Method for removing fluoride from activated alumina

At this stage, the main methods used to remove fluoride in industrial production include: adsorption method, ion exchange method, electrodialysis, reverse osmosis membrane method and other methods. The following is a brief introduction to two methods of fluoride removal.

1. Principle of fluoride removal by adsorption method:

The adsorption method is to put equipment equipped with activated alumina, polymerized aluminum salt, lignite adsorbent, functional fiber adsorbent, activated carbon and other adsorbents into industrial wastewater, so that fluoride ions can undergo special or conventional ion exchange with solid media or Chemical reaction, eventually adsorbed on the adsorbent and removed, the adsorbent can also be regenerated to restore the exchange capacity.

2. Precautions for adsorption method:

In order to ensure the treatment effect, the pH value of the wastewater should not be too high, generally controlled at around 5. In addition, the adsorption temperature of the adsorbent should be controlled and should not be too high.

3. Advantages of adsorption method:

1. This method is generally used to treat low-concentration fluorine-containing wastewater, and the effect is very significant.

2. Due to its low cost and good fluoride removal effect, it is an important method for treating fluoride-containing wastewater.

1. Principle of fluoride removal by electrodialysis

The electrodialysis method applies an external DC electric field and utilizes the selective permeability of the ion exchange membrane to enable ions in the water to migrate in a directional manner.

1. Principle of fluoride removal by reverse osmosis membrane method

Reverse osmosis technology uses a higher pressure than the osmotic pressure to change the natural osmosis direction of water molecules in high-fluorine water and be separated through the reverse osmosis membrane. Currently used reverse osmosis membranes mainly include low-pressure composite membranes, seawater membranes, and cellulose acetate membranes.

The ion exchange method is a method that uses ion exchange resin or ion exchange fiber to remove fluoride ions. Ion exchange resin requires pretreatment and regeneration with aluminum salts, so the cost is relatively high. Compared with ion exchange resin, ion exchange fiber is low-cost, has a large specific surface area, strong adsorption capacity, fast exchange speed and regeneration speed, has good radiation resistance, and will not bring any pollution to the water body after treatment. On the contrary, it has a cleaning effect and is an ideal method to deeply remove fluoride ions from water.