Visible light responsive heterostructure HTDMA-BiPO4 modified clays for effective diclofenac sodium oxidation: Role of interface interactions and basal spacing

In the present study, we investigated comparatively role of hexadecyltrimethylammonium bromide (HDTMA) in enhancing adsorption and photocatalytic activity BiPO4 coated montmorillonite (M-BiPO4), smectite (S-BiPO4). Montmorillonite has large interlayer spacing compared to smectite. Firstly, it was found that simple hybridization with clays led enhance visible light response. The co-fixation HDTMA on clay supports reduces BET specific surface area, but enhances significantly ability. XPS analysis shows a notable Bi4f high resolution peak shifting case HDTMA-S-BiPO4, while such not observed terms HDTMA-M-BiPO4. Regarding tests, at lower concentration diclofenac (20 ppm), M-BiPO4 several times more effective than S-BiPO4. However, coating by showed different manner, wherein HDTMA-S-BiPO4 achieved an oxidation rate around 88% under solar within 90 min 140 ppm diclofenac. On contrary, HDTMA-M-BiPO4 only 22% same conditions. It deduced strong interactions between can form interfacial bridge which boosts response separation photogenerated charges.