Effective Removal of Hazardous Dyes from Aqueous Solutions Using Starch Based Hydrogel and Gamma Radiation

Ghada Adel Mahmoud,Samia E Abdel-Aal,Nabil A El-Kelesh,E A Alshafei

doi:10.13189/eer.2017.050703

Abstract

The adsorption performance of acrylamide/ starch hydrogel (AAm/starch) prepared by gamma radiation for removal of direct congo red (DCR) and direct blue (DB) dyes has been investigated. The physico-chemical parameters such as dye concentration, solution pH and temperature have been studied. Favorable adsorption occurred at pH 3 for DCR and pH 10 for DB. The adsorption of dyes onto AAm/starch hydrogels was endothermic process. Experimental data have been modeled by the Freundlich isotherm. Degradation test of DCR and DB dyes using gamma irradiation in aqueous solution under various radiation doses and pH was investigated and G-value was calculated. Destruction of 70% and 75% of the dye colour solutions was succeeded at radiation dose 40 and 30 kGy for DCR and DB, respectively. Comparing the removal percent of DCR and DB dyes by radiation degradation with that done by AAm/starch hydrogel adsorption was investigated. It was found that preferring removal of DCR and DB dyes by gamma radiation degradation. The remaining concentration of dyes was followed by adsorption onto the hydrogel. Complete removal of DCR and DB was performed by gamma radiation degradation followed by AAm/starch hydrogel adsorption.

Highlights

The pollution from dye wastewater is one of the most important environmental problems due to the fact that the use of a variety of dyes has increased [1, 2]
Comparing the removal percent of direct congo red (DCR) and direct blue (DB) dyes by radiation degradation with that done by AAm/starch hydrogel adsorption was investigated
The removal percent of 500 mg/L of DB by radiation degradation was 75 % and by adsorption was 28%. This means that preferring removal of DB dyes by gamma radiation degradation

Summary

Introduction

The pollution from dye wastewater is one of the most important environmental problems due to the fact that the use of a variety of dyes has increased [1, 2]. Many treatment processes have been applied for the removal of dyes from wastewater such as physical, chemical and biological treatments. The physical and chemical treatment methods include ozonization, adsorption, chemical precipitation, flocculation and coagulation [4]. Adsorption is one of the most common methods used in wastewater treatment because it is economical, effective and simple in design. The adsorption process is influenced by the nature of the adsorbate and the substituent groups of adsorbents [5]. The adsorption method can only transfer the contaminants (dyes) from one phase to the other leaving the problem essentially unsolved. This problem can be solved by combining the conventional techniques with other techniques. Attention has to be focused on techniques that lead to the complete destruction of the dye molecules [6, 7]

Methods

Results

Conclusion