Adsorption and characterization of MCPA on DDTMA- and raw-montmorillonite: Surface sites involved

ROSA M. TORRES SÁNCHEZ; M. FERNANDEZ; CINTIA C. SANTIGO

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART B - PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2016 vol. 5 p. 245 - 253

0360-1234

The 4-chloro-2-methylphenoxy acid (MCPA) is an herbicide widely used in agriculture, which generates agreat concern about contamination of surface water and serious consequences for human health and theenvironment. In this work, the adsorption of MCPA on an Argentine montmorillonite (MMT) and itsorgano-montmorillonite product (OMMT) with different dodecyl trimethyl ammonium loading wasinvestigated. MCPA adsorption on OMMT increases at least 3 times, with respect to the amountdetermined for MMT. X-ray diffraction and zeta potential analyses indicated the inner (interlayer) andouter surface participate as adsorption sites. Changes in surface electric charge and also interlayerexpansion suggest that dimethyl amine (MCPA counterion) was also surface-adsorbed. The largeraggregates of OMMT, without and with MCPA, obtained compared to those of MMT samples, generate animprovement in the coagulation efficiency. This property, particularly after MCPA retention, allows aneasier separation of the solids from the solution and enables a simple technological process application