The Synthesis Of Cationic Starch Modified Dicyandiamide-formaldehyde Flocculant And Its Application

The research, manufacture and application of high polymeric flocculants has made great development in the past decades. Among many kinds of these products, starch-modified cationic flocculant shows many advantages such as: low-priced, nontoxic, concentrated and biodegradable. In recent years. , much attention had been made to this kind of flocculant. In this thesis, cationic starch modified dicyandiamide-formaldehyde resin decolour flocculent agents are synthesized using starch, epichlorohydrin, trimethylammonium chloride, dicyandiamide and formaldehyde as the main materials and aluminum sulfate as catalyst. In addition, additive is applied to further improve the capability of the procucts. The products received high appraisals of the domestic interrelated factory and customer. The research details are listed as below: Firstly, the most efficient synthesis process for 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTMA) is investigated. The product can be used to prepare cationic starch directly; the results showed that the cationic starch showed excellent CODCr removal efficiency and decolorize efficiency for the treatment of reactive dye printing wastewater. Secondly, the products of dicyandiamide-formaldehyde resin decolour flocculent agent are synthesized by dicyandiamide and formaldehyde, using aluminum sulfate as catalyst. The additive is applied to implove the performance of product. The effect of formaldehyde, catalyst and addctives amount, reaction temperature on the property of the product was investigated. The optimized synthesis conditions were obtained. Finally, the products of cationic starch modified dicyandiamideform-aldehyde resin decolour flocculent agent are synthesized by dicyandiamide, cationic starch and formaldehyde, using aluminum sulfate as catalyst. The synthesis conditions have been optimized. It showed that the best results is as following: the removal efficiency of chemical oxygen demand (COD) is ≥91%, the decolorize efficiency is ≥99%. The results proved that this kind of flocculating agent is superior to others in sludge treatment, suspending agent, CODCr and color reducing.