Effects of water constituents on the stability of gas diffusion electrode during electrochemical hydrogen peroxide production for water and wastewater treatment

Technoeconomic Assessment of Electrochemical Hydrogen Peroxide Production with Gas Diffusion Electrodes under Scenarios Relevant to Practical Water Treatment

“…Compared with the quick deterioration of GDE stability in a real-water matrix (e.g., ∼40% decreases of ACEs in 60 h in municipal wastewater), the GDEs maintained relatively stable H 2 O 2 production for a significantly longer time during H 2 O 2 electrosynthesis in electrolyte solutions (Figure ). These results confirm that the lifetime of GDEs can be significantly extended when H 2 O 2 electrosynthesis is conducted in electrolyte solutions than in real-water matrices.…”

“…Nevertheless, sudden deterioration of H 2 O 2 production may occur during the process (Figure ). This change can be mainly attributed to the water flooding of GDE pores at the late stage of the multicycle experiments. , Due to the electrocapillary effect upon cathodic polarization, water can intrude into the internal pores of GDEs during H 2 O 2 electrosynthesis . The water intrusion generates a TPI among oxygen gas, water, and electrode inside the GDE, which is beneficial for ORR to H 2 O 2 .…”

“…During electrolysis, H 2 O 2 is produced at the triple-phase interface (TPI) among the oxygen, water, and electrode inside the pores of GDE. 15,32,34 The generated H 2 O 2 then diffuses from the pores to the bulk solution and is carried away by the recirculating electrolyte. Increasing flow rates can decrease the thickness of the boundary layer at the electrode surface and thus facilitate the diffusion of H 2 O 2 to the bulk.…”

“…15 Moreover, the mineral precipitates decrease the hydrophobicity of GDEs and thus facilitate progressive water intrusion into the depth of GDEs, which can eventually lead to electrode failure due to water flooding and penetration. 5,15 Due to the fast deterioration of GDE stability in the singlereactor configuration, some researchers have suggested that H 2 O 2 be produced in clean electrolyte solutions in a separate electrochemical reactor and then fed to the main reactor that contains the water to be treated (referred to as the dual-reactor system hereafter). 5,14,15,18 It has been expected that in this way, the lifetime of GDEs can possibly be considerably extended because of the avoidance of exposures to strong oxidants and fouling by complex water constituents.…”

O2-Involved Electro-activation of Persulfate on Oxidized Carbon Black for Effective Sulfamethoxazole Degradation: Key Role of Side-Reactive Oxygen Reduction

“…Cations (Ca 2+ , Mg 2+ , et al) might be precipitated in mineral form on the cathode surface during H 2 O 2 electroproduction to significantly block the oxygen, electron, and proton transfer processes, thus hindering the 2e – ORR activity and organics degradation. , To explore the influence of Ca 2+ and Mg 2+ in the O 2 -involved PDS electro-activation system on CB600, 90 mg L –1 Ca 2+ and 30 mg L –1 Mg 2+ were added for five working cycles at pH 7.0. As shown in Figure C, SMX removal efficiency decreased slightly from 87.6% (initial) to 82.3% (90 mg L –1 Ca 2+ and 30 mg L –1 Mg 2+ ) and sharply to 67.7% after five cycles.…”