Abstract
A flow through anaerobic microbial fuel cell (MFC) was designed and optimized for efficient treatment of recalcitrant textile wastewater. The membrane-less MFC was first time fabricated with a unique combination of electrodes, a novel bioanode of synthesized lignin-based electrospun carbon fiber supporting a biofilm ofGeobacter sulfurreducensfor acetate oxidation and an air-breathing cathode, consisting of a pyrolyzed macrocycle catalyst mixture on carbon bonded by polytetrafluoroethylene (PTFE). The effects of different organic loadings of acetate along with Acid Orange (AO5), operation time and ionic strength of auxiliary salts (conductivity enhancers) were investigated and responses in terms of polarization and degradation were studied. In addition, the decomposition of the organic species and the degradation of AO5 along with its metabolites and degraded products (2-aminobenzenesulfonic acid) were determined by chemical oxygen demand (COD) analysis, UV-Vis spectrophotometry and high-performance liquid chromatography (UV-HPLC) techniques. SEM and TEM images were also used to find out the biocompatibility of the microbes on lignin-based electrospun carbon felt anode and the morphology of the cathode. Reduction and breakage of the azo bond of AO5 occurs presumably as a side reaction, resulting in the formation of 2-aminobenzenesulfonic acid and unidentified aromatic amines. Maximum current density of anode 0.59 Am−2and power density of 0.12 Wm−2were obtained under optimized conditions. As a result, decolouration of AO5 and chemical oxygen demand (COD) removal efficiency was 81 and 58%, respectively. These results revealed that the low-cost MFC assembly can offer significant potential for anaerobic decolouration of recalcitrant textile wastewater.
Highlights
With growing concerns on freshwater, human health, aquatic life, climate change and environmental pollution, textile wastewater is receiving significant attention for cost-effective treatment and as a resource than waste (Javed et al, 2019; Maaz et al, 2019)
Fabrication and optimization of single chamber microbial fuel cell composed of porous carbon with PPM catalyst on carbon as cathode and novel bioanode for efficient removal of dyes and chemical oxygen demand (COD) reduction has been demonstrated
Exploiting advantages of the electrospun lignin-based fiber with the specific surface area, a superior performance has been achieved for dye removal
Summary
With growing concerns on freshwater, human health, aquatic life, climate change and environmental pollution, textile wastewater is receiving significant attention for cost-effective treatment and as a resource than waste (Javed et al, 2019; Maaz et al, 2019). More than 2,000 different azo dyes are used yearly in the textile, paper and food industries (Vijaykumar et al, 2007). Many of these dyes are toxic, carcinogenic and mutagenic (Carliell et al, 1998; Selvam et al, 2003; Fatima et al, 2017; Ahmad et al, 2018).During dyeing process, about 15% of the dye is not absorbed by the fabrics, is spilled into hydrosphere. In AO5, the azo bond exists in the para-phenyl position to a sulphonated electron withdrawing group (Figure 1). This configuration helps to withdraw of electrons from dye compound during redox reactions. Cleavage of azo bond to the corresponding aromatic amines occurs by the electrophilic attack of the electrons supplied from the oxidation of organic substrates (Eq 1)
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