Bacteria can accumulate heavy metals such as iron or lead from water. The metals deposit in a steelwool-like form outside the cell wall. Recent research shows this is an effective way to remove metals from water. The challenge has been separating the metals from the biomass. One exciting possibility is to use an intense magnetic field to concentrate the metals. This method is called High Gradient Magnetic Separation (HGMS). At Ole Miss we are studying metal uptake by bacteria. We are collaborating with scientists in California at Watson General to magnetically separate the metals. We work closely with Dr. Albert Mikell of our Department of Biology. We are concentrating on the metabolism of metal-organic acid complexes. Successful bioaccumulation from the complexes would allow the use of acids for extraction followed by accumulation and separation.
One approach to destroying organic pollutants is to oxidize them in the liquid phase. Oxidizing agents such as ozone or hydrogen peroxide can convert the pollutants to more harmless forms. Ultrasonic energy accelerates the reactions and generates highly reactive free radicals. A Ph.D. student (Mauricio Quiros, Degussa Corp., (201)818-3716) recently completed his research on this topic. He carried out a statistical analysis of significant parameters that affect the ultrasonically enhanced oxidation. We have on our campus the National Center for Physical Acoustics where personnel (Robert Hickling, Associate Director) have studied sonoluminescence (ultrasonically induced, light-producing reactions). Excellent opportunities exist to continue work with possible interdisciplinary efforts.
Contamination of groundwater with gasoline and chlorinated solvents is a major, widespread problem. Air sparging has been widely applied to drive out the contaminants. In urban areas, activated carbon is then used to absorb the organics from the air. In this research we are absorbing the organics directly into a nonvolatile organic liquid. This would simplify removal and recycling toxic organics. We have studied the absorption of toluene into mineral oil. We plan to extend this work to other nonvolatile solvents. A related topic of interest is solvent sublation by which the organic pollutant is "directly" transferred from the aqueous phase into the organic phase.
Many industrial and military operations have contaminated large volumes of soil. Currently, much of this soil must be secure landfilled or incinerated, costing hundreds of dollars per cubic yard. In this research, we have worked closely with the U.S. Army Corps of Engineers (Mark Bricka, Danny Averette, Restoration Branch, U.S. Army Corps of Engineers, Waterways Experiment Station, Environmental Lab, (601)634-3888) to study physically separating, or concentrating, the contaminants into a smaller volume of the soil. The focus of this work has been the development of methods to remediate soils contaminated with heavy metals and explosives. We have sought to exploit differences in size, density, and surface properties to selectively concentrate the contaminant. The technologies involved have been very well developed for the minerals processing industry.
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