植物单宁还原水体六价铬的动力学研究  

Reduction kinetics of aqueous Cr(VI) by plant tannin

作　　者：蒋晓锋 隆汶君 侯梦春 张文华[1,2] JIANG Xiao-feng;LONG Wen-jun;HOU Meng-chun;ZHANG Wen-hua(National Engineering Laboratory for Clean Technology of Leather Manufacture,Sichuan University,Chengdu 610065,China;The key laboratory of Leather Chemistry and Engineering of Ministry of Education,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学制革清洁技术国家工程实验室,四川成都610065 [2]四川大学皮革化学与工程教育部重点实验室,四川成都610065

出　　处：《化学研究与应用》2023年第11期2740-2747,共8页Chemical Research and Application

基　　金：国家重点研发计划项目(NO.2018YFC1802201)资助。

摘　　要：本文评估了不同来源植物单宁对水溶液中Cr(Ⅵ)还原效率,并研究了温度、离子强浓度对于Cr(Ⅵ)还原反应的影响。结果表明,在pH 3.0条件下,植物单宁可以高效还原Cr(Ⅵ)为Cr(Ⅲ),还原过程符合拟二级动力学。提高温度可显著加快Cr(Ⅵ)的还原,而离子强度的影响较小。对Cr(Ⅵ)还原的能力的顺序为:单宁酸>荆树皮单宁>橡椀单宁>落叶松单宁,富含连苯三酚结构的植物单宁,具有更高的还原能力。理论计算表明,模型多酚与铬酸形成酚酯中间体后,酚酯分子内电子转移,是植物单宁还原Cr(Ⅵ)的主要机理。The reduction of Cr(VI)in aqueous solution by plant tannin with different origins was studied by batch experiments.Effects of temperature and ionic strength on the reduction of Cr(VI)by tannin were tested.Results shows that plant tannin can effec-tively transformed Cr(VI)into Cr(III),which could be fitted by a pseudo-second order kinetics at pH 3.0.Increasing the reaction temperature can significantly increase the reduction rate of Cr(VI)by plant tannins,while ionic strength has litle effect on Cr(VI)reduction.The reducing ability of tannin follows the order of tannic acid>wattle tannin>valonia tannin>larch tannin,indicating the crucial role of pyrogallol.Theoretical calculation shows that Cr(VI)was reduced mainly via forming phenolic ester intermediate be-tween model polyphenol and HCrO_(4),followed by intramolecular electron transfer.

关 键 词：植物单宁 Cr(Ⅵ) 还原 动力学 DFT 

分 类 号：O643.1[理学—物理化学]