Poly(triazine imide) synthesized by the molten salt route with incorporation of Li+ and Cl- ions (PTI/Li+Cl-) was prepared by rational controlling of the washing extent. The surface transformation of the phase-pure PTI framework incurred by thorough washing has been confirmed by a systematic analysis based on x-ray diffraction, Ultraviolet Raman, atomic force microscope, and x-ray photoelectron spectroscopy measurements. Uranyl ion adsorption experiments further support the surface structural transformation from triazine-unit PTI to heptazine-based graphitic carbon nitride. Efforts on the expl...