不同pH的柠檬酸对茶园土壤溶出液中氟组分变化的影响  

Variation of fluoride composition in tea garden soil leachate under citric acid of different pH

作　　者：营浩 张显晨[2] 郜红建[1,2] 

机构地区：[1]安徽农业大学资源与环境学院,合肥230036 [2]安徽农业大学茶叶生物化学与生物技术教育部重点实验室,合肥230036

出　　处：《环境化学》2014年第11期1885-1892,共8页Environmental Chemistry

基　　金：国家自然科学基金(31272254);安徽省杰出青年科学基金(1408085J01)资助

摘　　要：通过连续流动搅拌法,研究了不同pH的柠檬酸对茶园土壤溶出液中氟组分变化的影响.结果表明,土壤溶出液的pH随溶出时间的延长而逐渐减小.土壤溶出液中的游离态氟和总氟的浓度随时间的延长和柠檬酸pH的升高而逐渐减小,且呈现初始(0—6h)溶出浓度较高,而后(6—10h)逐渐减缓的趋势.土壤氟的溶出过程用一级动力学方程、Elovich方程、扩散方程和双常数方程均有较好的拟合,决定系数(R2)均大于0.90.低pH(pH3.5)条件下,F主要以H-F形态存在,随着pH的升高(pH4.0—5.0),H-F形态的氟减小,Al-F络合态的氟增多,且随时间延长,溶出浓度均降低.反应开始的前1h,Al-F络合物主要以AlF3为主,占氟溶出总量的90%以上;至7h时,AlF+2的溶出量逐渐增大,并逐渐超过AlF3.低pH的柠檬酸促进土壤游离态氟和总氟的溶出,有利于络合态氟的形成,但对Al-F络合物的形态转化没有显著影响.Variation of fluoride（ F） composition in tea garden soil leachate under citric acid of different pH was studied by using the flow-stirred method. Results showed that soil solution pH decreased with the increase of reaction time. The amount of free F and total F released into soil solution increased with citric acid pH and reaction time. Moreover,the release of F from soil was initially fast and then slowed down. The concentration of F released into soil solution from 0 to 6 h was higher than from 6 to 10 h. The released of F from tea garden soil fitted the first-order reaction kinetics equation,Elovich equation,diffusion equation and double constant equation well,and the coefficient of determination（ R2） were higher than 0. 90. At low pH,H-F was the main form of F.The amount of Al-F complexes,released into soil solution increased,while the amount of H-F complexes released into soil solution decreased with citric acid pH. Amount of Al-F complexes and H-F complexes,decreased with the increase of reaction time. During the first 1 hour,AlF3 was the main form of Al-F complexes,accounting for 90% of the total F released from the tea garden soil. In addition,with the increase of reaction time,the amount of AlF＋2released from the tea garden soil increased and was higher than that of AlF3 after 7 hours. At low pH,citric acid promoted release of F from soil and facilitated formation of F-complexes,while it had no significant impacts on the transformation among Al-F complexes.

关 键 词：柠檬酸 茶园土壤 氟形态 释放 动力学 PH 

分 类 号：X131.3[环境科学与工程—环境科学]