Classical Analysis and Spectroscopic Elucidation of Humic Substances Extracted from Oil Sand Bitumen in Ondo State Nigeria

This study was carried out with a view to extract, quantify and characterize humic substances in Nigerian bitumen which desirable for soil fertility treatment. Bitumen samples were extracted from oil sands collected from four different locations: Agbabu, Mile 2, Olowo-Irele and Orisunbare in Ondo state, Nigeria. Extraction was done using Soxhlet extractor using toluene as extracting solvent. Varying concentrations of KOH solution were used and 3.5% of KOH was found to be the optimum concentration for the extraction of the humic substances. The gravimetric analysis showed 13.0, 6.3, 7.0, and 4.5% mean values of humic substances, extraction from Agbabu, Mile 2, Olowo-Irele, and Orisunbare respectively, while results of the humic acid determined by UV spectrophotometric method was 0.9, 0.7, 0.4 and 0.1% respectively. FTIR analysis results of the extracted humic substance samples showed peaks corresponding to the following functional groups: O–H, C–H, C=O, C=C, COO–, C–O, and C–O–C suggesting the presence of alcohol, carboxyl, phenol, carbonyl and esters which are present in the structure of humic and fulvic acids. The results of the elemental analysis revealed that humic substance extract was rich in the following elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, and Zn) which are needed for plants growth. Correlation and cluster analysis indicated strong and positive correlation among the detected elements, indicating similar sources or chemical affinity. The study concluded that the production of appreciable amount of humic substances, rich in minerals necessary for plant growth, from Nigerian bitumen is a possibility.