Adsorption of Rhodamine B dye from aqueous solution onto acid treated banana peel: Response surface methodology, kinetics and isotherm studies

Adeleke Abdulrahman Oyekanmi,Akil Ahmad,Kaizar Hossain,Mohd Rafatullah,Daniel Rittschof

doi:10.1371/journal.pone.0216878

Adeleke Abdulrahman Oyekanmi, Akil Ahmad + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0216878

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Journal: PloS one	Publication Date: May 15, 2019
Citations: 101	License type: CC BY 4.0

Affiliation: Universiti Sains Malaysia

Abstract

The adsorption of rhodamine B (RhB) using acid modified banana peels has been examined. Chemical characteristics of the adsorbents were observed in order to determine active functional groups. The major functional groups on the surface were OH, C = O, C = C and C-O-C. Interactions between operational parameters were studied using the central composite design (CCD) of response surface methodology (RSM). The predictions of the model output indicated that operational factors influenced responses at a confidence level of 95% (P<0.05). The optimum conditions for adsorption were pH 2 at a 0.2 g/L dose within 60 minutes of contact time. Isotherm studies were carried out using the optimized process variables. The data revealed that RhB adsorption fitted the Langmuir isotherm equation while the reduction of COD followed the Freundlich isotherm. Kinetic experiments fitted the pseudo second order model for RhB removal and COD reduction. The adsorption mechanism was not the only rate controlling step. Diffusion through the boundary layer described the pattern of adsorption.

Highlights

Effluents generated from rubber, plastic, leather and textile processing plants contain different kinds of synthetic dyes, such as malachite green, methyl violet, azure dye, indigo carmine and Rhodamine B (RhB) [1]
The Fourier Transform Irradiation (FT-IR) spectra of banana peel appeared similar to the observations of Memon et al 2008 [38]
The adsorption of RhB and COD reduction using acid modified banana peel was investigated under the operational condition of pH, adsorbent dosage and contact time

Summary

Introduction

Effluents generated from rubber, plastic, leather and textile processing plants contain different kinds of synthetic dyes, such as malachite green, methyl violet, azure dye, indigo carmine and Rhodamine B (RhB) [1]. The discharge of these dyes into the receiving waters produce negative biological and ecological effects, which have the propensity of inhibiting aquatic growth and resulting in the death of aquatic species. Synthetic dyes are complex in nature due to their aromatic structures, which are nonbiodegradable as a result of their optical, thermal and physic chemical stability [2, 3].

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