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Journal of Catalyst & Catalysis

Isotherm and Kinetic Studies of Methylene Blue Dye Adsorption Using Sulfuric Acid Activated Nigerian Montmorillonite Clay

  1. Onwuka K. E.
  2. Osigwe C.E.
  3. Achilike K.O.
  4. Ezeaku I.I.

Abstract

The Presence of methylene blue and other basic dyes in water causes various harmful effects for both human and aquatic species. In this study, montmorillonite clay in its raw and acid (0.5M H2SO4) activated states were investigated for the sorption of methylene blue dye. The structural changes due to acid treatment were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The studied parameters that affect adsorption efficiency were contact time and initial methylene blue concentration. Methylene blue dyes showed the best adsorption at pH 7, and equilibrium was attain in 100 minutes.  Kinetic data were analyzed by using two different kinetic models and the data fitted best to pseudo-second-order model. Langmuir isotherm showed best fit to the adsorption of methylene blue, with the Langmuir monolayer adsorption capacity of acid activated montmorillonite  found to be 31.05 mg/g at 28±20C. In addition, the adsorption capacity of the acid activated clay (M1) was found to be far more greater (4.96 mg/g) compared to that of the unactivated clay (0.17 mg/g), thus confirming the effectiveness of acid activated clays for sorption of basic dyes in aqueous solutions.

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