Improvement of Cr (VI) photoreduction under visible-light by g-C3N4 modified by nano-network structured palygorskite

In this paper, we firstly used the inorganic nano-network of palygorskite (IPAL) with multiporous structure fabricated from rigid nano-rods by ion beam bombardment to enhance the photoactivity of the graphitic carbon nitride (CN). Results of spectroscopy techniques show that the as-prepared sample (IPAL/CN) displays broader light absorption in the visible light region and low recombination of charge carriers. Photocatalytic illustrations of Cr (VI) (and methylene blue (MB)) in aqueous solution by IPAL/CN samples were investigated respectively. Results show that the IPAL/CN-1:6 composites exhibit a superior catalytic activity with 99.5% of Cr (VI) and 99.2% of MB removal efficiency in 100 min, which were almost 7.0 times and 9.5 times higher than that of pure CN, respectively. After four cycles, the IPAL/CN-1:6 exhibits great photoactivity. Moreover, the reaction can be conducted better under the low pH value of the solution, and the initial concentration can influence the reaction property. The theory of DLVO and zeta potential were used to analyze the dispersion effect on the samples. The higher photoactivity of the IPAL/CN samples could be attributed not only to the high adsorption capacity but also to the improved dispersion affected by the nano-network of IPAL. This study provides a new opportunity for the modification of photocatalyst by the inorganic nanomaterials formed easily by physical irradiation.