title: Synthesis and characterization of supported polysugar-stabilized palladium nanoparticle catalysts for enhanced hydrodechlorination of trichloroethylene.
abstract: Palladium (Pd) nanoparticle catalysts were successfully synthesized within an aqueous phase using sodium carboxymethyl cellulose (CMC) as a capping ligand which offers a green alternative to conventional nanoparticle synthesis techniques. The CMC-stabilized Pd nanoparticles were subsequently dispersed within support materials using the incipient wetness impregnation technique for utilization in heterogeneous catalyst systems. The unsupported and supported (both calcined and uncalcined) Pd nanoparticle catalysts were characterized using transmission electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction, and Brunauer-Emmett-Teller surface area measurement and their catalytic activity toward the hydrodechlorination of trichloroethylene (TCE) in aqueous media was examined using homogeneous and heterogeneous catalyst systems, respectively. The unsupported Pd nanoparticles showed considerable activity toward the degradation of TCE, as demonstrated by the reaction kinetics. Although the supported Pd nanoparticle catalysts had a lower catalytic activity than the unsupported particles that were homogeneously dispersed in the aqueous solutions, the supported catalysts retained sufficient activity toward the degradation of TCE. In addition, the use of the hydrophilic Al(2)O(3) support material induced a mass transfer resistance to TCE that affected the initial hydrodechlorination rate. This paper demonstrates that supported Pd catalysts can be applied to the heterogeneous catalytic hydrodechlorination of TCE.
authors: Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA.
authors: Deborah B
authors: DB
authors: Bacik
authors: Man
authors: M
authors: Zhang
authors: Dongye
authors: D
authors: Zhao
authors: Christopher B
authors: CB
authors: Roberts
authors: Mohinar S
authors: MS
authors: Seehra
authors: Vivek
authors: V
authors: Singh
authors: Naresh
authors: N
authors: Shah
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002384:Catalysis; D004785:Environmental Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D052918:Environmental Restoration and Remediation / Q000379:methods*; D055772:Green Chemistry Technology / Q000379:methods; D054879:Halogenation; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods; D010165:Palladium / Q000737:chemistry*; D033362:Powder Diffraction; D014241:Trichloroethylene / Q000737:chemistry* / Q000302:isolation & purification; D014961:X-Ray Diffraction
chemical_list: D004785:Environmental Pollutants; D014241:Trichloroethylene; D010165:Palladium; D002266:Carboxymethylcellulose Sodium