Decolorization of Erythrosine B by Rhizopus arrhizus biomass

Neeta A Salvi

doi:10.1007/s13201-018-0800-0

Abstract

The ability of Rhizopus arrhizus biomass for the removal of dye erythrosine B from aqueous solution was explored. The dye removal capacity of the biomass was evaluated by conducting batch tests using various parameters, viz. effect of pH, biomass dosage, contact time, modified biomasses and initial dye concentrations. The adsorption process followed a pseudo-second-order kinetic model suggesting chemisorption might be the rate-limiting step. The equilibrium process was found to be in good agreement with Langmuir adsorption isotherm, and maximum adsorption capacities of 355.9 mg/g and 363.6 mg/g were achieved with both waste and acid-treated fresh biomass, respectively.Graphical abstract

Highlights

Erythrosine (EB, Fig. 1) is a water-soluble cherry-pink anionic xanthene dye
After each chemical pre-treatment, the biomass was washed with distilled water until the pH was close to neutral, dried in the oven to a constant weight and referred as modified biomasses as follows: Spent R. arrhizus biomass (SB)-0.1 M HCl (2) [SB treated with 0.1 M HCl]; SB-0.01 M HCl (3) [SB treated with 0.01 M HCl]; SB-0.1 M AA (4) [SB treated with 0.1 M Acetic acid]; SB-0.01 M AA: (5) [SB treated with 0.01 M Acetic acid]; SB-0.01 M NaOH (6) [SB treated with 0.01 M NaOH]]; SB-10% HCHO/DW (7) [SB treated with 10% HCHO/ DW]; SB-10% HCHO/0.1 M HCl (8) [SB treated with 10% HCHO/0.1 M HCl]; SB-10% HCHO/0.1 M NaOH (9) [SB treated with 10% HCHO/0.1 M NaOH]; FB-0.01 M HCl (11) [FB treated with 0.01 M HCl]
The maximum % removal was 98.7 at pH 6–8. This might be due to increase in the electrostatic attraction between negatively charged dye anions and positive biosorbent surface binding sites which favoured the removal of dye anions

Summary

Introduction

Erythrosine (EB, Fig. 1) is a water-soluble cherry-pink anionic xanthene dye It is used for colouring textiles such as wool, silk and nylon. It can affect thyroid functions due to presence of iodine in the molecule, which may be released upon its degradation It can be one of the causes of atopic diseases (Uysal and Aral 1998). Consumption of this dye can prove to be fatal, as it is carcinogenic in nature and can lead to tumours (Borzelleca et al 1987; Sasaki et al 2002). Among several physical and chemical methods, the method of adsorption onto activated carbon has been found to be superior but uneconomical as its regeneration and reactivation procedures are expensive. (Hu and Srinivasan 2001; Chakraborty et al 2005; Rozada et al 2003) On the other hand, its photochemical and biochemical degradation too is not recommended due to formation of toxic by-products (Tonogai et al 1978)

Methods

Results

Conclusion