A method for measuring the degree of anionicity of polyacrylamide-based flocculants

A simple procedure was described for routine measurements of the degree of anionicity of polyacrylamide-based flocculants. The method relies on determining the total organic carbon content and assaying ion concentrations in a dilute solution (in distilled water at natural pH) of the tested flocculant. While the total carbon content in solution gives the total number of acrylic and acrylamide units in the polymer, the concentration of the counter-cation provides a measure of the number of acrylic units only. Thus a degree of anionicity can also be obtained from a simple equation. Five commercial flocculant samples of similar molecular weights but of different degrees of anionicity were then used for evaluating the proposed procedure, and the obtained degrees of anionicity were in excellent agreement with the data provided by the manufacturer of the flocculants. Potential advantages and limitations of the method were also discussed.