Preparation of composite flocculant and experimental study on decolorization of dyeing wastewater

Formaldehyde-dicyandiamide-polyaluminum chloride composite flocculant was prepared by di cyandiamide,formaldehyde,ammonium chloride and aluminum chloride as main raw materials.Effect of cata lyst,reaction time and reaction temperature on the properties of composite flocculant was investigated.Mean while,single factor and orthogonal experiments were conducted to determine the influence parameters and op timal process conditions of composite flocculant on the decolorization of dyeing wastewater.The results showed that the decolorization rate reached 90.36% under the optimum process conditions: solution tempera ture 30 ℃,pH=7 and 80 mg/L of flocculant.