Energy-Efficient H₂O₂ Electro-production Based on an Integrated Natural Air-Diffusion Cathode and Its Application

Abstract

Given the low oxygen mass transfer rate and high aeration energy consumption, the traditional two-electron oxygen reduction reaction (ORR) is restricted. In this study, the integrated natural air diffusion cathode (INAC) and a reactor configuration with the horizontal scale facing to air (FTA) demonstrated highly selective H 2 O 2 production for the removal of organic contaminants. Simply synthesized by shaping the mixture of carbon black and polytetrafluoroethylene, the INAC exhibited not only massive pores in all directions for sufficient mass transfer but also the integrated configuration for low charge transfer resistance. Based on the oxygen mass transfer models, for the ORR reaction kinetics, the interface oxygen concentration index was higher than 40, contributing to the high current efficiency of H 2 O 2 production (>90%). The oxygen diffusion model can provide the quantitative description of H 2 O 2 synthesis for porous electrode optimized design. Combining the INAC with the reactor configuration with the FTA mode for free additional O 2 /air source supply, the electrical efficiency per order was lower than 0.14 kWh m −3 , and the removal rate of sulfonamides per unit current could reach 11 mg min −1 A −1 , reaching the best reports. This ultraefficient process equipped with the INAC and the FTA mode provides a meaningful practical application prospect for wastewater treatment.

Model Unraveling the Ultra-Efficient Multi-Stage Flow-Through Anodes for Water Purification Application: Development of Design and Evaluation

“… ,,, The difference in the electrolyte concentration and electrode spacing in these studies would significantly affect the applied voltage of the system. Thus, the normalized contaminants removal per current value (RRC, ∼easily transformed to the equivalent removal of coulombs per charge) was assessed by eq RRC = M t · I where RRC is the normalized removal index (mg min –1 A –1 ), t is the reaction time (min), and M ( C 0 · V – C t · V , mg) is the removal mass of contaminants at the final time t , and I is the current (A).…”

“…The electrochemical energy input efficiency of contaminant removal was calculated using the electrolysis efficiency per one order (eqs 5−6). 46 (5) (6) where EE/O V or M is the electrolysis energy required for MIT removal by one order (kWh m −3 or kWh g −1 ), and C 0 and C are the MIT concentrations at the beginning and ending time (mg L −1 ), respectively. U is the cell voltage (V), t is the reaction time (h), V is the solution volume (L), and I is the current (A).…”

“…The electrochemical energy input efficiency of contaminant removal was calculated using the electrolysis efficiency per one order (eqs 5−6). 46…”

“…The electrochemical energy input efficiency of contaminant removal was calculated using the electrolysis efficiency per one order (eqs –) EE / O normalV = U · I · t V · log ( C 0 C ) EE / O normalM = U · I · t ( C 0 − C ) · V · log ( C 0 C ) where EE/ O V or M is the electrolysis energy required for MIT removal by one order (kWh m –3 or kWh g –1 ), and C 0 and C are the MIT concentrations at the beginning and ending time (mg L –1 ), respectively.…”

Ultraefficient Heterogeneous Electro–Fenton Process Integrated a Natural Dual-Interface Air-Diffusion Cathode for Water Decontamination

“…The electrical consumption of H 2 O 2 electrosynthesis (EC, kWh kg –1 ) was estimated using eq EC = 1000 U · I · t ( C t − C 0 ) · V where C 0 and C t are the H 2 O 2 content values at the beginning and ending times (mg L –1 ), respectively; U is the voltage (V); V is the solution volume (L); t is the reaction time (h); and I is the current (A).…”