Mittal Alok, Gajbe Vibha, Mittal Jyoti
Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal 462007, Madhya Pradesh, India.
J Hazard Mater. 2008 Jan 31;150(2):364-75. doi: 10.1016/j.jhazmat.2007.04.117. Epub 2007 May 3.
Bottom Ash a power plant waste material and De-Oiled Soya, an agricultural waste product have been successfully used for the removal and recovery of a hazardous triphenylmethane dye-Methyl Violet, from wastewaters. The characterization of each adsorbent has been carried out by I.R. and D.T.A. curves. Batch adsorption studies have been made by measuring effects of pH, sieve size, amount of adsorbent, contact time, temperature, concentration of the adsorbate solution, etc. Kinetic studies have been used to determine the nature of rate controlling step of the processes and confirm the applicability of the first order rate expression in the ongoing adsorption process. Various thermodynamic parameters have also been calculated by applying the linear forms of Langmuir and Freundlich adsorption isotherms. The linear nature of adsorption isotherms obtained shows the dependence of the processes on the Freundlich and Langmuir isotherm models. Furthermore, to ascertain the adsorption processes to be particle diffusion or film diffusion mechanism, Boyd and Reichenberg's expressions have been applied. For both the adsorbents, column operations have been carried out for the bulk removal of the dye. The adsorbed dye has been recovered by eluting hydrochloric acid of pH 3 through exhausted columns.
底灰（一种发电厂废料）和脱油大豆（一种农业废品）已成功用于从废水中去除和回收有害的三苯甲烷染料——甲基紫。每种吸附剂的表征已通过红外光谱和差热分析曲线进行。通过测量pH值、筛孔尺寸、吸附剂用量、接触时间、温度、吸附质溶液浓度等的影响进行了批量吸附研究。动力学研究已用于确定过程中速率控制步骤的性质，并确认一级速率表达式在当前吸附过程中的适用性。还通过应用朗缪尔和弗伦德利希吸附等温线的线性形式计算了各种热力学参数。所得吸附等温线的线性性质表明该过程依赖于弗伦德利希和朗缪尔等温线模型。此外，为确定吸附过程是颗粒扩散还是膜扩散机制，应用了博伊德和赖兴贝格的表达式。对于这两种吸附剂，都进行了柱操作以大量去除染料。通过用pH值为3的盐酸洗脱已耗尽的柱来回收吸附的染料。
