Preparation Of The Natural Modified Tannin Mannich Flocculant

The alkylated Tannin Mannich polymer is a new type of natural modified flocculant. Tannins are plant extracts that are easy to get, cheap, nontoxic and degradable, which are subdivided into two types, hydrolyzable and condensed, based on their structure. Condensed tannin extracts are often used for their higher average molecular weight. Tannins undergo Mannich aminomethylation by reaction with an aldehyde and an amine. The resulting "tannin Mannich" polymer possesses a much higher molecular weight due to formaldehyde and Mannich base crosslinking, and also possesses ampholytic character due to the presence of both cationic amines and anionic phenols on the polymers. Two series of Tannin Mannich polymers are prepared from arbutus Tannin, aldehydes and amines respectively in this dissertation .Preparation of The Natural modified Tannin Mannich flocculant named ZM-A and ZM-B.By mannich reaction, a sort of natural modified cationic flocculant (ZM series) is attained. First an aldehyde and an amine are mixed for an hour, then arbutus Tannin and soft water are heated to be dissolved with stirring in glass round bottom flask. While stirring, the mixture of aldehyde and amine are added. The reaction temperature is maintained 80℃ for certain time. Finally the reaction material is quenched by the addition of cooling water.ZM-A's best proportion is that Tannin : amine :aldehyde =1:4:3.5, the reaction pH =6.5, Tannin : soft water =1:1, the best reaction temperature is 80℃, reaction time is 4h. ZM-B's best proportion is that Tannin : amine :aldehyde =1:3:3, the reaction pH =6.5, Tannin : soft water =1:1, the best reaction temperature is 80℃, reaction time is 6h.The gem's stability are tested, the mixture can be active half an year. The transmittance of the treated activated sluge water reach 100% and COD is reduced to 170mg/l. Also its treatment effect is compared with aluminum sulfate's and ferric chloride's.The natural modified cationic flocculants (JK-A and JK-B)By quaterisation, two sorts of natural modified cationic flocculants (JK-A and JK-B) were attained. JK-A's best dosage is 2.5ml/L,The transmittance of the treated activated sluge water reached 95%,COD was reduced to 224mg/L. JK-B's best dosage is 4.0ml/L,The transmittance of the treated activated sluge water reached 87% ,COD is reduced to 321mg/L .Also theirs treatment effects are compared .By testing infrared spectrums the flocculanting mechanisms are discussed.Finally we analyze the economic benefit and social benefit of the natural modified flocculants.