γ-FeOOH graphene polyacrylamide carbonized aerogel as air-cathode in electro-Fenton process for enhanced degradation of sulfamethoxazole

Novel gamma-FeOOH graphene polyacrylamide carbonized aerogel (gamma-FeOOH GPCA) was used as the cathode in neutral electro-Fenton (EF) process to achieve degradation and mineralization of sulfamethoxazole (SMX). gamma-FeOOH GPCA cathode was fabricated by a multiple-phase carbonization method, leading to a good conductivity (26.37 Sm-1 with 7.5 mg mL(-1) GO) and high electrochemically active surface area (EASA). An in situ synthesis method of gamma-FeOOH was accomplished to distribute the catalyst uniformly and firmly into the carbonized aerogel framework. Two electron reduction could take place at the cathode, H2O2 and Fe2+ can be generated at GPCA cathode efficiently. A 5-batch comparative assessment between GPCA-EF and CF-EF process exhibited the distinguished catalytic stability of GPCA cathode with a total organic carbon (TOC) removal efficiency of 89.8 +/- 0.8%, 89.1 +/- 0.9% and 84.7 +/- 1.1% at the last 3 batches, respectively, versus 61.2 +/- 1.2, 60.9 +/- 1.1 and 59.4 +/- 0.9% by CF cathode. This carbonized aerogel cathode demonstrated a great potential for the EF process to remove organic pollutants in water at neutral pH.