Synthesis and study of properties and application of hydrophobic hybrid aerogel based on polymeric sorbent

Polymeric sorbent with hydrophobic property was prepared via sol-gel synthesis. The sol-gel process is based on the evolution of inorganic networks through the formation of liquid colloidal suspension (sol) and gelation of the sol to form a network in a continuous solid phase (gel). The sols based on silica were prepared by Tetraethylorthosilicate (TEOS) and Methyltriethoxysilane (MTES) as primary precursors. To achieve suitable physical properties such as high porosity and small pore size, formaldehyde-phenol resin was used as polymeric phase. The results of FESEM and nitrogen adsorption indicated that the structure of this polymeric sorbent is uniform, highly porous, and colloid like network. Also this polymeric sorbent was hydrophobic due to the formation of CH3 groups on the pore walls and the value of the contact angle obtained was about 147˚. The hydrophobic polymeric sorbent was used for removal of phenol from water. The study was carried out as functions of pH, contact time and initial phenol concentration. The experiments showed that maximum phenol removal under optimum conditions, was obtained at neutral pH without buffered 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 adsorbent capacity was 97.09 mg g−1. Kinetic studies indicated that the adsorption process was described better by pseudo-secondorder model.