Performance evaluation of sodium dodecyl sulfate aqueous solutions absorption in montmorillonite soil

Nowadays, large amounts of surfactant containing SDS are seen in domestic and urban waste stream and the input of the treatment plant. The aim of this study was to evaluate the effectiveness adsorption of surfactant sodium dodecyl sulfate (SDS) on montmorillonite soil as an inexpensive adsorbent is available in Iran. This research is empirical. Impact of initial sodium dodecyl sulfate (SDS) concentration, absorbent mass, and reaction time on the removal of sodium dodecyl sulfate by soil absorbent montmorillonite was studied. Experiment was carried out by synthetic samples containing different concentrations of 10, 30 and 50, mg dodecyl sulfate. Dodecyl sulfate concentrations were determined by spectrophotometer at a wavelength of 625 nm. Values 0.1, 0.25 and 0.5 g mass of adsorbent at pH 4, 7, 10 in terms of complete mixing with air at time (2.5, 5.10, 20, 30) minute was examined. In different stages, SDS quantity and COD was measured. With increasing of absorbent mass and reaction time removal of pollutant was increased and with increasing initial concentration dodecyl sulfate was reduced. The data showed that the maximum dodecyl sulfate absorption by montmorillonite is in test duration of 30 min and reached in Equilibrium. Most of removal and absorption capacity in optimum conditions (initial concentration 10mg / l, mass of absorbent 0.5 g/l and pH=7), was happened. SDS and COD removal was 77.5 and 76 percent. Evaluateion the efficiency of SDS absorbed on soil particle indicated that minor changes in different pH so that the pH increased from 4 to 10 the removal efficiency slightly increased but no significant difference between the values of the efficiency of different pH is. Absorption process is also influenced by the mass of absorbent and initial concentration of SDS that with increasing of absorbent mass and reducing initial concentration of pollutants the efficiency of absorption is increased.