Effect of Time of Deacetylation on Molecular Weight Distribution,Acetyl Content,Viscosity,and Performance of Chitosan as a Conditioning Agent for Activated Sludge,

摘要

Analysis of chitosan products differing only in time of deacetylation showed that ash and moisture contents ranged from 0.05to 0.2and 5.6to 10.0,respectively. Degree of deacetylation decreased sharply in the first 30minutes from 14% to 67%,then slowly decreased to 79% in 5hours. Viscosity also decreased sharply in the first one hour,then in the next 2to 5hours slowly decreased to about 200cps at 10 g/l in 2% acetic acid solution. The effectiveness of the different chitosan products as coagulants in dewatering activated sludge grown on vegetable processing wastes was highest for the sample deacetylated for 2hours. This product was more effective than those deacetylated for shorter or longer times than two hours. Correlation of effectiveness vs. viscosity or molecular weights of products was attempted for products deacetylated for 0.5, 1,and 2hours. Molecular weight distribution data showed better correlation with effectiveness as a waste treatment agent than did viscosity data.