化工学报2012，Vol.63Issue(11)：3680-3687,8.DOI:10.3969/j.issn.0438-1157.2012.11.044
负载金属捕获剂改性PAC吸附低温水中低浓度Cr(Ⅵ)特性
Adsorption characteristics of metal-capture-agent immobilized PAC for low concentration Cr(Ⅵ) in water at low temperature
摘要
Abstract
As a kind of metal-capture-agent, food grade tannic-acid (TA) was immobilized on commercial powdered activated carbon (PAC). Adsorption of low concentration Cr(Ⅵ)(0. 500 mg · L-1) on the TA-PAC was investigated at various dosage and pH, and adsorption capacities and adsorption isotherms were measured at 275 K. Compared with HNO3- and NaOH-modified PAC (N-PAC and OH-PAC), the results obtained from the BET, Boehm's titration and FTIR indicated that TA-PAC is of larger specific surface area, total pore volume and more abundant acid functional groups. The performance of TA-PAC, expressed by removal efficiency of Cr( Ⅵ ) and total chromium, is much more excellent than N-PAC and OH-PAC. Its adsorption capacity for Cr(Ⅵ) was found to be pH-dependent, the removal efficiency both Cr(Ⅵ) and total chromium were notably higher in the acidic medium (pH - 3. 0-6. 0) than in alkaline medium (pH=7. 0-10.0). The adsorption data for total chromium were fitted using two-parameter isotherm models and the related parameters were estimated. Freundlich model is the best for data of Ce from 0. 010 to 0. 404 mg · L-1 , R2 = 0. 9941, indicating a heterogeneous coverage of chromium on TA-PAC. Langmuir ( Ⅰ ), Langmuir (Ⅱ ) and Temkin models didn't fit the data well, because of occurring piecewise node at 0. 149 mg · L-1 , 0. 151 mg · L-1 and 0. 163 mg · L-1 respectively. The adsorption mechanism of TA-PAC for Cr (Ⅵ) was assumed to be chemical process, such as surface reduction of Cr(Ⅵ) ,esterification between chromate and catechol, and ion exchange.关键词
粉末活性炭/六价铬/金属捕获剂/食品级单宁酸/表面改性Key words
PAC/ hexavalent chromium/ metal-capture-agent/ food-grade tannic acid/ surface modification分类
建筑与水利引用本文复制引用
公绪金,李伟光,张多英,刘柏音..负载金属捕获剂改性PAC吸附低温水中低浓度Cr(Ⅵ)特性[J].化工学报,2012,63(11):3680-3687,8.基金项目
国家水体污染控制与治理科技重大专项(2011ZX07415-001) （2011ZX07415-001）
黑龙江省杰出青年基金项目(JC200708) （JC200708）
黑龙江省教育厅青年学术骨干支持计划项目(1251G049). （1251G049）
