Ultrasonic-assisted synthesis of mesoporous g-C3N4/Na-bentonite composites and its application for efficient photocatalytic simultaneous removal of Cr(VI) and RhB.

Graphitic carbon nitride (g-C 3 N 4) is a new type of nonmetal polymeric semiconductor photocatalyst for removal of pollutants. To overcome the low BET surface and the low electron–hole recombination rate of the g-C 3 N 4 photocatalysts, we successfully synthesized g-C 3 N 4 /Na-bentonite composites using an ultrasonic-assisted method. The XRD showed that the composite was composed of g-C 3 N 4 and Na-bentonite. The analyses of TEM and XPS indicated that graphite carbon nitride was successfully intercalated on Na-bentonite via the ultrasonic-assisted strategy, and the g-C 3 N 4 /Na-bentonite nanocomposites presented remarkable light absorption capacities and mesoporous structure observed by UV–vis DRS and BET method. In addition, the as-prepared composites can be used for the photocatalytic removal of single RhB or Cr(VI), and the efficiencies of the Cr(VI) reduction are increased from 53.2% to 88.6% in RhB/Cr(VI) mix-system. Superior stability and high efficiencies of g-C 3 N 4 /Na-bentonite composites were also exhibited for up to 4 cycles. The photocatalytic enhancement was due to the strong adsorption and the higher charge separation efficiency of as-prepared g-C 3 N 4 /Na-bentonite composites. [ABSTRACT FROM AUTHOR]