Feasibility of in-situ removal of heavy metals by electroremediation of offshore muds

UnrestrictedThe present experimental work is directed towards investigation of the electokinetically-enhanced transport of soil contaminants (specifically heavy metals) in clay media and offshore muds.; The electrokinetic process is an emerging technology for in-situ soil decontamination, in which chemical species, both ionic and nonionic, are transported to electrode sites in soil. Electrokinetics refers to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface-charged particles such as soil, the pore fluid containing ions are made to flow to the collection sites under the applied electric field (Pamukcu et al., 1993).; Remediation of anthropogenically contaminated clay-soil media were conducted by Dr. Pamukcu at Lehigh University. Experiments of high concentrations of heavy metals in clay-soil media were conducted at the University of Southern California by the writer. Water containing acids were used for pH control.; The EK tests were performed for 24 hrs, and the initial and final concentrations were analyzed using an ICP-MS equipment. The removal efficiency, initial and final pH of slurry at 3 positions was recorded.; The effectiveness of the process demonstrated that up to 99% of initial concentrations of metals can be removed from soil. In this process, the pH and contaminant type was found to influence the removal rather than the electroosmotic flow. In the absence of pH control mechanisms, the basic conditions developed at the cathode, causing most of the metals to precipitate near the cathode as carbonates and hydroxides. pH adjustment at the cathode appeared to minimize such precipitation and to enhance the removal of some heavy metals.; Applicability of this electrokinetic technology in remediating offshore muds from heavy metals was not evaluated to date. Tests were made using 22 different offshore mud samples from different locations in Abu Dhabi, U.A.E., contaminated with 29 different heavy metals. The experimental work was performed by the writer at the newly-established Electrokinetic laboratories at the Petroleum Institute in Abu Dhabi, U.A.E. In the process it was determined that D.C. current can be used to decontaminate the offshore muds from heavy metals