Preparation of cellulose acetate supported zero-valent iron nanoparticles for the dechlorination of trichloroethylene in water L. Wu 1 , M. Shamsuzzoha 2 and S.M.C. Ritchie 1, * 1 Chemical and Biological Engineering Department, University of Alabama, Tuscaloosa, AL 35487, USA; 2 Department of Metallurgical and Materials Engineering, University of Alabama, Tuscaloosa, AL 35487, USA; *Author for correspondence (Tel.: +1-205-3482712; Fax: +1-205-3487558; E-mail: sritchie@ bama.ua.edu) Received 11 March 2005; accepted in revised form 21 March 2005 Key words: dechlorination, membrane, sorption and reaction, trichloroethylene, zero-valent iron, colloids Abstract Chlorinated hydrocarbons are an immense concern for human health and the environment because they are highly toxic and are present in many contaminated sites. Zero-valent iron has been shown to be very effective for the dechlorination of chlorinated olefins and paraffins. This behavior is enhanced when the particle size is in the nanometer range. The activity of these nanoparticles is very high, and thus supporting the particles is important to preserve their chemical nature by inhibiting oxidation until they can be contacted with the chlorinated stream. In this paper, we present the preparation of membrane (cellulose acetate) supported zero-valent iron nanoparticles. The highly active nanoparticles were syn- thesized in a water-oil micro-emulsion, mixed with cellulose acetate-acetone solution, and then formed into a porous membrane by phase inversion. The unsupported iron particles and membrane supported iron particles were characterized using transmission electron microscopy. Batch experiments were con- ducted to characterize the activity of the supported zero-valent iron nanoparticles to dechlorinate trichloroethylene in water, as well as to investigate synergistic effects of the polymer support matrix. Abbreviations: AA: Atomic absorption spectroscopy; CA: Cellulose acetate; CTAB: Cetyltrimethylammo- nium bromide; FID: Flame ionization detector; GPC: Gel permeation chromatography; TCE: Trichloro- ethylene; TEM: Transmission electron microscopy; XRD: X-ray diffraction; w/o: Water in oil; ZVI: Zero-valent iron. Introduction The contamination of soil and groundwater with chlorinated organic compounds is a widespread problem. These chemicals were widely used as degreasing agents and solvents (Li et al., 2003). Because of improper disposal practices, they are frequently found in soil and groundwater. They persist in the environment and pose a significant health threat, particularly in the area of kidney and liver damage (Reif et al., 2003; Gilbert et al., 2004). One potential solution to this problem is the use of zero-valent metals for dechlorination (Helland et al., 1995; Orth et al., 1996; Johnson et al., 1998). Extensive research efforts have shown the excellent ability of zero-valent iron (ZVI) to dechlorinate a range of chlorinated organics, particularly chlorinated olefins and paraffins (Wang et al., 1997; Zhang et al., 1998). This Journal of Nanoparticle Research (2005) 7: 469–476 Ó Springer 2005 DOI 10.1007/s11051-005-4271-5