Adsorption Structure and Mechanism of Styryl Phosphoric Acid at the Rutile–Water Interface

Wei Xiao,Wenqing Qin,Fen Jiao,Guanzhou Qiu,Hongbo Zhao,Jun Wang

doi:10.3390/min8080360

Abstract

The microstructure and mechanism of styryl phosphoric acid (SPA) adsorbed at the rutile–water interface were investigated through zeta potential measurement, ultraviolet-visible spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results of the zeta potential measurement illustrate that SPA is mainly electrostatically adsorbed on the rutile surface, and the adsorption process and result can be well fitted by the Stern-Grahame equation. The adsorption is severely affected by pH due to different species of SPA occurring in different pH solutions. The compound of P–O–Ti, with a structure of bidentate binuclear or bidentate mononuclear complexes, is formed after SPA is adsorbed on the rutile surface. SPA can be adsorbed on the rutile surface through the coordination of self-polymerization and bidentate mononuclear, which greatly increases the hydrophobicity of the rutile surface. Based on the above analysis and discussion, we proposed the adsorption model of SPA at the rutile–water interface, which was conducive to the modification and synthesis of a highly efficient flotation collector of the primary rutile ore.

Highlights

The titanium industry has become more and more important and popular due to its extensive applications in medicine, navigation, aerospace, functional materials, and catalytic industries [1,2,3,4,5,6]
The isoelectric point (IEP) of the TiO2 sample occurred at pH 4.5 where the net surface charge was zero, which is very consistent with the previously reported data [40]
The results of the zeta potential measurement indicate that styryl phosphoric acid (SPA) is adsorbed on the TiO2 surface in the form of negatively charged inner-sphere complexes

Summary

Introduction

The titanium industry has become more and more important and popular due to its extensive applications in medicine, navigation, aerospace, functional materials, and catalytic industries [1,2,3,4,5,6]. In the contemporary industrial system, titanium metallurgy sponge and titanium metal use rutile (TiO2 ) and ilmenite (FeTiO3 ) as raw materials. The titanium in rutile is relatively easy to utilize, with a natural advantage in quality. Many studies have begun to focus on rutile beneficiation [7,8,9,10]. The majority of rutile ores are refractory ores, the concentration of which is very difficult to gauge due to the fine grain sizes associated with the gangues, the complexity of the mineralogy, and the brittleness leading to it being over-ground [11]. The concentration of rutile ores is obtained by combining gravity, magnetic, and electrostatic separation techniques, flotation is one of the most efficient solutions to the issue [8]

Methods

Results

Discussion

Conclusion