An investigation of the effectiveness of locally available materials as oil spill sorbents for Sri Lanka

Abstract

The effectiveness of seven locally avai lable natural organ ic materials as oi I spi II sorbents was tested.The study specifically focused on determining, the behaviour of loose material on a layer of oil, oilsorption capacity of different types of materials and the viability of using them under actual fieldconditions. The seven natural organic materials were chosen based on their availability and cost. Theamount of oi I sorption by each was determined by the gravimetric method and the rate of sorption wasdetermined. A commercially available synthetic oil sorbent, polyurethane. was used as the positivecontrol. Out of the seven natural organic materials tested, human hair was found to be the mosteffective sorbent. Compared to the positive control, Polyurethane, there was no significant differencewith respect to the oil sorption capacity of human hair. Therefore, all the subsequent experimentswere carried out using human hair only. As hair has a tendency to sink in sea water after oil sorption,hair was compacted in to pillows to facilitate the recovery after sorption. First, the affect of the pillowthickness on the oil sorption capacity was tested. Oil sorption capacity increased significantly as thethickness of the pillow increased and a thickness of Iern was found to yield the most efficient sorption.Then sorption capacity of oil by pillows was compared on a sea water oil interphase. only on oil and oilon sand. No significant difference was detected in the oil sorption capacity of hair filled pillows underthese three conditions. Finally, a field trial was conducted where pillows were developed up to the sizeof commercially avai lable synthetic pi llows and placed on an artificially created oil spi II and tested theoil sorption capacity under actual field conditions. A total offour pillows were used for the field trialand the pillows were removed at different time intervals after placing it on the artificial oil slick. Theresults of th is experiment were not conclusive as amount of oi I absorbed by all four pi llows did notreach the expected value calculated based on results obtained during laboratory experiments. due toseveral shortcomings in the experimental design. The results of this study clearly demonstrate thathuman hair can be used as an effective oil sorption material. As waste human hair is cheap andreadily available, it is a much more viable alternative to expensive synthetic organic material availablein the market.