Montmorillonite-based photoresponsive microcapsules for efficient removal of chromium

Pickering emulsion method is used to construct photo-responsive metal-free microcapsules comprising graphitic carbon nitride (g-C 3 N 4 ) nanosheets dispersed in montmorillonite (Mt) colloidosomes. Morphology characterization revealed a spherical-shaped microcapsule with diameter ranges from 5 to 50 µm. Cr (VI) was employed as a target contaminant to evaluate the photocatalytic performance of the microcapsules. Batch investigation showed pH 3 to be the optimal condition with a complete Cr (VI) removal. XPS analysis proved that the as-prepared microcapsule is able to reduce Cr (VI) to Cr (III).