Separation and Purification Technology, Vol.149, 124-131, 2015
Enhanced electrochemical oxidation of organic pollutants by boron-doped diamond based on porous titanium
The main aim of the present study was to explore the potential of boron-doped diamond (BDD) film electrode on porous titanium (Ti) substrate to promote the electrochemical oxidation of organic pollutants. Porous Ti endowed the Ti/BDD film three-dimensional porous structure. The electrochemical effective surface area for porous Ti/BDD anode was 837 cm(2)/cm(2), 3.2 times as much as that of two-dimensional flat Ti/BDD electrode. Furthermore, the generation ability and rate of hydroxyl radical ((OH)-O-center dot) on porous BDD electrode were enhanced due to the porous structure of BDD film. The step currents on porous Ti/BDD were about 2 times of those on flat Ti/BDD electrode from chronoamperometry curves, porous Ti/BDD exhibited superior indirect electrochemical oxidation ability. The results of electrodegradation of several typical organic pollutants (oxalic acid, phenol, sodium dodecylbenzene sulfonate, xylenol orange) revealed that current efficiencies on porous Ti/BDD electrode were about 30% higher compared with flat BDD electrode, corroborating the enhanced of electrochemical oxidation as the introduction of porous Ti substrate. Moreover, the discrepancy between promotion of COD removal rate and enhancement of (OH)-O-center dot was discussed. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Boron-doped diamond;Porous titanium;Electrochemical oxidation;Hydroxyl radical;Wastewater treatment