Water treatment

Adsorption & desorption of fluorine


Water treatment for industries
using fluorine is serious issue

Various industries use and discharge fluoric fluid

Semiconductor manufacturer
uses fluoric fluid to clean silicon wafers

Glass manufacturer and processor
uses 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 desulfurization system

Water treatment is serious issue

Regulation of discharge of fluorine (8mg/l) must be followed
Existing solution requires a lot of cost

  • Large quantity of sludge, which is industrial waste, is generated
  • Resin solution, discharging small amount of waste, is expensive

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


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

Before Hydrothermal process

Specific surface area:83m2 g-1

After Hydrothermal process

Specific surface area : 278m2 g-1

Fluorine is removed from its solution as a result of precipitation of fluorine ion as sodium fluorosilicate

Sodium fluorosilicate is valuable as a law material for hydrofluoric acid

Process flow of fluorine water treatment with Porous Alpha

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 different agent for adsorption of fluorine


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


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

Case Study

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 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 high concentration of fluorine, the adsorption process should be repeated

・Required quantity of Porous Alpha per 1 step: 5% of quantity of fluid

・Concentration of fluorine after adsorption process: less than 8ppm
– Not guaranteeing 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.