Electro-Fenton
Pharmaceutical, printing and dyeing, chemical, landfill leachate and other refractory wastewater often contains highly toxic, highly colored, and poorly biodegradable organics. Traditional Fenton requires purchasing and storing large amounts of hydrogen peroxide and ferrous salts, involves high chemical dosing, produces large amounts of iron sludge, and demands strict pH control. This product electrochemically generates Fe²⁺ and H₂O₂ in situ within the reactor and uses current to drive the Fe³⁺/Fe²⁺ cycle. It features low chemical dosing, greatly reduced iron sludge, and a controllable operation process, making it an efficient choice for pretreatment and advanced oxidation of refractory wastewater.
I. Product Positioning
The Electro-Fenton reactor is an electrochemical advanced oxidation (AOP) equipment that integrates electrolysis and Fenton oxidation: an iron-based anode dissolves Fe²⁺ under applied current, and a gas diffusion cathode is supplied with air/pure oxygen to generate H₂O₂ via in-situ electroreduction. Under weakly acidic conditions, the Fenton reaction occurs, producing large amounts of hydroxyl radicals (·OH) that mineralize organics; the cathode can also reduce Fe³⁺ back to Fe²⁺ to lower iron consumption. The equipment integrates a power supply, aeration/oxygen supply, pH adjustment, and subsequent neutralization, precipitation, and separation, and is used for advanced oxidation and pre-biochemical pretreatment of refractory wastewater.
II. Working Principle (Brief)
Influent acidification: Acid is dosed into the wastewater to adjust it to weakly acidic conditions (pH about 2.5–4.0), creating a suitable environment for the Fenton reaction before entering the electrolytic cell.
Anodic iron dissolution: The iron-based anode dissolves Fe²⁺ under applied current, serving as the iron source for the Fenton reaction.
Cathodic H₂O₂ generation: Air/pure oxygen is supplied to the gas diffusion cathode, where O₂ is electroreduced in situ to generate H₂O₂.
Fenton reaction: Fe²⁺ reacts with H₂O₂ to generate Fe³⁺ and highly active ·OH; ·OH non-selectively cleaves chains, mineralizes organics, decolorizes, and detoxifies.
Iron cycle regeneration: The cathode (or auxiliary voltage) reduces Fe³⁺ back to Fe²⁺, sustaining reagent efficacy and reducing iron consumption and iron sludge.
Post-treatment separation: The effluent is neutralized and precipitated to separate the generated iron sludge (significantly less than traditional Fenton), and the clear liquid enters subsequent processes.
Process schematic: Wastewater → Acidification (pH 2.5–4) → Electrolytic cell (iron anode dissolves Fe²⁺ + gas diffusion cathode generates H₂O₂) → Fenton reaction (·OH mineralization) → Fe³⁺/Fe²⁺ electrochemical cycle → Neutralization and precipitation (less sludge) → Clear liquid for subsequent treatment
The core lies in "in-situ reagent generation + electron cycling": H₂O₂ and Fe²⁺ are generated and used on-site within the cell, eliminating the need for external purchase, storage, and precise dosing; the current continuously drives Fe³⁺→Fe²⁺ regeneration, allowing limited iron to participate repeatedly in the reaction, thereby significantly reducing iron consumption and iron sludge production, and making the oxidation process flexibly adjustable with load.
III. Core Advantages
① In-situ reagent generation Fe²⁺ and H₂O₂ are generated on-site, eliminating external purchase, storage, and cumbersome dosing, with precise dosing.
② Less iron sludge The Fe³⁺/Fe²⁺ electrochemical cycle enables repeated iron utilization, significantly reducing iron consumption and sludge compared with traditional Fenton.
③ Strong oxidation ·OH non-selectively cleaves and mineralizes, simultaneously reducing COD, decolorizing, and breaking biological toxicity.
④ Controllable operation Current, aeration, and pH are adjustable, with flexible start-stop and easy PLC automation integration.
⑤ Strong compatibility Can be coupled with three-dimensional electrodes, ultraviolet (photo-Fenton), electrocatalysis, and other enhancement methods.
⑥ Small footprint Skid-mounted integrated design, easy to integrate with existing biochemical/membrane systems for capacity expansion.
IV. Main Technical Parameters (Reference Range)
Item | Parameter Range / Description | Remarks |
|---|---|---|
Treatment capacity | 0.5 – 50 m³/h | Skid-mounted to engineered, typical range reference |
Influent COD (applicable) | ≤ 2000 mg/L | Pretreatment or advanced stage, typical range reference |
COD removal rate | 30% – 80% | Varies with water quality and operating conditions, typical range reference |
Operating pH | 2.5 – 4.0 | Weakly acidic Fenton window, typical range reference |
Current density | 20 – 200 A/m² | Depends on cathode and water quality, typical range reference |
Oxygen supply method | Air / pure oxygen (O₂ electroreduction) | Pure oxygen yields higher H₂O₂ efficiency, typical range reference |
Reaction retention time | 30 – 120 min | Affects oxidation degree, typical range reference |
Electrode configuration | Iron-based anode + gas diffusion carbon cathode (can be equipped with titanium-based DSA) | Customized according to process, typical range reference |
* The above are typical range reference values. Actual scale, removal rate, and power consumption are determined by design calculations and on-site bench tests/commissioning.
V. Typical Application Scenarios
Scenario / Industry | Adaptation Description / Main Function |
|---|---|
Pharmaceutical wastewater | Detoxification and mineralization of antibiotic mother liquor, highly toxic and refractory organics |
Printing and dyeing wastewater | Efficient decolorization, TOC reduction, and breakdown of chromophores |
Chemical / pesticide wastewater | Advanced oxidation pretreatment of refractory and toxic organics |
Landfill leachate | Advanced COD reduction of NF/RO concentrate or raw liquid |
Coking wastewater | Chain cleavage and mineralization of phenols, cyanides, and polycyclic aromatic hydrocarbons |
Electroplating / PCB | Advanced polishing combined with complex breaking and COD reduction |
Industrial park comprehensive wastewater | Advanced upgrading after biochemical treatment to ensure stable compliance |
VI. Applicable Boundaries and Selection Recommendations
This product is suitable for pretreatment and advanced oxidation of refractory toxic wastewater. Operation requires acidification, and effluent requires neutralization, precipitation, and supporting iron sludge disposal; high concentrations of carbonate and strong complexing agents in water will quench ·OH or lock up iron, and must be pre-removed or conditioned. Ultra-high concentration organic raw water should first undergo biochemical/physicochemical load reduction and should not directly enter the tower.
Selection is based on water volume, influent COD and biodegradability, and target removal rate to determine the cell body, current, and cathode type; it is recommended to first conduct bench tests with water samples to determine the optimal pH, current density, and retention time, and then scale up accordingly. Compared with homogeneous Fenton, Electro-Fenton features in-situ reagent generation, iron cycling, low sludge, and controllability; compared with iron-carbon micro-electrolysis, Electro-Fenton requires applied current and generates H₂O₂ in situ, resulting in more complete oxidation; it can be used in conjunction with titanium anodes (insoluble core components). Iron sludge post-treatment units must be planned simultaneously.
Let refractory wastewater be "electrified" into activity first
Rihong Environmental can provide process selection, electrode configuration, bench test verification, and complete equipment solutions for Electro-Fenton reactors. Welcome to call or leave a message for a customized design.
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