Layered Double Hydroxide-Bismuth Molybdate Hybrids toward Water Remediation via Selective Adsorption of Anionic Species

The steady release of anthropogenic toxins into the biosphere is compromising water security globally. Herein, CoAl layered double hydroxide, a claylike layered material with a cationic surface charge, was organically modified and used to template the growth of Bi2MoO6. The resulting nanohybrid selectively removed the anionic dye methyl orange from aqueous solution and showed an enhancement of greater than 300% in the maximum adsorptivity (1.95 mmol/g) compared to modified CoAl layered double hydroxide (0.42 mmol/g). Interestingly, the observed improvement in adsorption occurs without any significant increase in the surface area of the hybrids. Furthermore, these hybrids exhibit increased broadband visible light absorption, and their photoactivity is slightly improved compared to CoAl layered double hydroxide. This study demonstrates that composites of clay-like materials with Aurivillius oxides are promising sorbent materials for water decontamination and photocatalytic antifouling membranes and shows that the synthetic strategy that was first established with an anionic layered silicate nanoclay can be generalized to other ionic layered materials.

Automated summary

The continuous release of anthropogenic toxins into the environment has become a global threat to water security. In this study, a modified claylike layered material called CoAl layered double hydroxide was used as a template to synthesize Bi2MoO6 nanohybrids, which exhibited significantly enhanced adsorption capacity and broadband visible light absorption compared to the modified CoAl layered double hydroxide. These nanohybrids hold great promise for water decontamination and photocatalytic antifouling membranes, and the synthetic strategy can be applied to other ionic layered materials.