A Green Approach of Leaching Trace Metals From Petroleum Source Rock

The extraction of trace metals (manganese, nickel, vanadium and molybdenum) from petroleum source rock using nonionic surfactant solutions with the assistance of oven heat was investigated. The results revealed that time, temperature and pH have significant influence on the extraction yields of the trace metals. The effect of sample/solvent ratio was significant for extraction of some trace metals. The optimum extraction temperature using both polyoxyethylene(23)dodecyl ether (Brij 35) and polyoxyethylene(10)dodecyl ether C12E10) solutions as extracting solvents was 150 & DEG;C except nickel that had highest yield at 90 & DEG;C when C12E10 solution was used. For both Brij 35 and C12E10, most of the trace metals had highest yields at 3 hr. The yields of the trace metals were more significant in acidic medium. The yields of the trace metals were significantly higher using Brij 35 than C12E10. Validation of the new oven-assisted nonionic surfactant extraction (OANSE) method using SGR-1b standard reference material revealed excellent recoveries for the trace metals except vanadium that had an average recovery, which indicates that the new method is very efficient for leaching of manganese (Mn), nickel (Ni) and molybdenum (Mo) from petroleum source rock while the recovery of vanadium can be improved in acidic medium. This study revealed that OANSE is efficient and readily available green analytical protocol for the determination of trace metals in source rock.