Chemical Engineering Department, University of Calcutta, Kolkata, West Bengal, India.
Colloids Surf B Biointerfaces. 2011 May 1;84(1):221-32. doi: 10.1016/j.colsurfb.2011.01.004. Epub 2011 Jan 12.
Cr(VI) is a major water pollutant from industrial effluent whose concentration is to be reduced within the permissible limit. Present study reports a systematic evaluation of six different natural adsorbents for the removal of Cr(VI) from aqueous solutions in batch process. The adsorption kinetic data were best described by pseudo-second order model. The values of mass transfer coefficient for Cr(VI) adsorption indicated that the velocity of the adsorbate transport from the bulk to the solid phase was quite fast. The effective diffusivity of Cr(VI) removal for all the adsorbents were of the order of 10(-10) m(2)/s which suggested chemisorption of the process. The adsorption process was jointly controlled by film diffusion and intraparticle diffusion. Maximum monolayer adsorption capacities onto the natural adsorbents used were comparable to the other natural adsorbents used by other researchers. The thermodynamic studies and sorption energy calculation using Dubinin-Radushkevich isotherm model indicated that the adsorption processes were endothermic and chemical in nature. FT-IR studies were carried out to understand the type of functional groups responsible for Cr(VI) binding process. Desorption study was carried out with different concentration of NaOH solutions. Application study was carried out using electroplating industrial wastewater.
六价铬是工业废水中的主要水污染物，其浓度需要降低到允许的限度内。本研究系统评估了六种不同的天然吸附剂，用于在批处理过程中从水溶液中去除六价铬。吸附动力学数据最好用伪二级模型来描述。六价铬吸附的传质系数表明，吸附质从主体到固相的迁移速度相当快。所有吸附剂的有效扩散系数均在 10(-10) m(2)/s 左右，表明该过程为化学吸附。吸附过程由膜扩散和颗粒内扩散共同控制。天然吸附剂的最大单层吸附容量与其他研究人员使用的其他天然吸附剂相当。热力学研究和Dubinin-Radushkevich 等温模型的吸附能计算表明，吸附过程是吸热和化学性质的。傅里叶变换红外光谱（FT-IR）研究用于了解负责六价铬结合过程的官能团类型。使用不同浓度的氢氧化钠溶液进行解吸研究。应用研究使用电镀工业废水进行。
