Assessment of Rhodamine B Dye Removal by ZnO Nanodisks under Visible Light

Nanomixture of 0-D ternary metal oxides (TiO2- SnO2-Al2O3) cooperating with 1-D hydroxyapatite (HAp) nanorods for RhB removal from synthetic wastewater and hydrogen evolution via water splitting

This work was carried out to devise a feasible alternative to remove cationic dyes from industrial wastewater. A nanomixture of (TiO₂-SnO₂-Al₂O₃) cooperating with Hydroxyapatite (HAp) nanorods was synthesized in this regard as a catalyst to degrade Rhodamine B (RhB) dye from aqueous medium. The physicochemical properties of the hydrothermally prepared Hydroxyapatite Nano Mixture (HNM) were revealed through XRD, FESEM, TEM, XPS, FTIR, BET-BHJ, UV-Vis, and Raman spectroscopy techniques. The synthesized material which was found to be nanorods of average crystallite size 12.53 nm and BET Specific Surface area 60.81 m² g^-1 proved to be very effective for the removal of RhB at various pH conditions (acid, basic, and neutral). Maximum removal of 97% was achieved within 30 min of UV irradiation using 5 ppm RhB in acidic medium while at a higher concentration (20 ppm), it takes just 90 min to achieve 98% degradation of RhB under the same reaction conditions. A further catalytic potential of the prepared nanomixture for hydrogen (H₂) evolution via water splitting was explored where 129.45 μmol g^-1 of H₂ was evolved within 60 min. Our findings suggest that the prepared nanomixture could be used as an efficient catalyst for removing spent dyes used in industrial processes and also as a catalyst for hydrogen gas production.

UV responsive quercetin derived and functionalized CuO/ZnO nanocomposite in ameliorating photocatalytic degradation of rhodamine B dye and enhanced biocidal activity against selected pathogenic strains

Quercetin was investigated for its role as a reducing agent in biosynthesizing CuO/ZnO nanocomposite, its subsequent surface functionalization and influence in Rhodamine B dye degradation and biocidal activity. The as synthesized quercetin functionalized CuO/ZnO nanocomposite (CuO/ZnO@Q) was analyzed using X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), Transmission electron microscopy (TEM), Energy dispersive spectroscopy (EDS) and Ultraviolet-visible spectroscopy (UV-Vis). XRD showed the formation of crystalline CuO, ZnO phases and FTIR analysis revealed the incorporation of quercetin functional groups in the synthesized nanocomposite. TEM image displayed the formation of quercetin deposited spherical CuO/ZnO nanostructure with the EDAX results confirming the presence of organic carbon composition from quercetin. The UV absorption spectra ascertained the presence and role of quercetin in the enhanced absorption of radiation in the UV range. CuO/ZnO@Q showed improved photocatalysis with complete Rhodamine B dye degradation after 75 min of UV irradiation, as against pure CuO/ZnO, which exhibited incomplete dye degradation even after 90 min of irradiation. Moreover, quercetin surface functionalization effectively ameliorated its antimicrobial activity against E. coli, S. aureus, Shigella, B. subtilis, A. niger and C. albicans, proving its potential in significantly enhancing biocidal activity along with photocatalytic dye degradation in a natural and eco-friendly route.