Adsorption of Phenol by Super Hydrophobic Phenol-Formaldehyde/Silica Hybrid Aerogel

Document Type: Original Research Paper

Authors

1 ACECR, Production Technology Research Institute, Chemical Engineering Department, Ahwaz, Iran

2 Department of Chemical Engineering, Islamic Azad University, Abadan Branch, Iran

3 Chemistry Department, Production Technology Research Institute-ACECR, Ahvaz, Iran

Abstract

Phenol-formaldehyde/silica hybrid gel with hydrophobic character, high porosity, and the
small pore size mean was prepared via sol-gel polymerization under solvent saturated vapor
atmosphere and was dried by ambient drying method. The silica sols were prepared based on
Tetraethoxysilane (TEOS) and Methyltrimethoxysilane (MTES) as hydrophilic and hydrophobic
precursors, respectively. Phenol-formaldehyde resin was used as organic phase to achieve
suitable physical properties. The contact angle of this aerogel was about 147˚ and it is a result
of formation of CH3 groups on the pore walls. The results of FESEM and nitrogen adsorption
indicated that the structure of this aerogel is highly porous, uniform, and colloid like network.
The Phenol-formaldehyde/silica hybrid aerogel was used for removal of phenol from aqueous
solution. The study was carried out as functions of contact time, pH and initial phenol
concentration. The experiments demonstrated that maximum phenol removal was obtained
at neutral pH in unbuffered condition and it takes 40 min to attain equilibrium. Langmuir,
Freundlich and Temkin isotherm models were applied to fit adsorption equilibrium data. The
best-fitted data was obtained with the Langmuir model and the adsorption capacity was 97.09
mg g−1. Kinetic studies indicated that the adsorption process was described better by pseudosecond-
order model.

Keywords