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© 2020, The Author(s). Multi walled carbon nanotubes (MWCNTs) were decorated by activated carbon nanoparticles of resorcinol-formaldehyde aerogels. Carbon nanospheres and MWCNTs were mixed by equal mass ratios for different durations. The products were characterized by Raman spectroscopy, thermal gravimetric analysis, nanoscanning electron microscopy, transmission electron microscopy and x-ray diffraction. The results indicated that a significant decoration with carbon nanoparticles occurred onto the MWCNTs. This publication was made possible by the NPRP award (NPRP 08-014-2-003) from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Technical support from the Department of Chemical Engineering, the Central Laboratories Unit (CLU) and Gas Processing Centre (GPC) at Qatar University is also acknowledged. The publication of this article was funded by the Qatar National Library.

With the anticipated rise in global demand for natural gas (NG) and liquefied natural gas (LNG), sour gas reserves are attracting the attention of the gas industry as a potential resource. However, to monetize these reserves, sour natural gas has to be sweetened by removing acid gases (carbon dioxide and/or hydrogen sulfide) before liquefaction. The solidification of these acid gases could be the basis for their separation from natural gas. In this study, a state-of-the art solid-vapor (SV) separation unit is developed for removal of acid gases from methane and simulated using a customized Aspen Plus operation unit. The operating principles and conditions, mathematical model, and performance results are presented for the SV unit. Further performance analyses, means of optimization and comparisons to conventional methods used by the industry were studied. Results showed that for similar sweet gas purity, the developed SV unit consumes only 27% of the energy required by the amine sweetening unit. Furthermore, it saves on capital costs, as it requires less equipment and does not suffer from high levels of corrosion. Scopus 2-s2.0-85136430090

Since the early spring of 2020, the coronavirus pandemic (COVID-19) outbreak has hindered traditional face-to-face teaching and hands-on, traditional delivery of laboratory courses, forcing universities to migrate from the traditional way of teaching to a remote online approach. Although few studies addressed the pandemic's impact on educational outcomes, no studies are found to investigate the impact of the remote online teaching approach on laboratory courses. This paper highlights the impact of the online teaching approach, coupled with flipped learning pedagogy, as a substitute for traditional laboratories. The course learning outcomes and assessment tools are analyzed and discussed for 46 students enrolled in the Unit Operations Laboratory course in the chemical engineering program at Qatar University. Results show that the course learning outcomes are achieved effectively using the hybrid online-flipped learning pedagogy, which can be considered for computerized traditional laboratories as a moderation solution to alleviate pandemic COVID-19 confinement on learning outcome. This methodology can also be sustained in the future to facilitate the teaching of such lab courses, even in normal conditions, to optimize the resources and avail the delivery of such courses to a larger audience who may have various obstacles to attending traditional lab courses.Other Information Published in: SN Social Sciences License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s43545-021-00117-6

Activated carbons of resorcinol-formaldehyde aerogels (AC-RFA) were prepared and mixed with multiwall carbon nanotubes (MWCNTs) with various ratios. Samples were characterized by different techniques. The novelty of the study is in evaluating the effect of uniformity of carbon nanocomposites on their performance for the adsorption of CH4 and CO2 gases as well predicting the separation of their mixtures. The results indicated that, by increasing the percentage of MWCNTs into the sample, its structural uniformity and order ascend. The capacities of CH4 and CO2 by adsorption were measured at various temperatures, and were correlated with the extended dual site Langmuir (DSL) model. Overall, results showed that the adsorption capacity of MWCNTs towards gases is relatively very low compared to that of activated carbons. The DSL model was utilized to forecast the separation of the binary CO2/CH4 mixed gas based on knowledge of single component adsorption isotherm parameters. Adsorption equilibrium data of the CO2/CH4 binary gas mixture was forecasted at different temperatures by DSL model in accordance with the perfect-negative (PN) or perfect-positive (PP) behaviors on the heterogeneous surface of the adsorbent. Acknowledgments: This publication was made possible by the NPRP award (NPRP 08-014-2-003) from the Qatar National Research Fund (a member of Qatar Foundation). Statements made herein are the sole responsibility of the authors. Technical support from the Department of Chemical Engineering, Central Laboratory Unit (CLU) and Gas Processing Centre (GPC) at Qatar University is also acknowledged. Further, the publication of this article was funded by the Qatar National Library. Scopus 2-s2.0-85099223656

To cover the expected increased demand for natural gas, energy industry has to exploit sour gas reserves located around the world. However, acid gases have to be removed before the natural gas produced from these fields could be used. One of the novel concepts in this field is the utilization of solid phase formation of carbon dioxide and/or hydrogen sulfide. The main aim of this study is to develop an empirical correlation model based on Peng-Robinson equation of state (PR EoS), with fugacity expressions, that is able for the first time to describe the solid-fluid phase equilibria for the ternary system of CH4-CO2-H2S at pressures from 5 to 30 bar and over a wide range of temperature (130-200 K). The model was first tested on the binary systems of CH4-CO2, CO2-H2S and CH4-H2S with optimized interaction parameters. When proven to be successful, it was then expanded in a predictive manner to describe the ternary system of CH4-CO2-H2S. The model predictions for the solidification points of 5 different mixtures were within the acceptable error when compared to the experimental data available in the literature. A model based on equilibrium stage separation unit was used to study the separation of three different feed compositions of this ternary system. Overall, it was found that separation of CO2 in solid phase improves when increasing the operating pressure up to 20 bar, and decreases at higher temperatures. Similarly, the separation of H2S in either liquid or solid phase improves at higher pressures and lower temperatures. The recovery of CH4 was high over the entire ranges of operating conditions, expect at high pressure (30 Bar) at temperatures below 190 K. This work provides scientists and engineers with an accurate tool that may be used with confidence for predicting solid-fluid phase equilibria. Consequently, this model eliminates difficulties associated with the need for experiments on ternary system solid-fluid phase equilibria. 2021 The Author(s) The publication of this article was funded by the Qatar National Library . Scopus 2-s2.0-85109171275

ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 are utilized in adsorbing nitrogen (N2), methane (CH4), and carbon dioxide (CO2) gases at temperatures between 25 and 55°C and pressures up to ~1 MPa. Equilibrium adsorption isotherms and adsorption kinetics are studied. The dual-site Langmuir equation is employed to correlate the nonisothermal adsorption equilibrium behavior. Generally, N2 showed the lowest equilibrium adsorption quantity on the three samples, whereas CO2 showed the highest equilibrium adsorption capacity. Amid the ZIF samples, the biggest adsorption quantities of N2 and CH4 were onto Zn/Co-ZIF-8, whereas the highest adsorption quantity of CO2 was on ZIF-8. The isosteric heats of adsorbing these gases on ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 were examined. Moreover, the overall mass transfer coefficients of adsorption at different temperatures were investigated. Other information Published in: Journal of Nanomaterials License: http://creativecommons.org/licenses/by/4.0 See article on publisher's website: http://dx.doi.org/10.1155/2019/6130152

Screening alternatives for producing paraffinic phase change materials (PCMs) from natural gas‐based products was investigated. Based on the quality and cost of these PCMs, two sources were identified: (i) hydrogenated gas‐to‐liquid (GTL) products such as heavy detergent feedstocks; and (ii) linear alpha olefins. Fractionation of a typical hydrogenated GTL mixture, containing C14 – C18 alkene and alkane hydrocarbons, has been experimentally conducted to produce five paraffinic PCMs with melting points between 3 and 28 °C. ChemCAD simulation has been proved to be a valid tool for predicting the behaviour of the GTL fractionation, including optimum experimental conditions and compositions of products. Also, hydrogenation of technical 1‐octadecene was experimentally carried out in order to evaluate the quality of PCM produced from one of the available technical alpha‐olefins. All PCMs produced in this work were analysed by gas chromatography equipped with flame ionization detector to determine their compositions and by differential scanning calorimetry to determine their latent heats. The results showed that the PCM with a melting temperature in the range 22 to 25 °C can be technically produced through hydrogenation of commercial 1‐octadecene showing a higher latent heat compared to the PCM produced from fractionation of hydrogenated GTL mixture. Copyright © 2017 John Wiley & Sons, Ltd. This publication was made possible by the NPRP award [NPRP 5-093-2-034] from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Scopus

Silica nanosheets (SiO2 NS) are considered to be a promising material in clinical practice for diagnosis and therapy applications. However, an appropriate surface functionalization is essential to guarantee high biocompatibility and molecule loading ability. Although SiO2 NS are chemically stable, its effects on immune systems are still being explored. In this work, we successfully synthesized a novel 2D multilayer SiO2 NS and SiO2 NS coated with carbon (C/SiO2 NS), and evaluated their impact on human Peripheral Blood Mononuclear Cells (PBMCs) and some immune cell subpopulations. We demonstrated that the immune response is strongly dependent on the surface functionalities of the SiO2 NS. Ex vivo experiments showed an increase in biocompatibility of C/SiO2 NS compared to SiO2 NS, resulting in a lowering of hemoglobin release together with a reduction in cellular toxicity and cellular activation. However, none of them are directly involved in the activation of the acute inflammation process with a consequent release of pro-inflammatory cytokines. The obtained results provide an important direction towards the biomedical applications of silica nanosheets, rendering them an attractive material for the development of future immunological therapies.

In spite of the increasing levels of greenhouse gases in the atmosphere and their sever impact on the environment, the demand for natural/bio gas is expected to increase significantly in the coming decades. To cover this demand, the global energy industry is continuously exploiting sour gas reserves located around the world. Nonetheless, sour gas has to be sweetened before the practical utilization of natural or biogas. On the other hand, the combustion of fossil fuels produces flue gases that contain huge amounts of carbon dioxide (CO2) every year. CO2 is a major greenhouse gas, which has negative impact on the environmental systems. Therefore, it is important to reduce or eliminate CO2 from flue gases before being released to the environment. On the other side, radioactive isotope byproducts (e.g., krypton and xenon) are found in off-gas streams released from nuclear power plants with light water reactors or from fuel reprocessing plants, and have to be separated from the off-gas stream. To our knowledge, so far there are no known processes to separate such noble gases, so this work will be the first to address this issue. The cryogenic separation technologies have emerged as a new approach to separate carbon dioxide (CO2) and hydrogen sulfide (H2S) from natural gas, and to capture CO2 gas from flue gas streams. To design cryogenic separation equipment, vapor-liquid equilibrium (VLE), solid-liquid equilibrium (SLE), solid-vapor equilibrium (SVE), and solid-liquid-vapor equilibrium (SLVE) data for the corresponding binary and ternary systems composing the corresponding gas mixtures. In this study, we successfully develop an empirical correlation model based on the Peng-Robinson equation of state (PR EoS), with fugacity expressions, that is able to describe the SLVE behaviors for the ternary systems of CH4-CO2-H2S (resembling a sample natural gas mixture), N2-kr-Xe (resembling noble gases in nitrogen), and N2-O2-CO2 (resembling flue gas mixtures) over wide ranges of pressures and temperatures. Additionally, and based on this model, an equilibrium stage separation unit was modeled and used to construct phase diagrams of the solid-fluid regions for the above-mentioned systems. The results showed that separating the unwanted gases in the solid-vapor equilibrium (SVE) region by selective freezing (solidification) is efficient and results in high recovery rates, the recovery of acid gases (such as CO2) could exceed 99%. Based on that, and by implementing the model developed, a state-of-the art solid-vapor (SV) separation unit was modeled using the Aspen Custom Modeler (ACM) software. The SV unit was then simulated by importing the ACM code into an Aspen Plus simulator; and its performance was studied and analyzed. The SV separation unit offers some key advantages over the traditional technologies (such as amine scrubbing units);including lower energy requirements, less capital costs, lower maintenance and operation expenses and the avoidance of contaminating the gases with other components (such as solvents). In natural gas sweetening, the developed SV unit consumes only ~27% of the energy required by the amine sweetening unit; while for CO2 capture from flue gases, it saves about half of the energy needed by traditional units. For separating noble gases from nitrogen, the SV unit also achieved high recoveries, especially for xenon gas; however the operating temperature would be too low, thus requiring high energy for cooling.