TY - JOUR
T1 - Electrochemical oxidation of electrodialysed reverse osmosis concentrate on Ti/Pt-IrO2, Ti/SnO2-Sb and boron-doped diamond electrodes
AU - Bagastyo, Arseto Y.
AU - Batstone, Damien J.
AU - Rabaey, Korneel
AU - Radjenovic, Jelena
N1 - Funding Information:
This study was supported by the Australian Research Council ( LP0989159 ), Veolia Water Australia , Seqwater , Magneto Special Anodes and the Urban Water Security Research Alliance . The authors would like to acknowledge Dr. Renu Patel from Queensland Health Forensic and Scientific Service for performing the analyses of trihalomethanes and haloacetic acids. Arseto Bagastyo is currently also a staff member on leave at Institut Teknologi Sepuluh Nopember, Indonesia.
PY - 2013/1/1
Y1 - 2013/1/1
N2 - Reverse osmosis concentrate from wastewater reclamation contains biorefractory trace organic contaminants that may pose environmental or health hazard. Due to its high conductivity, electrochemical oxidation of brine requires low voltage which is energetically favourable. However, the presence of chloride ions may lead to the formation of chlorinated by-products, which are likely to exert an increased toxicity and persistence to further oxidation than their non-chlorinated analogues. Here, the performance of Ti/Pt-IrO2, Ti/SnO2-Sb and Si/BDD anodes was evaluated for the electrochemical oxidation of ROC in the presence of chloride, nitrate or sulfate ions (0.05 M sodium salts). In order to investigate the electrooxidation of ROC with nitrate and sulfate ions as dominant ion mediators, chloride ion concentration was decreased 10 times by electrodialytic pretreatment. The highest Coulombic efficiency for chemical oxygen demand (COD) removal was observed in the presence of high chloride ions concentration for all anodes tested (8.3-15.9%). Electrooxidation of the electrodialysed concentrate at Ti/SnO2-Sb and Ti/Pt-IrO2 electrodes exhibited low dissolved organic carbon (DOC) (i.e. 23 and 12%, respectively) and COD removal (i.e. 37-43 and 6-22%, respectively), indicating that for these electrodes chlorine-mediated oxidation was the main oxidation mechanism, particularly in the latter case. In contrast, DOC removal for the electrodialysed concentrate stream was enhanced at Si/BDD anode in the presence of SO42- (i.e. 51%) compared to NO32- electrolyte (i.e. 41%), likely due to the contribution of SO4·- and S2O82- species to the oxidative degradation. Furthermore, decreased concentration of chloride ions lead to a lower formation of haloacetic acids and trihalomethanes at all three electrodes tested.
AB - Reverse osmosis concentrate from wastewater reclamation contains biorefractory trace organic contaminants that may pose environmental or health hazard. Due to its high conductivity, electrochemical oxidation of brine requires low voltage which is energetically favourable. However, the presence of chloride ions may lead to the formation of chlorinated by-products, which are likely to exert an increased toxicity and persistence to further oxidation than their non-chlorinated analogues. Here, the performance of Ti/Pt-IrO2, Ti/SnO2-Sb and Si/BDD anodes was evaluated for the electrochemical oxidation of ROC in the presence of chloride, nitrate or sulfate ions (0.05 M sodium salts). In order to investigate the electrooxidation of ROC with nitrate and sulfate ions as dominant ion mediators, chloride ion concentration was decreased 10 times by electrodialytic pretreatment. The highest Coulombic efficiency for chemical oxygen demand (COD) removal was observed in the presence of high chloride ions concentration for all anodes tested (8.3-15.9%). Electrooxidation of the electrodialysed concentrate at Ti/SnO2-Sb and Ti/Pt-IrO2 electrodes exhibited low dissolved organic carbon (DOC) (i.e. 23 and 12%, respectively) and COD removal (i.e. 37-43 and 6-22%, respectively), indicating that for these electrodes chlorine-mediated oxidation was the main oxidation mechanism, particularly in the latter case. In contrast, DOC removal for the electrodialysed concentrate stream was enhanced at Si/BDD anode in the presence of SO42- (i.e. 51%) compared to NO32- electrolyte (i.e. 41%), likely due to the contribution of SO4·- and S2O82- species to the oxidative degradation. Furthermore, decreased concentration of chloride ions lead to a lower formation of haloacetic acids and trihalomethanes at all three electrodes tested.
KW - Boron-doped diamond
KW - Electrochemical oxidation
KW - Electrodialysis
KW - Mixed-metal oxide electrode
KW - Reverse osmosis concentrate
UR - http://www.scopus.com/inward/record.url?scp=84870059128&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2012.10.001
DO - 10.1016/j.watres.2012.10.001
M3 - Article
C2 - 23137830
AN - SCOPUS:84870059128
SN - 0043-1354
VL - 47
SP - 242
EP - 250
JO - Water Research
JF - Water Research
IS - 1
ER -