Microbial Electrolysis Desalination Cell Research Articles

Role of microbial electrolysis desalination cell in sustainable water and energy management: Performance assessment of platinum and nickel foam cathodes and simulating integration with reverse osmosis systems

This research introduces the microbial integrated cell (MIC), a bioelectrochemical system that combines microbial electrolysis and desalination for sustainable energy and water purification. Efficiency evaluations of nickel foam and Pt/CC cathodes for hydrogen production and desalination showed nickel foam achieving a 91% desalination efficiency, closely following Pt/CC's 99%, with hydrogen generation rates of 0.96 m3H2/m3/d for Pt/CC cathodes and 0.72 m3H2/m3/d for nickel foam. Despite marginally lower performance, the cost advantages of nickel foam suggest its feasibility for large-scale deployment. Further exploration into MIC integration with reverse osmosis (RO) system aims to enhance the sustainability of the combined system. Simulation outcomes indicate that MIC-RO integration can significantly reduce energy consumption and brine concentration discharged into the sea, highlighting its potential to improve desalination plants' efficiency and environmental impact. This research facilitates the transition of these green technologies to practical applications, optimizing efficiency and environmental benefits.

Heavy metal contaminated soil remediated by a bioelectrochemical system: Simultaneous promotion of electrochemically active bacteria and bipolar membrane

A modified microbial electrolysis desalination cell (BP–C-MEDC) equipped with a bipolar membrane (BPM) and a cation exchange membrane (CEM) was fabricated to efficiently remove heavy metals from polluted soil, compared with microbial electrolysis desalination chemical-production cell and conventional MEDC at various solid-to-liquid (S/L) ratios. At optimal 0.1 g/mL of S/L ratio, the BP-C-MEDC showed the highest current density due to BPM application to alleviate the acidification of the anode chamber and obtain the lowest resistance. Simultaneously, the lowest desalination efficiency (3.88 ± 1.73%) of the BP-C-MEDC led to less weight loss in the soil at the S/L ratio due to less self-diffusion induced by anion exchange membrane loss. The BP-C-MEDC had negligible organics pollution, where the total organic carbon concentration of the cathode chamber was only 5.2 ± 0.6 mg/L after 12 h of treatment with the S/L ratio. The lowest pH and the highest current density derived from the direct application of BPM brought about the highest removal efficiencies of Cd (81.10%), Pb (23.05%), and Zn (30.14%) at the S/L ratio of the BP-C-MEDC, along with the lowest energy consumption of metal removal. The results suggest that the proposed system has the potential to efficiently treat heavy metals and inefficiently release organics from the contaminated soil.

Recent progress in environmentally friendly bio-electrochemical devices for simultaneous water desalination and wastewater treatment

Bio-electrochemical systems (BESs) use electroactive micro-organisms for degrading organic materials in wastes for energy and/or chemical production. Microbial based desalination system is a cost-effective and environmentally friendly technique that can be used for water desalination with simultaneous wastewater treatment and energy harvesting. These systems can be used as a standalone technology for water desalination such as microbial desalination cell, microbial electrolysis desalination cell, or a hybrid with other desalination technology. This review summarized the recent progress in using BESs for water desalination, including microbial fuel cell-based desalination (MDC) and microbial electrolysis cell-based desalination (MEDC). The different scaling up trials to commercialize this technology, including the controlling parameters, are discussed. Moreover, the different hybrid desalination systems based on BES are summarized. Finally, the challenges facing the commercialization of the MDC systems were summarized.

Simultaneous desalination and nutrient recovery during municipal wastewater treatment using microbial electrolysis desalination cell

The removal of organics and saline while simultaneously recovering nutrients in municipal wastewater was achieved in a microbial electrolysis desalination cell (MEDC). System performance in terms of organics removal, desalination, and nitrogen and phosphate recovery was investigated under different ion exchange membrane (IEM) pairs and applied voltages. Compared with single-IEM stack MEDC, the MEDC with multi-IEM pairs proved to be able to perform an effective performance for chemical oxygen demand (COD) removal, desalination, and nutrient recovery. The energy consumption for netrient separation and recovery was 0.12 kWh/m3 with 3-IEM stacks at applied voltage of 2 V. The MEDC system with 3-IEM stacks showed 75.5 ± 1.4% COD removal and 8.5 ± 1.1% Coulombic efficiency. The conductivity in effluent decreased to 545 μS/cm (lower than the single-IEM stack, 934 μS/cm), while conductivity in the product chamber was concentrated to 2160 μS/cm (higher than the single-IEM stack, 998.5 μS/cm). Moreover, the recovery efficiencies of nitrogen and phosphate reached 66 ± 5.3% and 66.7 ± 4.7%, respectively. Furthermore, the CV curve and microbial community structure showed that electrical stimulation increased the abundances of electrogenic bacteria (Rhodocyclaceae and Geobacter), which enhanced COD removal and electron transfer. These results clearly demonstrate that the MEDC is an energy efficient technology for the treatment of municipal wastewater, while simultaneously recovering nitrogen and phosphate resources.

A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production

The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4±0.6mmol/Lh) and the lowest energy consumption (0.35±0.14kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors.

Development of the Microbial Electrolysis Desalination and Chemical-Production Cell for Desalination as Well as Acid and Alkali Productions

By combining the microbial electrolysis cell and the microbial desalination cell, the microbial electrolysis desalination cell (MEDC) becomes a novel device to desalinate salty water. However, several factors, such as sharp pH decrease and Cl(-) accumulation in the anode chamber, limit the MEDC development. In this study, a microbial electrolysis desalination and chemical-production cell (MEDCC) was developed with four chambers using a bipolar membrane. Results showed that the pH in the anode chamber of the MEDCC always remained near 7.0, which greatly enhanced the microbial activities in the cell. With applied voltages of 0.3-1.0 V, 62%-97% of Coulombic efficiencies were achieved from the MEDCC, which were 1.5-2.0 times of those from the MEDC. With 10 mL of 10 g/L NaCl in the desalination chamber, desalination rates of the MEDCC reached 46%-86% within 18 h. Another unique feature of the MEDCC was the simultaneous production of HCl and NaOH in the cell. With 1.0 V applied voltage, the pH values at 18 h in the acid-production chamber and cathode chamber were 0.68 and 12.9, respectively. With the MEDCC, the problem with large pH changes in the anode chamber was resolved, and products of the acid and alkali were obtained.