Study of acids herbicides removal by calcined Mg-Al-CO3-LDH

Mg-Al-CO3-LDH is an anionic clay capable of removing anions from a solution by regenerating its layered structure. The mixed Mg,Al-oxide formed from calcined Mg-Al-CO3-LDH is a promising sorbent for organic anions. The aim of this work is to study the capacity of calcined Mg-Al-CO3-LDH to remove the acid herbicides 2,4-D, MCPA and Picloram from aqueous solution, as well as investigate the influence of pH on the regeneration process. To study this we looked into the kinetics of the regeneration process and being obtained the sorption isotherms of these anions on the clay. The regeneration process proved to be fast, the layered structure regenerated after contact of the calcined LDH with the anions solution for 15 min. Removal of the organic contaminants occurs mainly in first six hours. Intercalation of the organic anions showed to be dependent on their concentrations in solution. (c) 2006 Elsevier Ltd. All rights reserved.