Application of synthesized acetylated silica in the remediation of oily wastewater

Abstract

Acetylated materials have been applied successfully in oily water remediation with some degree of success. Many of these materials which have been acetylated are, however, from seasonal fruits and other plant parts. This work reports the successful acetylation of silica extracted from diatomaceous earth by refluxing silica and acetic anhydride using 1% N-bromosuccinimide as a catalyst. The functionalization was confirmed by the presence of absorption bands at 1406 cm−1 (C–O) and 1568 cm−1 (C=O) on an IR spectrum and the presence of C, Si, and increased amount of O on the EDX spectrum. The synthesized materials were applied in the optimization of the removal of oil from synthetic oily wastewater using response surface methodology giving a percentage oil removal of 99.7%. The optimum conditions for oil removal were as follows; 7867 mg/L oil concentration, with adsorbent dosage of 0.001 g and a duration of 21.6 h, and the adsorption capacity under these conditions was found to be 1039 mg/g. The outcomes proved that acetylated silica is an excellent material for oil adsorption and can therefore be used in oil spill clean-ups.

Keywords

• oily wastewater
• response surface methodology
• adsorption
• silica
• acetylated silica