Papers by Ah-Hyung Alissa Park
This report on carbon capture, use, and storage (CCUS) answers the Secretary of Energy's requ... more This report on carbon capture, use, and storage (CCUS) answers the Secretary of Energy's request for advice on the actions needed to deploy CCUS technologies at scale in the United States. The report concludes that at-scale deployment requires strong collaboration between industry and government; improved policies, financial incentives, and regulations; broad-based innovation and technology development; and increased understanding and confidence in CCUS–to create a roadmap for achieving at-scale deployment over the next 25 years
Chemical Engineering Journal, 2020
heattreated serpentine were studied by 29 Si MAS NMR. • Chemical stabilities of different silicat... more heattreated serpentine were studied by 29 Si MAS NMR. • Chemical stabilities of different silicate structures (Q 0-Q 4) were determined. • The amorphous Q 1 and Q 2 structures were most reactive in carbonic acid. • This study identified different reaction pathways for CO 2 sequestration.
Chemical Engineering Journal
Journal of The Electrochemical Society
Nanoscale
Liquid nano-absorbents have become a topic of interest as a result of their enhanced mass-transfe... more Liquid nano-absorbents have become a topic of interest as a result of their enhanced mass-transfer performance for CO2 capture. They are believed to revolutionize conventional CO2 chemisorption process by largely...
Energy Procedia
District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.
Green Chemistry
The amount of electronic waste (e-waste) globally has doubled in just five years, from approximat... more The amount of electronic waste (e-waste) globally has doubled in just five years, from approximately 20 million tons to 40 million tons of e-waste generated per year. In 2016, the...
ACS Photonics
To fabricate passive metasurface devices, silicon wafers were cleaned using Acetone, IPA, and DI ... more To fabricate passive metasurface devices, silicon wafers were cleaned using Acetone, IPA, and DI water, followed by oxygen plasma cleaning for 5 mins. Then an 80-nm Au thin film was deposited onto the pre-cleaned silicon wafers using electron-beam (e-beam) deposition. Next, a 400-nm SiO 2 layer was deposited onto the gold coated silicon wafers using plasma enhanced chemical vapor deposition (PECVD), followed by oxygen plasma cleaning for 2 mins. To pattern nanoantennas on the SiO 2 /Au/Si wafers, two layers of poly(methyl methacrylate) (PMMA) e-beam resist (i.e., 495K PMMA A4 and 950K PMMA A2) were spun onto the wafers. The wafers were baked at 180 o C for 5 mins after spin-coating of the first e-beam resist layer (i.e., 495K PMMA A4) and for 3 mins after spin-coating of the second layer (i.e., 950K PMMA A2). To prevent strong charging effects during e-beam exposure, a layer of Espacer 300Z was spun on the wafers, followed by baking at 100 o C for 2 mins. The nanoantenna array was patterned using e-beam lithography (i.e., electron-beam exposure using JEOL6300-FX at a beam current of 200 pA). Proximity effect correction was used during e-beam exposure. After exposure, the devices were first rinsed in DI water to remove Espacer, and then developed in a mixture of IPA and DI at 5 o C. Finally, a 4-nm Ti adhesion layer and a 45-nm Au thin film were deposited onto the devices using e-beam
Aerosol and Air Quality Research
Accelerated carbonation using alkaline solid wastes has been considered an effective approach to ... more Accelerated carbonation using alkaline solid wastes has been considered an effective approach to mineralizing flue gas CO 2 from industries or power plants. Despite its recent progress, mechanistic understanding and modelling at interface levels are still needed to control the reactivity and equilibrium of the reaction system. This review focuses on several phenomenological models for accelerated carbonation that look at the solid-fluid interface. We first illustrate the principles of kinetic and mass transfer driven reactions for CO 2-mineral-water systems. Then, we provide an overview into the reaction mechanisms and modelling for CO 2 mineralization including leaching-precipitation model, shrinking core model and surface coverage model. Advanced models considering multiple mechanisms, such as two-layer diffusion model, are also discussed. Finally, the perspectives and prospects are provided to shine a light on future directions, including incorporation of structural and physical properties in phenomenological models, identification of dynamic speciation by in-situ high-resolution equipment, and integration of heat transfer in reaction modelling for system optimization.
Journal of Energy Chemistry
Green Energy & Environment, 2016
The development of alternative CO 2 capture solvents such as ionic liquids (ILs) and nanoparticle... more The development of alternative CO 2 capture solvents such as ionic liquids (ILs) and nanoparticle organic hybrid materials (NOHMs) have provided interesting options for CO 2 capture. In this study, CO 2 interactions with 1,3-dimethylimidazolium dimethylphosphate ([MMIM]DMP), 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DMP) and 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM]DEP) that contain inorganic ester groups based on phosphate, were investigated using ATR FT-IR spectroscopy. CO 2-induced swelling, CO 2 diffusivity and CO 2 capture capacity were simultaneously measured to identify CO 2 capture mechanisms, kinetics and diffusion behaviors as a function of the alkyl chain length of the cation. Henry's law constants of CO 2 were found to be in the range of 4e11 MPa, which is in agreement with those reported in other studies.
Chemical Engineering Science, 2017
Biopolymers, 2014
Mineralization has emerged as a promising strategy for long-term carbon sequestration. These proc... more Mineralization has emerged as a promising strategy for long-term carbon sequestration. These processes involve carbon dioxide hydration followed by mineral precipitation. We have explored the production of whole-cell biocatalysts engineered with carbonic anhydrase (CA) activity to accelerate the CO₂ hydration reaction. In this study, short polypeptides were displayed on the surface of E. coli cells and whole-cell biocatalysts containing periplasmically expressed CAs in an attempt to enhance calcite mineral formation. It was found that cells coexpressing recombinant periplasmic CA and surface-displayed GPA peptide (PEVPEGAFDTAI) outperformed other peptide-expressing biocatalysts evaluated in terms of the amount of precipitate formed, as well as the overall formation rate of solids. Cells expressing the Cab CA isoform (BLR-pCab) and Cam isoform (BLR-pCam) with the surface-displayed GPA peptide exhibited 36 and 59% improvements in precipitation amounts, as well as 18 and 60% improvemen...
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Papers by Ah-Hyung Alissa Park