FENTON OXIDATIVE MECHANISM AND ITS KINETICS ON THE REMEDIATION OF SOIL CONTAMINATED WITH UNREFINED PETROLEUM OIL.

Abstract

Total petroleum hydrocarbon is the major constituent in unrefined petroleum oil that has severe adverse effect on soil properties, qualities and biota. Optimum conditions for fenton oxidation of total petroleum hydrocarbon (TPH) in unrefined petroleum oil contaminated soil are the most pertinent factor to be considered for effective and efficient degradation of TPH to be achieved. Soil was artificially spiked with unrefined petroleum oil in the laboratory to achieve 10% contamination in order to determine the effect of the contaminant on soil properties and overall efficiency of fenton oxidation mechanism in ameliorating the contaminated soil. Optimum treatment conditions of the fenton oxidation process were established from a well conducted optimization study as well its process kinetics, environmental friendliness and technological impact of the method on the remediated soil. Petroleum oil contamination adversely affected the pH, conductivity and total phosphorus content of the soil.  Optimum conditions obtained and used for the Fenton-oxidative method were 300,000ppm H2O2 and 400ppm FeSO4 at ambient temperature (28-32oC) within a pH range of 3-5. The fenton reactants are environmentally friendly products which produced environmentally neutral species (CO2 and H2O) from the degradation process. The fenton oxidation method was found to be very rapid and effective with 79.96% remediation efficiency achieved at the end of six hours. The reaction was highly exothermic and its kinetics found to be pseudo-first order with a rate constant k¹ of 0.199hour-1 and half life of 3 hours 30 minutes. The fenton oxidative degradation isotherm Kd gave negative value of unity. pH and conductivity were significantly improved at the end of the remediation process with concentration of heavy metals such as cadmium, nickel and vanadium reduced. Fenton oxidation process was therefore considered as an advance technology for the remediation of soil contaminated with unrefined petroleum oil.Keywords: Fenton oxidation, Optimization study, Degradation isotherm, Kinetics, Total petroleum hydrocarbon.