Water treatment | Adsorption & desorption of fluorine

Water treatment for industries using fluorine is a serious issue

Porous Alpha can reduce the cost of fluorine water treatment.
Our technology “Fluorine adsorption agent and fluorine-containing water treatment” is patented

Various industries use and discharge fluoric fluid

  • Semiconductor manufacturer uses fluoric fluid to clean silicon wafers
  • The glass manufacturers and processors use the fluoric fluid as material for etching
  • Liquid crystal display manufacturer use fluoric fluid for etching glass
  • Metal processing company use fluoric fluid for pickling
  • Coal thermal power plant discharge waters with fluorine from the desulfurization system

Water treatment is a serious issue

Regulation of discharge of fluorine (8 mg/l) must be followed
The existing solution requires a lot of costs

  • A large quantity of sludge, which is an industrial waste, is generated
  • Resin solution, discharging a small amount of waste, is expensive

The hydrothermally-processed Porous Alpha has increased specific surface area which adsorbs fluorine

Before Hydrothermal process After Hydrothermal process
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Specific surface area:83m2 g-1 Specific surface area: 278m2 g-1

Fluorine is removed from its solution as a result

of precipitation of fluorine ion as sodium


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Sodium fluorosilicate is valuable as a law material for hydrofluoric acid



Process flow of fluorine water treatment with Porous Alpha


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Fluorine adsorption and desorption process could be implemented in a simple manner with Porous Alpha

Porous Alpha’s capacity of adsorption of fluorine is drastically higher than other agents

Adsorption capacity and contact time for a different agent for adsorption of fluorine


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Fluoric water treatment with Porous Alpha has a wider range of use and/or is more cost-effective than others


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In addition to the above, a simple plant structure can realize the small size of the initial investment

Our solution for fluoric water treatment is under verification in liquid crystal manufacturer


Customer: Manufacturer of liquid crystal related product

Concentration of fluorine before treatment: Hundreds of thousand ppm

Currently, they’re using the combination of precipitation method with calcium and aluminum to remove fluorine. They have the intention to use our technology to reduce the discharging cost of industrial waste (sludge)

Specification and applied conditions for fluorine adsorption and desorption by Porous Alpha


  • Minimum contact time: 1hour
  • Fluorine adsorption capacity per 1g of Porous Alpha: 400mg
    • In case of a high concentration of fluorine, the adsorption process should be repeated


  • The required quantity of Porous Alpha per 1 step: 5% of the quantity of fluid
  • The concentration of fluorine after adsorption process: less than 8ppm
    • Not guaranteed to decrease the concentration to 0.8 ppm (for potable water)


  • The purity of precipitation on sodium fluorosilicate is decreased according to the concentration of Fe (III) and Al(III)
  • Technical issues to be solved
    • The fluoric water discharged from glass etching contains boron. As a water treatment solution, the removal of BF4 is also required. Now we are developing to remove the boron alongside with fluorine.
    • To provide as a system for water treatment of fluoric discharging water, it is required to remove boron at the same time
    • Methodology to remove boron is now under investigation.