Evaluation and Predictive Modeling of Removal Condition for Bioadsorption of Indigo Blue Dye by Spirulina platensis.

Robledo-Padilla Robledo-Padilla,Alemán-Nava Alemán-Nava,Zavala-Yoe Zavala-Yoe,Parra-Saldívar Parra-Saldívar,Aquines Aquines,Iqbal Iqbal,Silva-Núñez Silva-Núñez,Castillo-Zacarías Castillo-Zacarías,Ramirez-Mendoza Ramirez-Mendoza

doi:10.3390/microorganisms8010082

Robledo-Padilla Robledo-Padilla, Alemán-Nava Alemán-Nava + Show 7 more

Open Access

https://doi.org/10.3390/microorganisms8010082

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Abstract

Among the different chemical and physical treatments used to remove the color of the textile effluents, bioremediation offers many benefits to the environment. In this study, we determined the potential of Spirulina platensis (S. platensis) for decolorizing indigo blue dye under different incubation conditions. The microalgae were incubated at different pH (from 4 to 10) to calibrate for the optimal discoloration condition; a pH of 4 was found to be optimal. The biomass concentration in all experiments was 1 g/L, which was able to decolorize the indigo blue dye by day 3. These results showed that S. platensis is capable of removing indigo blue dye at low biomass. However, this was dependent on the treatment conditions, where temperature played the most crucial role. Two theoretical adsorption models, namely (1) a first-order model equation and (2) a second-order rate equation, were compared with observed adsorption vs. time curves for different initial concentrations (from 25 to 100 mg/L). The comparison between models showed similar accuracy and agreement with the experimental values. The observed adsorption isotherms for three temperatures (30, 40, and 50 °C) were plotted, showing fairly linear behavior in the measured range. The adsorption equilibrium isotherms were estimated, providing an initial description of the dye removal capacity of S. platensis.

Highlights

In recent years, the presence of micro and nanopollutans in water resources has become a common challenging issue for water and wastewater treatment processes
We examined the potential of the microalga S. platensis, which is rich in carbohydrates and proteins, to remove the dye
We found that S. platensis is capable of removing indigo blue dye at low biomass under different temperature and pH conditions

Summary

Introduction

The presence of micro and nanopollutans in water resources has become a common challenging issue for water and wastewater treatment processes. To remove the color of the textile effluents, sometimes different chemical treatments are used, including physical and biological agents [20,21,22,23,24] Some of these methods are impractical for application due to their high costs or waste production. The treatment of textile wastewater containing indigo dye is one of the most difficult because the dye is of synthetic origin and has a molecular structure aromatic complex, which is more stable and harder to biodegrade [27,28,29] The alteration of their chemical structures can result in the formation of new compounds xenobiotics, which may be more toxic than the potential compounds [30]. Adsorption equilibrium isotherms were estimated, providing an initial description of the dye removal capacity of the algae

Inoculum Preparation

Experimental Design

Mathematical Models

Optimum pH

Findings

Measurement of the Effect of the Temperature and Concentration