均质化莲子草根系分泌物对黏土吸附四环素的影响

Effects of Homogenization of Alternanthera philoxeroides Root Exudates on Tetracycline Adsorption by Clay

在不同比例空心莲子草粗根(TR)和细根(FR)分泌物均质化条件下,研究膨润土和高岭土对四环素(TC)的等温吸附特征,并分析pH值、温度和离子浓度对TC吸附的影响。结果表明,分泌物均质化后黏土对TC的吸附符合Henry模型,FR均质化对TC吸附的促进作用比TR均质化更强,高岭土对TC吸附的增长幅度比膨润土更大;在pH值2~10、温度5℃~40℃、离子浓度0.01 mol/L~0.5 mol/L条件下,分泌物均质化后黏土对TC的吸附量与温度呈正相关,随pH值和离子浓度增加均呈现先增大后减小的趋势;均质化后黏土对TC的吸附是一个自发、吸热、熵增的反应过程,莲子草根系分泌物能够增强黏土对TC的固定能力。

Under the homogenization of thick root(TR)exudates and fine root(FR)exudates of Alternanthera philoxeroides in different proportions,the isothermal adsorption characteristics of tetracycline(TC)by bentonite and kaolin were studied,and the effects of pH value,temperature and ion concentration on TC adsorption were analyzed.The results showed that the adsorption of TC by clay conformed to Henry model after homogenization of root exudates.The promoting effect of FR homogenization on TC adsorption was stronger than that of TR homogenization.The increase of TC adsorption by kaolin was larger than that of bentonite.Under the conditions of pH value of 2~10,temperature of 5℃~40℃and ion concentration of 0.01 mol/L~0.5 mol/L,after homogenization of root exudates,the adsorption capacity of TC on clay was positively correlated with temperature,and increased first and then decreased with the increase of pH value and ion concentration.After homogenization,the adsorption of TC by clay was a spontaneous,endothermic and entropy increasing reaction process.The root exudates of Alternanthera philoxeroides could enhance the fixation ability of clay to TC.