摘要
Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8-6.7. Coexisting cations, such as Na＋, K＋, and Ca2＋, can enhance the adsorption of tannic acid on poly- aniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorp- tion process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 rag.g〈 at 35℃and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the ad- sorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.
Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8-6.7. Coexisting cations, such as Na+, K+, and Ca2+, can enhance the adsorption of tannic acid on poly-aniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorp-tion process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 mg·g-1 at 35 ℃ and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the ad-sorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.
基金
Supported by the National Major Research Plan for Water Pollution Control and Treatment of China （2008ZX07010-003-002）, the National Natural Science Foundation of China （21107065） and the Scientific Research Program Funded by Shaanxi Pro- vincial Education DePartment （HJK0769）.
