Study On Carboxymethyl-chitosan Prepartion And Application

Carboxmethylation of chitosan under microwave irradiations is studied in the aqueous solution system in this paper.Carboxymethyl-chitosan(CMC) is prepared using chloroacetic acid as modifier, the sodium hydroxide as basificationer and the ethanol as separating agent under microwave irradiations. The effects of reaction conditions, such as the amounts of alkali and chloroacetic acid, reaction tempreture and the microwave heating time Influencing the yield, degree of substitution and viscosity were respectively investigated, and we got the best of conditions of preparing N, O-CMC by single factors and tests that were handed in. The optimum reaction condition are as follows: chitosan 1 g; NaOH 3g; chloroacetic acid 5g; reaction tempreture 30℃; microwave heating time 27min. The degree of substitution and yield of Carboxymethyl-chitosan can reach to 1.23 and 84.5%. The N, O-CMC was characterized and analyzed by degree of substitution, viscosity, molecular weight and infrared spectrum, and the tests of N, O-CMC which was used in treatment of wastewater inclding Cd²⁺ proved that N, O-CMC product was a kind of good flocculation.So the N, O-CMC is better useful for practicability.The conventional methods of preparing N, O-CMC were longer reaction time,more preparing processes, and using organic solvents such asisopropyl alcohol and propyl alcohol which made against purification, increasing reclaim equipments. So the cost of N, O-CMC was increasing.Carboxmethylation of chitosan under microwave irradiations include basification, microwave irradiation carboxylic reaction and separating out of production. In comparison with the conventional methods, Carboxmethylation of chitosan under microwave irradiations increased preparing processes, cost, which is a meaning matters of preparing.