Cationic cellulose betainate for wastewater treatment

High molecular-weight, cationic and water-soluble cellulose-based polyelectrolytes were synthesized and their performance in water purification was tested. Dissolving pulp samples were acylated with chlorobetainyl chloride in dimethylacetamide/lithium chloride to obtain betaine esters of cellulose (cellulose betainates). A series of application tests was carried out with samples of different degree of substitution to examine the performance of these cellulose derivatives as flocculants. Commercial synthetic polyacrylamide and polyamine flocculants were used as reference materials to obtain a realistic picture about the performance of cellulose betainates. According to the fixing test, one of the derivatives exhibited a performance equal to, or better than the reference flocculant. In addition, the cellulose betainates exhibited excellent floc strength in the flocculation testing. In the capillary suction test, the performance of the derivatives was also relatively good. In all, this research demonstrated that the cationic cellulose betainate can be successfully used in flocculation and other water purification applications. The current approach for wastewater treatment with bio-based polymers offers a sustainable and biodegradable alternative to conventional synthetic polymers.