Electrocatalytic Fenton Oxidation Coupling for Wastewater Treatment
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Solution Overview
Problem
Existing electrocatalytic Fenton oxidation processes for treating chemical wastewater face challenges such as the need for external aeration or hydrogen peroxide addition, slow degradation of refractory iron complexes, and excessive iron sludge production, which limits their efficiency and practicality.
Innovation Solution
An electrocatalytic Fenton oxidation-electrochemical oxidation coupling process that uses a narrow-channel design to produce hydrogen peroxide in situ and reduces iron complexes through decomplexation, coupled with a pH adjustment step to recycle iron ions, minimizing sludge production and enhancing COD removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional Fenton oxidation is used to treat chemical wastewater, then COD removal effect is achieved, but large amount of iron sludge is produced and iron ion loss is serious
Solution Approach 1:
The patent recovers iron ions from the wastewater treatment process by adjusting pH to precipitate iron hydroxide, then reduces it back to ferrous ions using electrochemical reduction. This closed-loop recovery system minimizes iron sludge disposal and enables iron ion recycling, directly addressing the iron loss problem while maintaining COD removal effectiveness
Solution Approach 2:
The patent replaces the traditional chemical Fenton oxidation system with an electrochemical oxidation system that uses electrical energy to drive the oxidation process. This substitution eliminates the need for external hydrogen peroxide addition and enables in-situ generation of oxidants through electrochemical reactions, reducing iron sludge production while maintaining treatment efficacy
2Productivity
If electro-Fenton technology is used, then oxidation efficiency is improved, but external aeration or hydrogen peroxide addition is required
Solution Approach 1:
The patent implements a self-service system where the electrochemical oxidation process generates hydrogen peroxide in-situ through the reduction of oxygen at the cathode. This internally generated H2O2 immediately participates in the Fenton reaction with ferrous ions produced at the anode, eliminating the need for external H2O2 addition or aeration while maintaining high oxidation efficiency
Solution Approach 2:
The patent merges the electrochemical oxidation process with the Fenton reaction into a unified electrocatalytic Fenton oxidation system. The anode and cathode reactions are coupled such that ferrous ions generated at the anode immediately react with in-situ generated hydrogen peroxide at the cathode, creating a self-sustaining oxidation system that eliminates external reagent addition
3Productivity
If electrocatalytic Fenton oxidation is used, then treatment efficiency is improved, but degradation of refractory iron complexes is slow
Solution Approach 1:
The patent uses electrochemical reduction at the cathode to rapidly convert ferric iron complexes back to ferrous ions, providing a much faster degradation pathway than conventional chemical reduction methods. This electrochemical approach directly addresses the slow degradation issue while maintaining the overall treatment efficiency of the system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process achieves efficient COD removal rates of 50-85% without external aeration or hydrogen peroxide addition, effectively addressing the limitations of traditional Fenton oxidation by recycling iron ions and reducing sludge production, making it suitable for both pretreatment and advanced treatment of chemical wastewater.
Implementation Method 1
oxygen produced by an anode oxygen evolution reaction is in contact with a cathode to produce H2O2
Implementation Method 2
Fe2++H2O2→Fe3++·OH+OH−
Implementation Method 3
oxygen produced by an anode oxygen evolution reaction is in contact with a cathode
Implementation Method 4
the iron sludge is dissolved into iron ions to return to the electrochemical oxidation step
Implementation Method 5
the iron (III) complexed with low-molecular organic acid is more stable and the cathode is reduced to the complex state iron (II)
Data Source
AI summary
The present invention discloses an electrocatalytic Fenton oxidation-electrochemical oxidation coupling process and apparatus for efficient treatment of chemical wastewater, and belongs to the field of sewage treatment. The process includes an electrocatalytic Fenton oxidation step, an electrochemical oxidation step, and a pH adjustment step. A spacing between a cathode and an anode in the electrocatalytic Fenton oxidation step is controlled, so that oxygen produced at the anode reacts at the cathode to produce H2O2. The treatment requirements can be met without external aeration or external addition of H2O2, and meanwhile, the efficiency of COD removal by electro-Fenton oxidation is effectively improved. Further, by connecting a pH adjusting tank with the electrocatalytic Fenton oxidation-electrochemical oxidation coupling apparatus in series, a coupling treatment process with near-zero production of iron sludge is realized.