Degradation of Cationic Polyacrylamide Flocculants upon Contact with Metal Surfaces During Rheological Measurements

This research shows that cationic polyacrylamide (CPAM) flocculants, widely used in wastewater treatment, are susceptible to degradation when in contact with various metallic surfaces. This is evidenced by the investigation of the evolution of CPAM’s rheological properties during degradation within metallic Couette tools, observing a transition from elastic to viscous behavior. The degradation is clearly evident on various metallic surfaces, while thermoplastic surfaces have significantly less effect on CPAM degradation. Key findings indicate that chemical interactions, rather than mechanical stress, are the primary cause of degradation, and this reaction is activated by temperature. Techniques such as Fourier Transform Infrared spectroscopy, Nuclear Magnetic Resonance analysis, and polyelectrolyte titration provided some initial understanding of this mechanism. This research offers valuable insights into CPAM’s interactions with metal surfaces, with important implications for environmental and industrial applications, and establishes the appropriate protocol for characterizing the intrinsic rheological properties of these materials.