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   Saidi, Wissam A.; Shadid, Waseem; Veser, Götz (June 2021, The Journal of Physical Chemistry Letters)
2. Improving Absorbent-Enhanced Ammonia Separation For Efficient Small-Scale Ammonia Synthesis

   https://doi.org/10.1021/acs.iecr.3c04351  

   Onuoha, Chinomso E; Kale, Matthew J; Malmali, Mahdi; Dauenhauer, Paul J; McCormick, Alon V (April 2024, Industrial & Engineering Chemistry Research)

   Synthesized ammonia exiting a reactor with hydrogen and nitrogen can be selectively absorbed by MgCl2 for renewable absorbent-based Haber-Bosch for dispersed ammonia manufacturing. Such separation can be more efficient even at elevated temperatures compared to the condensation method used in the conventional Haber-Bosch process. To determine the optimal conditions to capture and release the most ammonia per thermal cycle of the sorbent salt, the sorbent capacity was measured with varying regeneration temperature, regeneration time, and sweep rate under steady-state cycling conditions. In all cases, uptake was limited to bed breakthrough, and cyclic steady state was achieved. By using a lower temperature for MgCl2 regeneration (200 °C), the working capacities were maintained comparable to those at higher desorption temperatures (∼400 °C), even without the use of inert sweep gas. Using a sufficiently high regeneration temperature (∼200 °C) allowed for sufficiently low sweep gas so that the product ammonia can exceed 72 mol % purity in a mixture of N2 and H2. These results were achieved with a short regeneration time of 20 min or less, which is an improvement from the hour-long regeneration time previously reported. These measurements identified new operating parameters for more efficient absorber design to produce economical renewable ammonia at small scale. 

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3. Decomposition of ammonia on ZrB2(0001)

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4. A Decade of Electrochemical Ammonia Synthesis

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5. Thermophilic Geobacillus WSUCF1 Secretome for Saccharification of Ammonia Fiber Expansion and Extractive Ammonia Pretreated Corn Stover

   https://doi.org/10.3389/fmicb.2022.844287  

   Bhalla, Aditya; Arce, Jessie; Ubanwa, Bryan; Singh, Gursharan; Sani, Rajesh K.; Balan, Venkatesh (May 2022, Frontiers in Microbiology)

   A thermophilic Geobacillus bacterial strain, WSUCF1 contains different carbohydrate-active enzymes (CAZymes) capable of hydrolyzing hemicellulose in lignocellulosic biomass. We used proteomic, genomic, and bioinformatic tools, and genomic data to analyze the relative abundance of cellulolytic, hemicellulolytic, and lignin modifying enzymes present in the secretomes. Results showed that CAZyme profiles of secretomes varied based on the substrate type and complexity, composition, and pretreatment conditions. The enzyme activity of secretomes also changed depending on the substrate used. The secretomes were used in combination with commercial and purified enzymes to carry out saccharification of ammonia fiber expansion (AFEX)-pretreated corn stover and extractive ammonia (EA)-pretreated corn stover. When WSUCF1 bacterial secretome produced at different conditions was combined with a small percentage of commercial enzymes, we observed efficient saccharification of EA-CS, and the results were comparable to using a commercial enzyme cocktail (87% glucan and 70% xylan conversion). It also opens the possibility of producing CAZymes in a biorefinery using inexpensive substrates, such as AFEX-pretreated corn stover and Avicel, and eliminates expensive enzyme processing steps that are used in enzyme manufacturing. Implementing in-house enzyme production is expected to significantly reduce the cost of enzymes and biofuel processing cost. 

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