Study On The Decolorization Of Dyeing Wastewater By Chemical Modification Of Chitosan

Research of new type of coagulants are becoming the hotspot in the field of environment due to the deepening of industry. Using the proper coagulant can bring both economic and environmental interest.In this paper, a new kind of highly efficient decolouriser was synthesized with chitosan- dicyandiamine as main raw material to treat the dye wastewater: decolouriser (Ⅰ) and decolouriser (Ⅱ). The decolorization rates of the 4 typical types of dye-stuff (500 mg/L)under the tests were all over 90%. The results of experiment showed that under the conditions of the reaction temperature is 50℃, chitosan / dicyandiamine (mol ratio)=1: 2, pH=2, reaction time is 3 hour, the decolorization rates of decolouriser (Ⅰ) is best; and under the conditions of the reaction temperature is 50℃, chitosan / dicyandiamine /aluminum sulfate(mol ratio)=1: 4: 1.5, reaction time is 2.5 hour, the decolorization rates of decolouriser (Ⅱ) is best.A study on the treatment of waste water in Shang Yu Waste Water Plant by inorganic decolouriser is presented. Such aspects as trace experiment, the amount of inorganic coagulants, pH value and recombination of coagulants were considered. It's found that the remove COD rate was advanced 20%.This study forms the basis for exploring the new type of decolouriser.