聚乙烯亚胺促进乙基纤维素在宽pH范围内去除六价铬。
Polyethylenimine facilitated ethyl cellulose for hexavalent chromium removal with a wide pH range.
作者信息
Qiu Bin, Guo Jiang, Zhang Xi, Sun Dezhi, Gu Hongbo, Wang Qiang, Wang Huanwen, Wang Xuefeng, Zhang Xin, Weeks Brandon L, Guo Zhanhu, Wei Suying
机构信息
Integrated Composites Laboratory (ICL) Dan F Smith Department of Chemical Engineering Lamar University , Beaumont, Texas 77710, United States.
出版信息
ACS Appl Mater Interfaces. 2014 Nov 26;6(22):19816-24. doi: 10.1021/am505170j. Epub 2014 Nov 10.
Ethyl cellulose (EC) composites modified with 20.0 wt % polyethylenimine (PEI) (PEI/ECs) demonstrated effective hexavalent chromium, [Cr(VI)], removal from solutions with a wide pH range. For example, 4.0 mg/L Cr(VI) solution with a pH below 3.0 was completely purified by 3.0 g/L PEI/ECs within 5 min, much faster than the as-received EC (2 h) and activated carbon (several hours). These PEI/ECs adsorbents has overcome the low pH limitation of Cr(VI) removal; for example, 4.0 mg/L Cr(VI) solution with a pH of 11.0 was completely purified within 15 min. These adsorbents followed chemical adsorption as revealed from the pseudo-second-order kinetic study. These PEI/ECs following the isotherm Langmuir model have a maximum adsorption capacity of 36.8 mg/g, much higher than pure EC (12 mg/g), tetrabutylammonium-modified celluloses (16.67 mg/g), and magnetic carbon (16 mg/g). The reduction of Cr(VI) to Cr(III) by the oxidation of amine groups and hydroxyl groups of PEI/ECs was verified as the main mechanism for the Cr(VI) removal.
用20.0 wt%聚乙烯亚胺（PEI）改性的乙基纤维素（EC）复合材料（PEI/ECs）在很宽的pH范围内对溶液中的六价铬[Cr(VI)]具有高效的去除能力。例如，3.0 g/L的PEI/ECs在5分钟内就能完全净化pH低于3.0的4.0 mg/L Cr(VI)溶液，比原样的EC（2小时）和活性炭（数小时）快得多。这些PEI/ECs吸附剂克服了去除Cr(VI)时低pH的限制；例如，pH为11.0的4.0 mg/L Cr(VI)溶液在15分钟内就能被完全净化。伪二级动力学研究表明这些吸附剂遵循化学吸附。遵循等温线朗缪尔模型的这些PEI/ECs的最大吸附容量为36.8 mg/g，远高于纯EC（12 mg/g）、四丁基铵改性纤维素（16.67 mg/g）和磁性碳（16 mg/g）。PEI/ECs的胺基和羟基氧化将Cr(VI)还原为Cr(III)被证实是去除Cr(VI)的主要机制。
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