Bioelectrochemical system for recalcitrant p-nitrophenol removal

Area of Science:

• Environmental Science
• Electrochemistry
• Wastewater Treatment

Background:

• Recalcitrant organic pollutants like p-nitrophenol (PNP) pose significant challenges in wastewater treatment.
• Conventional methods often struggle with efficiency and high operational costs for PNP removal.

Purpose of the Study:

• To investigate the efficacy of bioelectrochemical systems (BES) for the removal of p-nitrophenol (PNP).
• To evaluate the energy consumption and removal rates associated with BES technology for PNP.
• To identify the primary reduction product of PNP in the BES.

Main Methods:

• Utilized a bioelectrochemical system with a graphite cathode to treat PNP-containing wastewater.
• Varied operational parameters including cathode potential, influent PNP concentration, and hydraulic retention time (HRT).
• Analyzed PNP removal rates, energy consumption, coulombic efficiencies, and identified reduction products.

Main Results:

• Achieved effective PNP removal rates up to 9.14 ± 0.48 mol m(-3)d(-1) with low energy consumption (0.010 ± 0.002 kWh mol(-1) PNP).
• PNP removal was enhanced by negative cathode potential, higher influent PNP concentration, and shorter HRT.
• Demonstrated high coulombic efficiencies for PNP removal at the cathode (>70%), significantly reducing cosubstrate requirements compared to anaerobic processes.
• Identified p-aminophenol (PAP) as the dominant reduction product at the abiotic graphite cathode.

Conclusions:

• Bioelectrochemical systems show significant potential for the efficient and cost-effective removal of nitrophenol pollutants from wastewater.
• The high coulombic efficiencies at the cathode make BES a promising alternative to conventional treatment methods.
• Further research can optimize BES design and operation for industrial-scale PNP remediation.