Removal of heavy metals and organic contaminants from aqueous streams by novel filtration methods. 1998 annual progress report

Abstract

'Graphite nanofibers are a new type of material consisting of nanosized graphite platelets where only edges are exposed. Taking advantage of this unique configuration the authors objective is: (1) To produce graphite nanofibers with structural properties suitable for the removal of contaminants from water. (2) To test the suitability of the material in the removal of organic from aqueous solutions. (3) To determine the ability of the nanofibers to function as an electrochemical separation medium the selective removal of metal contaminants from solutions. This report summarizes work after 1.5 of a 3-year project. During this period, efforts have been concentrated on the production, characterization and optimization of graphite nanofibers (GNF). This novel material has been developed in the laboratory from the metal catalyzed decomposition of certain hydrocarbons (1). The structures possess a cross-sectional area that varies between 5 to 100 nm and have lengths ranging from 5 to 100 mm (2). High-resolution transmission electron microscopy studies have revealed that the nanofibers consist of extremely well-ordered graphite platelets, which are oriented in various directions with respect to the fiber axis (3). The arrangement of the graphene layers can be tailored to a desired geometry by choice of the correct catalyst system and reaction conditions, and it is therefore possible to generate structures where the layers are stacked in a ribbon, herring-bone, or stacked orientation. The research has been directed on two fronts: (a) the use of the material for the removal of organic contaminants, and (b) taking advantage of the high electrical conductivity as well as high surface area of the material to use it as electrode for the electrochemical removal of metal pollutants from aqueous streams.'