Performance Comparison of Raw and Thermal Modified Rice Husk for Decontamination of Oil Polluted Water

Abstract

The efficiency of raw rice husk (RRH) and the thermally treated one including black rice husk ash (BRHA) and white rice husk ash (WRHA) was examined for the removal of three oil compounds with different viscosities (crude, engine, and spent oils) from aqueous solution. The sorbents were characterized by CHNS analyzer, scanning electron microscopy, Fourier transform infrared, and thermogravimetric analysis. The results showed that the adsorption kinetic was described by pseudo‐second‐order model. The oil adsorption on BRHA was well fitted by the Langmuir model, while the oil adsorption on RRH and WRHA, except for engine oil on RRH, followed the Freundlich model. The efficiency of the sorbents for the removal of oil compounds from water was in the order: BRHA > RRH > WRHA. Maximum adsorption capacity of BRHA for the adsorption of engine, spent, and crude oils was 2000, 1250, and 1000 mg g−1, respectively. The required amount of BRHA for the total removal of engine, spent, and crude oils from aqueous solutions was two, three, and six times of oil concentration, respectively.