Naiya T K, Bhattacharya A K, Das S K
Department of Chemical Engineering, University of Calcutta, Kolkata 700 009, India.
J Colloid Interface Sci. 2008 Sep 1;325(1):48-56. doi: 10.1016/j.jcis.2008.06.003. Epub 2008 Jun 5.
Clarified sludge is a major waste generating during steel making process. In India and in most industrial countries, the use of clarified sludge as a road ballast and land filter has had a very long history. In present study, clarified sludge has been characterized and used for the removal of Cd(II) from aqueous solutions. The effect of pH, adsorbent dosage, adsorbate concentration, contact time and temperature on adsorption process was studied in batch experiments. Kinetics data were best described by pseudo-second order model. The effective diffusion co-efficient of Cd(II) is of the order of 10(-11) m(2)/s. The maximum uptake was 36.23 mg/g. The adsorption data can be well described by Langmuir isotherm. The result of the equilibrium studies showed that the solution pH was the governing factor affecting the adsorption. Mass transfer analysis was also carried out for the adsorption process. The thermodynamic studies indicated that the adsorption was spontaneous and exothermic in nature. The sorption energy calculated from Dubinin-Radushkevich isotherm indicated that the adsorption process is chemical in nature. Desorption as well as the application studies were carried out considering the economic viewpoint of wastewater treatment plant operations.
澄清污泥是炼钢过程中产生的主要废弃物。在印度和大多数工业国家，将澄清污泥用作道路道碴和土地过滤材料已有很长的历史。在本研究中，对澄清污泥进行了表征，并用于去除水溶液中的Cd(II)。通过批量实验研究了pH值、吸附剂用量、吸附质浓度、接触时间和温度对吸附过程的影响。动力学数据用伪二级模型描述效果最佳。Cd(II)的有效扩散系数约为10(-11) m(2)/s。最大吸附量为36.23 mg/g。吸附数据可用朗缪尔等温线很好地描述。平衡研究结果表明，溶液pH值是影响吸附的主要因素。还对吸附过程进行了传质分析。热力学研究表明，吸附是自发的且本质上是放热的。根据杜宾宁-拉杜什凯维奇等温线计算的吸附能表明吸附过程本质上是化学吸附。从废水处理厂运营的经济角度出发，进行了解吸以及应用研究。
