The Research Of The Modified Chitosan Preparing Craft And Its Flocculant Qualities

Chitosan is one of the natural polysaccharide flocculants. Advantages of Chitosan, such as harmless, living compatibilities and multi-function, made it promising in application. Therefore, research works carried out on chitosan have become popular recently. This paper develops a new method of the preparation of chitosan in which deacetylation of chitin under immersed-static conditions is evaluated and the produce-craft of Chitosan is modified as well. This paper also strengthens its stability of measured value by improving the measurement of chitosan mass-weight. Further more, research on how different factors influenced the flocculant capabilities of chitosan will be provided.The key findings of this paper include:①Deacetylation of chitin under immersed-static conditions (solids/solvent ratio (v/v)=l:l;no agitating;with70%NaOH;118℃ for 4h) is evaluated for the preparation of chitosan. The results indicate that this approach can reduce the dosage of the exhausted alkaline approximately 70%. Treated chitosan shows similar degree of deacetylation (78 ±3%), but significantly higher molecular mass (6x105) compared with those of the commercial chitosan. Comparing with the traditional craft, this method does not need the machine agitation, reduces the production cost and has a better social performance.②This research discovers that different mass weights are acquired from differentoriginal density of chitosan solution. However, within the range of 0.05g/50mL-　0.2g/50mL, the result measured of molecular weight is stable. Aqua density is over low if it is lower than 0.05g/50mL, and the line behavior is not good. If it is higherthan 0.2g/50mL, the trend of descent is too sharp to measure the molecular weight.③Serious pollution comes with the production of chitosan normally and the current pollution — treatment methods are not perfect. This paper provides a superior method to treat the wastewater. It costs very little to acquire the protein and calcium hydroxide, and at the same time the wastewater exhausted can be reused in craft-wash after beingtreated.④In this paper, the phenomenon of flocculating kaolinite aqua is tested. The result indicates that the higher the D.D and mass weight are, the higher the removing rate will be. In particular, when the D.D exceeds 75%, the removing result is not increasing obviously and on the other hand with the increase of D.D, the cost of preparing is higher. So the expected D.D is 75%. The influence of D.D to flocculation is more important than it is of the mass weight. Moreover, treating the Cu2+ wastewater with chitosan also acquires a good result.