Remediation of Lubricating Oil Waste using Biogenic Silica Granules

Small spills of oils and similar liquid hydrocarbons (such as lubricating oils, fuel oils, cooking oils, and radiator coolants) occur from time to time in workshops, industrial processes, domestic and farming activities. Such spills are sometimes collected using sand, sawdust, ‘kitty litter’ and similar materials which have limited absorbent capacity, low biodegradability and perform poorly if they become wet, often releasing much of the absorbed pollutants. They also leach downward and contaminate the groundwater if disposed onto soil surface. Recently, specialized biogenic products have been developed which provide a greater absorption and retention capacity than conventional granular materials. These natural based absorbent materials are preferred due to their non-toxicity, excellent biodegradability and nonflammability. Agro-industrial residues are also being used by researchers to produce a new absorbent product which is able to remove toxic elements. The biogenic modified silica produced in aqueous media from rice husk ash has shown excellent sorption. The experimental studies were carried out to study the leaching characteristics at various depths of the soil layers, time intervals and variation in oil- biogenic silica compositions on its sorbent capacity. Also the effect of the oil-laden silica on soil properties was also evaluated. A comparison of these effects with oil-laden sawdust was also carried out.