欢迎访问过程工程学报, 今天是

过程工程学报 ›› 2019, Vol. 19 ›› Issue (4): 714-720.DOI: 10.12034/j.issn.1009-606X.218294

• 反应与分离 • 上一篇    下一篇

颗粒活性炭载纳米零价铁去除水中的Cr(VI)

刘 剑*, 黄 莉, 彭 钢, 易正戟   

  1. 衡阳师范学院功能金属有机化合物湖南省重点实验室,湖南 衡阳 421008
  • 收稿日期:2018-09-28 修回日期:2019-01-03 出版日期:2019-08-22 发布日期:2019-08-15
  • 通讯作者: 刘剑 liu.jian1@mail.scut.edu.cn
  • 基金资助:
    利用铁还原菌溶矿作用阻滞Fe(0) -PRB的钝化和促进铀尾矿渗滤液中铀酰的去除;微纤包覆活性炭-纳米零价铁复合材料对含铅废水修复研究

Removal of Cr(VI) from water by granular activated carbon supported nanoscale zero-valent iron

Jian LIU*, Li HUANG, Gang PENG, Zhengji YI   

  1. Key Laboratory of Functional Metal?Organic Compounds of Hunan Province, Hengyang Normal University, Hengyang, Hunan 421008, China
  • Received:2018-09-28 Revised:2019-01-03 Online:2019-08-22 Published:2019-08-15
  • Contact: LIU Jian liu.jian1@mail.scut.edu.cn

摘要: 以Fe2+溶液为原料、NaBH4为还原剂,采用传统液相还原技术合成了颗粒活性炭(GAC)载纳米零价铁(nZVI)复合材料GAC-nZVI,用扫描电镜对GAC-nZVI进行表征,通过间歇实验考察了其对去除Cr(VI)的影响。结果表明,GAC能阻止nZVI颗粒聚集,合成的GAC-nZVI能有效去除水中的Cr(VI)。在Cr(VI)初始浓度50 mg/L、温度40℃和pH=2.0、投加GAC-nZVI 3.0 g/L的条件下反应5 min,Cr(VI)去除率为99.4%。pH=2.0?4.0时,处理后水中总铬浓度均低于1 mg/L,表明残留少量Cr(III)。随pH值和Cr(VI)浓度增加,Cr(VI)去除率降低;随反应温度和GAC-nZVI投加量增加,Cr(VI)去除率增加。准一级动力学模型可用于描述Cr(VI)的去除过程。相同条件下,GAC-nZVI去除Cr(VI)的反应速率常数达0.19797 min?1,为原颗粒活性炭反应速率常数0.0023 min?1的86倍。随pH值降低或反应温度和GAC-nZVI投加量增加,反应速率常数增加。

关键词: 颗粒活性炭, 纳米零价铁, Cr(VI), 间歇实验

Abstract: The removal rate of Cr(VI) from water by using granular activated carbon (GAC) supported nanoscale zero-valent iron (nZVI) composites (GAC-nZVI) was studied through batch experiments. The GAC-nZVI composites were synthesized from Fe2+ aqueous solution by traditional liquid-phase reduction technique with NaBH4 as a reducing agent. The composites were characterized by SEM. The effects of pH value, reaction temperature, GAC-nZVI composites addition and initial Cr(VI) concentration on the removal rate of Cr(VI) were studied. The removal processes were analyzed by a pseudo first-order kinetic model. The results showed that granular activated carbon supports could effectively prevent nanoscale zero-valent iron particles from aggregating together. Synthesized GAC-nZVI composites was efficient in removing Cr(VI) from water, 99.4% of Cr(VI) was removed from water containing 50 mg/L Cr(VI) within 5 min using 3.0 g/L GAC-nZVI composites at pH 2.0 and 40℃. The total Cr concentration in treated water was below 1 mg/L at pH 2.0?4.0, suggesting that little Cr(III) was residue. When pH was 1.0, the removal rate of Cr(VI) reached 98.8% within 2 min, but the total Cr concentration in water after reaction was 32.506 mg/L. The removal rate of Cr(VI) decreased with the increase of pH value and initial Cr(VI) concentration, and increased with the increase of reaction temperature and GAC-nZVI composites addition. Pseudo first-order kinetic model was suitable for describing the removal process of Cr(VI), and the fitting correlation coefficients R2 were all over 0.98 (except R2=0.9367 with GAC, R2=0.9277 when pH=3.0). The reaction rate constant (k) of GAC-nZVI composites was 0.19797 min?1, it was 86 times of original granular activated carbon (0.0023 min?1) at the same experimental conditions. The reaction rate constant increased with decreasing the initial pH value or increasing the reaction temperature and GAC-nZVI composites addition.

Key words: granular activated carbon, nanoscale zero-valent iron, Cr(VI), batch experiment