Carboxymethyl cellulose binding to mineral substrates: Characterization by atomic force microscopy–based Force spectroscopy and quartz-crystal microbalance with dissipation monitoring

• Published in: Journal of colloid and interface science 2013-07, Vol.402, p.58-67
• Main Authors: Pensini, Erica, Yip, Christopher M., O’Carroll, Denis, Sleep, Brent E.
• Format: Article
• Language: English
• Subjects: aqueous solutions; Atomic force microscopy–based force spectroscopy; Attachment; calcium chloride; Carboxymethyl-cellulose; carboxymethylcellulose; Chemistry; Colloidal state and disperse state; dispersions; Exact sciences and technology; General and physical chemistry; ionic strength; Iron oxides; monitoring; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Quartz-crystal microbalance with dissipation monitoring; salt concentration; Silicates; sodium; solubility; spectroscopy; Surface physical chemistry; van der Waals forces
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2013.03.053

[Display omitted] •CMC attachment onto silica was negligible in water at pH 4, 5.5, and 8 and in 100mM NaCl at pH 5.5.•CMC did not attach onto silicates in water at pH 4, 5.5, and 8 and in 100mM NaCl at pH 5.5.•CMC could weakly attach onto silica and silicates in 100mM CaCl2.•Attachment of CMC onto iron oxides was significant in water at pH 4 and 5.5, but not at pH 8.•CMC attachment on iron oxides was promoted by NaCl and CaCl2, with CaCl2 having the greatest effect. The attachment of the sodium salt of carboxymethyl cellulose (CMC) onto iron oxide and various silicate substrates in aqueous solution as a function of salt concentration and pH was studied by atomic force microscopy–based force spectroscopy (AFM) and quartz-crystal microbalance with dissipation monitoring (QCM-D). Both ionic strength and cation valency were found to influence substrate binding. Notably, QCM-D experiments strongly suggested that the solubility of CMC is directly impacted by the presence of CaCl2. Such data are critical for the design of new molecules for stabilizing mineral floc dispersions and for assessing the mobility of CMC-coated particles in the subsurface. Modeling of AFM data with an extended Ohshima theory showed that van der Waals and steric forces played a major role in the interactions between CMC and mineral substrates, and that hydration forces were also important.