Abstract:
Application of cassava starch graft poly (acrylic acid) and poly [(acrylic acid)-co-acrylamind] for wastewater from textile industry was studied. The two polymers were complexed with aluminium sulfate, calcium hydroxide, and ferric sulfate to give 6 types of complex compound. These complex compounds were used for treating the direct dye synthetic wastewater and textile industry wastewater which were compared with aluminium sulfate, calcium hydroxide, and ferric sulfate. The results were found as follows. The complexes of poly [(acrylic acid)-co-acrylamide] with aluminium sulfate, calcium hydroxide, and ferric sulfate have the water absorption in the range from 0.4 ± 0.1 to 8.4 ± 2.2 g/g. The complexes of cassava starch graft poly (acrylic acid) with aluminium sulfate, calcium hydroxide, and ferric sulfate have the water absorption in the range from 1.2 ± 0.7 to 6.8 ± 0.5 g/g as a result of chemical bonding between the cation with the carboxylate or amide group. When they were used for the synthetic wastewater treatment in which only one blue-shade direct dye with a color concentration of 50 mg/l at pH 7 was prepared. We found that the complex of poly [(acrylic acid)-co¬-acrylamind] with calcium hydroxide at a ratio of 1:2 is the most effective condition for wastewater treatment. The polymer complex concentration of 500 mg/l could reduce the color concentration by 88%, and the COD by 55% with the pH after treatment of 12. However, when it was used for the textile industry wastewater treatment, at the same condition, it could only reduce the COD by 4.2%. Because the textile wastewater contained three types of direct dye in the presence of sodium chloride as a dyeing aid, which reduced the complex efficiency in removing color and reducing COD