Promoting the solar-light-driven mesoporous BaFe12O19/g-C3N4 photocatalysts for photoreduction and removal of Hg(II) ions

In this contribution, synthesis of BaFe12O19/g-C3N4 nanocomposites with mesostructured and large surface area for the first time utilizing both soft and solid templates has been achieved for Hg(II) photoreduction in aqueous solution. XRD results indicated the construction of single-phase BaFe12O19 without impurities phases. BaFe12O19 particles (10 nm) are highly distributed onto g-C3N4 surface. Mesoporous 3% BaFe12O19/g-C3N4 nanocomposite was exhibited a considerable photoreduction rate of Hg(II) about 940 mu molg(-1)h(-1) and similar to 100% removal efficiency during 30 min illumination time compared with the pristine either g-C3N4 (75.20 mu molg(-1)h(-1), 15%) or mesoporous BaFe12O19 (163.88 mu molg(-1)h(-1), 30%). The Hg(II) reduction rate over 3% BaFe12O19/g-C3N4 nanocomposite was enhanced 5.74 and 12.50 fold larger than BaFe12O19 and g-C3N4.The rate constant over 3% BaFe12O19/g-C3N4 nanocomposite was promoted 21 and 9.5 fold larger than g-C3N4 and BaFe12O19. The enhancement photoreduction efficiency of BaFe12O19/g-C3N4 nanocomposites could be referred to, the accessible surface area and the synergistic effect and small particle size, which can expedite photoinduced charge separation and facilitate Hg(II) reduction process. The synthesized photocatalysts are appropriate candidates with narrow bandgap value for visible light photocatalysis reactions owing to the construction of BaFe12O19/g-C3N4 nanocomposites. After the Hg(II) photoreduction reaction, the collection and recycling of photocatalyst could be readily completed.

Automated summary

BaFe12O19/g-C3N4 nanocomposites with mesostructured and large surface area were synthesized for Hg(II) photoreduction in aqueous solution using both soft and solid templates. The nanocomposites exhibited high photoreduction rate and removal efficiency, as well as enhanced reduction rate and rate constant compared to BaFe12O19 and g-C3N4. This improvement in efficiency is attributed to the accessible surface area, synergistic effect, and small particle size of the nanocomposites.