African Journal of
Pure and Applied Chemistry

  • Abbreviation: Afr. J. Pure Appl. Chem.
  • Language: English
  • ISSN: 1996-0840
  • DOI: 10.5897/AJPAC
  • Start Year: 2007
  • Published Articles: 332

Full Length Research Paper

Removal of methylene blue from aqueous solutions using biochar prepared from Eichhorrnia crassipes (Water Hyacinth)-molasses composite: Kinetic and equilibrium studies

Mupa Mathew
  • Mupa Mathew
  • Department of Chemistry, Faculty of Science, Bindura University of Science Education, Private Bag 1020, Bindura, Zimbabwe.
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Rutsito D. Desmond
  • Rutsito D. Desmond
  • Department of Chemistry, Faculty of Science, Bindura University of Science Education, Private Bag 1020, Bindura, Zimbabwe.
  • Google Scholar
Musekiwa Caxton
  • Musekiwa Caxton
  • Department of Chemistry, Faculty of Science, Bindura University of Science Education, Private Bag 1020, Bindura, Zimbabwe.
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  •  Received: 06 September 2016
  •  Accepted: 21 October 2016
  •  Published: 30 November 2016

Abstract

A biochar based adsorbent prepared from Eichhornia crassipes-molasses bio-composite was tested for its ability to remove methylene blue from aqueous solutions. Molasses were used as a granulating media for powdered biomass making it easier to prepare the biochar under set conditions. The Biochar adsorbent was prepared by igniting biomass granules at 400°C. A maximum adsorption capacity of 44.13 mg∙g-1 was achieved at an optimum pH 8, with a bio-sorbent dosage of 0.8 g and an initial concentration of 50 mg∙L-1. Experimental data fitted well onto Freundlich adsorption isotherm with an R2 value of 0.9819. Adsorption processes followed pseudo-second order kinetics with an R2 value of 0.9877. FT-IR spectra reveal typical absorption bands around 1563, 1375 and 1028 cm-1. SEM image show the biochar consisted of irregular particles with a microporous structure and appeared to be fibrous. BET results showed that biochar particles had a surface area of 0.8923 m2g-1, a pore volume of 0.00246 cm3∙g-1 and a pore diameter of 10.87 nm.

 

Key words: Bio-sorbent, biochar, Eichhornia crassipes, methylene blue, isotherm.