Department of Chemistry, Birla Institute of Technology and Science, Pilani-Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, India.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2011;46(13):1598-610. doi: 10.1080/10934529.2011.609460.
The remediation of heavy metals requires the development of efficient adsorbents. Macroporous polystyrene divinyl benzene based resins are known for their excellent surface characteristics for the effective adsorption of metals. In this paper, we propose an effective adsorption procedure for chromium (VI) using aliphatic primary amine as a guest in Amberlite XAD-4 polymeric sorbent as the host. The adsorption of chromium was quantitative at pH 2.5. The adsorption process was in accordance with pseudo second order kinetics and the maximum adsorption capacity was found to be 75.93 mg g(-1) with good adherence to Langmuir isotherm model. The free energy change ΔG(0) increased with temperature and the negative ΔH(0) and ΔS(0) values indicate the exothermic nature of adsorption and decreased randomness at the adsorbent-solution interface. In aqueous medium, the water molecules surround the hydrophobic host polymeric matrix and this cage effect is responsible for the reduction in entropy of the system. The regeneration of the adsorbent was effective in alkaline medium and the efficacy of the adsorbent was tested for the removal of chromium from tannery waste water.
重金属的修复需要开发高效的吸附剂。大孔聚苯乙烯二乙烯基苯基树脂以其优异的表面特性而闻名，可有效吸附金属。在本文中，我们提出了一种使用脂肪伯胺作为主体 Amberlite XAD-4 聚合物吸附剂中的客体来有效吸附六价铬的方法。在 pH 2.5 时，铬的吸附是定量的。吸附过程符合拟二级动力学，最大吸附容量为 75.93mg g(-1)，并很好地符合朗缪尔等温模型。自由能变化 ΔG(0)随温度升高而增加，负的 ΔH(0)和 ΔS(0)值表明吸附是放热的，并且在吸附剂-溶液界面处的随机性降低。在水介质中，水分子包围疏水性主体聚合物基质，这种笼效应导致系统熵的降低。在碱性介质中，吸附剂的再生是有效的，并且已经测试了该吸附剂从制革废水中去除铬的功效。
