甲萘威在蒙脱石和高岭石表面的吸附行为研究

研究了甲萘威在蒙脱石和高岭石两种粘土矿物表面的吸附行为,考察了时间、pH值和农药浓度对吸附的影响,并用FTIR探讨了其吸附机理。结果表明,蒙脱石和高岭石对甲萘威的吸附是一个先快后慢的过程,10h吸附可基本达到平衡。用动力学方程对甲萘威的吸附过程进行拟合,发现Elovich方程为最佳模型(R20.93,p0.05,n=12),其次是一级动力学方程和双常数方程;甲萘威在蒙脱石和高岭石表面的等温吸附均很好地符合Langmuir方程(R20.99,p0.05,n=6),其最大吸附量分别为3.651mg/g和1.688mg/g;蒙脱石对甲萘威的吸附强度大于高岭石;在实验pH范围内,甲萘威在两种矿物表面的吸附量均随体系初始pH的升高而减小;红外光谱分析结果表明,甲萘威分子可能通过氢键与蒙脱石和高岭石发生结合。

Dsorption of Carbaryl on Surface of Montmorillonite and Kaolinite

Adsorption characteristics of carbaryl on the surface of montmorillonite and kaolinite were investigated,as a function of time,pH and pesticide concentration.Mechanisms of adsorption were analyzed by Fourier Transform Infrared Spectroscopy (FTIR).Results indicted that the adsorption of carbaryl on the surface of montmorillonite and kaolinite was a first fast and later slow process,and reached equilibrium within 10h.The sorption kinetics of carbaryl could be described by Elovich equation very well,followed by first order equation and two-constant equation.The equilibrium adsorption of carbaryl on the minerals could be fitted by Langmuir model quite well,with the adsorption capacity of montmorillonite and kaolinite for carbaryl as 3.651 and 1.688mg/g respectively.Montmorillonite presents a greater affinity for carbaryl as compared to kaolinite.The adsorption amounts of carbaryl decreased with the increasing of pH value.FTIR spectra showed that the adsorption of carbaryl onto the surfaces of minerals could be caused by hydrogen bond in the process.