Adsolubilization of organic compounds by hydrophobic silica modified with EO/PO triblock copolymers

Abstract

This work focused on the modification of hydrophobic silica particles with EO/PO triblock copolymer surfactants, which are Pluronic L31, PI23, L64, 17R2, 25R4, and 10R5, and used the modified hydrophobic silica to adsolubilize various target aromatic organic compounds, including phenol, 2-naphthol, and naphthalene. The adsorption results show that all triblock copolymers used in this study were shown to preferably adsorb onto the hydrophobic silica surface. The configuration, HLB values, and EO/PO ratio of copolymers were found to be important factors affecting adsorption. In contrast to our previous work, the hydrophobic silica is a better substrate for EO/PO triblock copolymers than hydrophilic silica because larger range of HTB values can be used. In the adsolubilization study, the hydrophobic silica modified with copolymers has shown to be very effective in adsolubilizing the model aromatic organic molecules from aqueous phase. The EO/PO ratio and number of EO groups of copolymers were found to affect the phenol adsolubilization. While 2-naphthol adsolubilization was affected by only the number of EO groups in the same trend with phenol. For naphthalene, the adsolubilization has shown to be nearly the same for all copolymers studied with the exception of L31. In addition, the hydrophobic silica modified with EO/PO triblock copolymers shows higher ability to adsolubilization of aromatic organic compounds than the hydrophilic silica used in our previous study.