Oil Removal from Water through the Sorption on Natural Agrowaste Materials

The aim of this work is to investigate the ability of three agrowaste materials (corncobs, palm tree petioles, and sawdust) to remove diesel motor oil and oily waste from demineralized water and natural seawater. Sorption capacity (SC), reusability, and calorific value (CV) were evaluated. It was found that agrowaste materials have high SC; they are capable of absorbing many times their weight in oil: $12.49–13.56\mathrm{g}/\mathrm{g}$ for palm tree petioles, $6.99–7.56\mathrm{g}/\mathrm{g}$ for corncobs, and $4.19–4.28\mathrm{g}/\mathrm{g}$ for sawdust. The recovery of oils from water surface by sorption on these biomaterials is seen as a quasi-instantaneous mechanism, especially for palm tree petioles and corncobs. However, separation of oils from contaminated water by sawdust can reach its maximum after $15\min$ for diesel motor oil and $20\min$ for oily waste. In water, palm tree petioles, corncobs, and sawdust keep up to 99.34%–99.46%, 94.78%–98.56%, and 72.17%–81.40% of their maximal oil sorption capacities, respectively. Squeezing of saturated sorbents leads to their partial regeneration. Corncobs, palm tree petioles, and sawdust saturated with oils have high calorific values (36.45–38.85, 32.31–34.72, and $28.92–30.86\mathrm{MJ}/\mathrm{kg}$, respectively) and can be considered as combustibles.