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Ammonium Bicarbonate

The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Bruce E Logan – 1st expert on this subject based on the ideXlab platform

  • evaluating battery like reactions to harvest energy from salinity differences using Ammonium Bicarbonate salt solutions
    Chemsuschem, 2016
    Co-Authors: Mohammad Rahimi, Bruce E Logan, Christopher A Gorski

    Abstract:

    Mixing entropy batteries (MEBs) are a new approach to generate electricity from salinity differences between two aqueous solutions. To date, MEBs have only been prepared from solutions containing chloride salts, owing to their relevance in natural salinity gradients created from seawater and freshwater. We hypothesized that MEBs could capture energy using Ammonium Bicarbonate (AmB), a thermolytic salt that can be used to convert waste heat into salinity gradients. We examined six battery electrode materials. Several of the electrodes were unstable in AmB solutions or failed to produce expected voltages. Of the electrode materials tested, a cell containing a manganese oxide electrode and a metallic lead electrode produced the highest power density (6.3 mW m−2). However, this power density is still low relative to previously reported NaCl-based MEBs and heat recovery systems. This proof-of-concept study demonstrated that MEBs could indeed be used to generate electricity from AmB salinity gradients.

  • Comparison of hydrogen production and electrical power generation for energy capture in closed-loop Ammonium Bicarbonate reverse electrodialysis systems
    Physical Chemistry Chemical Physics, 2014
    Co-Authors: Marta C Hatzell, Ivan Ivanov, Roland D. Cusick, Xiuping Zhu, Bruce E Logan

    Abstract:

    Currently, there is an enormous amount of energy available from salinity gradients, which could be used for clean hydrogen production. Through the use of a favorable oxygen reduction reaction (ORR) cathode, the projected electrical energy generated by a single pass Ammonium Bicarbonate reverse electrodialysis (RED) system approached 78 W h m(-3). However, if RED is operated with the less favorable (higher overpotential) hydrogen evolution electrode and hydrogen gas is harvested, the energy recovered increases by as much ~1.5× to 118 W h m(-3). Indirect hydrogen production through coupling an RED stack with an external electrolysis system was only projected to achieve 35 W h m(-3) or ~1/3 of that produced through direct hydrogen generation.

  • evaluation of flow fields on bubble removal and system performance in an Ammonium Bicarbonate reverse electrodialysis stack
    Journal of Membrane Science, 2013
    Co-Authors: Marta C Hatzell, Bruce E Logan

    Abstract:

    Abstract Ammonium Bicarbonate has recently been demonstrated to be an excellent thermolytic solution for energy generation in reverse electrodialysis (RED) stacks. However, operating RED stacks at room temperatures can promote gaseous bubble (CO2, NH3) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were analyzed to determine how both fluid flow and the buildup and removal of bubbles affected performance. In the presence of a spacer, the membrane resistance increased by ∼50 Ω, resulting in a decrease in power density by 30% from 0.140 W m−2 to 0.093 W m−2. Shorter channels reduced concentration polarization affects, and resulted in 3−23% higher limiting current density. Gas accumulation was minimized through the use of short vertically aligned channels, and consequently the amount of the membrane area covered by bubbles was reduced from ∼20% to 7% which caused a 12% increase in power density. As Ammonium Bicarbonate RED systems are scaled up, attention to channel aspect ratio, length, and alignment will enable more stable performance.

Ewan J Mcadam – 2nd expert on this subject based on the ideXlab platform

  • Controlling shell-side crystal nucleation in a gas–liquid membrane contactor for simultaneous Ammonium Bicarbonate recovery and biogas upgrading
    Journal of Membrane Science, 2020
    Co-Authors: Andrew J Mcleod, P Buzatu, Olivier Autin, Bruce Jefferson, Ewan J Mcadam

    Abstract:

    Abstract A gas–liquid hollow fibre membrane contactor (HFMC) process has been introduced for carbon dioxide (CO2) separation from biogas where aqueous ammonia (NH3) is used to chemically enhance CO2 absorption and initiate heterogeneous nucleation of the reaction product Ammonium Bicarbonate at the membrane–solvent interface. Aqueous ammonia absorbents (2–7 M) were initially used in single pass for CO2 separation from a synthetic biogas where nucleation of Ammonium Bicarbonate crystals was observed at the perimeter of the micropores. Recirculation of the aqueous ammonia absorbent encouraged the growth of Ammonium Bicarbonate crystals on the shell-side of the membrane that measured several microns in diameter. However, at high aqueous NH3 concentrations (3–7 M), lumen side crystallisation occurred and obstructed gas flow through the lumen of the HFMC. The suggested mechanism for lumen-side crystallisation was absorbent breakthrough into the lumen due to pore wetting which was promoted by low absorbent surface tension at high NH3 concentration. Preferential shell-side nucleation can therefore be promoted by (1) raising surface tension of the absorbent and (2) selection of a membrane with a more regulated pore shape than the PTFE membrane used (d/L 0.065) as both actions can diminish solvent ingress into the pore. This was evidenced using 2 M NH3 absorbent where shell-side crystallisation was evidenced without the onset of lumen side crystallisation. Raising surface tension through the inclusion of salt into the chemical absorbent also promoted greater CO2 flux stability. Importantly, this study demonstrates that chemically enhanced HFMC are an attractive prospect for gas–liquid separation applications where reaction product recovery offers further economic value.

  • recovery and concentration of ammonia from return liquor to promote enhanced co2 absorption and simultaneous Ammonium Bicarbonate crystallisation during biogas upgrading in a hollow fibre membrane contactor
    Separation and Purification Technology, 2020
    Co-Authors: Salvatore Bavarella, Mehrez Hermassi, A Brookes, A Moore, P Vale, Ilshik Moon, Marc Pidou, Ewan J Mcadam

    Abstract:

    Abstract In this study, thermal desorption was developed to separate and concentrate ammonia from return liquor, for use as a chemical absorbent in biogas upgrading, providing process intensification and the production of crystalline Ammonium Bicarbonate as the final reaction product. Applying modest temperature (50 °C) in thermal desorption suppressed water vapour pressure and increased selective transport for ammonia from return liquor (0.11MNH3) yielding a concentrated condensate (up to 1.7MNH3). Rectification was modelled through second-stage thermal processing, where higher initial ammonia concentration from the first stage increased mass transfer and delivered a saturated ammonia solution (6.4MNH3), which was sufficient to provide chemically enhanced CO2 separation and the simultaneous initiation of Ammonium Bicarbonate crystallisation, in a hollow fibre membrane contactor. Condensate recovered from return liquor exhibited a reduction in surface tension. We propose this is due to the stratification of surface active agents at the air-liquid interface during primary-stage thermal desorption which carried over into the condensate, ‘salting’ out CO2 and lowering the kinetic trajectory of absorption. However, crystal induction (the onset of nucleation) was comparable in both synthetic and thermally recovered condensates, indicating the thermodynamics of crystallisation to be unaffected by the recovered condensate. The membrane was evidenced to promote heterogeneous primary nucleation, and the reduction in the recovered condensate surface tension was shown to exacerbate nucleation rate, due to the reduction in activation energy. X-ray diffraction of the crystals formed, showed the product to be Ammonium Bicarbonate, demonstrating that thermal desorption eliminates cation competition (e.g. Ca2+) to guarantee the formation of the preferred crystalline reaction product. This study identifies an important synergy between thermal desorption and membrane contactor technology that delivers biogas upgrading, ammonia removal from wastewater and resource recovery in a complimentary process.

  • controlling shell side crystal nucleation in a gas liquid membrane contactor for simultaneous Ammonium Bicarbonate recovery and biogas upgrading
    Journal of Membrane Science, 2015
    Co-Authors: Andrew J Mcleod, P Buzatu, Olivier Autin, Bruce Jefferson, Ewan J Mcadam

    Abstract:

    Abstract A gas–liquid hollow fibre membrane contactor (HFMC) process has been introduced for carbon dioxide (CO2) separation from biogas where aqueous ammonia (NH3) is used to chemically enhance CO2 absorption and initiate heterogeneous nucleation of the reaction product Ammonium Bicarbonate at the membrane–solvent interface. Aqueous ammonia absorbents (2–7 M) were initially used in single pass for CO2 separation from a synthetic biogas where nucleation of Ammonium Bicarbonate crystals was observed at the perimeter of the micropores. Recirculation of the aqueous ammonia absorbent encouraged the growth of Ammonium Bicarbonate crystals on the shell-side of the membrane that measured several microns in diameter. However, at high aqueous NH3 concentrations (3–7 M), lumen side crystallisation occurred and obstructed gas flow through the lumen of the HFMC. The suggested mechanism for lumen-side crystallisation was absorbent breakthrough into the lumen due to pore wetting which was promoted by low absorbent surface tension at high NH3 concentration. Preferential shell-side nucleation can therefore be promoted by (1) raising surface tension of the absorbent and (2) selection of a membrane with a more regulated pore shape than the PTFE membrane used (d/L 0.065) as both actions can diminish solvent ingress into the pore. This was evidenced using 2 M NH3 absorbent where shell-side crystallisation was evidenced without the onset of lumen side crystallisation. Raising surface tension through the inclusion of salt into the chemical absorbent also promoted greater CO2 flux stability. Importantly, this study demonstrates that chemically enhanced HFMC are an attractive prospect for gas–liquid separation applications where reaction product recovery offers further economic value.

Hailin Wang – 3rd expert on this subject based on the ideXlab platform

  • an Ammonium Bicarbonate enhanced stable isotope dilution uhplc ms ms method for sensitive and accurate quantification of acrolein dna adducts in human leukocytes
    Analytical Chemistry, 2013
    Co-Authors: Chao Zhao, Meiling Lu, Moonshong Tang, Hailin Wang

    Abstract:

    Acrolein (Acr), a ubiquitous environmental pollutant, can react directly with genomic DNA to form mutagenic adducts without undergoing metabolic activation. To sensitively and accurately quantify Acr–DNA adducts (including structural isomers and stereoisomers) in human leukocytes, we developed an enhanced stable isotope dilution ultrahigh performance liquid chromatography (UHPLC)–tandem mass spectrometry (MS/MS) method using Ammonium Bicarbonate (NH4HCO3), which is thermally unstable and degrades readily to carbon dioxide and ammonia in heated gas phase. Interestingly, Ammonium Bicarbonate (as an additive to the mobile phase) not only improves the protonation of AcrdG adducts but also suppresses the formation of MS signal-deteriorating metal–AcrdG complexes during electrospray ionization, leading to the enhancement of their MS detection by 2.3–8.7 times. In contrast, routinely used Ammonium salts (Ammonium acetate and Ammonium formate) and formic acid do not show similar enhancement. The developed method …

  • An Ammonium Bicarbonate-Enhanced Stable Isotope Dilution UHPLC-MS/MS Method for Sensitive and Accurate Quantification of Acrolein–DNA Adducts in Human Leukocytes
    Analytical Chemistry, 2013
    Co-Authors: Chao Zhao, Meiling Lu, Moonshong Tang, Hailin Wang

    Abstract:

    Acrolein (Acr), a ubiquitous environmental pollutant, can react directly with genomic DNA to form mutagenic adducts without undergoing metabolic activation. To sensitively and accurately quantify Acr–DNA adducts (including structural isomers and stereoisomers) in human leukocytes, we developed an enhanced stable isotope dilution ultrahigh performance liquid chromatography (UHPLC)–tandem mass spectrometry (MS/MS) method using Ammonium Bicarbonate (NH4HCO3), which is thermally unstable and degrades readily to carbon dioxide and ammonia in heated gas phase. Interestingly, Ammonium Bicarbonate (as an additive to the mobile phase) not only improves the protonation of AcrdG adducts but also suppresses the formation of MS signal-deteriorating metal–AcrdG complexes during electrospray ionization, leading to the enhancement of their MS detection by 2.3–8.7 times. In contrast, routinely used Ammonium salts (Ammonium acetate and Ammonium formate) and formic acid do not show similar enhancement. The developed method …