Decolourization and degradation of C.I. Acid Red 73 by anodic oxidation and the synergy technology of anodic oxidation coupling nanofiltration

This work is conducted to study ability of anodic oxidation treatment azo dye C.I. Acid Red 73 (AR73) using the electrodes of Y doped Ti/SnO2–Sb electrodes prepared by thermal decomposition and Ti/SnO2–Sb electrodes prepared by electrodeposition. It has been shown that doping Y can enhances the electrochemical activity of the electrodes, but the accelerated service life was slightly reduced. Both the lifetime and electrochemical activity of Ti/SnO2–Sb electrodes prepared by electrodeposition in a new Sn–Sb electrodeposition bath outperform the Ti/SnO2–Sb electrodes prepared by thermal decomposition. Moreover, the effect of varying wastewater process indexes (initial pH (4–10), the addition of NaCl (0–9 mM) and initial dye concentration (0.5–2.0 g L−1)) on the performance of anodic oxidation using Ti/SnO2–Sb electrodes prepared by electrodeposition was investigated followed by the performance indicators analyses including color, chemical oxygen demand (COD), current efficiency and specific energy consumption. Finally, the synergy technology of anodic oxidation coupling nanofiltration was adopted to treat AR73 wastewater in order to overcome the low current efficiency of anodic oxidation. Preliminary results have shown that the synergy technology could cost-effectively treat AR73 wastewater.

► Ti/SnO2–Sb–Y electrodes show superior electrochemical activity.
► Electrodeposition method improves the service life and electrochemical activity.
► Increasing current density will increase the stable permeation flux.
► The color rejection reached 100% when current density exceeds 15 mA cm−2.
► The absorbance of permeation solution at around 200 nm increased obviously.