STUDY ON ELECTROKINETIC PARAMETERS OF COMPOSITE COAGULANTS-FLOCCULANTS

Abstract

In this work the electrokinetic parameters of composite coagulants-flocculants based on combination of polyaluminum chloride (aluminum oxychloride) and organic polymers were studied systematically. The experimental results, obtained by the streaming current and electrophoresis methods, witness that the combination of polyaluminum chloride and cationic organic polymer can effectively enhance the charge neutrality capacity. The results obtained directly indicate that after the combination of polyaluminum chloride and cationic organic polymer, the positive charge of suspended particles obviously enhances, and the ability of double electrical layer on solid surface with negative charge improves. The most important factor is that the charge neutrality capacity of composite coagulant is stronger, thus, in comparison with polyaluminum chloride efficiency, the efficiency of composite reagent is higher. Moreover, due to the existence of long molecular chain, adding cationic organic polymer into polyaluminum chloride can enhance the bridging coagulation between its particulate matters. The experimental results indicate that if to combine polyaluminum chloride with natural cationic organic polymer - chitin and industrial cationic organic polymer product C109P, its electric charge can be largely enhanced This fact undoubtedly deserves attention when developing compositions of coagulants-flocculants to improve their ability to charge neutrality in the processes of coagulation and agglomeration of suspended particles. When executing experiment on the use of anionic organic polymers, the regulation of the coagulation-flocculation theory that the main function of an anionic organic polymer in a composite reagent is the function of a bridge between solid particles was taken as a basis. At the same time, an effective influence on this property of the system can hardly lead to a decrease in the ability to neutralize the charge of polyaluminium chloride. Experimental data relating to the study of the composition reagent containing polyaluminium chloride and industrial anionic organic polymer products AH200P and AN910SH, confirm the fact that this combination does not reduce the ability to neutralize the charge.