Fundamental Study on Polymer Flocculation Behavior in Saline Solutions

  • Author / Creator
    Wang, Shanshan
  • In this work, the influence of solution salinity on settling performance of both commercial polymeric flocculant Magnafloc 1011(MF) and synthesized polymer flocculant Chitosan-graft-Polyacrylamide (chi-g-PAM) was systematically investigated. The effect of MgCl2 on the settling performance of MF was carried out on a model clay (i.e. kaolinite). High concentration of Mg2+ was found to increase the initial settling rate (ISR) and decrease the supernatant turbidity. Surface forces apparatus (SFA) and quartz crystal microbalance with dissipation (QCM-D) were applied to investigate the molecular and surface interactions of kaolinite particles and polymer, which suggested that the better settling behaviors in MgCl2 solutions as compared to that in Milli-Q water was mainly due to the different polymer-particle interactions and polymer conformations. Chitosan-grafted-Polyacrylamide (chi-g-PAM) was successfully synthesized and characterized. For the flocculation of chi-g-PAM on kaolinite suspensions, high concentrations of NaCl and CaCl2 reduce the ISR but lead to clear supernatant as compared to that in Milli-Q water. The complementary measurements by zeta potential analyzer, QCM-D, SFA and atomic force microscopy (AFM) demonstrate that high solution salinity conditions can affect the surface charge property of kaolinite particles and polymer configuration, therefore weaken the polymer-particle interaction and polymer adsorption, resulting in poor chi-g-PAM flocculation performance.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.