Bansal Manjeet, Garg Umesh, Singh Diwan, Garg V K
Department of Civil Engineering, National Institute of Technology, Kurukshetra 136119, India.
J Hazard Mater. 2009 Feb 15;162(1):312-20. doi: 10.1016/j.jhazmat.2008.05.037. Epub 2008 May 15.
This paper reports the feasibility of using pre-consumer processing agricultural waste to remove Cr(VI) from synthetic wastewater under different experimental conditions. For this, rice husk, has been used after pre-treatments (boiling and formaldehyde treatment). Effect of various process parameters, namely, pH, adsorbent dose, initial chromium concentration and contact time has been studied in batch systems. The removal of chromium was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration and other studied process parameters. Maximum metal removal was observed at pH 2.0. The efficiencies of boiled and formaldehyde treated rice husk for Cr(VI) removal were 71.0% and 76.5% respectively for dilute solutions at 20gl(-1) adsorbent dose. The experimental data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. It was found that Freundlich and D-R models fitted well. The results revealed that the hexavalent chromium is considerably adsorbed on rice husk and it could be an economical method for the removal of hexavalent chromium from aqueous systems. FTIR and SEM were recorded, before and after adsorption, to explore number and position of the functional groups available for Cr(VI) binding on to studied adsorbents and changes in adsorbent surface morphology.
本文报道了在不同实验条件下，利用消费前加工农业废弃物从合成废水中去除六价铬的可行性。为此，稻壳经过预处理（煮沸和甲醛处理）后被使用。在间歇系统中研究了各种工艺参数的影响，即pH值、吸附剂剂量、初始铬浓度和接触时间。铬的去除取决于吸附剂的物理化学特性、吸附质浓度和其他研究的工艺参数。在pH 2.0时观察到最大的金属去除量。在吸附剂剂量为20g l(-1)的稀溶液中，煮沸处理和甲醛处理的稻壳对六价铬的去除效率分别为71.0%和76.5%。使用弗伦德里希、朗缪尔和杜比宁-拉杜舍维奇（D-R）等温线模型对实验数据进行了分析。发现弗伦德里希模型和D-R模型拟合良好。结果表明，六价铬在稻壳上有相当程度的吸附，这可能是一种从水体系中去除六价铬的经济方法。在吸附前后记录了傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM），以探究用于六价铬结合到所研究吸附剂上的官能团的数量和位置以及吸附剂表面形态的变化。
