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Schematic diagram of the BIT adsorptive photo-Fenton-like degradation mechanism over NH2-MIL-53(Fe) under solar light irradiation.

The techno-economic analysis is vital for the large-scale industrialization of a particular potential amine solvent. This paper proposes a techno-economic evaluation method to assess amine-based CO2 capture processes rapidly. The method’s validity is verified by using the DEEA-HMDA blend as an example. The DEEA-HDMA blend was also compared with various conventional amine solutions in terms of the CO2 solubility, KGav, reaction heat technical indicators and its corresponding economic indicators. Operating expenditure (OPEX) included both solvent consumption and energy requirements, and capital expenditure (CAPEX) was mainly for packed column construction. CAPEX (0.989 MUSD/tCO2) and OPEX (0.196 MUSD/tCO2) of using DEEA-HMDA as a CO2 absorbent were lower than MEA solutions with percentages of 23.3% and 1.2%, respectively. In conclusion, using the techno-economic method proposed in this paper for the economic evaluation of seven amine solvents shows that DEEA-HMDA is a potential carbon capture alternative solvent.

We studied thermal evolution of isolated neutron stars (NSs) including the pion condensation core, with an emphasis on the stiffness of equation of state (EOS). Many temperature observations can be explained by the minimal cooling scenario which excludes the fast neutrino cooling process. However, several NSs are cold enough to require it. The most crucial problem for NS cooling theory is whether the nucleon direct Urca (DU) process is open. The DU process is forbidden if the nucleon symmetry energy is significantly low. Hence, another fast cooling process is required in such an EOS. As the candidate to solve this problem, we consider the pion condensation. We show that the low-symmetry-energy model can account for most cooling observations including cold NSs, with strong neutron superfluidity. Simultaneously, it holds the $2~M_{\odot}$ observations even if the pion condensation core exists. Thus, we propose the possibility of pion condensation, as an exotic state to solve the problem in low-symmetry-energy EOSs. We examined the consistency of our EOSs with other various observations as well., 21 pages, 8 figures, accepted by Int. J. Mod. Phys. E

Physical N2O solubility in pure 2-(ethylamino)ethanol (EAE) solvent was measured over the temperature range 289.6– 349.7 K. The physical solubility of CO2 in EAE was then derived via the “N2O analogy” method. The effect of structural characteristics such as carbon chain length, hydroxyl group, hydroxylmethyl group and amino group on the physical CO2 solubility was revealed through the comparison of various amines to determine the most advantageous structure for high physical solubility. The physical heat of CO2 absorption of the amine was correlated using Arrhenius equation to analyse the sensitivity of the solubility data to the temperature change. Likewise, physical N2O solubility in aqueous EAE solution was measured from 289.6 to 349.7 K and EAE concentration from 7.5 to 75.0 wt%. To correlate the solubility data in a binary EAE-H2O system, four mathematical models, polynomial, semi-empirical, Redlich-Kister equation and Arrhenius equation models were introduced with average absolute relative deviation (AARD) of 6.5%, 8.7%, 5.9% and 8.7%, respectively. A small extrapolation with respect to temperature at 283 and 363 K was made to further estimate the performance of these models.

The solubility constant of N2O in aqueous 1-dimethylamino-2-propanol (1DMA2P) solution in the concentration range of 0–3.0 mol/L was measured over the temperature range of 298–333 K, and the data used to fit existing models: Redlich-Kister, semi-empirical, and polynomial. A new model has also been developed to predict the solubility constant. Also, N2O diffusivity in aqueous 1DMA2P solution was measured over the concentration range of 0.5–2.0 mol/L and temperature range of 298–313 K. All models used fitted the solubility constant of N2O solubility in 1DMA2P solution data with absolute average deviations (ADDs) for the Redlich-Kister, semi-empirical, polynomial models and a new model of 12.2%, 8.1%, 0.2% and 2.2%, respectively. The data for N2O diffusivity in aqueous 1DMA2P solution were represented by the modified Stokes-Einstein and semi-empirical models (AADs of 2.3% and 13.6%, respectively). A new mechanism-based model was equally developed to better correlate experimental results and understand the process of diffusivity.

This work investigates the carbon dioxide (CO2) equilibrium solubility of seven novel tertiary amines, which include 1-(2-Hydroxyethyl)pyrrolidine (1-(2-HE)PRLD), 4-((2-hydroxyethyl)(ethyl)amino)-2-butanol (HEEAB), 3-diethylamino-1,2-propanediol (DE-1,2-PD), 4-(dipropylamino)-2-butanol (DPAB), 1-(2-Hydroxyethyl)-piperidine (1-(2-HE)PP), 4-((2-hydroxyethyl)(methyl)amino)-2-butanol (HEMAB) and 4-(dimethylamino)-2-butanol (DMAB). This analysis study was conducted at the amine concentration of 2.0 mol/L, over the temperature range of 298–333 K, and over the CO2 partial pressure range of 3–101 kPa. Two approaches were adopted in this study. Some thermodynamic models were employed to correlate and predict the experimental results of CO2 equilibrium solubility in the seven novel tertiary amines solution. The new Helei-Liu model and Liu et al. model for K2 correlation were also developed. A comparison of the performances of these models in predicting CO2 solubility showed that the Liu et al. model, which included the significant parameters of temperature, concentration of amine solution, physical solubility of CO2, and total pressure, gave the best performance in predicting CO2 equilibrium solubility in the newly formulated amine solutions. In addition, the artificial neutral network (ANN) approach was adopted for predicting the CO2 equilibrium solubility of the seven tertiary amines. The predicted values of CO2 solubility extracted from the ANN models were compared with those from the thermodynamic models in terms of the absolute average deviation (AAD).

In this work, nonaqueous binary absorbents were investigated for CO2 capture by mixing conventional amines (i.e. monoethanolamine MEA, methyldiethanolamin MDEA) and ionic liquids. Four ionic liquids [BMIM]BF4, [BEIM]BF4, [BPIM]BF4 and [BBIM]BF4 were synthesized. The thermal stability of the ionic liquids was evaluated and viscosity was measured over the temperature range of 298–348 K. The CO2 absorption performance of the pure ionic liquids was studied at ambient pressure and compared with the hybrid absorbents. The influence factors including temperature, stir rate and cycling numbers were then investigated. Finally, the CO2 absorption mechanism was verified using NMR spectroscopy. Results showed that additional amine could greatly promote the CO2 absorption performance of ionic liquids and mixed absorbents revealed different CO2 absorption behavior depending on the amine type. This work proved that the mixed absorbent MDEA + [BEIM]BF4 yields high cycling CO2 capacity, energy saving, good regenerability and especially, low viscosity.

Over 1500 DBZ or DZ white dwarfs (WDs) have been observed so far, and polluted atmospheres with metal elements have been found among these WDs. The surface heavy element abundances of known DBZ or DZ WDs show an evolutionary sequence. By using Modules for Experiments in Stellar Evolution, we create DB WDs, and simulate the element diffusion due to high gravitational fields and the metal-rich material accretion coming from the planet disrupted by the WD. In our models, the input parameters ($\alpha_{\rm MLT}$, $\alpha_{\rm th}$ and $Z$) have very weak effect on DB WD structures including interior temperatures, chemical profiles and convective zones.The mass-accretion rate and the effective temperature of DB WDs determine the abundances of heavy elements. The evolutionary sequence of Ca element for about 1500 observed DB or DBZ WDs cannot be explained by the model with a constant mass-accretion rate, but is consistent well with the model in which the mass-accretion rate decreases by one power law when $T_{\rm eff}>10$ kK and slightly increases by another power law when $T_{\rm eff}, Comment: 9 pages, 12 figures, accepted for publication in A&A

Employing the the stellar evolution code (Modules for Experiments in Stellar Astrophysics), we calculate yields of heavy elements from massive stars via stellar wind and core-collapse supernovae (CCSN) ejecta to interstellar medium (ISM). In our models, the initial masses ($M_{\rm ini}$) of massive stars are taken from 13 to 80 $M_\odot$, their initial rotational velocities (V) are 0, 300 and 500 km s$^{-1}$, and their metallicities are [Fe/H] = -3, -2, -1, and 0. The yields of heavy elements coming from stellar winds are mainly affected by the stellar rotation which changes the chemical abundances of stellar surfaces via chemically homogeneous evolution, and enhances mass-loss rate. We estimate that the stellar wind can produce heavy element yields of about $10^{-2}$ (for low metallicity models) to several $M_\odot$ (for low metallicity and rapid rotation models) mass. The yields of heavy element produced by CCSN ejecta also depend on the remnant mass of massive mass which is mainly determined by the mass of CO-core. Our models calculate that the yields of heavy elements produced by CCSN ejecta can get up to several $M_\odot$. Compared with stellar wind, CCSN ejecta has a greater contribution to the heavy elements in ISM. We also compare the $^{56}$Ni yields by calculated in this work with observational estimate. Our models only explain the $^{56}$Ni masses produced by faint SNe or normal SNe with progenitor mass lower than about 25 $M_\odot$, and greatly underestimate the $^{56}$Ni masses produced by stars with masses higher than about 30 $M_\odot$., 11 pages,9 figures

We model the quiescent luminosity of accreting neutron stars with several equation of states (EOSs), including the effect of pion condensation and superfluidity. As a consequence of comparison with the observations, we show that the results with Togashi EoS (the strong direct Urca process is forbidden) and TM1e EoS (mass at direct Urca process is $2.06 M_\odot$) can explain the observations well by considering pion condensation and the effect of superfluidity, while LS220 EoS and TM1 EoS can explain the observations well by considering the baryon direct Urca process and the effect of superfluidity. Besides, we compare the results with the observations of a neutron star RX J0812.4-3114 which has the low average mass accretion rate ($\langle\dot{M}\rangle\sim(4-15)\times 10^{-12}~M_\odot ~\rm yr^{-1}$) but high thermal luminosity ($L_q^\infty\sim(0.6-3)\times10^{33}~\rm erg ~ s^{-1}$), and we suggest that a low-mass neutron star ($, 12 pages, 8 figures, accepted by Phys. Rev. D

We study the quiescent luminosities of accreting neutron stars by a new mechanism as neutrino heating for additional deep crustal heating, where the neutrino heating is produced by charged pions decay from the nuclear collisions on the surface of neutron star during its active accretion. For low mass neutron star($\lesssim1.4~M_{\odot}$), as the neutrino heating is little($\lesssim1$ MeV per accreted nucleon) or there would be no neutrino heating, the quiescent luminsoity will be not affected or slightly affected. While for massive neutron star ($\gtrsim2~M_{\odot}$), the quiescent luminosity will be enhanced more obviously with neutrino heating in the range 2-6 MeV per accreted nucleon. The observations on cold neutron stars such as 1H 19605+00, SAX J1808.4-3658 can be explained with neutrino heating if a fast cooling and heavy elements surface are considered. The observations on a hot neutron star such as RX J0812.4-3114 can be explained with neutrino heating if the direct Urca process is forbidden for a massive star with light elements surface, which is different from the previous work that the hot observations should be explained with small mass neutron star and the effect of superfluidity., Comment: 9 pages, 5 figures, accepted for publication in Phys. Rev. D

As some neutron star transients require an additional unknown heat source (referred to as “shallow heating”) to explain their high temperatures at the beginning of quiescence, we investigate the effect of shallow heating as well as compressional heating on the thermal state of transiently accreting neutron stars with the use of evolutionary calculations in the present work. Through comparing our theoretical predictions of the equilibrium redshifted luminosities $(L_{\gamma}^{\infty})$ produced by both deep crustal heating and shallow heating/compressional heating for different time-averaged mass-accretion rates $\langle\dot{M}\rangle$ with 35 updated observations of soft X-ray transients, the results show that both shallow heating and compressional heating make significant contributions to the equilibrium redshifted luminosity. The hotter sources (XTE J1701, MAXI J0556, EXO 0748, Aql X-1 etc.) with higher accretion rates are more likely to be explained with the effect of shallow heating or compressional heating. In addition, for a proper shallow heat $q_\mathrm{sh}$ and mass-accretion rate $\dot{M}$, the effect of shallow heating could be simulated by compressional heating.

In this work, the equilibrium CO2 solubilities of five tertiary amines, namely Triethanolamine (TEA), N-methylethanolamine (MDEA), 2-(Dimethylamino)ethanol (DMEA), 3-dimethyl-amino-1-propanol (3DMA1P), and Diethylethanolamine (DEEA) were measured over the temperature range of 298.15–313.15 K, and at CO2 partial pressures up to 60.8 kPa. The activity-structure relationship was studied on the molecular level to account for the differences in equilibrium CO2 solubility. The M-KE model was applied to correlate the vapor-liquid-equilibrium data of the five tertiary amine-H2O-CO2 systems. Results show that the model is able to correlate experimental data very well and gives reasonable prediction results with average absolute deviation (AAD) of 2.5% for TEA, 3.3% for MDEA, 1.3% for DMEA, 1.0% for 3DMA1P and 0.8% for DEEA. In addition, the CO2 absorption heat was calculated using the Clausius-Clapeyron equation. The potential for the five amines to be considered as alternative solvents for CO2 capture was evaluated in terms of equilibrium CO2 solubility, second order reaction rate constant and CO2 absorption heat.

To enhance the energy efficiency of the CO2 desorption process, the regeneration behaviors of the CO2-loaded 6 M MEA-AMP-PZ (monoethanolamine, 2-amino-2-methyl-1-propanol and piperazine) tri-solvent blends with different AMP/PZ molar ratios with four different solid acid catalysts (H-ZSM-5, γ-Al2O3, SAPO-34 and SO42−/TiO2) and a blank at 96 °C were investigated in terms of CO2 desorption rate, cyclic capacity and relative heat duty. For the no-catalytic runs, the results showed that all the tri-solvent blended amines greatly increased CO2 desorption rate, cyclic capacity and decreased the relative heat duty in comparison with 5 M MEA. The 13C NMR analysis indicated that the 3 M MEA-2.5 M AMP-0.5 M PZ blend with the highest AMP/PZ ratio produced the largest amount of bicarbonate and less carbamate, which resulted in the best desorption performance. With regard to catalyst, when the solid acid catalysts were introduced, the regeneration performance of the blend was further improved. The best of the blends along with H-ZSM-5 provided the combination with the best performance in CO2 desorption, and reduced the relative heat duty by 61.6% as compared to 5 M MEA without catalyst (100%). Five relevant physicochemical properties of the catalyst were obtained and used to better understand the catalytic regeneration process. A possible catalytic CO2 desorption mechanism was analyzed. The results revealed that the mesopore surface area coupled with total acid sites of the catalyst had the most positive influence on improving the CO2 desorption performance. Findings from this work imply that the combination of solid acid catalyst with tri-solvent blended amines is a promising alternative method for further reduction of solvent regeneration energy requirement.

In this work, the equilibrium CO2 solubilities of the aqueous N-(2-hydroxyethyl) pyrrolidine (N-(2-HE) PRLD) at different concentrations (1.0 mol/L–5.0 mol/L) were measured at different temperatures (298 K–333 K) and pressures (8 kPa–101 kPa), using a vapor–liquid equilibrium apparatus. Four semi-empirical thermodynamic models (Cf model, Kent–Eisenberg model, Hu–Chakma model and Li–Shen model) were used to correlate and predict the CO2 solubility data of the N-(2-HE) PRLD-CO2–H2O system. The results showed that the Hu–Chakma model, which is one of the models that incorporates the effect of amine concentration and CO2 loading, and accounted for nonideality caused by higher temperature, species concentrations and CO2 loadings, was best able to predict results that are in agreement with the experimental vapor–liquid equilibrium measurements in this work.

In this work, the performance of CO 2 absorption into aqueous 2-amino-2-methyl-propanol (AMP) solution was investigated by measuring the amount of CO 2 in the liquid phase during CO 2 absorption process to identify initial CO 2 absorption rate. Then, the porous media material named as MCM41 was introduced into the amine solution to test its influence on CO 2 absorption. It was found that MCM41 increased initial CO 2 absorption rate and enhanced CO 2 absorption process. The physico-chemical properties of MCM41 were characterized in terms of specific surface area, average pore diameter, total pore volume and chemical properties, the amount of acidic sites and the Brϕnsted/Lewis (B/L) acid sites ratio. Results showed that MCM41 was a type of Lewis acid catalyst with large specific surface area and pore volume. In addition, the pKa of AMP solution with and without MCM41 was obtained using acid titration technology to help understand the effect brought by MCM41. A mechanism illustrating how MCM41 increases the CO 2 absorption rate of the AMP solution was proposed and demonstrated that MCM41 is a potential material for enhancing CO 2 absorption.

Ribosomal protein S9 (RPS9) is an essential functional gene that participates in DNA repair and developmental regulations. A sequence homolog of RPS9 has been found to be upregulated in the protoscoleces (PSCs) of Echinococcus granulosus treated with artemisinin. However, E. granulosus RPS9 (EgRPS9) has not been identified before. In the present study, the 657-base pair (bp) cDNA encoding EgRPS9 was cloned. Amino acid sequence analysis showed that EgRPS9 was similar to the RSP9 proteins from Schistosoma japonicum (SjRPS9, 86%) and Schistosoma mansoni (SmRPS9, 79%). Phylogenetic tree analysis showed that EgRPS9, SmRPS9, and SjRPS9 were clustered together. We detected the EgRPS9 gene and protein expression in PSCs exposed to artesunate (AS) which displayed a dose-dependent reduction in PSC viability for 24 hr. The results showed that the EgRPS9 ratio of the 10-μM AS-treated ( P0.01) and 40-μM AS-treated ( P0.05) groups were increased from that of the control group. In addition, the level of reactive oxygen species (ROS) in the AS-treated groups increased in a dose-dependent manner compared to the level in the control group. In conclusion, the expression of EgRPS9 could be induced by ROS and might participate in the oxidative damage-based anti-parasite mechanism of AS treatment.

The absorption/desorption performance of carbon dioxide (CO2) in aqueous 5 M monoethanolamine (MEA) solutions in the presence of various solution regeneration promoters was comprehensively investig...

The physical properties of densities, viscosities, and refractive indices, which are important in kinetics and mass transfer processes were measured for aqueous CO2-loaded and -unloaded (EAE) solutions applied in CO2 absorption in the temperature range from 293.15 to 323.15 K at atmospheric pressure. Due to the limitation of the instrument and corrosive behavior with increasing concentration, the mass fractions (w1) of aqueous EAE solutions selected were: as 0.089, 0.178, 0.267, and 0.356, which correspond to the molar concentrations of 1, 2, 3, and 4 mol·L–1, respectively. The determined density, viscosity and refractive index data for binary EAE+H2O and ternary CO2+EAE+H2O systems were correlated using Weiland et al. model, Redlich–Kister equation, extended Arrhenius equation, and a new proposed empirical function. All the calculated density, viscosity, and refractive index data fitted well with experimental values at all operational conditions.

In this work, the CO2 equilibrium solubility in 1-dimethylamino-2-propanol (1DMA2P) solution was determined as a function of 1DMA2P concentration (over the range of 1–5 M), temperature (in the range of 298–333 K), and CO2 partial pressure (in the range of 8–101 kPa), and the data used to fit the correlations for K2 using Kent-Eisenberg, Austgen, Li-Sheng and Hu-Chakma models. A new K2 correlation model was also developed to predict the CO2 equilibrium solubility in 1DMA2P solution. It was found that all of the models could fit the CO2 equilibrium solubility in 1DMA2P solution data with absolute average deviations (ADDs) for the models by Kent-Eisenberg, Austgen, Li-Sheng, Hu-Chakma and Liu et al. of 14, 15, 12, 6.3 and 10%, respectively. In addition, the heat of CO2 absorption in 1DMA2P solution estimated using Gibbs-Helmholtz equation was found to be −31.67 kJ/mol. Information or guidelines about effective utilization of data of screened solvents is provided based on three absorption parameters, namely, CO2 equilibrium solubility, second order reaction constant, and CO2 absorption heat.

In this work, the regeneration of rich CO 2 -loaded monoethanolamine (MEA) solvent with two catalysts (e.g. SAPO-34 and SO 4 2− /TiO 2 ) was investigated in order to reduce the energy requirement for solvent regeneration. The regeneration behavior with and without catalyst of a 5M MEA solution with an initial CO 2 loading of 0.5 mol CO 2 /mol amine at 96 °C was studied to compare their CO 2 desorption rate and heat duties. The results show that the two solid acid catalysts can reduce the heat duty for solvent regeneration and increase the CO 2 desorption rate in comparison with blank test. The mechanism of CO 2 desorption with catalyst in 5M MEA was proposed based on the result of catalyst characterization (e.g. N 2 absorption/desorption experiment, Py-IR, NH 3 -TPD, FT-IR and XRD) to better understand the desorption process. The results indicate that SAPO-34 with the higher joint value of Brϕnsted/Lewis acid sites ratio (B/L) and mesopore surface area (MSA) shows the faster CO 2 desorption rate and lower heat duty than SO 4 2− /TiO 2 . Based on the experimental results, the addition of solid acid catalysts into amine solution could be considered as one of choices to reduce the heat duty for CO 2 desorption from CO 2 -loaded amine solvent.

In this work, the CO 2 equilibrium solubility of 3-dimethylamino-1-propanol (3DMA1P) is presented over the concentration range of 1–3 mol/L, the temperature range of 298–333 K, and the CO 2 partial pressure of 3–101 kPa. Several thermodynamic models (i.e. Kent-Eisenberg model, Austgen model, Hu-Chakma model, Liu et al. model) were used to correlate and predict the CO 2 equilibrium solubility of 3DMA1P solution. It was found that the Liu et al. model could be considered to be an appropriate model to predict the CO 2 equilibrium solubility in 3DMA1P solutions with an absolute average deviation (ADD) of 9.4%. In addition, the ANNs models (BPNN and RBFNN model) were developed and used to correlate the CO 2 equilibrium solubility of 3DMA1P. It was found that the ANNs models could predict the experimental values very well with excellent ADDs of 3.0% for the BPNN model and 4.4% for the RBFNN model, respectively. In addition, a comparison of thermodynamic models and ANN models was presented in terms of prediction of CO 2 solubility in 3DMA1P solution.

In this work, the speciation (i.e., 1DMA2P molecule as well as 1DMA2PH+, HCO3–, and CO32– ions) for the CO2 reactive absorption of CO2 in aqueous 1-dimethylamino-2-propanol solution (i.e., into a 1DMA2P–H2O–CO2 system) was studied using the 13C nulcear magnetic resonance (NMR) technique at a temperature of 301 K over the 1DMA2P concentration range of 0.5–2.0 mol/L and CO2 loading range of 0–1.0 mol CO2/mol amine. Also, in addition to other material conservation laws, a new criterion for selection of the protonation calibration curves, the charge balance of the 1DMA2P–H2O–CO2 system, was added in order to generate results with better accuracy. In addition, the equilibrium constants, K1 and K5, were also obtained using the NMR technique, which had good agreement with those from other works with absolute average deviations of 2.2% and 3.5%, respectively.

CO2 absorption into aqueous solutions of two tertiary alkanolamines, namely, MDEA and DMEA with and without carbonic anhydrase (CA) was investigated with the use of the stopped-flow technique at temperatures in the range of 293–313 K, CA concentration varying from 0 to 100 g/m3 in aqueous MDEA solution with the amine concentration ranging from 0.1 to 0.5 kmol/m3, and CA concentration varying from 0 to 40 g/m3 in aqueous DMEA solution with the amine concentration ranging from 0.05 to 0.25 kmol/m3. The results show that the pseudofirst-order reaction rate (k0, amine; s−1) is significantly enhanced in the presence of CA as compared with that without CA. The enhanced values of the kinetic constant in the presence of CA has been calculated and a new kinetics model for reaction of CO2 absorption into aqueous tertiary alkanolamine solutions catalyzed by CA has been established and used to make comparisons of experimental and calculated pseudo first-order reaction rate constant (k0, with CA) in CO2-MDEA-H2O and CO2-DMEA-H2O solutions. The AADs were 15.21 and 15.17%, respectively. The effect of pKa on the CA activities has also been studied by comparison of CA activities in different tertiary amine solutions, namely, TEA, MDEA, DMEA, and DEEA. The pKa trend for amines were: DEEA > DMEA > MDEA > TEA. In contrast, the catalyst enhancement in amines was in the order: TEA> MDEA> DMEA> DEEA. Therefore, it can be seen that the catalyst enhancement in the amines decreased with their increasing pKa values. © 2017 American Institute of Chemical Engineers AIChE J, 2017