title: Fabrication of photocatalyst based on Eu3+-doped ZnS-SiO2 and sodium alginate core shell nanocomposite.
abstract: This research paper reports the photocatalytic properties of Zn-SiO2-Eu3+ and sodium alginate (Alg) based nanocomposites for the degradation of indigo carmine dye. Initially, Eu3+ doped ZnS-SiO2 nanophorphor was synthesized and after that it was incorporated within the grafted crosslinked polymer matrix of Alg with acrylamide-co-acrylic acid in different concentrations. Synthesized materials were characterized using XRD, Raman spectroscopy, FTIR, SEM/EDX, TEM and UV-vis diffuse reflectance spectroscopy. XRD and TEM analyses confirmed the formation of nanoparticles as well as the uniform distribution of the nanoparticles within the polymer matrix. The UV-vis and UV-vis DRS spectral analysis indicated that Eu3+ doping causes a red-shift in the absorption band, resulting in the reduction in band gaps. The synergic effect of ZnS and Eu3+ in the SiO2 evidenced the photocatalytic performance of the catalyst. Alg-cl-poly(AAM-co-MAA)/ZnS-SiO2-Eu3+ nanocomposites were found to be very effective for the degradation of indigo carmine under visible light. Highest photocatalytic performance (93.4%) was shown by the nanocomposite with the 20% concentration of the nanoparticle after 5h. The photocatalytic activity was mainly attributed to the intense light absorption in the visible region and narrow band gap energy.
authors.affiliation: Department of Applied Chemistry, University of Johannesburg, South Africa.
authors.forename: E S
authors.initials: ES
authors.lastname: Agorku
authors.affiliation: Department of Applied Chemistry, University of Johannesburg, South Africa.
authors.forename: H
authors.initials: H
authors.lastname: Mittal
authors.affiliation: Department of Applied Chemistry, University of Johannesburg, South Africa.
authors.forename: B B
authors.initials: BB
authors.lastname: Mamba
authors.affiliation: Nanotechnology and Application Centre, University of Allahabad, India.
authors.forename: A C
authors.initials: AC
authors.lastname: Pandey
authors.affiliation: Department of Applied Chemistry, University of Johannesburg, South Africa. Electronic address: amishra@uj.ac.za.
authors.forename: A K
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002384:Catalysis; D005063:Europium / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008027:Light; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013440:Sulfides / Q000737:chemistry*; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D013440:Sulfides; D017967:Zinc Compounds; D005063:Europium; D012822:Silicon Dioxide; D020723:Glucuronic Acid; C031238:zinc sulfide
keywords: Crosslinking; Graft copolymerization; Hydrogel; Indigo carmine; Photocatalysis