Removal of humic acid by organo-montmorillonites: Influence of surfactant loading and chain length of alkylamonium cations

FERNANDEZ, M.; CURUTCHET, G.; TORRES, R.

WATER AIR AND SOIL POLLUTION

SPRINGER

Lugar: Berlin; Año: 2014

0049-6979

In this study, the characterization and adsorptionproperties of montmorillonite (MMT) andorganomontmorillonites with different surfactant/cationic exchange capacity (CEC) ratios (1 and 2) oftetradecyl trimethylammonium (TDTMA+) andhexadecyl trimethylammonium (HDTMA+) cations wereevaluated. The particle apparent diameter, determined bylaser and scanning electron microscopy showed aggregateformation, which varied with loading and cationlength of the surfactant used. X-ray diffraction analysisrevealed the formation of a pseudotrilayer arrangement ofboth surfactants in the interlayer space, FTIR showed thecharacteristic bands of the surfactants and micelle formations,and zeta potential determinations indicated neutralor negative surface charge values, except for sampleobtained with one CEC concentration exchanged withHDTMA+ (HDTMA1-MMT) where a charge reversal topositive was found. Higher adsorption amounts of humicacid (HA) were found for HDTMA1-MMT andTDTMA1-MMT samples than for MMT sample, whilethe increase in the loading of both surfactants decreasedthe amounts of HA adsorbed could be assigned to ahigher micelle formation and different packing densityof alkyl chain, in the external surface. The correlationfound between the total surface area and negative zetapotential values and the HA adsorption rate, within eachsurfactant, indicated the strong influence that these propertieshave on HA adsorption.