Lead Removal from Aqueous Solutions Using Novel Gel Adsorbent Synthesized from Natural Condensed Tannin

作     者：占新民 赵璇 AKANE Miyazaki YOSHIO Nakano 

作者机构：State Key Joint Laboratory on Environment Simulation and Pollution Control Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China Section of Environmental TechnologyInstitute of Nuclear Energy Technology Tsinghua University Beijing 100084China Department of Environmental Chemistry and Engineering Interdisciplinary Graduate School of Science and Engineering Tokyo Institute of Technology Nagatsuta 4259 Midori-ku Yokohama 226-8502 Japan 

出 版 物：《Chinese Journal of Chemical Engineering》 (中国化学工程学报（英文版）)

年 卷 期：2003年第11卷第4期

页      面：426-430页

核心收录：

学科分类：081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 

主　　题：condensed tannin lead removal surface precipitation tannin gel adsorbent 

摘      要：Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92 mg·g-1 (based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value, which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.