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

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