Fast microwave-assisted green synthesis of xanthan gum grafted acrylic acid for enhanced methylene blue dye removal from aqueous solution

Edwin Makhado; Sadanand Pandey; Philiswa N Nomngongo; James Ramontja

doi:10.1016/j.carbpol.2017.08.093

Fast microwave-assisted green synthesis of xanthan gum grafted acrylic acid for enhanced methylene blue dye removal from aqueous solution

Carbohydr Polym. 2017 Nov 15:176:315-326. doi: 10.1016/j.carbpol.2017.08.093. Epub 2017 Aug 25.

Authors

Edwin Makhado¹, Sadanand Pandey², Philiswa N Nomngongo¹, James Ramontja³

Affiliations

¹ Department of Applied Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa.
² Department of Applied Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa; Centre for Nanomaterials Science Research, University of Johannesburg, South Africa. Electronic address: spandey@uj.ac.za.
³ Department of Applied Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa; Centre for Nanomaterials Science Research, University of Johannesburg, South Africa.

PMID: 28927614
DOI: 10.1016/j.carbpol.2017.08.093

Abstract

In the present project, graft polymerization was employed to synthesis a novel adsorbent using acrylic acid (AA) and xanthan gum (XG) for cationic methylene dye (MB⁺) removal from aqueous solution. The XG was rapidly grafted with acrylic acid (CH₂=CHCOOH) under microwave heating. Fourier-transform infrared spectroscopy (FTIR), Proton Nuclear magnetic resonance spectroscopy (¹H NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Thermal gravimetric analysis (TGA) techniques were used to verify the adsorbent formed under optimized reaction conditions. Optimum reaction conditions [AA (0.4M), APS (0.05M), XG (2gL^-1), MW power (100%), MW time (80s)] offer maximum %G and %GE of 484 and 78.3, respectively. The removal ratio of adsorbent to MB⁺ reached to 92.8% at 100mgL^-1. Equilibrium and kinetic adsorptions of dyes were better explained by the Langmuir isotherm and pseudo second-order kinetic model respectively. The results demonstrate xanthan gum grafted polyacrylic acid (mw XG-g-PAA) absorbent had the universality for removal of dyes through the chemical adsorption mechanism.

Keywords: Acrylic acid (PubChem CID: 6581); Adsorption; Ammonium persulfate (PubChem CID: 62648); Biopolymer; Deuterium Oxide (D2O) (PubChem CID: 24602); Dye; Graft co-polymerisation; Hydrochloric acid (PubChem CID: 313); Methanol (PubChem CID: 887); Methanol D4(PubChem CID: 71568); Microwave assisted synthesis; Potassium bromate (PubChem CID: 23673461); Sodium hydroxide (PubChem CID: 14798); Xanthan gum (PubChem CID: 7107); methylene blue (PubChem CID: 6099).