A study of sodium oleate adsorption on Ca2+ activated quartz surface using quartz crystal microbalance with dissipation

作者：Kou, J.^*; Xu, S.; Sun, T.; Sun, C.; Guo, Y.; Wang, C.

来源：International Journal of Mineral Processing, 2016, 154: 24-34.

DOI：10.1016/j.minpro.2016.06.008

• Quartz
• QCM-D
• Sodium oleate
• Adsorption
• Activation

The adsorption kinetics, density and structural property of sodium oleate on Ca2+ activated quartz surface have been studied using the techniques of quartz crystal microbalance with dissipation (QCM-D) and atomic force microscope (AFM). The real-time measurements of frequency (Delta f) and dissipation shifts (Delta D) with SiO2 coated sensor have revealed the changes in surface property of the quartz during the entire activation and adsorption process at different Ca2+ concentrations and pH's. An activation layer with an adsorption density of 89 ng/cm(2) was observed at pH = 12.0. Since pseudo-first-order model fitted well with adsorption process of sodium oleate, the mass transfer (diffusion-controlled) was the rate determining step at pH 12.0. Therefore, the reactions of (RCOO-/RCOO)(2)(2-)) and Ca(OH)+/Ca2+ is considered to be the dominant process in the solution at pH 12.0 which generated (RCOO)(2)Ca precipitation and formed poorly-organized dissipative adsorption layer on activated quartz surface. Two distinct adsorption stages were identified from the different slopes K-2 > K-3 and K-3 <= 0.2 of Delta D-Delta f plots which demonstrated the existence of conformational changes in the adsorption layer.

• 出版日期2016-9-10
• 单位北京科技大学