title: Facile synthesis of reduced graphene oxide-gold nanohybrid for potential use in industrial waste-water treatment.
abstract: Here, we report a facile approach, by the photochemical reduction technique, forin situsynthesis of Au-reduced graphene oxide (Au-RGO) nanohybrids, which demonstrate excellent adsorption capacities and recyclability for a broad range of dyes. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) data confirm the successful synthesis of Au-RGO nanohybrids. The effect of several experimental parameters (temperature and pH) variation can effectively control the dye adsorption capability. Furthermore, kinetic adsorption data reveal that the adsorption process follows a pseudo second-order model. The negative value of Gibbs free energy (ΔG0) confirms spontaneity while the positive enthalpy (ΔH0) indicates the endothermic nature of the adsorption process. Picosecond resolved fluorescence technique unravels the excited state dynamical processes of dye molecules adsorbed on the Au-RGO surface. Time resolved fluorescence quenching of Rh123 after adsorption on Au-RGO nanohybrids indicates efficient energy transfer from Rh123 to Au nanoparticles. A prototype device has been fabricated using Au-RGO nanohybrids on a syringe filter (pore size: 0.220 μm) and the experimental data indicate efficient removal of dyes from waste water with high recyclability. The application of this nanohybrid may lead to the development of an efficient reusable adsorbent in portable water purification.
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences , Kolkata , India.
authors.forename: Prasenjit
authors.initials: P
authors.lastname: Kar
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences , Kolkata , India.
authors.forename: Samim
authors.initials: S
authors.lastname: Sardar
authors.affiliation: Institute for Condensed Matter Physics, TU Braunschweig , Braunschweig , Germany.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Advanced Mechanical and Material Characterization Div., CSIR-Central Glass & Ceramics Research Institute , Kolkata , India.
authors.forename: Monjoy
authors.initials: M
authors.lastname: Sreemany
authors.affiliation: Institute for Condensed Matter Physics, TU Braunschweig, Braunschweig, Germany; Laboratory for Emerging Nanometrology, TU Braunschweig, Braunschweig, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Lemmens
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences , Kolkata , India.
authors.forename: Srabanti
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences , Kolkata , India.
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Pal
keywords: 10. Engineering and structural materials; 104 Carbon and related materials; 212 Surface and interfaces; 503 TEM, STEM, SEM; 505 Optical/Molecular spectroscopy; Au-RGO nanohybrid; Graphene oxide; NSET; Rhodamine 123; surface adsorption