Process and kinetics of azo dye decolourization in bioelectrochemical systems: effect of several key factors

Abstract

This study explored the influence of several key factors on the process and kinetics of azo dye decolourization in bioelectrochemical systems (BESs), including cathode potential, dissolved oxygen (DO) concentration of catholyte and biofilm formed on the cathode. The results show that azo dye methyl orange (MO) decolourization in the BES could be well described with the pseudo first-order kinetics. The MO decolourization efficiency increased from 0 to 94.90 ± 0.01% and correspondingly the reaction rate constant increased from 0 to 0.503 ± 0.001 h−1 with the decrease in cathodic electrode potential from −0.2 to −0.8 V vs Ag/AgCl. On the contrary, DO concentration of the catholyte had a negative impact on MO decolourization in the BES. When DO concentration increased from zero to 5.80 mg L−1, the MO decolourization efficiency decreased from 87.19 ± 4.73% to 27.77 ± 0.06% and correspondingly the reaction rate constant reduced from 0.207 ± 0.042 to 0.033 ± 0.007 h−1. Additionally, the results suggest that the biofilm formed on the cathode could led to an adverse rather than a positive effect on azo dye decolourization in the BES in terms of efficiency and kinetics.

Developing a Fluorescent Hybrid Nanobiosensor Based on Quantum Dots and Azoreductase Enzyme forMethyl Red Monitoring

“…Various instrumental techniques have been utilized for textile wastewater detection and purification, including activated carbon adsorption [ 11 ] , instrumental coagulation-flocculation [ 12 ] , advanced oxidation processes [ 13 ] , and photocatalytic decomposition [ 14 ] , as well as chromatography procedures such as TLC [ 15 ] , GC/MS [ 16 ] , and HPLC [ 17 , 18 ] . Despite the extensive use of the above-mentioned routine processes in the wastewaters, these techniques have a number of limitations, including laboratory dependent, high cost, low efficiency, complex operational options, high sludge formation, and limited applicability [ 19 , 20 ] . Therefore, a great interest in exploring and developing biological sensing systems to monitor the concentration of dye substances in aqueous solutions is growing up [ 21 , 22 ] .…”

Biodegradation of Indanthrene Blue RS dye in immobilized continuous upflow packed bed bioreactor using corncob biochar

“…Biological processes using bacteria, algae, yeast, and fungi are excellent alternative methods compared to physicochemical methods in decolorizing textile effluents. They have less operational cost, are eco-friendly, and under optimal operating conditions, produce less sludge compared to other methodologies 18 , 19 . This biodegradation process has become a promising method as it completely decolorizes the dye and transforms them into a non-toxic chemical form 20 , 21 .…”

Biosorption and Biodegradation of Anthraquinone Based Dye (Indanthrene Blue RS) by the Immobilized Microbial Consortium in a Continuous Packed bed Bioreactor Using Corn-Cob Biochar

“…Biological processes using bacteria, algae, yeast, and fungi are excellent alternative methods as compared to physicochemical methods in decolorizing the textile effluents. They have less operational cost, are eco-friendly, and under optimal operating conditions produce less sludge compared to other methodologies [18,19] . This biodegradation process has turned out to be a promising method as it completely decolorizes the dye and transforms them into a non-toxic chemical form [20,21] .…”