The Synthesis And Application Of The Flocculants Of Tannic

It obtains a water treatment flocculation agent in this paper that uses the tannic acid as raw material and makes use of the molecular structure of the phonemic group structure more of its cationic poly-acryl modification. This paper can be divided into three parts:modification of flocculants synthetic experiment, modified tannins and inorganic salt ions blends with experiment and flocculation experiment.In this paper, it obtains amine methylamine tannins by using tannic acid as raw material to modify Xi tannins through formaldehyde, acryl amide reacted to hydrolysis. As the standard by the remaining amount of formaldehyde, do the orthogonal optimization experiments on the reaction of synthesis of the main four factors:the ratio of raw materials, reaction temperature, reaction time and dropping temperature of formaldehyde. Ultimately getting the best reaction conditions are:tannic acid:formaldehyde:acryl amide=1:1:1, the reaction temperature 80℃, reaction time 3h, the best temperature for formaldehyde dropping 50℃. Besides, do the infrared spectra test on tannic acid modified product and obtain the amine methylamine confirmed tannin through infrared spectra picture.Epichlorohydrin is an organic crosslinking agent. It can be quaternizatly reacted to methylated tannin and becomes quaternary ammonium tannin. Because tannin quaternary ammonium cation contains a lot of epichlorohydrin and the Epichlorohydrin cross-link greatly improve the quaternary ammonium molecular weight, make it a natural organic polymer flocculants. As a standard by flocculation of the reaction products through the experiments of COD and turbidity removal efficiency, do orthogonal design experiments on the three affecting the response factors:ratio of raw materials, reaction temperature, and reaction time. Finally, getting the best reaction conditions are:amine methylated tannin:epichlorohydrin-1:1, reaction time 3h, the reaction temperature 90℃. And do the flocculation experiments to the obtained tannin, the dosage 310mg/L, pH=9, room temperature (25℃), flocculation experiments on the small cyanogen wastewater. The results are the maximum removal rate of COD 9.39%, the maximum removal of turbidity 98% or more.Although quaternary ammonium effect of tannic flocculants turbidity removal efficiency is more than 98%, its effect on the COD removal rate is not ideal. Through tannins and quaternary ammonium compound aluminum for experiments, obtain a new type of composite compound flocculants. By research, the best conditions are:quaternary ammonium tannin: aluminum chloride=1:4, reaction temperature 30℃, reaction time 2h. Flocculation of composite flocculants for experiments at room temperature (25℃), pH 8.0, flocculant dosage of 180mg/L, on the small cyanogen wastewater flocculation are follows:COD removal rate is 13.35% and turbidity Removal rate is of 98%.Through tannins on the quaternary ammonium and quaternary ammonium compound flocculants tannin-comparison of aluminum chloride flocculation experiments, find that COD removal rate of composite flocculants significantly more improved. After the coagulant compound is used for wastewater containing heavy metalions, the removal of heavy metal ions removal also reaches good results.