Paper Title
Adsorption of Toluene from Aqueous Solution onto Dodecyl Dimethyl-3-Ammonio-1-Propane Sulfonate (DPS) Surfactant Modified Natural Zeolite

Abstract
This study focuses on increasing the ability of natural zeolite adsorption by modifying it with DPS (Dodecyl Dimethyl-3-Ammonio-1-Propane Sulfonate) surfactants for adsorption of toluene as nonpolar organic compounds from aqueous solution. This study started with natural zeolite (ZR) from Klaten-Central Java of Indonesia being activated using acid (HCl) and then zeolite modified with two times DPS surfactant (ZD). The success of ZR activation and modification of natural zeolite is characterized by infrared spectroscopy, x-ray diffraction, surface area and pore analysis and cation exchange capacity. Adsorption of toluene ion determine using UV-Vis spectrophotometer. This study adsorption begins with variation of several pH and times of toluene adsorption on ZD. Then, study of toluene concentration variation on ZD and ZR. The results showed that toluene (optimum pH 2) has a higher adsorption capacity in ZD than ZR because DPS surfactant contain nonpolar sites from its carbon chain that can interact better with nonpolar toluene, not like ZR. The adsorption of toluene in ZD following the Freundlich isotherm because correlation constant (R2) is larger and close to 1 than Langmuir models. This Freundlich isotherm occurs cooperativelydue to its 1/n value > 1. The adsorption strength (Kf) of ZD of toluene is 1.8810-32 mg/g. Thus, toluene adsorption is better on adsorbentsZD> ZR. Index Terms - Zeolite, Adsorption, Surfactant, Toluene, Isotherm, Kinetic.