Preparation, characterization and application of nanostructured materials at direct and /or photo-assisted electrochemical degradation of pollutants

Abstract

INCD-ECOIND, as a partner within this project, was assigned the task for preparing, characterising and testing of some modified oxide structures to be used for electro-oxidative degradation processes of pollutants such as phenols and azo dyes. Electrocatalytically modified films on SnO2 anodes: Ti/RuO2/SnO2- Sb2O5-RuO2 and Ti/RuO2/SnO2-Sb2O5-Bi2O3 were characterized with respect to their structure (by using infrared spectrometry and scanning electron microscopy) and electrochemical properties (cyclic voltammetry). The influence of operating parameters on the degradation process at the modified oxide nanostructures was studied for azo dyes and ethoxylated nonyl phenols. The degradation process was assessed by using UV-VIS spectroscopy. The removal yields of the colour ranged from 92 to 99% for Reactive Blue 4, Reactive Black 5 and Reactive Red 147 by using the modified films on SnO2 anodes and the following working conditions: pHs of 6.2, 11 and 13, electrolysis duration of 120 min and dye initial concentration of 100 mg/L. At 300 A/m2 and 120 min electrolysis duration, Ti/RuO2/SnO2-Sb2O5- RuO2 anode and an initial pollutant concentration of 100 mg/L, the residual concentrations were 26.52 mg/L for NF16 and 35.23 mg/L for NF40. By working under the same working conditions, at Ti/RuO2/SnO2-Sb2O5-Bi2O3, the residual concentrations of NF16 and NF40 were lower than 10 mg/L.