Removal of Metal Ions and Organic Compounds from Aqueous Environments Using Versatile Carbon Nanotube/Graphene Hybrid Ad
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Removal of Metal Ions and Organic Compounds from Aqueous Environments Using Versatile Carbon Nanotube/Graphene Hybrid Adsorbents Anthony B. Dichiara, Michael R. Webber and Reginald E. Rogers* Department of Chemical Engineering, 160 Lomb Memorial Dr., Rochester, NY 14623, U.S.A. ABSTRACT The contamination of water by a large variety of molecules is a major environmental issue that will require the use of efficient and versatile materials to purify hydrological systems from source to point-of-use. The present study describes the aqueous-phase adsorption of heavy metal ions and multiple organic compounds at environmentally relevant concentrations onto graphene-single-walled carbon nanotube free-standing hybrid papers. Optical absorption spectroscopy results clearly showed that the hybrid nanocomposites exhibit superior adsorption properties compared to activated carbon, the most widely used adsorbent to date. INTRODUCTION The surge of industrial, agricultural and domestic activities has inevitably resulted in an increased flux of toxic pollutants in aqueous environments worlwide. Growing number of contaminants are entering water supplies from human activities, among which most can have bio-accumulative, persistent, carcinogenic, mutagenic and detrimental effects on the survival of aquatic organisms, flora, fauna as well as human health [1]. The deleterous effects of water pollution being more apparent, the development of efficient technologies for the purification of hydrological systems is of paramount importance. Conventional treatments are either expensive or operationally intensive, whereas adsorption-based methods, where undesirable chemicals are transferred from the fluid phase to the surface of a solid, are simple and easy to implement for point-of-use water applications, yet their capacity to uptake contaminants is limited [2]. Because there are multiple types of pollutants with different properties in untreated aqueous environments, the merit of using one versatile material to efficiently eliminate a large variety of undesirable chemicals is obvious. Opportunities exist for enhanced adsorption using innovative nanocomposite adsorbents comprised of graphene and carbon nanotubes (CNTs). Both CNTs and graphene share interesting properties, such as antimicrobial capability, large delocalized π electrons and hydrophobic surface, which make them very compelling for water purification and separation applications [3-5]. Moreover, each nanostructure shows different affinities for given molecules, therefore their combination can increase the variety of pollutants that may be adsorbed. This study aims at exploring the potential of graphene-CNTs free-standing hybrid papers to remove diverse chemicals, both organic and inorganic, from aqueous environments. Batch adsorption kinetics and isotherm studies have been conducted to investigate the versatility and the efficiency of the nanocomposites compared activated carbon (AC), the most widely used adsorbent to date.
EXPERIMENTAL DETAILS Adsorbates of interest Copper nitrate
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