KDF Filter Media Working Principle

KDF is composed of more than two different metals, and when in contact with water, the positive potential of copper in the alloy becomes the cathode, and the negative potential of zinc as the anode, constituting the galvanic cell. The zinc anode loses electrons in the reaction and generates zinc ions into the solution. The reduction reaction of free chlorine occurs on the copper cathode without the dissolution of copper metal. Water and chlorine become the final electron acceptor, and hydrogen ions, hydroxide ions and chloride ions are generated at the same time.

Zn+HClO+H2O+2e →Zn2++Cl-+H++2OH-

KDF, through REDOX reaction and catalysis, enables soluble heavy metal ions in water, such as lead, mercury, copper, nickel, cadmium, chromium, antimony, aluminum, etc., to be plated on the surface of the KDF treatment medium or into the KDF lattice, thereby binding toxic heavy metal pollutants to KDF.

Take lead as an example, KDF reduces lead ions dissolved in water to insoluble lead atoms, and is plated on the surface of KDF medium, the chemical reaction is as follows:

Zn/Cu/Zn+Pb(NO3)2 →Zn/Cu/Pb + Zn(NO3)2

When the water pipe made of iron and steel is corroded, the iron oxidation forms FeO colloid, and the groundwater in some areas also contains a large amount of FeO colloid, KDF converts the soluble iron compound into insoluble iron oxide (Fe2O3) through the form of a catalyst, which precipitates on the surface of KDF. The chemical reaction is as follows:

2Cu+FeO→Cu2O+Fe

4Fe+3O2 →2 Fe2O3

KDF reacts with arsenic ions in water, the zinc in KDF loses electrons, the arsenic gains electrons, and the arsenic is coated on the surface of KDF treated medium. The reaction formula is as follows:

3Zn2++As2O3+6H+→Zn3As2↓+3H2O

3Zn2++2H3As → Zn3As2↓+6H+