title: [Electrochemical degradation of 4-chlorophenol using a Pd/MWNTs catalytic electrode].
abstract: Nitric acid in various volume fraction (8%, 15%, 20%, and 68%) was used on the multi-wall carbon nanotubes (MWNTs) pre-treatment and then the formaldehyde reduction method was utilized for the preparation the Pd/MWNTs catalysts which were fully characterized by Boehm titration method, X-ray diffraction (XRD), infrared spectroscopy, scanning electron microscopy (SEM), and cyclic voltammetry(CV) techniques. The electrochemical degradation of 4-chlorophenol was investigated in a diaphragm electrolysis system using the Pd/MWNTs gas-diffusion cathode. The results indicated that the active organic function groups increased on the surface of the carbon nanotube pre-treated by using 68% nitric acid. Pd particles with an average size of 9.2 nm were highly dispersed in the carbon nanotube with an amorphous structure. Additionally, the Pd/MWNTs catalyst in Pd/MWNTs gas-diffusion electrode system accelerated the two-electron reduction of O2 to hydrogen peroxide (H2O2) when feeding air. The Pd/MWNTs gas-diffusion cathode can not only reductively dechlorinate 4-chlorophenols by feeding hydrogen gas, but also accelerate the two-electron reduction of O2 to H2O2 by feeding air. Therefore, the removal efficiency and the average removal efficiency of 4-chlorophenol in terms of total organic carbon (TOC) reached about 86.9% and 71.6% after 140 min electrolysis, respectively.
authors.affiliation: College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China. weixiangjia4626@126.com
authors.forename: Xiang-Jia
authors.initials: XJ
authors.lastname: Wei
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Zhao-Yong
authors.initials: ZY
authors.lastname: Bian
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Sun
mesh_terms: D002384:Catalysis; D002733:Chlorophenols / Q000737:chemistry / Q000302:isolation & purification*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004572:Electrolysis; D005557:Formaldehyde / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D002733:Chlorophenols; D005557:Formaldehyde; D037742:Nanotubes, Carbon; D010165:Palladium; D062065:Wastewater; C029107:4-chlorophenol