Determination of partially hydrolyzed polyacrylamide in wastewater produced from polymer flooding by colloid titration

Colloid titration has been widely used to determine the charge carried by macromolecules and the concentration of anionic and cationic polyelectrolytes in paper making and food service industries. This method is simple and the materials used are non-volatile and harmless, but it has not previously been used to determine the partially hydrolyzed polyacrylamide (HPAM) in wastewater produced from polymer flooding. In this paper, colloid titration was used to determine the HPAM in wastewater produced from polymer flooding in an oilfield. When the HPAM concentration (Cp) was <200 mg/l, the relationship between the Cp and the titration value (Vp) was linear. This linear relationship was influenced by the pH of wastewater and the hydrolysis degree of HPAM; Vp increased with the pH and the hydrolysis degree. However, it was independent of the concentration of solubilized crude oil and salt concentration in the wastewater and the molecular weight of the HPAM. Recovery tests showed that the determination of HPAM in the wastewater by colloid titration was reliable. It was also found that the colloid titration and starch iodide method had similar accuracies for determination of the HPAM and that colloid titration was a better method for the analyst.