Adsorption behavior of heptyl xanthate on surface of ZnO and Cu(II) activated ZnO using continuous online in situ ATR-FTIR technology

Abstract

A continuous online in situ attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopic technique was used to investigate the adsorption and desorption kinetics of heptyl xanthate (KHX) on the surface of ZnO and Cu(II) activated ZnO. The results showed that Cu(II) facilitated the xanthate adsorption process on the surface, and led to the formation of cuprous xanthate (CuX), dixanthogen (X2) and xanthate aggregates. The adsorption of xanthate on the surface of ZnO and Cu(II) activated ZnO was found to both follow the pseudo-first-order kinetic model. When the NaOH solution was used as a desorption agent, the adsorbed xanthate can largely be removed due to the competition between OH− and HX−. However, for Cu(II) activated ZnO, the peak intensities at 1197 and 1082 cm−1 had no obvious weakening, and the absorption intensities at 1261 and 1026 cm−1 increased in the first 5 min, indicating an ion-exchange reaction between OH− and surface zinc bonded xanthate HX− and the reorganization of adsorbed xanthate.