Removal of lead from aqueous solutions by condensed tannin gel adsorbent
Lead has caused serious environmental pollution due toits toxicity, accumulation in food chains and persistence innature. In this paper, lead removal from aqueous solutions wasinvestigated using condensed tannin gel adsorbent synthesized froma natural tannin compound. It is found that the adsorption isstrongly affected by pH values of aqueous solutions. Within pHrange of 3.5-6, when initial lead concentration is 100 mg/L,removal efficiency is more than 90%. Adsorption equilibrium isreached within 150 minutes. The adsorption isotherm fits well withthe Langmuir equation, by which the saturated adsorption uptake of190 mg Pb2+/g dry tannin gel adsorbent is obtained. By means of thermodynamics analysis, it is revealed that the process isexothermic and the adsorption heat is up to 38.4 kJ/mol. Withrespect to high efficiency, moderate pH requirement and minimizedsecond pollution, the tannin gel adsorbent exhibits a promisingpotential in the removal of lead from wastewater.
作 者： ZHAN Xin-min ZHAO Xuan AKANE Miyazaki YOSHIO Nakano 作者单位： ZHAN Xin-min(Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China)ZHAO Xuan(Section of Environmental Science and Technology, Institute of Nuclear Energy Technology, Tsinghua University, Beijing 100084,China)
AKANE Miyazaki,YOSHIO Nakano(Department of Environmental Chemistry and Engineering,Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama 226-8502, Japan)
刊 名： 环境科学学报(英文版) ISTIC SCI 英文刊名： JOURNAL OF ENVIRONMENTAL SCIENCES 年，卷(期)： 2003 15(1) 分类号： X52 关键词： lead removal Mimosa tannin synthesis tannin gel adsorbent