Movilidad y control del herbicida picloram en arcillas

J. L. MARCO BROWN; C. M. BARBOSA; R. M. TORRES SÁNCHEZ; M. DOS SANTOS AFONSO

Las Fronteras de la Física y Química Ambiental en Ibero América

UNSAM

Año: 2008; p. 496 - 502

&amp;amp;lt;!-- /* Font Definitions */ @font-face {font-family:SimSun; panose-1:2 1 6 0 3 1 1 1 1 1; mso-font-alt:????¨¬??; mso-font-charset:134; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:3 680460288 22 0 262145 0;} @font-face {font-family:"@SimSun"; panose-1:2 1 6 0 3 1 1 1 1 1; mso-font-charset:134; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:3 680460288 22 0 262145 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0pt; margin-bottom:.0001pt; mso-pagination:widow-orphan; text-autospace:none; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:ES;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 85.05pt 70.85pt 85.05pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&amp;amp;gt; Illite, kaolinite, nontronite and montmorillonite (428 and wyo) clays were characterized. Adsorption of herbicide picloram (4-amino-3,5,6-trichloropicolinic acid) was studied and it was found a dependence with the pH of the media, finding a greater adsorption in acid media. Adsorptionisotherms were conducted for wyo montmorillonite finding a maximum coverage of 10 μmol/g of clay. While maximum coverages for particle fractions wyo > 2 m and wyo < 2 m were 6 and 16 μmol/g ofclay, respectively. The solid sample, product of adsorption, was analyzed by DRX and it was found a shift of the d(001) reflexions toward lower values of 2 theta revealing that picloram was introduced inthe clay interlayer. Picloram-clay systems were also analyzed by XPS. It was found that the herbicide bond by the piridinic nitrogen to all the clays, excepting for kaolinite.