Fabrication of a hydrophobic SDBS-PbO2 anode for electrochemical degradation of nitrobenzene in aqueous solution

Highlights: • A novel hydrophobic SDBS-PbO₂ anode was fabricated. • The hydrophilic property of SDBS-PbO₂ anode improved the OH generation. • Nitrobenzene was readily degraded at SDBS-PbO₂ anode. • The novel SDBS-PbO₂ anode had much longer lifetime than pure PbO₂ anode. In present work, a hydrophobic PbO₂ electrode modified by sodium dodecyl benzene sulfonate (SDBS-PbO₂) was fabricated using electrodeposition method. The effect of SDBS concentration in electroplating bath on the surface morphology, structure, electrochemical properties, hydrophilicity, OH generation ability and stability of SDBS-PbO₂ electrodes was studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), water contact angle, fluorescence probe technique, and accelerated life test, respectively. Results showed that SDBS modification not only increased the electro-catalytic activity, but also prolonged the service life of PbO₂ electrode. The electrode prepared from the electroplating bath containing 10 mg/L SDBS (SDBS-PbO₂-10 mg/L) showed the highest electrocatalytic activity and the longest service life. The electrochemical degradation of nitrobenzene (NB) in simulated wastewater was used to evaluate the potential application of SDBS-PbO₂ electrodes for wastewater treatment. The highest NB removal efficiency and total organic carbon (TOC) removal efficiency of 89.35% and 52.62% were both obtained by SDBS-PbO₂-10 mg/L anode. Thus, the SDBS-PbO₂-10 mg/L anode was used to systematically investigate the effects of applied current density, initial NB concentration, temperature, and pH value on the reaction kinetics and mineralization current efficiency (MCE) of NB degradation. It was found that the increase of applied current density and the reduction of initial NB concentration exerted a prominent effect on the degradation of NB, but caused the decrease of MCE, while high temperature and low pH value improved both NB degradation rate and MCE. These results show that the SDBS-PbO₂-10 mg/L electrode may become a promising anode for organic pollutant degradation.