化工学报 ›› 2012, Vol. 63 ›› Issue (11): 3680-3687.DOI: 10.3969/j.issn.0438-1157.2012.11.044

• 能源和环境工程 • 上一篇    下一篇

负载金属捕获剂改性PAC吸附低温水中低浓度Cr(Ⅵ)特性

公绪金1, 李伟光1, 张多英2, 刘柏音3   

  1. 1. 哈尔滨工业大学市政环境工程学院, 黑龙江 哈尔滨 150090;
    2. 黑龙江东方学院, 黑龙江 哈尔滨 150086;
    3. 中国环境科学研究院, 北京 100012
  • 收稿日期:2012-03-22 修回日期:2012-05-04 出版日期:2012-11-05 发布日期:2012-11-05
  • 通讯作者: 李伟光
  • 作者简介:公绪金(1985-),男,博士研究生。
  • 基金资助:

    国家水体污染控制与治理科技重大专项(2011ZX07415-001);黑龙江省杰出青年基金项目(JC200708);黑龙江省教育厅青年学术骨干支持计划项目(1251G049)。

Adsorption characteristics of metal-capture-agent immobilized PAC for low concentration Cr(Ⅵ) in water at low temperature

GONG Xujin1, LI Weiguang1, ZHANG Duoying2, LIU Baiyin3   

  1. 1. School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, Heilongjiang, China;
    2. East University of Heilongjiang, Harbin 150086, Heilongjiang, China;
    3. Chinese Research Academy of Environmental Science, Beijing 100012, China
  • Received:2012-03-22 Revised:2012-05-04 Online:2012-11-05 Published:2012-11-05
  • Supported by:

    supported by the Water Pollution Control and Treatment Special Project(2011ZX07415-001),the Outstanding Youth Science Foundation of Heilongjiang Province(JC200708)and the Outstanding Academic Youth Project of Heilongjiang Province(1251G049).

摘要: 针对低温微污染水中(275 K)低浓度Cr(Ⅵ)离子(0.500 mg·L-1),制备基于表面负载食品级单宁酸为金属捕获剂的改性PAC(TA-PAC),以HNO3、NaOH氧化改性PAC为对照,研究了TA-PAC的表面物理化学特性和吸附性能,并进行了pH影响和吸附等温线拟合研究。结果表明:TA-PAC的比表面积、总孔容积和表面极性大小最佳。TA-PAC对低温水中Cr(Ⅵ)及总铬的去除效果优于N-PAC和OH-PAC。酸性范围内(pH=3.0~6.0)TA-PAC对Cr(Ⅵ)及总铬的去除率均大于碱性范围(pH=7.0~10.0)。Freundlich 双参数吸附等温式对TA-HNC吸附水中低浓度总铬的吸附等温线拟合效果最好(R2=0.9941)。TA-PAC吸附低温水中低浓度Cr(Ⅵ)是一个极为复杂的过程,主要吸附机理可能包括表面还原作用、酯化/螯合作用和离子交换作用等。

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

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.

Key words: PAC, hexavalent chromium, metal-capture-agent, food-grade tannic acid, surface modification

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