EVALUATION OF COCONUT HUSK SORBENT FOR CLEANUP OF PETROLEUM CONTAMINATED ENVIRONMENTS.

Abstract

In this study coconut husk was tested for removal of crude oil, diesel and kerosene from land and aqueous medium. Oil sorption capacity, recovery of sorbed oil and retain ability of sorbed oil by coconut husk was evaluated and compared with that of a conventional synthetic sorbent used in the oil industry for oil spill clean-up. The experiment was conducted by batch sorption method. The result of the study shows that the conventional synthetic sorbent has higher oil sorption capacity and sorbed oil recoverability than coconut husk, while coconut husk retained more of the sorbed oils. Coconut husk sorbed per unit mass 4.03 ±0.1I g of crude oil, 3.60 ±0.63g of diesel and 2.85 ±0.44g of kerosene while the synthetic sorbent sorbed 11.50 ±0.54g of crude oil, 10.35 ±0.77g of diesel and 8.20 ±0.93g of kerosene. 9.67 ±0.36g of crude oil, 8.40 ±0.95g of diesel and 6.50 ±0.49g of kerosene were recovered from a unit mass of the synthetic sorbent  while 3.00 ±0.21g of crude oil, 2.55 ±0.83g of diesel and 2.00 ±0.71g of kerosene were recovered from a unit mass of coconut husk. 1.05 g of crude oil (26 % of sorbed crude oil), 1.05 g of diesel (29 % of sorbed diesel), and 0.80 g of kerosene (28 % of sorbed kerosene) were retained by coconut husk, while, 1.83 g of crude oil (15 % of sorbed crude oil), 1.94 g of diesel (19 % of sorbed diesel) and 1.70 g of kerosene (20 % of sorbed kerosene) were retained by synthetic sorbent. Langmuir adsorption model and pseudo second order models fitted the sorption process more precisely. Intraparticle diffusion mechanism and liquid film diffusion mechanism were part of the rate determining step of the sorption mechanism of the oils onto both sorbents. The synthetic sorbent and coconut husk can be applied on oil spill clean-up on land and surface waters. Coconut husk is not a very efficient sorbent for oil spill clean-up, but can be employed in oil spill clean-up because of its oil retain ability especially when  oil recovery is not required but disposal after oil spill clean-up.Keywords:  Coconut husk, adsorption isotherm, adsorption kinetics, crude oil, diesel.