Synergy of adsorption and photocatalysis on removal of high-concentration dye by Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O nanocomposite using Bi12O17Cl2 as bismuth source

摘要： Novel basic bismuth nitrite nanocomposite-Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O has been applied to remove high-concentration methyl orange (MO). The nanocomposite was prepared by a two-step method with Bi12O17Cl2 as bismuth source. XRD, TEM, HRTEM and IR analyses were performed to clarify the composition and microstructure. TEM and HRTEM images reveal that the nanocomposite is consisted of plate-stacking Bi6O4(OH)4(NO3)6·H2O ultrathin nanosheets, where monodispersed AgCl (3-7 nm) and Ag (10-120 nm) nanoparticles are uniformly distributed. Influences of contact time, MO concentration and solution pH on adsorption capacity have been studied. Adsorption capacity is 349 mg g-1 at natural state, 740 mg g-1 at pH=3, and 141 mg g-1 at pH=9. Visible-light photocatalytic performance was evaluated by degradating high-concentration MO of 500 mg L-1 at natural state, 1500 mg L-1 at acidic condition, and 300 mg L-1 at the alkaline condition. Combining with distinct composition and structure of the nanocomposite, removal mechanism is proposed based on the synergy of adsorption and photocatalysis.