型吸附剂,将水体中毒性极强的重金属Cr(Ⅵ)还原为低毒性甚至无毒的Cr(Ⅲ)的去除效果。通过吸附等温模型和吸附动力学模型对试验参数进行拟合,并通过SEM、BET、FTIR、XPS等多种表征方法对吸附机理进行探讨。结果表明:茶梗粒径越大、投加量越多,pH≤11时,茶梗对Cr(Ⅵ)都有较高的去除率;且共存离子Ca(Ⅱ)和Ni(Ⅱ)对茶梗还原吸附Cr(Ⅵ)的影响很小。吸附过程较好地符合Freundlich吸附等温模型和准二级动力学模型。一定条件下,铁观音茶梗、普洱茶茶梗、甲醛改性茶梗对Cr(Ⅵ)的去除效果优于活性炭。表征结果证明茶梗主要通过还原吸附作用去除水中的Cr(Ⅵ),羟基、氨基和酰基等活性基团参与了Cr(Ⅵ)的还原吸附。A series of single factor experiments were employed to study the effect of a novel adsorbent,Tieguanyin tea stalk,for the reduction of the high toxic heavy metal Cr（Ⅵ）to Cr（Ⅲ）which is low toxic even nontoxic.Two adsorption isotherm models and two adsorption kinetic models were used to simulate the experimental data.The characterization methods,SEM,BET,FTIR and XPS were employed to discuss the reduction and adsorption mechanism.The results show that the bigger tea stalk diameter,the more dosing quantity or pH≤11,the higher removal rate of Cr（Ⅵ）;The influence of the coexisting ions Ca（Ⅱ）and Ni（Ⅱ）to adsorption of Cr（Ⅵ）by tea stalk are weak.The Freundlich isotherm model and the Pseudo-second-order model fit closely to the experimental data.Tieguanyin tea stalk,Pu＇er tea stalk and Tieguanyin tea stalk modified by maldehyde show better performance than activated carbon under certain conditions.The characterization results show that the reduction and adsorption plays important roles on the removal efficiency of Cr（Ⅵ）in water by tea stalk,and the functional groups of the hydroxyl,amino andacyl are involved in the reduction and adsorption of Cr（Ⅵ）by tea stalk.

关 键 词：茶梗 铬 吸附 氧化还原 X射线光电子能谱 

分 类 号：X703[环境科学与工程—环境工程]