Adsorption and photocatalytic degradation of anionic dyes on Chitosan/PVA/Na–Titanate/TiO2 composites synthesized by solution casting method

Published Date

20 September 2016, Vol.149:317–331, doi:10.1016/j.carbpol.2016.04.127

Title 

Adsorption and photocatalytic degradation of anionic dyes on Chitosan/PVA/Na–Titanate/TiO₂composites synthesized by solution casting method

• Author 

• Umma Habiba ^a
• Md. Shariful Islam ^a
• Tawsif A. Siddique ^b
• Amalina M. Afifi ^a,,
• Bee Chin Ang^a

• aCenter of Advanced Materials, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia
• bDepartment of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia

Received 1 March 2016. Revised 19 April 2016. Accepted 29 April 2016. Available online 3 May 2016.

Highlights

• •
  Chitosan/PVA/Na–Titanate/TiO₂ by solution casting method prepared as a new chitosan based composite.
• •
  Characteristics of prepared chitosan/PVA/Na–Titanate/TiO₂ was evaluated.
• •
  The composite was used for adsorption and photocatalytic degradation of Methyl orange and Congo red.
• •
  Mechanism of adsorption and photocatalytic degradation of Methyl orange and Congo red was studied.

Abstract

Chitosan/PVA/Na–titanate/TiO₂ composite was synthesized by solution casting method. The composite was analyzed via Fourier Transform Infrared Spectroscopy, X-ray diffraction, Field Emission Scanning Electron Microscopy, Thermal gravimetric analysis and water stability test. Incorporation of Na-titanate shown decrease of crystallinity for chitosan but increase water stability. However, the composite structure was deteriorated with considerable weight loss in acidic medium. Two anionic dyes, methyl orange and congo red were used for the adsorption test. The adsorption behavior of the composites were described by pseudo-second-order kinetic model and Lagergren-first-order model for methyl orange and congo red, respectively. For methyl orange, adsorption was started with a promising decolorization rate. 99.9% of methyl orange dye was removed by the composite having higher weightage of chitosan and crystalline TiO₂ phase. On the other hand, for the congo red the composite having higher chitosan and Na-titanate showed an efficient removal capacity of 95.76%. UV–vis results showed that the molecular backbone of methyl orange and congo red was almost destroyed when equilibrium was obtained, and the decolorization rate was reaching 100%. Kinetic study results showed that the photocatalytic degradation of methyl orange and congo red could be explained by Langmuir–Hinshelwood model. Thus, chitosan/PVA/Na–titanate/TiO₂ possesses efficient adsorptivity and photocatalytic property for dye degradation.

Keywords

• Chitosan
• Adsorption
• Polymer composite
• Photocatalytic effect
• Kinetics

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• ⁎ 
  Corresponding author.

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