Electrochemical water treatment processes are a unique, economical and environmentally friendly option for meeting discharge standards and compliance requirements. Most environmental pollutants can be successfully eliminated or converted to non-toxic species through one or more processes, including electro-oxidation (EO), electro-reduction, electro-coagulation (EC), electro-coagulation flotation (ECF) and advanced oxidation processes Titanium electrodes are popular in all of these processes because they are very effective in promoting the release of chlorine and oxygen.
Electrocoagulation technology
The technology uses the electrochemical principle to use alloy metals such as aluminum and iron as the main electrode, and generates electrochemical reactions with the help of external pulse high voltage to convert electrical energy into chemical energy. It uses sacrificial anode metal electrodes to generate metal cation flocculants, and separates pollutants from water bodies through coagulation, floatation, reduction and oxidation decomposition to achieve a technology of purifying water bodies.
High-voltage electrocoagulation equipment is the latest generation of electrochemical water treatment equipment in the world today. This technology breaks through the traditional low-voltage and high-current electrolysis method, and instead uses high-voltage and low-current (high-voltage pulse electrocoagulation method--HVES) electrolysis method. Using the electrochemical principle, an electrochemical reaction is generated with the help of external high voltage to convert electrical energy into chemical energy. In a specific reaction tank, the organic or inorganic pollutants in the wastewater are oxidized and reduced, and then coagulated and floated to separate pollutants from the water body. It can effectively remove heavy metals such as Cr, Zn, Ni, Cu, Cd, CN, grease, phosphate, and various harmful pollutants such as COD, SS and chroma in the wastewater.
High-voltage pulse electrocoagulation technology, American scientist Dr. Dictrich and Taiwanese technicians with more than 20 years of practical engineering experience, through key improvements to electrocoagulation technology equipment and treatment processes, finally have the core technology of independent intellectual property rights-a new generation of high-voltage pulse electrocoagulation (EC) water treatment technology, which is a new technology for environmental protection.
Years of research and development and application practice have achieved the production and installation and commissioning of a series of complete sets of equipment, stable and reliable product quality and professional engineering treatment technology services. Reasonable solutions can be formulated for different wastewater conditions and customer needs to achieve the best environmental and economic benefits. A water treatment process innovation based on high-voltage pulse electrocoagulation (EC) water treatment proprietary technology and serialized equipment combined with mature biological treatment technology and membrane technology has been formed. We have successfully completed a number of wastewater treatment and water reuse projects, mainly heavy metal wastewater (electroplating, circuit boards, alumina, metallurgy, surface treatment); difficult-to-degrade industrial wastewater (dyes, printing and dyeing, chemicals, papermaking, pharmaceuticals, coal chemical industry); complex organic wastewater (oil fields, machining, acidified oil, high-concentration difficult-to-degrade, kitchen waste leachate, domestic waste leachate), etc., providing a more environmentally friendly, more effective and more economical solution for industrial water treatment and reuse, and have been well received by users.
1) Electrolytic oxidation
Oxidation in the electrolysis process can be divided into two categories. One is direct oxidation, that is, the pollutants directly lose electrons at the anode and oxidize; the other is indirect oxidation, using anions with lower electrode potential in the solution, such as OH, Cl, which lose electrons at the anode to generate new active substances with stronger oxidants such as [O], [OH], Cl2, etc. These active substances are used to oxidize and decompose BOD5, COD, NH3-N, etc. in water.
(2) Electrolytic reduction
The reduction effect in the electrolytic process can be divided into two categories. One is direct reduction, that is, the pollutants directly obtain electrons at the cathode and undergo reduction. The other is indirect reduction, in which the cations in the pollutants first obtain electrons at the cathode, so that the high-valent metal cations in the electrolyte obtain electrons at the cathode and are directly reduced to low-valent cations or metal precipitates.
(3) Electrolytic flocculation
Soluble anodes such as iron and aluminum, after being passed through high-voltage pulse direct current, lose electrons at the anode to form metal cations Fe and Al, which combine with OH in the solution to form highly active flocculating groups with extremely strong adsorption capacity and better flocculation effect than ordinary flocculants. By utilizing its adsorption bridging and net capture and sweeping effects, pollutants in the wastewater can be adsorbed and co-precipitated to remove them.
(4) Electrolytic flotation
Electrolytic flotation is the electrolysis of wastewater, in which water molecules are ionized to produce H and OH, which migrate in a directional manner under the drive of the electric field and precipitate hydrogen and oxygen on the surface of the cathode plate and anode plate respectively. The diameter of the newly generated bubbles is very small, with hydrogen bubbles of about 10 to 30 μm and oxygen bubbles of about 20 to 60 μm; compared with the bubble diameters generated by pressurized dissolved air flotation (100 to 150 μm) and mechanical stirring (800 to 1000 μm), they are smaller. It can be seen that the ability of bubbles generated by electrolysis to capture impurity particles is higher than the latter two, and the dispersion of bubbles is high. As a carrier, they adhere to suspended solids in the water and float up, which makes it easy to remove pollutants. Electrolytic flotation can remove both hydrophobic and hydrophilic pollutants in wastewater.
Equipment function
The electrode plates of the electroflocculation equipment can be made of different materials according to the different substances to be removed, producing strong flocculation, strong oxidation, strong reduction, strong flotation and other effects to achieve the best treatment effect. Iron, aluminum, titanium, graphite, lead dioxide, etc. are often used. Each material has its own suitable application field. The design of the electroflocculation equipment and the selection of electrode plates are determined after a large number of R&D tests and rich engineering practice experience.
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