SORPTION OF TRITON X-100 IN SOILS WITH VARIOUS GRAIN SIZE COMPOSITIONS: KINETICS, EFFECT OF pH, ELECTROLYTE AND TEMPERATURE

A study was conducted on the sorption of the surfactant Triton X-100, with a static method, through shaking of 2 g of soil (Albic Luvisols, Haplic Luvisols, Haplic Cambisols) in 10 cm(3) of solution during 24 hours. The kinetics was also studied of the process and the efficiency of sorption of triton X-100 from solutions with different values (1-12) of pH, in the presence of electrolytes: KCl, NH4Cl and CaCl2, and at temperatures of 20, 25, 30, 35 and 50 degrees C. Experimental results showed good agreement with results calculated from the Langmuir's equation and from a pseudo quadratic equation of kinetics. In the loamy soil, sorption of TX-100 increased in a nearly linear manner within the whole range of concentrations studied, while in the loess and sandy soils it had a linear course in the range of low initial concentrations. A high rate of sorption was found within the initial 30 min of TX-100 contact with the soils, following which the sorption increased more slowly and to a lesser degree. The value of pH had no effect on the sorption of the surfactant from solution with concentration of 250 mg . dm(-3). At concentrations of 1000 and 2000 mg . dm(-3) significantly higher sorption was observed for solutions with pH = 1, in all of the soils under study, and from solution with pH = 12 - in the loess and sandy soils. The presence of electrolyte caused an increase in triton sorption, but in a degree dependent on the type of electrolyte and on the soil properties, and on the concentration of the surfactant. A slight effect of temperature on the sorption of TX-100 in the soils was observed.