5
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Effective Photodegradation of Methyl Orange Using Fluidized Bed Reactor Loaded with Cross-Linked Chitosan Embedded Nano-CdS Photocatalyst

      , , , ,
      International Journal of Chemical Engineering
      Hindawi Limited

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Chitosan-based photocatalyst composites containing CdS nanocrystals with and without glutaraldehyde or epichlorohydrin cross-linking treatments were investigated and the catalyzed photodegradation of methyl orange in aqueous solution was examined. In addition, the effects of catalyst dosage, initial dye concentration, and initial pH of the dye solution on the photodegradation kinetics were investigated. In this study, the effect of initial solution pH was more important than other factors. The photocatalyst composite could remove 99% dye in 80 minutes at pH 4. The catalyst composite was characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared (FT-IR), and visible reflectance spectroscopy. The dye removal mechanism of methyl orange involved an initial sorption process followed by photodegradation. The sorption process underwent the pseudo-second order kinetics, while photodegradation followed the Langmuir-Hinshelwood kinetics. Although the glutaraldehyde cross-linked chitosan enhanced the initial dye sorption, the epichlorohydrin cross-linked catalyst composite demonstrated a better overall dye removal performance, especially in the photodegradation step. Both chitosan encapsulated catalyst with and without epichlorohydrin cross-linking demonstrated the same pseudo-first order photodegradation kinetic constant of 0.026 min −1and the same dye removal capacity. The catalyst composite could be reused but the photocatalytic activity dropped successively in each cycle.

          Related collections

          Most cited references62

          • Record: found
          • Abstract: not found
          • Article: not found

          Critical review in adsorption kinetic models

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Removal of copper(II) ions from aqueous solution onto chitosan and cross-linked chitosan beads

              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Some studies of crosslinking chitosan-glutaraldehyde interaction in a homogeneous system.

              Chitosan dissolved in acetic acid reacted with glutaraldehyde solution, ranging in concentration from 0.10 to 25.0 x 10(-2) mol dm3. The modified polymers were characterized by means of carbon, hydrogen and nitrogen elemental analysis, scanning electron microscopy, X-ray diffractometry, 13C nuclear magnetic resonance (NMR), infrared and Raman spectroscopies. The uptake of metallic cations in aqueous medium was checked through copper. The obtained data from 13C NMR, infrared and Raman spectroscopies evidenced the formation of an ethylenic double bond in the chitosan glutaraldehyde interaction. These data suggest that free pendant amine groups of chitosan polymer interact with the aldehydic group of the glutaraldehyde to form stable imine bonds, due to the resonance established with adjacent double ethylenic bonds. The crosslinking is formed by the nonuniform length of chains and by terminal unities. The crosslinking formation can involve two chitosan unities belonging, or not, to the same polymeric chain. The sequence of reactions was established for a chitosan:glutaraldehyde molar proportion of 1:20. The degree of crystallinity and particle size decreased as the amount of glutaraldehyde was increased in the polymer. Physical and chemical properties are not just affected for the chitosan glutaraldehyde reaction, but are also affected strongly by the dissolution of the natural chitosan.
                Bookmark

                Author and article information

                Journal
                International Journal of Chemical Engineering
                International Journal of Chemical Engineering
                Hindawi Limited
                1687-806X
                1687-8078
                2014
                2014
                : 2014
                :
                : 1-16
                Article
                10.1155/2014/270946
                6a299b45-287a-425c-805e-244d90051c73
                © 2014

                http://creativecommons.org/licenses/by/3.0/

                History

                Comments

                Comment on this article