Anodic metabolic activity regulates the desalination efficiency in microbial catalysed electrochemical system

• Published in: Bioresource technology 2020-08, Vol.309, p.123334-123334, Article 123334
• Main Authors: Vanitha, T.K., Hemalatha, Manupati, Venkata Mohan, S.
• Format: Article
• Language: English
• Subjects: Bioelectric Energy Sources; Catalysis; Electrodes; Ionic gradient; Ions; Microbial fuel cell (MFC); Total dissolved solids (TDS); Wastewater treatment; Water Purification
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2020.123334

[Display omitted] •Anodic metabolic rate showed significant influence on desalination.•Closed-circuitry mode of external resistance improves overall system performance.•Increased potential difference influenced electrogenic activity and ionic migration.•Anodic redoz rates showed varied shapes and sizes of cathodic salt depositions. Anodic metabolic rate showed regulatory influence on the desalination performance of microbial desalination cell (MDC) under open (OC) and closed circuit (CC) operations. In this study, three MDCs were tested for desalination with three different organic substrate loads 1500 ± 55 mg/L in MDC-A; 3500 ± 10 g/L in MDC-B; 4500 ± 12 g/L in MDC-C. Higher desalination and substrate removal rates were observed in CC than OC. Average desalination was MDC-C (51.4%-CC) > MDC-B (47.3%-CC) > MDC-A (45.3%-CC) and COD removal efficiencies were MDC-C (68.4%-CC) > MDC-B (64.4%-CC) > MDC-A (51.9%-CC). Increase in organic load resulted in higher desalination efficiency which was due to higher electrochemical and ionic gradient apart from anodic metabolic activity. The voltage and current density were observed to be maximum in MDC-C (685 mV; 2.16 mA/m2) followed by MDC-B (598 mV; 1.98 mA/m2) and MDC-A (501 mV; 1.76 mA/m2). This study demonstrated that the MDCs performance can be regulated by varying organic load and circuitry modes.