Study on adsorption of glyphosate (N-phosphonomethyl glycine) pesticide on MgAl-layered double hydroxides in aqueous solution.

Feng Li, Yunfeng Wang, Qiaozhen Yang, David G Evans, Claude Forano, Xue Duan

Index: J. Hazard. Mater. 125(1-3) , 89-95, (2005)

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Abstract

MgAl-layered double hydroxides with different interlayer anions (nitrate, carbonate and chloride) were evaluated for their abilities to adsorb the organic pesticide glyphosate (N-phosphonomethyl glycine, Gly). The adsorption isotherms of Gly on layered double hydroxides (LDHs) nitrate were described by the Langmuir equation at lower equilibrium concentration of Gly (C(e)<1.0 mmol/L), and the Gly adsorption capacity on LDHs increased with the layer charge density, i.e. the structural Al3+/Mg2+ ratio. Gly adsorption on LDHs nitrate generally occurred through two processes, external surface adsorption and interlayer anion exchange. The adsorption amount on LDHs at C(e)=1.0 mmol/L decreased in the order of interlayer anions: Cl(-)>NO3(-)>CO3(2-).