title: Reductive dechlorination of 2,4-dichlorophenol by Pd/Fe nanoparticles prepared in the presence of ultrasonic irradiation.
abstract: Palladium/Iron (Pd/Fe) nanoparticles were prepared by using ultrasound strengthened liquid phase reductive method to enhance dispersion and avoid agglomeration. The dechlorination of 2,4-dichlorophenol (2,4-DCP) by Pd/Fe nanoparticles was investigated to understand its feasibility for an in situ remediation of contaminated groundwater. Results showed that 2,4-DCP was first adsorbed by Pd/Fe nanoparticles, then quickly reduced to o-chlorophenol (o-CP), p-chlorophenol (p-CP), and finally to phenol (P). The induction of ultrasound during the preparation of Pd/Fe nanoparticles further enhanced the removal efficiency of 2,4-DCP, as a result, the phenol production rates increased from 65% (in the absence of ultrasonic irradiation) to 91% (in the presence of ultrasonic irradiation) within 2h. Our data suggested that the dechlorination rate was dependent on various factors including Pd loading percentage over Fe(0), Pd/Fe nanoparticles availability, temperature, mechanical stirring speed, and initial pH values. Up to 99.2% of 2,4-DCP was removed after 300min reaction with these conditions: Pd loading percentage over Fe(0) 0.3wt.%, initial 2,4-DCP concentration 20mgL(-1), Pd/Fe dosage 3gL(-1), initial pH value 3.0, and reaction temperature 25°C. The degradation of 2,4-DCP followed pseudo-first-order kinetics reaction and the apparent pseudo-first-order kinetics constant was 0.0468min(-1).
authors.affiliation: College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, PR China.
authors.forename: Deming
authors.initials: D
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Dexing
authors.initials: D
authors.lastname: Zhang
authors.forename: Shams Ali
authors.initials: SA
authors.lastname: Baig
authors.forename: Xinhua
authors.initials: X
authors.lastname: Xu
mesh_terms: D002733:Chlorophenols / Q000302:isolation & purification*; D060587:Groundwater / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D013010:Sonication / Q000379:methods*; D013016:Sound; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D002733:Chlorophenols; D014874:Water Pollutants, Chemical; D010165:Palladium; D007501:Iron; C004762:2,4-dichlorophenol