Synthesis of quaternary ammonium salt of hyperbranched polyester and its application in dyeing wastewater treatment

A novel unique macromolecule, quaternary ammonium salt of hyperbranched polyester (H20-EPTAC) was prepared by the reaction of hyperbranched polyester Boltom H20 with 2, 3-epoxypropyltrimethylammonium chloride (EPTAC) using sodium hydroxide as an alkaline catalyst in DMF. A series of products were obtained by varying the molar ratio of H20 to EPTAC. The flocculation properties of H20-EPTAC for dyeing wastewater were studied. The influences of the dosage of H20-EPTAC, pH and initial concentration of dye on the efficiency of dye removal were discussed. The dye removal efficiency of Acid Rubine APP, Direct Blue 4GL and Acid Black BR reached 93%, 90% and 97%, respectively. The optimum dosage was different for different types of dyes. The dye removal efficiency increased with increasing molar ratio of EPTAC. These results indicated that H20-EPTAC had a good potential for treating dyeing wastewater. The flocculation mechanism may be due to the theory of charge neutralization and molecular trestle bridge.