Department of Chemistry, Indian Institute of Technology Guwahati, Assam, India.
J Hazard Mater. 2011 Feb 15;186(1):575-82. doi: 10.1016/j.jhazmat.2010.11.036. Epub 2010 Nov 13.
Malachite nanoparticles of 100-150 nm have been efficiently and for the first time used as an adsorbent for the removal of toxic arsenate and chromate. We report a high adsorption capacity for chromate and arsenate on malachite nanoparticle from both individual and mixed solution in pH ∼4-5. However, the adsorption efficiency decreases with the increase of solution pH. Batch studies revealed that initial pH, temperature, malachite nanoparticles dose and initial concentration of chromate and arsenate were important parameters for the adsorption process. Thermodynamic analysis showed that adsorption of chromate and arsenate on malachite nanoparticles is endothermic and spontaneous. The adsorption of these anions has also been investigated quantitatively with the help of adsorption kinetics, isotherm, and selectivity coefficient (K) analysis. The adsorption data for both chromate and arsenate were fitted well in Langmuir isotherm and preferentially followed the second order kinetics. The binding affinity of chromate is found to be slightly higher than arsenate in a competitive adsorption process which leads to the comparatively higher adsorption of chromate on malachite nanoparticles surface.
100-150nm 的孔雀石纳米粒子首次被高效用作吸附剂，用于去除有毒的砷酸盐和铬酸盐。我们报道了在 pH 值约为 4-5 的单一和混合溶液中，孔雀石纳米粒子对铬酸盐和砷酸盐具有很高的吸附能力。然而，吸附效率随着溶液 pH 值的增加而降低。批量研究表明，初始 pH 值、温度、孔雀石纳米粒子剂量以及铬酸盐和砷酸盐的初始浓度是吸附过程的重要参数。热力学分析表明，铬酸盐和砷酸盐在孔雀石纳米粒子上的吸附是吸热和自发的。借助吸附动力学、等温线和选择性系数（K）分析，对这些阴离子的吸附也进行了定量研究。铬酸盐和砷酸盐的吸附数据均很好地符合朗缪尔等温线，优先遵循二级动力学。在竞争吸附过程中，发现铬酸盐的结合亲和力略高于砷酸盐，这导致铬酸盐在孔雀石纳米粒子表面的吸附较高。
