Construction of BiOClxI1-x solid solutions and novel 2D/2D Z-scheme g-C3N4/BiOCl0.7I0.3 heterojunctions for visible-light driven photocatalytic removal of ammonium dinitramide

The eco-friendly and cost-effective visible-light driven photocatalytic technology is a promising strategy for achieving sustainable remediation of explosive wastewater pollution. Ammonium dinitramide (ADN), as a high-energy oxidant in explosives, few studies on its photocatalytic removal have been reported. Thus, this study focuses on photocatalytic remediation of ADN from water over two-dimensional (2D) BiOClxI1-x solid solutions and 2D/2D Z-scheme g-C3N4/BiOCl0.7I0.3 (CN/BCI) heterojunctions. First, BiOClxI1-x solid solutions were constructed through a hydrothermal process. Because of the formation of thinner 2D nanosheets and the increase of specific surface area, the degradation rate of ADN over BiOCl0.7I0.3 is higher than those over other monomers after visible-light illumination for 60 min. In order to further enhance the photocatalytic performance, 2D/2D CN/BCI composite nanosheets were further synthesized by an in-situ hydrothermal method. It suggests that the degradation rate can reach 99.9 % with CN mass ratio of 30 %, due to the formation of a large number of tight contact interfaces in Z-scheme 30CN/BCI heterojunction, which not only further increases the specific surface area, but also promotes the transfer of charge carriers at the interfaces. In addition, the capture experiments indicate that center dot O-2(-), e(-) and h(+) are the key active species. This study is expected to provide a new perspective for efficient photocatalytic remediation of ADN-based explosive wastewater.