QUANTITA TIVE DETERMINATION OF TRACE METALS AND SULPHUR CONTENT IN NIGERIAN PETROLEUM PRODUCTS USING AAS AND GRAVIMETRIC ANALYSIS TECHNIQUE

Abstract

Eighteen trace heavy metals were quantitatively analyzed using atomic absorption spectroscopy; five samples of petroleum products were collected from Kaduna Refining and Petrochemical Company . Three different preparation methods wer e adopted for the determination of trace and heavy metals present in the various petroleum products viz: Direct sample aspiration into the flame after solvent dilution, Total acid (wet) digestion of the sample, Ashing of the sample and dissolution with an appropriate acid. Sample treatment with organic acid prior to aspiration proved to be more reliable and it gave good results for trace and heavy metals in petroleum products except for kerosene sample, where most of the elements responded positively to ash ing preparation method. The level of eighteen elements analyzed in Petrol (PMS), Kerosene (DPK), Gas Oil (AGO), LPFO and Residual fuel are shown in table 3.7 which revealed t hat Potassium(120 mg/l, 340 mg/l, 120 mg/l, 2900 mg/l, 2050 mg/l) and Sodium ( 26 0 mg/l, 180 mg/l, 160 mg/l, 1800 mg/l, 1200 mg/l) are the most abundant elements in both the five sample under study followed by Iron ( 1.20 mg/l, 1.74 mg/l, 1.25 mg/l, 0.60 mg/l), Manganese ( 1.28 mg/l, 1.04 mg/l, 1.46 mg/l, 6.6 mg/l4.8 mg/l), Lead ( 0.50 mg/l , 0.16 mg/l, 0.40 mg/l, 27.8 mg/l, 24.6 mg/l) and Aluminium (0.42 mg/l, 1.06 mg/l, 0.32 mg/l, 0.82 mg/l, 24.6 mg/l). The concentration ranges of trace heavy metals analyzed are within the permissible levels set by World Health Organisation.