Browsing by Author "Qin, Mohan"

Now showing 1 - 6 of 6
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    Nanoparticulate Ni(OH)₂ Films Synthesized from Macrocyclic Nickel(II) Cyclam for Hydrogen Production in Microbial Electrolysis Cells
    Qin, Mohan; Maza, William A.; Stratakes, Bethany M.; Ahrenholtz, Spencer R.; Morris, Amanda J.; He, Zhen (Electrochemical Society, 2016-01-01)
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    Recovery of nitrogen and water from landfill leachate by a microbial electrolysis cell-forward osmosis system
    Qin, Mohan; Molitor, Hannah; Brazil, Brian; Novak, John T.; He, Zhen (Elsevier, 2016-01-01)
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    Resource Recovery By Osmotic Bioelectrochemical Systems Towards Sustainable Wastewater Treatment
    Qin, Mohan (Virginia Tech, 2017-11-14)
    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 internal (osmotic microbial fuel cells, OsMFC) or external (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 external configuration of 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).
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    Understanding Ammonium Transport in Bioelectrochemical Systems towards its Recovery
    Liu, Ying; Qin, Mohan; Luo, Shuai; He, Zhen; Qiao, Rui (Nature Publishing Group, 2016-03-03)
    We report an integrated experimental and simulation study of ammonia recovery using microbial electrolysis cells (MECs). The transport of various species during the batch-mode operation of an MEC was examined experimentally and the results were used to validate the mathematical model for such an operation. It was found that, while the generated electrical current through the system tends to acidify (or basify) the anolyte (or catholyte), their effects are buffered by a cascade of chemical groups such as the NH₃/NH₄⁺ group, leading to relatively stable pH values in both anolyte and catholyte. The transport of NH₄⁺ ions accounts for ~90% of the total current, thus quantitatively confirming that the NH₄⁺ ions serve as effective proton shuttles during MEC operations. Analysis further indicated that, because of the Donnan equilibrium at cation exchange membrane-anolyte/catholyte interfaces, the Na+ ion in the anolyte actually facilitates the transport of NH₄⁺ ions during the early stage of a batch cycle and they compete with the NH₄⁺ ions weakly at later time. These insights, along with a new and simple method for predicting the strength of ammonia diffusion from the catholyte toward the anolyte, will help effective design and operation of bioeletrochemical system-based ammonia recovery systems.
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    When Bioelectrochemical Systems Meet Forward Osmosis: Accomplishing Wastewater Treatment and Reuse through Synergy
    Lu, Yaobin; Qin, Mohan; Yuan, Heyang; Abu-Reesh, Ibrahim M.; He, Zhen (MDPI, 2014-12-23)
    Bioelectrochemical systems (BES) and forward osmosis (FO) are two emerging technologies with great potential for energy-efficient water/wastewater treatment. BES takes advantage of microbial interaction with a solid electron acceptor/donor to accomplish bioenergy recovery from organic compounds, and FO can extract high-quality water driven by an osmotic pressure. The strong synergy between those two technologies may complement each other and collaboratively address water-energy nexus. FO can assist BES with achieving water recovery (for future reuse), enhancing electricity generation, and supplying energy for accomplishing the cathode reactions; while BES may help FO with degrading organic contaminants, providing sustainable draw solute, and stabilizing water flux. This work has reviewed the recent development that focuses on the synergy between BES and FO, analyzed the advantages of each combination, and provided perspectives for future research. The findings encourage further investigation and development for efficient coordination between BES and FO towards an integrated system for wastewater treatment and reuse.