Preparation method and application of chitosan quaternary ammonium salt

Chitosan Quaternary Ammonium Salt

[Preparation method] In addition to directly dissolving in water, the chitosan quaternary ammonium salt can also be mixed with some organic solvents in any ratio, such as mixing 10% chitosan hydroxypropyltrimethylammonium chloride solution with ethanol , propylene glycol , When glycerin was mixed in any ratio, no precipitation or turbidity was observed

The chemical structure of chitosan is modified with glycidyl trimethylammonium chloride, and a quaternary ammonium salt group can be introduced into the chitosan molecule to obtain a chitosan quaternary ammonium salt.

Weigh-Place a quantitative amount of chitosan in a three-necked flask, add isopropanol, heat in a water bath, and stir to raise the temperature to 80-90°C, then add 2,3-epoxypropyltrimethylammonium chloride ( EPTAC) aqueous solution, stirred at a constant temperature for 8-9 hours, the product is filtered, washed, suction filtered, dried, and stored for testing

In addition, the reaction activity of epoxy quaternary ammonium salt is used to introduce a strong hydrophilic quaternary ammonium salt group into the —NH ₂ group of chitosan to prepare N-carboxypropyl trimethyl quaternized chitosan

[Application] Quaternized chitosan can be used in the fields of medicine, oil field sewage and oil refining wastewater treatment

(1) Medical field

With concentrated DNA and effective gene delivery

The transfection efficiency of DOTAP-DNA lipoplex and chitosan complex in Caco-2 cell culture medium is reduced, but quaternized chitosan oligomer is better than DOTAP

(2) Oilfield sewage and oil refining wastewater treatment

Oilfield sewage and oil refining wastewater often contain large amounts of suspended solids, colloids, emulsified oil beads and bacteria

Phenol is an important industrial chemical reagent, which is volatile and can cause air pollution

Therefore, the tyrosinase chitosan membrane can be used to detect and remove phenol vapor

Refinery wastewater (taken from the conditioning tank of the water treatment workshop of the refinery) mainly comes from the dehydration of heavy diesel oil, the circulating water of each workshop (contains a certain amount of oil due to the leaking of the pipeline), the cleaning water of the equipment container, and the cooling water tower and Boiler blowdown, steam condensate

Table 3-72 Properties of refinery wastewater

It can be seen from the test that the chitosan quaternary ammonium salt can achieve excellent flocculation effect when only adding 5mg/L chitosan quaternary ammonium salt solution under the coagulation aid effect of bentonite, and the remaining turbidity can be as low as 2NTU or less , The turbidity removal rate is 99.

Table 3-73 Effects of different flocculants in the treatment of refinery wastewater

Chitosan quaternary ammonium salt is a cationic organic polymer compound, which mainly plays a role of adsorption and bridging in flocculation

After adding bentonite to oil refinery wastewater, the effect of flocculation is significantly improved.