Adsorption of mefenacet on sepiolite and attapulgite

Adsorption is an important process in governing the fate of pesticides in soil system. Adsorption on minerals was shown to control the transport, transformation and biological processes of pesticides. It was also of great significance in evaluating the potential effects on soil and groundwater and developing soil chemical remediation. In this study, sepiolite and attapulgite were selected as absorbent. Batch equilibrium experiments were performed to study the adsorption characteristics and adsorption mechanisms of mefenacet on sepiolite and attapulgite.It was indicated that the adsorption process of mefenacet on the two clay minerals could be divided into two phases:rapid adsorption stage and slow adsorption equilibrium stage,and equilibrium phase was 6 h.Its adsorption behavior could be described by Pseudo-second-order kinetics. The adsorption isotherms of mefenacet on the two clay minerals were well fitted by Linear equation and Freundlich equation. The adsorption capacity of mefenacet on sepiolite was larger than on attapulgite. FTIR spectroscopy and XRD analysis indicated that mefenacet could enter the interlayer of sepiolite and attapulgite. Hydrogen bonds, charge transfer and charge-dipole might exist between mefenacet and sepiolite or attapulgite.