Effects of current generation and electrolyte pH on reverse salt flux across thin film composite membrane in osmotic microbial fuel cells

Qin, Mohan; Abu-Reesh, Ibrahim M.; He, Zhen

doi:10.1016/j.watres.2016.09.028

Cited by 43 publications

(19 citation statements)

References 41 publications

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“…To improve our understanding of enhanced electricity generation in OsMFCs, a mathematical model has been developed and used to predict a reduction of internal resistance with increasing osmotic pressure gradient and water flux, thereby confirming the enhanced current generation (Qin et al, 2015). It was also reported that in an OsMFC, reverse salt flux 5 (RSF), which is backward transport of salt ions across the FO membrane into the treated wastewater, was significantly inhibited by the current generation (Qin et al, 2016a).…”

Section: Introductionmentioning

confidence: 96%

Ammonium removal from synthetic wastewater promoted by current generation and water flux in an osmotic microbial fuel cell

Qin

Hynes

Abu-Reesh

et al. 2017

Journal of Cleaner Production

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Recovering useful resource from wastes represents a new approach of clean production with significant environmental and economic benefits. Ammonium nitrogen, which is an important inorganic contaminant and also a resource for fertilizer, can be removed and recovered from wastewater. As the first step of recovery, ammonium removal was successfully demonstrated in this study by using an innovative treatment system-osmotic microbial fuel cells (OsMFC). This OsMFC achieved the removal efficiency of 80.1 ± 2.0 % with an anolyte flow rate of 0.4 mL min-1. Current generation was a key driving force for ammonium ion movement and increasing current generation from 0 to 1.8 ± 0.1 A m-2 could greatly enhance the removal efficiency from 40.7 ± 2.4 % to 85.3 ± 3.5 %. When current generation was similar, water flux could contribute significantly to facilitating ammonium removal, and as a result the OsMFC exhibited 55.2 ± 6.5 % higher ammonium removal with water flux of 1.3 ± 0.2 LMH than that without water flux. In addition, ion diffusion and ion exchange contributed to 17.3 ± 2.4 % and 2.8 ± 0.1 % of ammonium removal, respectively, with 35 g L-1 NaCl as a catholyte. The key challenges such as the exact mechanism of ammonium transport, disposal of ammonium residue after recovery, effects of draw solutes, and system scaling up have been identified and discussed. The results of this study will help develop an efficient approach for NEW recovery (NEW: nutrient, energy and water) from wastewater.

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Section: Introductionmentioning

confidence: 96%

Ammonium removal from synthetic wastewater promoted by current generation and water flux in an osmotic microbial fuel cell

Qin

Hynes

Abu-Reesh

et al. 2017

Journal of Cleaner Production

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“…It was reported that bioelectricity generation in an OsMFC could significantly reduce RSF. When the total Coulomb production increased from zero (open circuit) to 311 C, RSF was reduced from 16.3 ± 2.8 to 3.9 ± 0.7 gMH (Qin et al 2016a). …”

Section: Figure 24 Mutual Benefits Between Bes and Fo In Osbesmentioning

confidence: 99%

“…A previous study has reported that the cation flux could be increased when sodium was in the feed solution and ammonium was in the draw solution in FO process, resulting from the ion exchange of cation ions (Lu et al 2014a). But bioelectricity generation in an OsMFC could greatly inhibit back flux of cations (e.g., sodium ions) from the draw into the feed (Qin et al 2016a) and facilitate forward movement of ammonium from the feed into the draw. Our analysis showed that ion exchange was not a major contributor to ammonium movement in the present OsMFC (more details in next section).…”

Section: Effects Of Water Fluxmentioning

confidence: 99%

“…To improve our understanding of enhanced electricity generation in OsMFCs, a mathematical model has been developed and used to predict a reduction of internal resistance with increasing osmotic pressure gradient and water flux, thereby confirming the enhanced current generation (Qin et al 2015). It was also reported that in an OsMFC, reverse salt flux (RSF), which is backward transport of salt ions across the FO membrane into the treated wastewater, was significantly inhibited by the current generation (Qin et al 2016a). …”

Section: Introductionmentioning

confidence: 95%

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Resource recovery by osmotic bioelectrochemical systems towards sustainable wastewater treatment

Qin

2017

Environ. Sci.: Water Res. Technol.

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(academic)Recovering valuable resources from wastewater will transform wastewater management from a treatment focused to sustainability focused strategy, and creates the need for new technology development. An innovative treatment concept -osmotic bioelectrochemical system (OsBES), which is based on cooperation between bioelectrochemical systems (BES) and forward osmosis (FO), has been introduced and studied in the past few years. An OsBES can accomplish simultaneous treatment of wastewater and recovery of resources such as nutrient, energy, and water (NEW). The cooperation can be accomplished in either an integrated (osmotic microbial fuel cells, OsMFC) or coupled (microbial electrolysis cell-forward osmosis system, MEC-FO) configuration.In OsMFC, higher current generation than regular microbial fuel cell (MFC) was observed, resulting from the lower resistance of FO membrane. The electricity generation in OsMFC could greatly inhibit the reverse salt flux. Besides, ammonium removal was successfully demonstrated in OsMFC, making OsMFCs a promising technology for "NEW recovery" (NEW: nutrient, energy and water). For the coupled OsBES, an MEC-FO system was developed. The MEC produced an ammonium bicarbonate draw solute via recovering ammonia from synthetic organic solution, which was then applied in the FO for extracting water from the MEC anode effluent. The system has been advanced with treating landfill leachate. A mathematical model developed for ammonia removal/recovery in BES quantitatively confirmed that the NH4 + ions serve as effective proton shuttles across cation exchange membrane (CEM). Resource Recovery by Osmotic Bioelectrochemical Systems towards Sustainable Wastewater TreatmentMohan Qin Abstract (general audience)Nowadays, wastewater is no longer considered as waste. Instead, it is a pool for different kinds of resources, such as nutrient, energy, and water (NEW). Various technologies were developed to achieve NEW recovery from wastewater. A novel concept, osmotic bioelectrochemical system (OsBES) has been introduced and studied in the past few years. OsBES is based on two technologies: bioelectrochemical systems (BES) and forward osmosis (FO); and the corporation between these two technologies could accomplish simultaneous wastewater treatment and resource recovery. We investigated two kinds of OsBES: one is osmotic microbial fuel cells (OsMFC), and the other is microbial electrolysis cell-forward osmosis system (MEC-FO). For OsMFC, a mathematical model was built to understand the internal resistance, which will affect the current generation according to Om's law (I=U/R). The salt transport across the cation exchange membrane (CEM) is related to the current generation. The ion transport, especially ammonium/ammonia transport, across CEM membrane in BES was modelled, which will help the BES design and operation for ammonia recovery systems. The system performance for wastewater treatment and resource recovery in MEC-FO was fully investigated with both synthetic wastewater and landfill leach...

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“…It was found that the movement of electrons (electrically driven) could affect ion transport across FO membrane. Compared to the open circuit (no electricity generation), a closed circuit mode can facilitate the forward transport of cations (from the anode to the cathode) in the OsMFC due to the electrons moving from the anode electrode to the cathode electrode, resulting in decreased reverse cation diffusion; this decreased cation transport would repel the reversed anions transport for charge balance, leading to the reduction of RSF . Prior studies have screened for appropriate DS for FO applications and studied 14 DS selected from more than 500 inorganic compounds .…”

Section: Introductionmentioning

confidence: 99%

Examination of inorganic‐based draw solutes and mitigation of their reverse solute flux in osmotic microbial fuel cells

Qian

2018

J of Chemical Tech & Biotech

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BACKGROUND: Osmotic microbial fuel cells (OsMFCs) integrate microbial fuel cell (MFC) and forward osmosis (FO) and can simultaneously achieve wastewater treatment, electricity generation and water recovery. The selection of appropriate draw solutes (DS) and reduction of reverse solute flux (RSF) are the key challenges for OsMFC operation. This study has examined ten inorganic-based DS and investigated the effect of electricity generation on the RSF. RESULTS: The OsMFC exhibited stable electricity generation with Na + -series and K + -series DS. For NH 4+ -series DS, the ammonia-nitrogen loss percentage, which varied from 12.5 ± 0.4% to 47.7 ± 2.4%, was significant due to the high pH and aeration in the cathode. Inorganic scaling/precipitation was observed with Mg 2+ -series and Ca 2+ -series DS with DS loss percentage from 13.5 ± 2.8% to 28.0 ± 0.3%. Electricity generation could reduce the specific RSF by 70.3 ± 4.9% and 56.7 ± 13.4% for the Na + and K + DS, respectively. CONCLUSION: The Na + -series and K + -series DS was identified as the ideal DS for the OsMFC because of stable electricity generation and water flux and significant RSF reduction. NH 4 + -series, Mg 2+ -series and Ca 2+ -series DS were not appropriate due to significant loss. Bioelectricity generation could reduce both RSF and specific RSF. Industry NH 4 HCO 3 DS increased from 1.76 ± 0.11 to 3.83 ± 0.06 g m −2 h −1 and from 1.67 ± 0.08 to 3.38 ± 0.20 g m −2 h −1 with the NH 4 Cl DS, resulting in NH 4 + concentrations in the anolyte increasing

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Effects of current generation and electrolyte pH on reverse salt flux across thin film composite membrane in osmotic microbial fuel cells

Cited by 43 publications

References 41 publications

Ammonium removal from synthetic wastewater promoted by current generation and water flux in an osmotic microbial fuel cell

Ammonium removal from synthetic wastewater promoted by current generation and water flux in an osmotic microbial fuel cell

Resource recovery by osmotic bioelectrochemical systems towards sustainable wastewater treatment

Examination of inorganic‐based draw solutes and mitigation of their reverse solute flux in osmotic microbial fuel cells

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