Nonlinear dependence (on ionic strength, pH) of surface charge density and zeta potential in microchannel electrokinetic flow
Daming Chen,
Nicolas Arancibia-Miranda,
Mauricio Escudey,
Jiao Fu,
Qin Lu,
Cristina H. Amon,
Daniela Galatro,
Amador M. Guzmán
Affiliations
Daming Chen
Facultad de Ingeniería, Departamento de Ingeniería Mecánica, Universidad de Santiago de Chile, Av. B. O'Higgins 3363, 9170020, Santiago, Chile; Corresponding author. Facultad de Ingeniería, Departamento de Ingeniería Mecánica, Universidad de Santiago de Chile, Av. B. O'Higgins 3363, 9170020, Santiago, Chile.
Nicolas Arancibia-Miranda
Center for the Development of Nanoscience and Nanotechnology, CEDENNA, 9170124 Santiago, Chile; Facultad de Química y Biología, Universidad de Santiago de Chile, Av. B. O'Higgins, 3363 Santiago, Chile
Mauricio Escudey
Center for the Development of Nanoscience and Nanotechnology, CEDENNA, 9170124 Santiago, Chile; Facultad de Química y Biología, Universidad de Santiago de Chile, Av. B. O'Higgins, 3363 Santiago, Chile
Jiao Fu
Xi'an key laboratory of advanced control and intelligent process, Xi'an University of Posts and Telecommunications, Xi'an, 710121, China; Corresponding author. Xi'an key laboratory of advanced control and intelligent process, Xi'an University of Posts and Telecommunications, Xi'an, 710121, China.
Qin Lu
Xi'an key laboratory of advanced control and intelligent process, Xi'an University of Posts and Telecommunications, Xi'an, 710121, China
Cristina H. Amon
Department of Mechanical and Industrial Engineering, Faculty of Applied Science and Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, Faculty of Applied Science and Engineering, University of Toronto, 200 College Street, Toronto, Ontario, Canada
Daniela Galatro
Department of Chemical Engineering and Applied Chemistry, Faculty of Applied Science and Engineering, University of Toronto, 200 College Street, Toronto, Ontario, Canada
Amador M. Guzmán
Solar and Thermal Energy Conversion and Storage Device and System Laboratory, STECTEC, Santiago, Chile; Department of Mechanical and Industrial Engineering, Faculty of Applied Science and Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada; Corresponding author. Department of Mechanical and Industrial Engineering, Faculty of Applied Science and Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada
In this work, a numerical method is proposed to predict the electrokinetic phenomena and combined with an experimental study of the surface charge density (ρs) and zeta potential (ζ) behavior is investigated for borosilicate immersed in KCl and NaCl electrolytes, and for imogolite immersed in KCl, CaCl2, and MgCl2 electrolytes. Simulations and experiments of the electrokinetic flows with electrolyte solutions were performed to accurately determine the electric double layer (EDL), ζ, and ρs at various electrolyte concentrations and pH. The zeta potential was experimentally determined and numerically predicted by solving the coupled governing equations of mass, species, momentum, and electrical field iteratively. Our numerical prediction shows that ζ for borosilicate develops strong nonlinear behavior with the ion concentration following a power-law. Likewise, the ρs obeys a nonlinear behavior, decreasing as the concentration increases. Moreover, for imogolite, both ζ and the ρs behave nonlinearly with the pH. The EDL for borosilicate and imogolite becomes thinner as the electrolyte concentration and pH increase; this behavior is caused by increased ρs, resulting in the higher attraction of the free charges. The reported nonlinear behavior describes more accurately the interaction of the nanoparticle surface charge with the electrolytes and its effect on the electrolyte transport properties.
