Abstract: Pure phase g-C3N4 was synthesized by thermal polymerization， and Mo/g-C3N4 two-dimensional nanosheets were prepared by ball milling combined with air oxidation etching by use of X-ray diffractometer（XRD）， scanning electron microscope（SEM）， X-ray diffraction spectroscopy（EDS）， Fourier transform infrared spectroscopy（FTIR）， UV-visible absorption spectroscopy（UV-Vis）and photoluminescence spectroscopy（PL） to characterize Mo/g-C3N4 two-dimensional nanosheets. The results show that Mo ions are successfully doped into the two-dimensional g-C3N4 nanosheet lattice， which broaden spectral response range and improve quantum transmission efficiency. The photocatalytic degradation activity of two-dimensional Mo/g-C3N4 nanosheets was explored by simulating the ore dressing wastewater with isobutyl sodium xanthate solution. The results showed that the degradation rate of isobutyl sodium xanthate was 90.12% by Mo/g-C3N4 nanosheets under the conditions of pH=7， initial concentration of xanthate 50 mg/L and degradation time of 6 h，by five times circulation，the degradation rate can also up to 81.2%.The photocatalysis stability of Mo/g-C3N4 is well.

Key words: Carbon nitride, Molybdenum ion doping, Isobutyl sodium xanthate, Photocatalysis, Beneficiation wastewater