Evaluation of the Adsorption Capacity of the Expanded Perlite to Remove Linear Alkyl Benzene Sulphonic Acid LABSA from Aqueous Solution

Abstract

Linear alkyl benzene sulphonic acid (LABSA) is the major anionic surfactant material used in detergent formulations so that it is frequently present in domestic and civil wastewater. In this study, removal of LABSA has been carried out from its aqueous solutions by using the expanded perlite (EP) as potential adsorbent. Perlite products are made from an amorphous alumino-silicate rock, which has some very special properties: it contains water, which expands into steam on heating, producing a foamed structure. The EP particles used for adsorption process were in the range of 0.85-1.6 mm. Optimum parameters for the adsorption of LABSA over EP have been determined by studying the effect of pH, temperature, concentration of LABSA, amount of adsorbent and contact time. LABSA has been adsorbed over under batch measurements and adsorption process is monitored using UV spectrophotometer. The optimum pH value for adsorption capacity and removal efficiency of LABSA were 9.00 by (EP). The contact time of 3 hours was found to be sufficient to reach equilibrium, and so it was selected in further experiments. Thermodynamic parameters such as enthalpy change (AH?), free energy change (AG®) and entropy change (AS°) were estimated. The experimental isotherm data were analyzed using Langmuir and Freundlich isotherm models. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that the adsorption process obeyed the pseudo second order kinetic model. The present study has demonstrated that EP can be employed for the removal of LABSA from wastewater and potential as a cheap alternative to commercial adsorbents.