Abstract:
Removal of organic contaminants in the environment by surfactant have been applied to many applications. Surfactant-modified adsorbents can enhance the efficiency of organic compounds removal. In this research study, the solubilization and adsolubilization on aluminum oxide surface using rhamnolipid biosurfactant mixed three linker molecules; butanol (4-carbon), octanol (8-carbon) and dodecanol (12-carbon). Two organic compounds with different dipole-dipole forces including styrene and ethylcyclohexane were evaluate in solubilization and adsolubilization studies. The results showed that the adsorption capacity of all surfactant on aluminum oxide surface increased when surfactant concentration increased. The rhamnolipid biosurfactant mixed with octanol showed the highest maximum adsorption capacity while the rhamnolipid biosurfactant mixed with butanol showed the lowest adsorption capacity. For adsolubilization study, the rhamnolipid biosurfactant mixed with linker molecules showed greater adsolubilization capacity than rhamnolipid biosurfactant alone. The result indicated that the adsolubilization capacity increased with increasing carbon chain lengths of linker molecules. For solubilization study, the rhamnolioid biosurfactant without the linker molecules showed greater solubilization capacity than rhamnolipid biosurfactant with the linker molecules. The result indicated that the solubilization capacity decreased when the number of carbons in the linker molecule chain increased. The adsolubilization and solubilization capacity of ethylcyclohexane showed higher than styrene. This could be due to ethylcyclohexane has lower water solubility than styrene. Therefore, ethylcyclohexane prefers to partition into the surfactant admicelle and micelle rather than solubilize in the aqueous phase. In addition, the organic solutes solubilization capacity was higher than adsolubilization capacity due to the surfactant micelle with the area for solubilizing of organic solutes than the admicelle. For desorption study, the rhamnolipid biosurfactant with and without the linker molecules showed surfactant loss from the surface of aluminum oxide in small quantities. Thus, the linker molecules can reduce surfactant molecule desorption from the solid surface. The result demonstrated that surfactant-modified adsorbents have been evaluated for removal of organic contaminants and to be applied in environmental applications