Removal of PCBs from wastewater using fly ash

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• 作者：Nollet ; Hendrik ; Roels ; Murielle ; Lutgen ; Pierre ; Van der Meeren ; Paul ; Verstraete ; Willy
• 关键词：Polychlorinated biphenyl ; Fly ash ; Adsorption ; Kinetics ; Activation energy
• 刊名：Chemosphere
• 出版年：2003
• 期刊代码：15_00456535
• 类别：env
• 出版时间：November, 2003
• 卷：53
• 期：6
• 页码：655-665
• 文件大小：238 K

摘要

Liquids and sludges containing polychlorinated biphenyls (PCBs) can be treated to concentrate the PCBs in a solid residue. The latter can then be handled to destroy the PCBs. A study on sorption kinetics of PCBs on fly ash was conducted in controlled batch systems. TCB and HeCB are removed at 25 °C by adsorption on fly ash up to 97%at pH 7, with an adsorbent dose of 5 g/l. An examination of the thermodynamic parameters shows that the adsorption of TCB and HeCB by fly ash is a process occuring spontaneously at ambient conditions. Activation energies for the sorption process ranged between 5.6 and 49.1 kJ/mol. It was observed that the rate at which TCB and HeCB are adsorbed onto fly ash showed a diffusion limitation. The uptake rate of TCB and HeCB increases with increasing initial concentration and gradually tends to a constant value. A decrease in the adsorption of TCB and HeCB was observed when interfering ions and other PCB congeners were present. Changing the pH in the aqueous solution from 2 to 10 had no effect on the adsorption process. Overall, fly ash can be used for an efficient removal of PCBs from several aqueous solutions.