Accelerated decolorization of azo dye Congo red in a combined bioanode–biocathode bioelectrochemical system with modified electrodes deployment

Abstract

h i g h l i g h t sCR decolorization was accelerated with combined bioanode-biocathode BES. The biocathode played an important role in accelerating CR decolorization. Three electrodes deployments were compared based on startup, DE and EIS analysis. The surrounding mode was the best, followed by vertical and horizontal ones. The possible mechanism for the combined bioanode-biocathode was discussed. a r t i c l e i n f o In this study, BES with bioanode and biocathode was applied to decolorize an azo dye Congo red (CR). Results showed that the Congo red decolorization efficiency (CR-DE) within 23 h in a combined bioanode-biocathode single chamber BES was 98.3 ± 1.3%, significantly higher than that of mixed solution in a dual chamber BES (67.2 ± 3.5%) (P < 0.005). Various electrodes deployments (horizontal, vertical and surrounding) in the combined bioanode-biocathode BES were further compared based on the decolorization performance and electrochemical characterization. Results indicated that CR-DE within 11 h improved from 87.4 ± 1.3% to 97.5 ± 2.3%, meanwhile the internal resistance decreased from 236.6 to 42.2 X as modifying the horizontal deployment to be a surrounding deployment. It proved that the combination of bioanode and biocathode with suitable electrodes deployment could accelerate the decolorization of azo dye Congo red, which would be great potential for the application of bioelectrochemical technology in azo dye wastewater treatment.

Improved azo dye decolorization in an advanced integrated system of bioelectrochemical module with surrounding electrode deployment and anaerobic sludge reactor

“…The higher current in the integrated system may be attributed to a more efficient electron transfer or a lower cathode resistance . It would cause the stronger stress to induce a higher electrochemical activity based on the electrons interaction between biofilm and the electrode, and resulted in the higher electrochemical reaction kinetics in the integrated system (Kong et al, 2014a), which was consistent to the decolorization results.…”

“…The working volume for the inner anode chamber was 70 mL, resulting in the working volume for cathode to be 210 mL as the module inserted. Both anode and cathode electrode materials were carbon brush (ID 3 cm  8 cm) displaced to be surrounding deployment as described previously with the electrode ratio of 1:3 (Kong et al, 2014a). When the BES module was inserted without anaerobic sludge, it became a sleeve-type BES reactor (Fig.…”

“…Activated sludge as described was used as the inoculum of the anode and cathode (Kong et al, 2014a). Sodium acetate (1 g L À1 ) was used as the sole electron donor in the anode chamber, and azo dye, acid orange 7 (AO7, 100 mg L À1 ), was used as the electron acceptor in the cathode chamber.…”

A horizontal plug-flow baffled bioelectrocatalyzed reactor for the reductive decolorization of Alizarin Yellow R

“…Several studies have reported the reductive decolorization of azo dyes by the quick cleavage of azo bonds in either traditional dual-chamber BESs Kong et al, 2014Kong et al, , 2013Liu et al, 2009;Mu et al, 2009;Sun et al, 2011) or BESs with the improved configurations (Cui et al, 2012;Hou et al, 2011;Sun et al, 2013;Wang et al, 2013). These studies suggested a promising potential employment of BES for the enhanced degradation of azo dye-laden wastewater.…”

Improved 4-chlorophenol dechlorination at biocathode in bioelectrochemical system using optimized modular cathode design with composite stainless steel and carbon-based materials

“…In order to treat wastewater in more sustainable way, bioelectrochemical system (BES) was introduced to achieve this goal for its resource recovery from wastewater and low energy consumption (Friman et al, 2013;Kong et al, 2014a;Liang et al, 2013;Wang et al, 2011). It has been demonstrated that BES is of great potential for the dechlorination, including reduction at anode and cathode (Aulenta et al, 2011;Chun et al, 2013;Huang et al, 2012;Kong et al, 2014b;Wen et al, 2013).…”