Recent Submissions

  • Electropolymerization of robust conjugated microporous polymer membranes for rapid solvent transport and narrow molecular sieving

    Zhou, Zongyao; Li, Xiang; Guo, Dong; Shinde, Digambar; Lu, Dongwei; Chen, Long; Liu, Xiaowei; Cao, Li; Aboalsaud, Ammar M.; Hu, Yunxia; Lai, Zhiping (Nature Communications, Springer Science and Business Media LLC, 2020-10-21) [Article]
    Abstract Pore size uniformity is one of the most critical parameters in determining membrane separation performance. Recently, a novel type of conjugated microporous polymers (CMPs) has shown uniform pore size and high porosity. However, their brittle nature has prevented them from preparing robust membranes. Inspired by the skin-core architecture of spider silk that offers both high strength and high ductility, herein we report an electropolymerization process to prepare a CMP membrane from a rigid carbazole monomer, 2,2’,7,7’-tetra(carbazol-9-yl)-9,9’-spirobifluorene, inside a robust carbon nanotube scaffold. The obtained membranes showed superior mechanical strength and ductility, high surface area, and uniform pore size of approximately 1 nm. The superfast solvent transport and excellent molecular sieving well surpass the performance of most reported polymer membranes. Our method makes it possible to use rigid CMPs membranes in pressure-driven membrane processes, providing potential applications for this important category of polymer materials.
  • A comprehensive experimental and kinetic modeling study of 1- and 2-pentene

    Dong, Shijun; Zhang, Kuiwen; Ninnemann, Erik; Najjar, Ahmed; Kukkadapu, Goutham; Baker, Jessica; Arafin, Farhan; Wang, Zhandong; Pitz, William J.; Vasu, Subith S.; Sarathy, Mani; Senecal, Peter K.; Curran, Henry J. (Combustion and Flame, Elsevier BV, 2020-10-15) [Article]
    1- and 2-pentene are components in gasoline and are also used as representative alkene components in gasoline surrogate fuels. Most of the available ignition delay time data in the literature for these fuels are limited to low pressures, high temperatures and highly diluted conditions, which limits the kinetic model development and validation potential of these fuels. Therefore, ignition delay time measurements under engine-like conditions are needed to provide target data to understand their low-temperature fuel chemistry and extend their chemical kinetic validation to lower temperatures and higher pressures. In this study, both a high-pressure shock tube and a rapid compression machine have been employed to measure ignition delay times of 1- and 2-pentene over a wide temperature range (600–1300 K) at equivalence ratios of 0.5, 1.0 and 2.0 in ‘air’, and at pressures of 15 and 30 atm. At high-temperatures (> 900 K), the experimental ignition delay times show that the fuel reactivities of 1- and 2-pentene are very similar at all equivalence ratios and pressures. However, at low temperatures, 1-pentene shows negative temperature coefficient behavior and a higher fuel reactivity compared to 2-pentene. Moreover, carbon monoxide time-histories for both 1- and 2-pentene were measured in a high-pressure shock tube for a stoichiometric mixture at 10 atm and at high temperatures. Furthermore, species versus temperature profiles were measured in a jet-stirred reactor at φ = 1.0 and 1 atm over a temperature range of 700–1100 K. All of these experimental data have been used to validate the current chemistry mechanism. Starting from a published pentane mechanism, modifications have been made to the 1- and 2-pentene sub-mechanisms resulting in overall good predictions. Moreover, flux and sensitivity analyses were performed to highlight the important reactions involved in the oxidation process.
  • Developing a Theoretical Approach for Accurate Determination of the Density and Thermochemical Properties of Energetic Ionic Liquids

    Li, Yang; Oommen, Charlie; Sarathy, Mani (Propellants, Explosives, Pyrotechnics, Wiley, 2020-10-14) [Article]
    Energetic ionic liquids (EILs) are novel explosives and propellants which are useful for a variety of military and industrial applications. The physicochemical properties of EILs play an important role in determining their performance in practical applications. In this study, a combination of ab initio and empirical methods has been developed to accurately predict the key properties of EILs: a) temperature-dependent heat of formation (ΔHf), entropy (S) and heat capacity (Cp) of cation/anion pairs in the gas phase; b) 298 K density (ρ) and heat of formation (ΔHf) of EILs in the condensed phase. Ab initio methods were selected based on comprehensive validations of the thermochemical properties of closed shell molecules (glyoxal), open shell radicals (vinylperoxy), triplet carbines (oxoethylidene), and the densities of various simple salts (LiF, NaF, KF, MgF2, CaF2, LiCl, NaCl, KCl, MgCl2, CaCl2). The CBS-APNO/G3/G4//M06-2X/6-311++G(d,p) level of theory was selected for the calculation of geometries, frequencies, energies, etc., and the CBS-APNO level of theory was chosen for calculating the original volumes of cations and anions. The proposed methods/approach calculated: a) the gas-phase thermochemistry of the cation/anion pairs of simple salts (Li+, Na+, K+, Mg2+, Ca2+, F− and Cl−) and six triazolium-based energetic salts (ESs) or EILs representatives (3-azido1,2,4-triazolium, 1-methyl-3-azido-1,2,4-triazolium, 1,4-dimethyl-3-azido-1,2,4-triazolium, nitrate and perchlorate), b) the condensed-phase density, lattice energy and heat of formation of ESs/EILs (3-azido1,2,4-triazolium nitrate, 3-azido-1,2,4-triazolium perchlorate, 1-methyl-3-azido-1,2,4-triazolium nitrate, 1-methyl-3-azido-1,2,4-triazolium perchlorate, 1,4-dimethyl-3-azido-1,2,4-triazolium nitrate and 1,4-dimethyl-3-azido-1,2,4-triazolium perchlorate). In comparison with experimental and theoretical results in literature, excellent agreement was observed for all properties. Overall, discrepancies were less than 10 %, a clear indication of the reliability of proposed methods/approach.
  • Investigating the Catalytic Active Sites of Mo/HZSM-5 and Their Deactivation During Methane Dehydroaromatization

    Wang, Ning; Dong, Xinglong; Liu, Lingmei; Cai, Dali; Wang, Jianjian; Hou, Yilin; Emwas, Abdul-Hamid M.; Gascon, Jorge; Han, Yu (SSRN Electronic Journal, Elsevier BV, 2020-10-09) [Article]
    Molybdenum supported on zeolite HZSM-5 (Mo/HZSM-5) is the most studied catalyst for methane dehydroaromatization (MDA). However, the nature of its catalytic active sites and their deactivation mechanisms remain unclear and controversial. Here we report new insights into this system, on the basis of advanced characterization and a rational design of experiments. We find that it is the size of the HZSM-5 crystal that determines the form and location of the catalytic active molybdenum carbide (MoCx) species, and thus the performance of Mo/HZSM-5; we also find that MoCx sites are preferentially deactivated over acid sites, when supported on nano-sized HZSM-5. These findings lead us to develop an “encapsulation” strategy, which effectively reconciles the deactivation rates at the MoCx sites and the acid sites, enabling a full utilization of both sites, and consequently leading to a 10-fold increase in catalyst lifetime and aromatics yield. Our results indicate that MoCx particles formed outside the micropores of HZSM-5, which are traditionally considered detrimental to the reaction, can serve as active sites for MDA, provided that they are properly protected from direct exposure to coke deposition. These findings allow us to design control experiments to answer an open question whether the acid sites, in addition to promoting the dispersion of Mo species, play a catalytic role in the MDA reaction, and the results show that acid sites are indeed essential for the conversion of methane.
  • Symmetry Breaking in Monometallic Nanocrystals toward Broadband and Direct Electron Transfer Enhanced Plasmonic Photocatalysis

    Shao, Wei; Pan, Qianqian; Chen, Qiaoli; Zhu, Chongzhi; Tao, Weijian; Zhu, Haiming; Song, Huijun; Liu, Xuelu; Tan, Ping-Heng; Sheng, Guan; Sun, Tulai; Li, Xiaonian; Zhu, Yihan (Advanced Functional Materials, Wiley, 2020-10-08) [Article]
    Metallic nanocrystals manifest themselves as fascinating light absorbers for applications in plasmon-enhanced photocatalysis and solar energy harvesting. The essential challenges lie in harvesting the full-spectrum solar light and harnessing the plasmon-induced hot carriers at the metal–acceptor interface. To this end, a cooperative overpotential and underpotential deposition strategy is proposed to mitigate both the challenges. Specifically, by utilizing both ionic additive and thiol passivator to introduce symmetry-breaking growth over gold icosahedral nanocrystals, the microscopic origin can be attributed to the site-specific nucleation of stacking faults and dislocations. By adopting asymmetric crystal shape and unique surface facets, such nanocrystals attain high activity toward photocatalytic ammonia borane hydrolysis, arising from combined broadband plasmonic properties and enhanced direct transfer of hot electrons across the metal–adsorbate interface.
  • Methane Dry Reforming on Supported Cobalt Nanoparticles Promoted by Boron

    Al Abdulghani, Abdullah; Park, Jung-Hyun; Kozlov, Sergey; Kang, Dong-Chang; Al-Sabban, Bedour E.; Pedireddy, Srikanth; Aguilar-Tapia, Antonio; Ould-Chikh, Samy; Hazemann, Jean-Louis; Basset, Jean-Marie; Cavallo, Luigi; Takanabe, Kazuhiro (Journal of Catalysis, Elsevier BV, 2020-09-26) [Article]
    Stable operations for catalytic dry reforming of methane (DRM) is essential for industrial applications. High stability for the syngas production can be achieved via a kinetic balance between formation of carbon species and their removal by oxygen species on the metal surface, which clears the surface for further reaction steps. This study reports highly stable performances by a boron-doped cobalt catalyst as a non-noble-metal, coking-free catalyst. Although the precise location of doped boron could not be identified experimentally because of its low concentration, density functional theory (DFT) calculations suggested that interstitial boron (B) is most likely present in the subsurface region of cobalt (Co) surfaces. B-doping was shown both experimentally and computationally to increase the reactivity of Co catalysts toward both methane (CH4) and carbon dioxide (CO2). Moreover, B-doping was found to balance the amounts of surface C and O and maintain the reduced state of Co surfaces while in a steadystate. Nevertheless, a negative kinetic order with respect to CO2 partial pressure indicates that steady-state surface coverage of oxygen species originating from CO2 dissociation was prevalent on B-doped Co, consistent with the coking-free nature of the catalyst. This study introduces a promising Co-B catalyst design for controlling metal surface reactivity toward DRM and relevant catalytic reactions.
  • CO2/CH4 Pure- and Mixed-Gas Dilation and Sorption in Thin (∼500 nm) and Ultrathin (∼50 nm) Polymers of Intrinsic Microporosity

    Ogieglo, Wojciech; Genduso, Giuseppe; Rubner, Jens; Hofmann-Préveraud de Vaumas, Jacques; Wessling, Matthias; Pinnau, Ingo (Macromolecules, American Chemical Society (ACS), 2020-09-23) [Article]
    In this work, we present (i) the dilation and refractive index variation associated with changes in film density and (ii) gas uptake of pure CO2 and CH4, as well as their equimolar mixture in thin films of two polymers of intrinsic microporosity (PIMs), that is, PIM-1 and poly(trimethylsilyl)propyne (PTMSP). A conventional low-free-volume glassy polymer, cellulose triacetate, was also investigated as the reference material. All experiments were performed with ∼50 and ∼500 nm-thick films up to partial pressures of 25 bar using in situ interference-enhanced spectroscopic ellipsometry. In all cases, film thickness reduction promoted the collapse of the frozen-in free volume. Particularly for thin PIM-1 and PTMSP films, the CO2 and CH4 pure-gas uptakes were generally lower than in bulk samples. In the most extreme case of the ultrathin ∼50 nm PTMSP film, we could detect a strikingly similar qualitative behavior to the penetrant partial molar volume and dilation in rubbery polymers. Remarkably, in PIM-1, the collapse of the frozen-in free volume seemed to be opposed by its ultra-micropores (<7 Å), which was not the case in PTMSP with larger micropores (>10 Å). In mixed-gas experiments, the refractive index response of all investigated films closely followed the trend observed during CO2 pure-gas sorption. In both thickness ranges and throughout the entire pressure range, the samples dilated less in the multicomponent environment than under the corresponding ideal pure-gas conditions. We found this phenomenon consistent with the pure- and mixed-gas uptake behavior of PIM-1 and PTMSP bulk films reported in the literature.
  • Experimental and theoretical evidence for the temperature-determined evolution of PAH functional groups

    Liu, Peng; Chen, Bingjie; Li, Zepeng; Bennett, Anthony; Sioud, Salim; Pitsch, Heinz; Sarathy, Mani; Roberts, William L. (Proceedings of the Combustion Institute, Elsevier BV, 2020-09-22) [Article]
    Elucidating the chemical evolution of various functional groups in polycyclic aromatic hydrocarbons (PAH) and soot aids in understanding soot formation chemistry. In this work, the chemical evolution of various functional groups, including aromatic Csingle bondH, aliphatic Csingle bondH, C=O, Csingle bondOH and Csingle bondOsingle bondC bonds, was experimentally investigated online, rather than with offline diagnostics. Oxidation was performed in a jet-stirred reactor (JSR), fueled with benzene/C2H2/air/N2 and benzene/phenol/C2H2/N2 for a temperature range of 600-1400 K. Kinetic modelling, including ab initio quantum chemistry calculations, reaction rate coefficient calculations and JSR simulations, were conducted to interpret the experimental data and the evolutionary chemistry of the various functional groups. Results show that the formation of functional groups on PAH and oxygenated PAH (OPAH) are highly sensitive to temperature. Aliphatic Csingle bondH bonds survive mainly in the form of Csingle bondCH2single bondC, Csingle bondCH2single bondCH2single bondC or Ctriple bondCH functional groups above 1200 K, and exist in the CHdouble bondCH2 functional group below 1000 K. For the OPAH, the Csingle bondOsingle bondC functional group presents stronger thermal stability than Csingle bondOH and C=O functional groups. Simulation results indicate that HACA-like pathway (hydrogen abstraction carbon addition), in which C2H2 attacks the O atom, followed by cyclization and H-atom elimination reactions, qualitatively describe the formation of OPAH with the Csingle bondO-C functional group at different temperatures. The addition reaction involving PAH radical and C2H4 / C2H3 captures the evolution of PAH with the CHdouble bondCH2 functional group, but fails to explain the formation of Csingle bondCH2single bondC and Csingle bondCH2single bondCH2single bondC functional groups.
  • Global sensitivity analysis of n-butanol ignition delay times to thermodynamics class and rate rule parameters

    Hantouche, Mireille; Sarathy, Mani; Knio, Omar (Combustion and Flame, Elsevier BV, 2020-09-14) [Article]
    We study the variability in the ignition delay time, τign, of n-butanol due to uncertainty in the enthalpies and entropies of the fuel and fuel radicals. A stoichiometric mixture reacting adiabatically at constant volume is considered, over a range of initial temperatures (700–1000 K) and pressures (10–80 bar). We develop a thermodynamic class approach to account for the variability in the thermodynamic properties of species of interest, and to define associated uncertainty ranges. To gain insight into the impact of the variability of the thermodynamic properties of individual species, a brute force sensitivity analysis is first performed. The results show that large variations in τign are mainly due to perturbations in the enthalpies of six species belonging to two thermodynamic classes. A refined 1D analysis is then conducted of the uncertain enthalpies and entropies of these six species. In particular, a complex, nonmonotonic dependence of τign on species enthalpies is observed, highlighting potential limitations in extrapolating local sensitivity results. The 1D analysis also shows that uncertainties in species entropies have a weaker impact on the variability in τign than the species enthalpies. A global sensitivity analysis of the impact of thermodynamic class uncertainties is then performed, namely using surrogates constructed using an adaptive pseudo-spectral method. The results indicate that the variability of τign is dominated by uncertainties in the classes associated with peroxy and hydroperoxide radicals. Lastly, we perform a combined sensitivity analysis of uncertainty in kinetic rates and thermodynamic properties. In particular, the results indicate that uncertainties in thermodynamic properties can induce variabilities in ignition delay time that are as large as those associated with kinetic rate uncertainties.
  • Counterflow ignition and extinction of FACE gasoline fuels

    Alfazazi, Adamu; Mairinger, Gerald; Selim, Hatem; Seshadri, Kalyanasundaram; Sarathy, Mani (Proceedings of the Combustion Institute, Elsevier BV, 2020-09-11) [Article]
    The demand for petroleum-derived gasoline in the transportation sector is on the rise. For better knowledge of gasoline combustion in practical combustion systems, this study presents experimental measurements and numerical prediction of autoignition temperatures and extinction limits of six FACE (fuels for advanced combustion engines) gasoline fuels in counterflow flames. Extinction limits were measured at atmospheric pressures while the experiments for autoignition temperatures were carried out at atmospheric and high pressures. For atmospheric pressure experiment, the fuel stream consists of the pre-vaporized fuel diluted with nitrogen, while a condensed fuel configuration is used for ignition experiment at higher chamber pressures. The oxidizer stream is pure air. Autoignition temperatures of the tested fuels are nearly the same at atmospheric pressure, while a huge difference is observed as the pressure is increased. Unlike the ignition temperatures at atmospheric pressures, minor difference exists in the extinction limits of the tested fuels. Simulations were carried out using a recently developed gasoline surrogate model. Both multi-component and n-heptane/isooctane mixtures were used as surrogates for the simulations. Overall, the n-heptane/isooctane surrogate mixtures are consistently more reactive as compared the multi-component surrogate mixtures. Transport weighted enthalpy and radical index analysis was used to explain the differences in extinction strain rates for the various fuels.
  • Exploring low temperature oxidation of 1-butene in jet-stirred reactors

    Chen, Bingjie; Ilies, Bogdan Dragos; Chen, Weiye; Xu, Qiang; Li, Yang; Xing, Lili; Yang, Jiuzhong; Wei, Lixia; Hansen, Nils; Pitsch, Heinz; Sarathy, Mani; Wang, Zhandong (Combustion and Flame, Elsevier BV, 2020-09-10) [Article]
    1-butene is an important intermediate in combustion of various hydrocarbon fuels and oxygenated biofuels (e.g., butanol). Understanding its oxidation chemistry can help improve ignition and combustion process in advanced engines and provide better emission control. This work addresses a discrepancy between experiments and simulations in 1-butene oxidation at low temperatures, wherein simulations with AramcoMech 3.0 model show greater fuel reactivity than experiments. To further explore 1-butene low temperature reaction pathways from 550 to 910 K, experiments were conducted in three jet-stirred reactors: two coupled to time-of-flight molecular beam mass spectrometers with synchrotron vacuum ultraviolet radiation as the photoionization source, and one coupled to gas chromatography mass spectrometer. Isomeric structure identification, comprehensive species datasets, and reactor cross examinations are provided by the combination of three experiments. The identified isomer-resolved species provide evidence of various 1-butene low temperature reaction pathways. For example, the identification of propanal confirms the Waddington reaction pathway. The kinetic model over-predicts fuel reactivity in the low temperature regime (550–700 K). Updating the rate coefficients of key reactions in the Waddington pathways, e.g., forward and reverse isomerization of hydroxyl-butyl-peroxide to butoxyl-peroxide and Waddington decomposition of butoxyl-peroxide reduces the discrepancies. The role of rate constant updates in each step of the Waddington pathway is evaluated and discussed to provide directions for future model development.
  • SOILING LOSS RATE MEASUREMENTS OF PHOTOVOLTAIC MODULES IN A HOT AND HUMID DESERT ENVIRONMENT

    Abdullah, Marwan; Khayyat, Ahmad; Basaheeh, Ali; Kotsovos, Konstantinos; Ballard, Ian; AlSaggaf, Ahmed; Gereige, Issam; Theron, Ricardo (Journal of Solar Energy Engineering, ASME International, 2020-09-10) [Article]
    Abstract Power generation from renewable energy sources, in particular solar photovoltaics (PV), has become extremely attractive thanks to its very low levelized cost of electricity (LCoE). In desert-like environments, the energy yield is drastically reduced due to dust accumulation. While effective and affordable cleaning strategies can be implemented in large, MW-size PV power plants, soiling remains an economic and logistic challenge. In this paper, we analyze the soiling loss rates of PV modules for different tilt angles measured during a period of 15 months in the Western Region of Saudi Arabia. We observe a strong correlation between weather parameters like humidity and wind speed, and the mechanism of dust accumulation. Our measurements show that, for specific weather conditions, soiled modules undergo a partial cleaning process. As a consequence, and for the first time, the soiling loss rates are shown to have a clear dependence on the current soiling state of the modules, with clean modules soiling twice as fast as soiled ones. This dependency is key for predicting the correct cleaning frequency of a PV power plant. Finally, the results obtained for vertically mounted modules (90°), where dust accumulation is negligible, point to a favorable case for the use of bifacial PV modules.
  • Removal of Bacteria and Organic Carbon by an Integrated Ultrafiltration—Nanofiltration Desalination Pilot Plant

    Rehman, Zahid Ur; Khojah, Bayan; Leiknes, TorOve; Alsogair, Safiya; Alsomali, Mona (Membranes, MDPI AG, 2020-09-04) [Article]
    Fouling caused by organic matter and bacteria remains a significant challenge for the membrane-based desalination industry. Fouling decreases the permeate quality and membrane performance and also increases energy demands. Here, we quantified the amount of organic matter and bacteria at several stages along the water-treatment train of an integrated ultrafiltration–nanofiltration seawater treatment pilot plant. We quantified the organic matter, in terms of Total Organic Carbon (TOC) and Assimilable Organic Carbon (AOC), and evaluated its composition using Liquid Chromatography for Organic Carbon Detection (LC-OCD). The bacterial cells were counted using Bactiquant. We found that ultrafiltration (UF) was effective at removing bacterial cells (99.7%) but not TOC. By contrast, nanofiltration (NF) successfully removed both TOC (95%) and bacterial cells. However, the NF permeate showed higher amounts of AOC than seawater. LC-OCD analysis suggested that the AOC was mostly composed of low molecular weight neutral substances. Furthermore, we found that the cleaning of the UF membrane using chemically enhanced backwash reduced the amount of AOC released into the UF permeate. By implementing the cleaning-in-place of the NF membrane, the pressure drop was restored to the normal level. Our results show that the UF and NF membrane cleaning regimes investigated in this study improved membrane performance. However, AOC remained the hardest-to-treat fraction of organic carbon. AOC should, therefore, be monitored closely and regularly to mitigate biofouling in downstream processes.
  • Simultaneous generation of atmospheric water and electricity using a hygroscopic aerogel with fast sorption kinetics

    Yang, Kaijie; Pan, Tingting; Pinnau, Ingo; Shi, Zhan; Han, Yu (Nano Energy, Elsevier BV, 2020-09-02) [Article]
    Sorption-based atmospheric water harvesting (AWH) is a promising technology to produce clean potable water in arid areas with scarce freshwater resources. However, most sorbents developed for this technology can only perform one cycle of water production per day due to slow water-sorption kinetics. Moreover, the heat produced during this process in current AWH systems is discarded and ultimately wasted. Here, we design and fabricate a hygroscopic aerogel material that has high water-sorption capacity, fast sorption kinetics, and excellent photothermal properties, and thus enables highly efficient solar-thermal driven AWH over a wide range of relative humidity. Furthermore, we demonstrate with this aerogel the concept of a dual-function system that simultaneously generates electricity while extracting fresh water from the air. The dual-function system achieves this by combining AWH with thermoelectric technology and using natural sunlight as the sole energy input. The model system can produce a maximum output power density of 6.6 mW/m2 during the moisture capture process at the relative humidity of 60%, and 520 mW/m2 during the water release process under 1 kW/m2 solar irradiation. We verify the real-world application and utility of this novel concept by conducting outdoor experiments using a homemade prototype.
  • Stable High-Pressure Methane Dry Reforming Under Excess of CO2

    Ramirez, Adrian; Lee, Kunho; Harale, Aadesh; Gevers, Lieven; Telalovic, Selvedin; Al Solami, Bandar; Gascon, Jorge (ChemCatChem, Wiley, 2020-08-24) [Article]
    Dry reforming of methane (DRM), the conversion of carbon dioxide and methane into syngas, offers great promise for the recycling of CO2. However, fast catalyst deactivation, especially at the industrially required high pressure, still hampers this process. Here we present a comprehensive study of DRM operation at high pressure (7–28 bars). Our results demonstrate that, under equimolar CH4 : CO2 mixtures, coke formation is unavoidable at high pressures for all catalysts under study. However, under substoichiometric CH4 : CO2 ratios (1 : 3), a stable high pressure operation can be achieved for most catalysts with no sign of deactivation for at least 60 hours at 14 bars, 800 °C and 7500 h−1. In addition to the enhanced stability, under these conditions, the amount of CO2 abated per mol of CH4 fed increases by a 50 %.
  • A droplet reactor on a super-hydrophobic surface allows control and characterization of amyloid fibril growth

    Zhang, Peng; Moretti, Manola; Allione, Marco; Tian, Yuansi; Ordonez-Loza, Javier; Altamura, Davide; Giannini, Cinzia; Torre, Bruno; Das, Gobind; Li, Erqiang; Thoroddsen, Sigurdur T; Sarathy, Mani; Autiero, Ida; Giugni, Andrea; Gentile, Francesco; Malara, N.; Marini, Monica; Di Fabrizio, Enzo M. (Communications Biology, Springer Science and Business Media LLC, 2020-08-20) [Article]
    Methods to produce protein amyloid fibrils, in vitro, and in situ structure characterization, are of primary importance in biology, medicine, and pharmacology. We first demonstrated the droplet on a super-hydrophobic substrate as the reactor to produce protein amyloid fibrils with real-time monitoring of the growth process by using combined light-sheet microscopy and thermal imaging. The molecular structures were characterized by Raman spectroscopy, X-ray diffraction and X-ray scattering. We demonstrated that the convective flow induced by the temperature gradient of the sample is the main driving force in the growth of well-ordered protein fibrils. Particular attention was devoted to PHF6 peptide and full-length Tau441 protein to form amyloid fibrils. By a combined experimental with the molecular dynamics simulations, the conformational polymorphism of these amyloid fibrils were characterized. The study provided a feasible procedure to optimize the amyloid fibrils formation and characterizations of other types of proteins in future studies.
  • A Reliable & Novel approach based on Thermodynamic Property estimation of Low to High Salinities Aqueous Sodium Chloride Solutions for Water-Energy Nexus (WEN) Applications

    Rehman, Lubna Muzamil; Dey, Ranjan; Lai, Zhiping; Ghosh, Asim K; Roy, Anirban (Industrial & Engineering Chemistry Research, American Chemical Society (ACS), 2020-08-17) [Article]
    There is a significant need for reliable and accurate thermodynamic property data of hypersaline solutions to understand the minimum heat and work of separation required and is quite useful for large scale desalination and water – energy nexus (WEN) applications. WEN related technological developments are posed to dominate the scientific pursuits in the coming decade. In this regard, an understanding on the thermo-acoustical parameters of hypersaline NaCl-water systems has been carried out in this study which may lead to a better understanding of WEN. An analysis of thermodynamic properties such as free volume, intermolecular free length, isothermal compressibility, isobaric expansibility, relaxation time, and internal pressures using ultrasonic velocity, has assisted us in understanding the various interactions occurring in hypersaline solutions (up to 100 g/kg). A new correlation for internal, osmotic and vapour pressure determination has been proposed in this work. The evaluation of relaxation time showed a minimum value around the concentration range of 25-40g/kg, which could explain the observed seawater salt concentrations at ambient temperatures. A linear variation was observed between osmotic pressure and internal pressure, which shed light on their interdependency. A detailed analysis on the energetics of hypersaline NaCl-water solutions has also been done to emphasize the fact that one must work on the extraction of osmotic power from hypersaline solutions. This work presents a comprehensive framework derived from an understanding of thermo-acoustical parameters of hypersaline solutions, their critical analysis and a look into its application in Osmotic Power Generation technologies.
  • CO2 Derived E-Fuels: Research Trends, Misconceptions, and Future Directions

    Ramirez, Adrian; Sarathy, Mani; Gascon, Jorge (Trends in Chemistry, Elsevier BV, 2020-08-15) [Article]
    The transport sector is responsible for nearly a quarter of total CO2 emissions and consumes more than 50% of the total liquid hydrocarbons produced, with more than 95% of the sector today continuing to rely on liquid hydrocarbons. There is an imminent need to commercialize low-carbon or carbon-neutral liquid hydrocarbon fuels using renewable H2 and CO2 as the building blocks, the so-called e-fuels. To completely replace the use of petroleum hydrocarbons, it is important for e-fuels to be fully (or to require very minor adaptations to be) compatible with existing fuel distribution infrastructure and vehicle technologies, such that they are literally drop-in replacements. This short opinion article highlights the necessary properties that e-fuels should display to become a drop-in alternative to traditional petroleum-derived fuels and revisits the current trends and limitations in the field of CO2 conversion to fuels.
  • Solution processable metal–organic frameworks for mixed matrix membranes using porous liquids

    Knebel, Alexander; Bavykina, Anastasiya; Datta, Shuvo Jit; Sundermann, Lion; Garzon Tovar, Luis Carlos; Lebedev, Yury; Durini, Sara; Ahmad, Rafia; Kozlov, Sergey; Shterk, Genrikh; Karunakaran, Madhavan; Carja, Ionela-Daniela; Simic, Dino; Weilert, Irina; Klüppel, Manfred; Giese, Ulrich; Cavallo, Luigi; Rueping, Magnus; Eddaoudi, Mohamed; Caro, Jürgen; Gascon, Jorge (Nature Materials, Springer Science and Business Media LLC, 2020-08-10) [Article]
    The combination of well-defined molecular cavities and chemical functionality makes crystalline porous solids attractive for a great number of technological applications, from catalysis to gas separation. However, in contrast to other widely applied synthetic solids such as polymers, the lack of processability of crystalline extended solids hampers their application. In this work, we demonstrate that metal-organic frameworks, a type of highly crystalline porous solid, can be made solution processable via outer surface functionalization using N-heterocyclic carbene ligands. Selective outer surface functionalization of relatively large nanoparticles (250 nm) of the well-known zeolitic imidazolate framework ZIF-67 allows for the stabilization of processable dispersions exhibiting permanent porosity. The resulting type III porous liquids can either be directly deployed as liquid adsorbents or be co-processed with state-of-the-art polymers to yield highly loaded mixed matrix membranes with excellent mechanical properties and an outstanding performance in the challenging separation of propylene from propane. We anticipate that this approach can be extended to other metal-organic frameworks and other applications.
  • Gas separation and water desalination performance of defect-free interfacially polymerized para-linked polyamide thin-film composite membranes

    Ali, Zain; Wang, Yingge; Ogieglo, Wojciech; Pacheco Oreamuno, Federico; Vovusha, Hakkim; Han, Yu; Pinnau, Ingo (Journal of Membrane Science, Elsevier BV, 2020-08-10) [Article]
    Introduction of interfacially polymerized (IP) polyamide thin-film composite (TFC) membranes in the 1980s revolutionized the reverse osmosis desalination industry. However, IP-derived TFCs have not achieved industrial success for gas separation applications due to the presence of membrane defects in their dry state. In this work, we report defect-free crosslinked polyamide thin-film composite membranes prepared from para-substituted aromatic and cycloaliphatic diamines, p-phenylenediamine (PPD) and piperazine (PIP), reacted with trimesoyl chloride (TMC). The key parameters in our modified IP process to mitigate defects are long reaction time (∼5 min) and high organic solution temperature (100 °C). The gas separation and desalination properties of the para-linked polyamide membranes were compared to previously reported polyamide TFCs made from meta-phenylenediamine (MPD) and TMC. The gas- and water permeances of the TFCs increased in the order: MPD-TMC < PPD-TMC < PIP-TMC, whereas gas-pair selectivities and salt rejections followed the opposite sequential trend: MPD-TMC > PPD-TMC ≥ PIP-TMC. Elimination of defects allowed exploitation of the ultra-selective nature of polyamide TFCs, specifically for hydrogen and helium separations. At 23 °C, PIP-TMC, PPD-TMC and MPD-TMC exhibited H2/CH4 selectivities of 312, 362 and 1290, respectively, with moderate H2 permeances of 37.4, 32.6 and 25.8 GPU (1 GPU = 10−6 cm3(STP) cm−2 s−1 cmHg−1). Furthermore, the TFCs demonstrated excellent performance for H2/CO2 separation with pure-gas selectivities of 10-14 at 23 °C. The strong size-sieving capability of the polyamide TFCs originated from tight interchain packing induced by strong hydrogen bonding. Wide-angle X-ray diffraction confirmed a dominant fraction of submicropores of less than ∼4 Å within PPD-TMC and PIP-TMC polyamide networks.

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