Effects of Crude Oil Pollution on Light Energy Harvesting Property of Chlorophylls

Benjamin N. Emelugo, Ikechukwu N.E. Onwurah, Kennedy C. Onyewuchi and Ngozi C. Okafor

1 Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka. 2 Department of Biochemistry, University of Nigeria, Nsukka. 3 Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka. 4 Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka.

Abstract

The light energy harvesting property of chlorophylls (a and b) was investigated under a solvent condition and different crude oil concentrations. The chlorophylls were extracted from maize leaves using standard biochemical methods. Various dilutions of the test crude oil in water were prepared so as to obtain 0.1%, 0.5%, 1.0% and 10.0% (v/v). The light energy harvesting property of different weights (g) of chlorophylls (0.5g, 1.0g, 1.5g and 2.0g) in the (water) solvent were determined under direct sunlight for a fixed period of 30 minutes throughout the experiment. The initial temperatures of the incubation mixtures were taken before exposure to sunlight, after which the final temperatures were recorded. The light energy harvested in each case was evaluated using the equation: Q = MxCxΔT where Q = Quantity of heat energy, M = Mass of solvent, C = Specific heat capacity of the solvent, ΔT = Change in temperature. Results show the light energy harvesting capacity of the extracted chlorophylls in all the experiments was highest in the absence of crude oil. There was a linear reduction in light energy harvested when 0.5g of chlorophyll was used except when there was a 10% level of contamination. The quantity of light energy (2.301.20J) was at the peak at 0.0% level when the weight of chlorophyll was 2.0g. While the lowest light energy harvested was also recorded at the same 10% level of contamination. The correlation between the concentration of crude oil and the quantity of light energy harvested for each weight of chlorophyll was more pronounced when 2.0g of chlorophyll was used.