Humic acid interaction with clay minerals. Modification of the surface properties by the calcium presence.

FERNÁNDEZ SOLARTE, A.M;; MARIELA A. FERNÁNDEZ; MARIA DOS SANTOS AFONSO; ROSA M. TORRES SÁNCHEZ

International Journal of Environment and Health

Inderscience Publishers

Año: 2015 vol. 7 p. 215 - 230

1743-4955

The environmental importance of humic acids (HA) is not only related to soil fertility to which is linked to chemistry reactions, but some human diseases can be developed by HA intake as well as prevent calcium assimilation. The environmental importance of humic acids (HA) is not only related to soil fertility to which is linked to chemistry reactions, but some human diseases can be developed by HA intake as well as prevent calcium assimilation. Physicochemical characterizations of a montmorillonite (Mt) and its thermal treated product (Mt550), to which HA, calcium or both were added, will help to better understand the surface behavior of the binary or ternary systems. Calcium adsorption produces a slightly modification of the Mt specific surface area (SSA) while a decrease is observed for Mt550. HA adsorption produced a decrease in SSA. X-ray diffraction indicate calcium presence and no entrance of humic acid in the interlayer of Mt, while in the ternary systems (calcium-HA-Mt) an hindrance to the calcium entrance was observed. The adsorption of HA produce an increase, while calcium adsorption generated a similar decrease, of the negative charge on the surface for both samples. Mt550 showed higher mean pore diameter (MPD) than that of Mt. However for Mt an increase of the MPD with Ca+2 adsorption, was evidenced even in presence of HA, while no changes was found after HA adsorption, contrarily to that found for Mt550.