Alkaline hydrolysis and flocculation properties of acrylamide-modified cellulose polyelectrolytes

By controlling the saponification hydrolysis of acylamino groups to carboxyl groups in alkaline medium, a series of acrylamide-modified cellulose polyelectrolyte (AMC) samples with various degree of hydrolysis (DH) were successfully obtained. The structure and solution properties of AMC were characterized by using elemental analysis, FT-IR, 13C NMR, viscometer, and zeta potential measurement. The results revealed that DH value of AMC samples could be controlled by adjusting the hydrolysis reaction time. The carboxyl group content and intrinsic viscosity ([η]) value increased with increasing DH value. Moreover, ferric hydroxide (Fe(OH)3) colloid was selected as a model to evaluate the flocculation properties of AMC. The results showed that AMC was an effective flocculant to Fe(OH)3 colloid, and the Fe(OH)3 colloid was almost removed (up to nearly 100%). Therefore, acrylamide-modified celluloses are applicable as novel flocculants with high flocculation efficiency, non-toxicity as well as biodegradability.