β-FeOOH self-supporting electrode for efficient electrochemical anodic oxidation process

Abstract

In this work, β-FeOOH was synthesized and grown on carbon paper with the assistance of dopamine (PDA) via a facile hydrothermal method, producing β-FeOOH self-supporting electrode eventually. Electrochemical anodic oxidation performance to methyl orange (MO) solution using β-FeOOH anode was investigated and the major influencing factors such as current density, initial pH value and initial MO concentration on MO degradation efficiency were further explored. Experimental results suggested that 99.4% degradation rate of MO could be achieved only after 25 min electrolysis, its pseudo first-order reaction kinetic constant was 11.3 ⅹ 10^-2 min^-1 and the COD removal ratio was 37.3% after 120 min electrolysis under optimized conditions: current density was 10 mA cm^-2, initial pH value was 3 and initial MO concentration was 10 mg L^-1. At the same time, β-FeOOH electrode also exhibited a high cycling stability and the MO removal ratio was still keeping at 84.9% after eight cycles. Moreover, this electrode showed efficient decomposition performance to multiple simulated pollutants, indicating the well potential practical application values of β-FeOOH electrode. At last, the proposed degradation mechanism of MO was evaluated according to the analyzing results of UV-vis and HPLC-MS to MO solution under different degradation durations.

Keywords: Advanced oxidation; Degradation mechanism; Methyl orange; β-FeOOH.