Department of Chemistry, Birla Institute of Technology and Science, Pilani-Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, R.R. Dist, 500 078 AP, India.
J Hazard Mater. 2012 Nov 15;239-240:213-24. doi: 10.1016/j.jhazmat.2012.08.065. Epub 2012 Sep 2.
Biopolymers as well as ionic liquids are known for their potential applications. In this work, we report the utility of chitosan as an excellent platform for impregnating the ionic liquid, tetraoctylammonium bromide by ultrasonication and its subsequent adsorption for chromium(VI). The effective mass transfer due to sonication coupled with the hydrogen bonding interaction between chitosan-ionic liquid and the electrostatic interaction involving the amino groups in chitosan and hexavalent chromium governs this three center (3c) co-operative mechanism. The adsorption followed a pseudo second order kinetics with a Langmuir adsorption capacity of 63.69 mg g(-1). Various isotherm models were used to correlate the experimental data and the adsorption process is exothermic with a decreased randomness at the solid-solution interface. The thermodynamics of the spontaneous adsorption process could be explained through a positive co-operative effect between the host (chitosan) and the guest (ionic liquid). The adsorbed chromium(VI) could be converted to ammonium chromate using ammonium hydroxide, thereby regenerating the adsorbent. The method could be translated into action in the form of practical application to a real sample containing chromium.
生物聚合物以及离子液体因其潜在的应用而闻名。在这项工作中，我们报告了壳聚糖作为一种极好的平台，通过超声浸渍离子液体四辛基溴化铵，并随后对六价铬进行吸附的应用。由于超声作用有效促进了传质，同时壳聚糖-离子液体之间的氢键相互作用以及壳聚糖中的氨基与六价铬之间的静电相互作用，共同控制了这种三中心（3c）协同机制。吸附过程遵循拟二级动力学模型，吸附容量为 63.69mg g(-1)。各种等温线模型被用来关联实验数据，吸附过程是放热的，同时固-液界面的随机性降低。通过主体（壳聚糖）和客体（离子液体）之间的正协同效应，可以解释自发吸附过程的热力学。吸附的六价铬可以用氨水转化为铬酸铵，从而使吸附剂再生。该方法可以通过实际应用于含有铬的实际样品的形式转化为实际行动。
