Aqueous solutions of 100 parts per billion (ppb) uranium at pH 7 were treated with granulated activated carbon (GAC) that had been modified with various formulations of hydrophobic aerogels. The composite materials were found to be superior in removing uranium from a stock solution compared to GAC alone evaluated by a modified ASTM D 3860-98 method for batch testing. The testing results were evaluated using a Freundlich adsorption model. The best performing material has parameters of n = 287 and Kf = 1169 compared to n = 1.00, and Kf = 20 for GAC alone. The composite materials were formed by mixing (CH3O)4Si with the hydrophobic sol-gel precursor, (CH3O)3SiCH2CH2CF3 and with specified modifiers, such as H3PO4, Ca(NO3)2, and (C2H5O)3SiCH2CH2P(O)(OC2H5)2, elation catalysts, and GAC in a supercritical reactor system. After gelation, supercritical extraction, and sieving, the composites were tested. Characterization by FTIR and 31P NMR indicate the formation of phosphate in the case of the H3PO4 and Ca(NO3)2 composites and phosphonic acid related compounds in the phosphonate composite. These composite materials have potential application in the clean up of groundwater at DOE and other facilities.

Environmental analysts are often hampered in communicating the risks of environmental contaminants due to the myriad of regulatory requirements that are applicable. The use of a qualitative, risk-based control banding strategy for assessment and control of potential environmental contaminants provides a standardized approach to improve risk communication. Presented is a model that provides an effective means for determining standardized responses and controls for common environmental issues based on the level of risk. The model is designed for integration within an occupational health and safety management system to provide a multidisciplinary environmental and occupational risk management approach. This environmental model, which utilizes multidisciplinary control banding strategies for delineating risk, complements the existing Risk Level Based Management System, a proven method in a highly regulated facility for occupational health and safety. A simplified environmental risk matrix is presented that is stratified over four risk levels. Examples of qualitative environmental control banding strategies are presented as they apply to United States regulations for construction, research activities, facility maintenance, and spill remediation that affect air, water, soil, and waste disposal. This approach offers a standardized risk communication language for multidisciplinary issues that will improve communications within and between environmental health and safety professionals, workers, and management.

No abstract

No abstract

No abstract