Sodium Dodecyl Sulfate Modified-Zeolite as a Promising Adsorbent for the Removal of Natural Organic Matter From Aqueous Environments

Abstract

Background: High concentrations of natural organic matter (NOM) may cause the production of harmful compounds in treated drinking water. Surfactant-modified zeolites (SMZs) with various loadings of sodium dodecyl sulfate (SDS) have been used as adsorbents to remove NOM from aqueous solution. SMZ has presented higher NOM adsorption more efficiency than natural zeolite. NOM affects the quality of drinking water in several points. Objectives: The purpose this study was to investigate the SDS-modified isotherm of natural Iranian zeolite obtained from Semnan mines, for the removal of NOM from aqueous solution. Materials and Methods: The adsorption of NOM onto SDS-modified zeolite as a function of contact time, initial NOM concentrations, adsorbent dose and solution pH was investigated. The isotherm experiments were carried out with fixing the adsorbent dose and varying the initial concentration of NOM. Results: The results indicated that SDS-modified zeolite showed greatly enhanced adsorption capacity. Findings revealed that the Langmuir isotherm best described the NOM adsorption on the adsorbent. The adsorption isotherm was well fitted to the Langmuir model. The maximum adsorption capacity of SMZ with surfactant bilayer coverage for NOM was 111 mg/g at 25°C and pH = 5. Conclusions: The findings of this study showed that the modification of natural zeolites can achieve higher adsorption capacity for organics. In addition, based on the results, natural zeolite being modified with SDS as a cationic surfactant had good efficiency for the adsorption of NOM.