Mittal Alok, Gupta V K, Malviya Arti, Mittal Jyoti
Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal 462007,MP, India.
J Hazard Mater. 2008 Mar 1;151(2-3):821-32. doi: 10.1016/j.jhazmat.2007.06.059. Epub 2007 Jun 20.
Bottom Ash and De-Oiled Soya have been used as adsorbents for the removal of a hazardous azo dye-Metanil Yellow from its aqueous solutions. Adsorption of Metanil Yellow on these adsorbents has been studied as function of time, temperature, concentration and pH. Batch adsorption studies, kinetic studies and column operations enabled extraction of lethal dye from wastewaters. Adsorption equilibrium data confirms both Langmuir and Freundlich isotherm models and monolayer coverage of dye over adsorbents. Kinetic data have been employed to calculate specific rate constants, indicating thereby involvement of first order kinetics in the on-going adsorption and activation energy was determined as 0.813 and 1.060 kJ mol(-1) for Bottom Ash and De-Oiled Soya, respectively. For both adsorbents, the adsorption process has been found governing by film diffusion, over the entire concentration range. Column operations have also been performed for the bulk removal of the dye and also to examine the practical utilization of fixed bed adsorption technique in elimination of dangerous effluent. Saturation factors for Bottom Ash and De-Oiled Soya columns have been calculated as 99.15 and 99.38%, respectively. Attempts have also been made to regenerate the dye from the exhausted columns using aqueous sodium hydroxide as eluent.
底灰和脱油大豆已被用作吸附剂，用于从其水溶液中去除有害的偶氮染料——甲基橙黄。研究了甲基橙黄在这些吸附剂上的吸附情况，考察了时间、温度、浓度和pH值等因素的影响。通过间歇吸附研究、动力学研究和柱操作实现了从废水中提取这种有害染料。吸附平衡数据证实了朗缪尔等温线模型和弗伦德里希等温线模型，以及染料在吸附剂上的单层覆盖。利用动力学数据计算了比速率常数，结果表明正在进行的吸附过程涉及一级动力学，底灰和脱油大豆的活化能分别确定为0.813和1.060 kJ mol(-1)。对于这两种吸附剂，在整个浓度范围内，吸附过程均受膜扩散控制。还进行了柱操作以大量去除染料，并考察固定床吸附技术在消除危险废水方面的实际应用。底灰柱和脱油大豆柱的饱和因子分别计算为99.15%和99.38%。还尝试使用氢氧化钠水溶液作为洗脱剂，从耗尽的柱中再生染料。
