Adsorption of Some Aromatic Compounds by a Synthetic Mesoporous Silicate

Abstract

Water pollution by toxic organic compounds is of concern and demands for effective adsorbents for removal of the toxic compounds are increasing. Here we synthesized a mesoporous material, FSM-16, and investigated its ability to take up model compounds (benzene, toluene, phenol, and benzoic acid) from aqueous solutions by batch experiments. The adsorption isotherms were linear and adsorption capacities were small. Benzene and toluene have very similar adsorption isotherms, suggesting the side chain of toluene, i.e., alkyl chain, did not have significant effect on its adsorption. The amount of adsorption and isotherm slope were in the order of toluene ≈ benzene > benzoic acid > phenol. The occupation ratios of those organic compounds on the surfaces of FSM-16 were estimated less than 1%. Solubility of the compounds seems the major factor determining their adsorption by FSM-16. Phenol has the highest solubility and thus was least adsorbed by FSM-16. In contrast, toluene and benzene have very low solubilities and are the most adsorbed ones.

Keywords:

• Adsorption
• Mesoporous material
• FSM-16
• Aromatic hydrocarbon

Acknowledgments

I thank Dr H. Yamada (NIMS) for his useful discussion, and Mr. K. Kurashima for his help in TEM observation.