Electrochemical in-situ hydrogen peroxide generation in a packed-bed reactor for Fenton oxidation of p-nitrophenol in aqueous solution

Abstract

Advancements in electrochemical generation of hydrogen peroxide (H2O2) in Fenton systems hasten the realization of a “chemical-free” treatment of organic pollutants in water. The present study used a novel air-sparged, packed-bed electrode configuration with reticulated vitreous carbon (RVC) as packing material for electrochemical H2O2 generation. The effects of initial pH, applied current, sparging rate, mass of RVC and electrolyte concentration on cumulative H2O2 generation and current efficiency were evaluated. From the results, the operating conditions that gave the optimal cumulative H2O2 generation and current efficiency were pH0 = 2.0, applied current = 50 mA, air sparging rate = 0.5 L min−1, mass of RVC = 0.75 g, and electrolyte concentration = 100 mM Na2SO4. The same reactor configuration was used for the treatment of the model contaminant from aqueous solution and caused the complete removal of p-nitrophenol (pnP) within a 2 h duration. Mineralization of aromatic intermediates was confirmed by gas chromatography – mass spectroscopy analyses of samples and supported by the reduction in chemical oxygen demand and total organic carbon.