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Chin. J. Process Eng. ›› 2015, Vol. 15 ›› Issue (5): 788-794.DOI: 10.12034/j.issn.1009-606X.215238

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Extraction of Cr(VI) in Aqueous Solution with L35-Ammonium Sulfate Aqueous Two-phase System

WANG Hao-cong CHEN Fang-fang WANG Hai-yang LI Meng-han HUANG Hui-ming ZHANG Yong-qiang   

  1. College of Environmental and Chemical Engineering, Yanshan University College of Environmental and Chemical Engineering, Yanshan University College of Environmental and Chemical Engineering, Yanshan University College of Environmental and Chemical Engineering, Yanshan University College of Environmental and Chemical Engineering, Yanshan University College of Environmental and Chemical Engineering, Yanshan University
  • Received:2015-06-08 Revised:2015-07-31 Online:2015-10-20 Published:2015-10-20
  • Contact: ZHANG Yong-qiang

L35-硫酸铵双水相体系萃取水溶液中Cr(VI)

王浩聪 陈芳芳1 王海洋 李梦寒 黄慧明 张永强   

  1. 燕山大学环境与化学工程学院 燕山大学环境与化学工程学院 燕山大学环境与化学工程学院 燕山大学环境与化学工程学院 燕山大学环境与化学工程学院 燕山大学，环境与化学工程学院
  • 通讯作者: 张永强

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Abstract: Cr(VI) in simulated waste water was extracted with L35-(NH4)2SO4-H2O aqueous two-phase system, the effects of initial concentration of Cr(VI), pH value of aqueous phase, amount of charge modifier (1812), extraction time, phase-separating time, amount of L35 and ammonium sulfate, and extraction temperature on the extraction rate of Cr(VI) were studied. The results show that the extraction rate and distribution coefficient of Cr(VI) are mainly affected by pH value of aqueous phase, and increase obviously after addition of charge modifier, and decrease gradually with increasing of extracting temperature. The extraction rate of Cr(VI) increases gradually and then is close to steady value with increasing of concentrations of L35 and ammonium sulfate. The equilibrium times of extraction and phase-separating are all short. Under the optimum conditions, the extraction rate of Cr(VI) reaches 92% and the distribution coefficient of Cr(VI) is above 15 in single stage extraction. The theoretical calculation and experimental results are basically consistent, and the concentration of Cr(VI) decreases from 2 g/L to below 0.5 mg/L, which meets the national discharge standards of waste water. The extraction mechanism analysis indicates that two modes can be deduced, one is in the form of solubility mode into L35 micellar interior by its relatively hydrophobic property, and another in the form of electrostatic attraction into L35 micellar interior by FT-IR and DLS. The stripping rate of Cr(VI) achieves above 99.5%(w) by single stage stripping with NaOH aqueous solution.

Key words: aqueous two-phase system, extraction, L35, charge modifier, Cr(VI)

摘要： 以L35-(NH4)2SO4-H2O双水相体系萃取模拟废水中Cr(VI)，考察了初始Cr(VI)浓度、水相pH值、胶束电荷调节剂1812用量、萃取时间、相分离时间、L35浓度、(NH4)2SO4浓度及萃取温度对Cr(VI)萃取率的影响. 结果表明，溶液pH值对Cr(VI)萃取率和分配系数影响最大；加入1812后，Cr(VI)萃取率和分配系数明显提高；随温度升高，两者均逐渐降低；随L35和(NH4)2SO4浓度增加，Cr(VI)萃取率逐渐提高并趋于恒定；萃取和相分离时间均较短；在最佳萃取条件下，Cr(VI)单级萃取率达92%(w)，分配系数达15以上. 四级错流萃取的理论计算和实验结果基本一致，Cr(VI)浓度由2 g/L降到0.5 mg/L以下，达到国家排放标准. Cr(VI)依靠其相对疏水性以增溶方式及静电引力方式进入L35胶束内部而被萃取. 用NaOH水溶液对萃取相单级反萃取，Cr(VI)反萃率达99.5%(w)以上，浓缩倍数>4.

关键词: 双水相体系, 萃取, 聚氧乙烯聚氧丙烯醚, 电荷调节剂, Cr(VI)

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