The 50 most-cited articles in Industrial & Engineering Chemistry Research, 2021

Because of the problems associated with the generation and storage of hydrogen in portable applications, the use of ammonia has been proposed for on-site production of hydrogen through ammonia decomposition. First, an analysis of the existing systems for ammonia decomposition and the challenges for this technology are presented. Then, the state of the art of the catalysts used to date for ammonia decomposition is described considering the catalysts composed of noble and non-noble metals and their combinations, as well as novel materials such as alkali metal amides and imides. The effect of the supports and promoters used is analyzed in detail, and the catalytic activity obtained is compared. An analysis of the kinetics of the reaction obtained with different catalysts is also presented and discussed, including the reaction mechanism, the determining step of the reaction, and the apparent activation energy. Finally, the structured reactors used to date for the decomposition reaction of ammonia are explored, as well as the possibilities offered by catalytic membrane reactors, which…

Hydrogen plays a key role in many industrial applications and is currently seen as one of the most promising energy vectors. Many efforts are being made to produce hydrogen with zero CO2 footprint via water electrolysis powered by renewable energies. Nevertheless, the use of fossil fuels is essential in the short term. The conventional coal gasification and steam methane reforming processes for hydrogen production are undesirable due to the huge CO2 emissions. A cleaner technology based on natural gas that has received special attention in recent years is methane pyrolysis. The thermal decomposition of methane gives rise to hydrogen and solid carbon, and thus, the release of greenhouse gases is prevented. Therefore, methane pyrolysis is a CO2-free technology that can serve as a bridge from fossil fuels to renewable energies.

Daunorubicin is a famous anthracycline anticancer chemotherapy drug with many side effects that is very important to measure in biological samples. A daunorubicin electrochemical biosensor was fabricated in this study using ds-DNA as the biorecognition element and glassy carbon electrode (GCE) amplified by Pt/SWCNTs as a sensor. The synthetization of Pt/SWCNTs was done by the polyol method, and their characterization was accomplished via XRD, EDS, and TEM methods. The results showed a diameter of about 5.0 nm for the Pt nanoparticle decorated at the surface of SWCNTs. The morphological and conductivity properties of Pt/SWCNTs/GCE were investigated by EIS and AFM methods, and the results confirmed that Pt/SWCNTs/GCE had a high surface area and high conductivity. ds-DNA/Pt/SWCNTs/GCE showed an oxidation signal relative to that of the guanine base at the potential of 847 mV and a positive shift after interaction with the daunorubicin anticancer drug. This point confirms the intercalation reaction between the guanine base in the ds-DNA structure and the drug that could be used as an…

The Temkin isotherm equation is increasingly being used to correlate adsorption isotherms of water contaminants. This research note shows that the Temkin isotherm as used in environmental adsorption research suffers from a fundamental flaw of dimensional inconsistency. In addition, an important but frequently overlooked issue concerns the approximate nature of the Temkin isotherm which limits its ability to fit type I isotherms: it has neither a Henry’s law limit at low loadings nor a finite saturation limit at high loadings. A different approximate Temkin isotherm, which approaches a linear isotherm at low concentrations and commences at the (0,0) origin, is shown to outperform the commonly used Temkin isotherm in terms of fitting ability and resembles the Langmuir and Freundlich isotherms in describing adsorption data without a saturation plateau. It is hoped that the material presented in this research note will lead to a better comprehension of the Temkin isotherm.

The hydrogen economy is being pursued quite vigorously since hydrogen is an important and green energy source with a variety of applications as fuel for transportation, fuel cell, feedstock, energy vector, reforming in refineries, carbon dioxide valorization, biomass conversion, etc. Steam reforming of alcohols is a well-established technique to obtain syngas. Methanol is viewed to be a lucrative alternative for fossil fuels, due to its flexibility in being generated from multiple sources, high energy density, and low operating temperatures. The catalysts used for reforming govern the methanol conversion rate and the ratio of gaseous products, i.e., H 2, CO, and CO 2 . Group VIII–XII metals have been widely utilized for methanol steam reforming as they have a higher hydrogen yield. Several other catalysts and novel techniques have been developed and used to date. Quite a few strategies to enhance the performance of catalysts and reduce deactivation have been discussed. This review focuses on the metallic catalysts, mainly Cu, Pd, Zn, with different formulations and compositions for…

The human population is generally subjected to diverse pollutants and contaminants in the environment like those in the air, soil, foodstuffs, and drinking water. Therefore, the development of novel purification techniques and efficient detection devices for pollutants is an important challenge. To date, experts in the field have designed distinctive analytical procedures for the detection of pollutants including gas chromatography/mass spectrometry and atomic absorption spectroscopy. While the mentioned procedures enjoy high sensitivity, they suffer from being laborious, expensive, require advanced skills for operation, and are inconvenient to deploy as a result of their massive size. Therefore, in response to the above-mentioned limitations, electrochemical sensors are being developed that enjoy robustness, selectivity, sensitivity, and real-time measurements. Considerable advancements in nanomaterials-based electrochemical sensor platforms have helped to generate new technologies to ensure environmental and human safety. Recently, investigators have expanded considerable effort…

Adsorption-based CO2 capture has enjoyed considerable research attention in recent years. Most of the research efforts focused on sorbent development to reduce the energy penalty. However, the use of suitable gas–solid contacting systems is key for extracting the full potential from the sorbent to minimize operating and capital costs and accelerate the commercial deployment of the technology. This paper reviews several reactor configurations that were proposed for adsorption-based CO2 capture. The fundamental behavior of adsorption in different gas–solid contactors (fixed, fluidized, moving, or rotating beds) and regeneration under different modes (pressure, temperature, or combined swings) is discussed, highlighting the strengths and limitations of different combinations of gas–solid contactor and regeneration mode. In addition, the estimated energy duties in published studies and current technology readiness level of the different reactor configurations are reported. Other aspects, such as the reactor footprint, the operation strategy, suitability to retrofits, and the ability to…

High Resolution Image Download MS PowerPoint Slide Methanation of both CO and CO 2 with electrolysis-sourced hydrogen is a key step in power-to-gas technologies with nickel as the most prominent catalyst. Here, a detailed, thermodynamically consistent reaction mechanism for the methanation reactions of CO and CO 2 over Ni-based catalysts is presented. This microkinetic model is based on the mean-field approximation and comprises 42 reactions among 19 species. The model was developed based on experiments from a number of studies in powder and monolith catalysts. These are numerically reproduced by flow field simulations coupled with the kinetic scheme. The reaction mechanism features multiple paths for the conversion of CO and CO 2 into CH 4, including a carbide pathway and direct hydrogenation of CO 2 on the surface. The model developed describes the methanation process adequately over a wide range of temperatures, catalyst loadings, support materials, and reactant ratios. Hence, it can serve as a microkinetic basis for reaction engineering and up-scaling purposes.

High Resolution Image Download MS PowerPoint Slide This paper reports the results of an investigation of industrial requirements for thermodynamic and transport properties carried out during the years 2019–2020. It is a follow-up of a similar investigation performed and published 10 years ago by the Working Party (WP) of Thermodynamics and Transport Properties of European Federation of Chemical Engineering (EFCE). 1 The main goal was to investigate the advances in this area over the past 10 years, to identify the limitations that still exist, and to propose future R&D directions that will address the industrial needs. An updated questionnaire, with two new categories, namely, digitalization and comparison to previous survey/changes over the past 10 years, was sent to a broad number of experts in companies with a diverse activity spectrum, in oil and gas, chemicals, pharmaceuticals/biotechnology, food, chemical/mechanical engineering, consultancy, and power generation, among others, and in software suppliers and contract research laboratories. Very comprehensive answers were received…

Today’s competitive world economy is creating an indispensable demand for increased efficiency of engineering components that operate in harsh environments (i.e., very high-temperature, corrosive, or neutron irradiation environments), for applications in the energy, automotive, aerospace, electronics, and power industries. Increased research is being done on thermal barrier coatings (TBCs) for protecting such components, since the versatility of manufacturing techniques and the scale of deployment result in increased life, economics, performance, and durability. This review focuses on the advances that led to using TBCs for component life extension and, more recently, as an integral part of advanced component design for high-temperature and other types of harsh environments, such as those found in nuclear-related applications. Factors that led to state-of-the-art advanced coating-fabrication techniques [e.g., electron-beam physical vapor deposition (EB-PVD), plasma spray deposition, and electrophoretically deposited TBCs, as well as functionally graded material (FGM) manufacturing]…

Sponge-based materials have recently gained much attention in the field of oil/water separation due to their easy fabrication, recyclability, environmental friendliness, and low cost. Commercial sponges such as melamine sponge, polyurethane sponge, graphene-based sponge, and cellulose sponge have large surface area and high absorption capability, but they are hydrophilic/oleophilic (absorb both oil and water) in nature, which makes them not applicable in oil/water separation. To make them applicable in oil/water separation, the sponges have been modified with low surface energy materials and nano/micro hierarchical roughness, hence changing their wettability to superhydrophobicity/superoleophilicity (absorb oil and repel water). These materials include organosilicons, carbon-based materials, oxides, and metal–organic frameworks (MOFs) among others. We summarized the modifying materials for the fabrication of superhydrophobic/superoleophilic sponges used in oil/water separation even under harsh conditions such as pH-universal, high temperature, and so on. Furthermore, ideas for…

Green biosynthesis of highly active materials for healthcare and hygiene products, such as medical textiles that allow us to wear comfortable clothes with potent protection elements, is in great demand nowadays, as our surroundings have become infected with dangerous microbes. Herein, CuO nanoparticles were biosynthesized successfully by exploiting the active enzymes/proteins secreted by fungi, with consideration of their cytotoxicity, for the production of antibacterial active textiles. The fungus, namely, Aspergillus terreus strain AF-1, was allowed to secrete active ingredients including enzymes and the protein needed to cap the formed CuO-NPs. Characterizations of the CuO-NPs were performed in order to assign the chemical and physical properties of the nanoparticles yielded using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Raman spectra, transmission electron spectroscopy (TEM), and energy dispersive X-ray and X-ray photoelectron (XPS) spectroscopies. Cotton fabrics were treated with CuO-NPs prior to experiment to investigate the cytotoxicity of CuO-NPs to…

Hydrogel-based flexible wearable devices have attracted wide attention from researchers due to their great potential application in human–computer interaction, electronic skin, and disease diagnosis. However, the preparation of conductive hydrogels integrating good biocompatibility, excellent mechanical (tensile and compressible) properties, self-adhesive properties, cyclic stretching, and compression stability remains a challenge. By the Schiff base reaction between dialdehyde carboxymethyl cellulose and amino gelatin to form the first layer of the network and by the free-radical polymerization of acrylic acid to form the second layer of the network, a multifunctional conductive dual-network (DN) hydrogel strain sensor was prepared. The composite DN hydrogel has excellent compression properties (the strength reached to 0.12 MPa when the hydrogel was compressed to 50% of its original height), good cyclic compression (≥10 000 times), repeatable adhesion (≥10 times), reliable electrical conductivity, and high sensitivity (gauge factor = 8.1). The biocompatible hydrogel can be used not…

Abstract A techno-economic analysis of viable scenarios for the aviation industry to achieve net-zero CO2 emissions is presented. These scenarios are based (i) on carbon capture and storage (CCS), where conventional fossil jet fuel is produced, and the corresponding emissions are offset by capturing CO2, either via direct air capture (DAC-CCS route) or via point-source capture (PSC-CCS route), and permanently storing it underground, and (ii) on carbon capture and utilization (CCU), where synthetic jet fuel is produced by using CO2 as feedstock, which is either captured from air (DAC-CCU route) or from a point-source emitter (PSC-CCU route). All routes are feasible and have their advantages and shortcomings. To ensure net-zero CO2 emissions, the feedstock of the point-source emitter, both for CCS- and CCU-based routes, must be of biogenic nature. A quantitative assessment of these scenarios and of a business-as-usual (BAU) scenario, where aviation emissions are subjected to a carbon tax, is performed based on jet fuel cost and carbon price projections until 2050. Cost reductions due…

Biobased polymer molecules are a goal for the future. Here, the different intermediate pathways toward renewable structural constituents, which can substitute petrochemically derived unsustainable ones, are evaluated. Various biomass resources are covered, such as cellulose, hemicellulose, lignin, lipids, and proteins, as well as their building blocks, such as sugars, glycerol, or itaconic acid. Further emphasis is put on the impact of the impurities in the biobased monomers and the possible separations steps to remove them. The kinetics of the radical polymerization process of reacting acrylic monomers, methacrylic monomers, and styrene is reviewed. Classical elementary mechanisms are briefly discussed, while focus is put on secondary chemical reactions that influence rates greatly at elevated system temperatures, starved-feed conditions, and unideal-mixed reactor units. These functional measures have now become a common standard practice in resin production manufacturing. Described breaking/forming transformations are the styrene self-initiation step, macromonomer carrier…

Janus materials with anisotropy shapes and chemical compositions, including Janus particles, Janus nanosheets, and Janus membranes, have a great significance in the development of new functional materials and expansion of the properties and applications of materials. This review summarizes recent works on Janus materials of preparation, application, assembly, and calculation. First, we briefly sort out the methods of preparing Janus particles and discuss the factors influencing the structure, shape, and size of Janus particles, pointing out their advantages and the direction of improvement. Then, we introduce in detail the applications field from a single Janus particle, assembly of Janus particles, 2D Janus nanosheet, and Janus membrane. We summarize the recent research on the self-assembly of Janus particles and point out the role of the combination of computational simulation and experiment in the research of Janus material. Finally, the research process of Janus materials is reviewed, and the development tendencies of Janus materials and the problems to be solved are summarized.

Styrene butadiene rubber (SBR) is commonly synthesized from 1,3-butadiene and styrene monomers via two ubiquitous synthetic pathways, by emulsion (ESBR) and solution (SSBR) processes. Emulsion SBR accounts for 70% of the share of the world SBR market but is slowly being taken over by SSBR, as the latter is in high demand for high-performance tires, compatible with polar fillers such as silica for SBR–silica composites. High performance tires provide the benefits of increase in fuel efficiency, low carbon footprints, and high abrasion and better skid resistance properties. ESBR manufacturers are slowly converting their technology into SSBR due to the high demand of the SSBR product. On the other hand, unlike ESBR, functionalized emulsion based SBR (FESBR) can be comparable with SSBR for making high performance tires. FESBR can be synthesized from green eco-friendly emulsion based heterogeneous process similar to ESBR. Synthetic route utilizes various polar reagents such as acrylates, glycidyl methacrylates, acrylonitrile, vinyl carboxylic acid, vinyl sulfonates, vinylic pyridine,…

Direct electrochemical reduction of CO 2 to C 2 products such as ethylene is more efficient in alkaline media, but it suffers from parasitic loss of reactants due to (bi)carbonate formation.A two-step process where the CO 2 is first electrochemically reduced to CO and subsequently converted to desired C 2 products has the potential to overcome the limitations posed by direct CO 2 electroreduction.In this study, we investigated the technical and economic feasibility of the direct and indirect CO 2 conversion routes to C 2 products.For the indirect route, CO 2 to CO conversion in a high temperature solid oxide electrolysis cell (SOEC) or a low temperature electrolyzer has been considered.The product distribution, conversion, selectivities, current densities, and cell potentials are different for both CO 2 conversion routes, which affects the downstream processing and the economics.A detailed process design and techno-economic analysis of both CO 2 conversion pathways are presented, which includes CO 2 capture, CO 2 (and CO) conversion, CO 2 (and CO) recycling, and product…

The processes that produce CO 2 and other acid gases (SO x, NO x, and H 2 S) generate value for society. However, these gases are environmental pollutants, and their emission into the atmosphere undermines the value they create. In the face of climate change, CO 2 emissions require attention on an unprecedented scale. Abatement technologies focused on carbon capture, storage, and utilization (CCUS) enable the continued use of processes and resources that produce CO 2 (and other acid gases) while minimizing their effect on the environment. This review explores the role sorbents play in emission abatement and the acid gas “economy”. We identify 15 sorbent categories, evaluating their performance at both the material and the system levels. We conclude with anticipated research opportunities and future trends in acid gas separation.

Nitrate pollution in surface and ground waters has become a potent threat to ecosystem and human health. Electrochemical nitrate reduction is a promising strategy to directly convert excessive nitrates in water into environmentally benign dinitrogen gas or value-added chemicals such as ammonia under mild conditions. Once coupled with renewable electricity, it represents an eco-friendly and energy-efficient route for the recirculation of nitrogen species into the nitrogen cycle and economy. Understanding fundamental mechanisms of nitrate reduction is therefore crucial to design and develop high-performing electrocatalysts. In this review, we first discuss recent discoveries of reaction mechanisms for electrochemical nitrate reduction, focusing on the various pathways to desirable products (nitrogen and ammonia). The direct electron transfer and atom hydrogen transfer pathways are discussed in detail. We then summarize and discuss recent advances in catalytic materials spanning the material space from precious metal, nonprecious metal, and nonmetal catalysts. The existing challenges…

Abstract Carbon dioxide (CO2) is currently considered as a waste material due to its negative impact on the environment. However, it is possible to create value from CO2 by capturing and utilizing it as a building block for commodity chemicals. Electrochemical conversion of CO2 has excellent potential for reducing greenhouse gas emissions and reaching zero net emissions by 2050. To date, Carbon Capture and Utilization (CCU) technologies have been studied independently. We report a novel methodology based on the integration of CO2 capture and conversion by the direct utilization of a CO2 capture media as electrolyte for electrochemical CO2 conversion. This has a high potential for reducing capital and operational cost when compared to traditional methodologies. A novel mixture of chemical and physical absorption solvents allowed for the captured CO2 to be converted to formic acid with faradaic efficiencies up to 50 % and with carbon conversion of ca. 30 %. By increasing the temperature in the electrochemical reactor from 20 °C to 75 °C, the productivity towards formic acid increased…

Most polymers possess low thermal conductivity and are therefore limited in thermal management applications. A key solution is to develop highly thermally conductive polymer composites by incorporating fillers into the polymer matrix, which has attracted intensive research efforts. Here we review recent advances in the rational design of thermal conductive polymer composites from both theoretical and experimental perspectives. First, the basic theories of thermal conduction in polymer composites are discussed. Second, special attention is given to the state-of-the-art design strategies that take into account the polymer–additive interface and the preconstruction of composite microstructure. Finally, the existing challenges and opportunities for future research in this field are highlighted.

© 2021 The Authors. Published by American Chemical SocietyThe increasing global levels of anthropogenic greenhouse gases (GHGs), especially CO2emissions, have caused environmental problems that impact humanity and the ecosystems. Therefore, gas capture and storage are a feasible solution to this global issue. Some aqueous amine solutions, such as monoethanolamine (MEA), have been used to capture GHGs, but they are not environment friendly. Research on greener solvents for this task led to deep eutectic solvents (DESs) as a novel option. This review explores the applications of different DESs; compares the differences between gas solubility methodologies; and studies the interference of the DESs’ molar ratio, the influence of HBA and HBD, and the differences between the solubility of some gases in these solvents. More than 40 DESs have been analyzed; however, some gaps need to be filled, such as data for gas solubility under higher pressures and thermodynamic modeling of experimental data.

Photochromic transparent wooden materials are highly critical and attractive for smart windows, which have been scarcely investigated. In this context, we develop photochromic and fluorescent translucent wood with a color switching ability in the UV and visible spectrum regions, which is associated with color shifting properties. The fluorescent and photochromic translucent wood were generated by permeating a lignin-modified wooden substrate using a formulation containing methyl methacrylate (MMA) and a photoluminescent lanthanide-doped aluminum strontium oxide (SrAl 2 O 4:Eu 2+, Dy 3+; ASOED) pigment characterized by good photo- and thermal stability. For a better preparation of photoluminescent transparent wood, the ASOED phosphor must be efficiently dispersed without aggregation in pre-polymerized MMA. This translucent wooden substrate demonstrated a color change from colorless in visible light to green under irradiation with UV as designated by CIE Lab colorimetric results. The morphological characteristics of the generated pigment nanoparticles (NPs) were studied using…

Direct air capture (DAC) shows exceptional promise for carbon dioxide removal on the scale required to fulfill the Paris Agreement. Even though planetary limitations do not constrain the scale of DAC, the currently high cost puts its feasibility in question. By observing cost reduction pathways of similar technologies, this paper explores the cost reduction opportunities that result from learning-by-doing. We developed an analytical buy-down model to investigate what it would take to lower the cost of DAC to $100/ton CO 2 . Our goal is not to accurately predict future costs, but our analysis demonstrates that if DAC follows a path similar to that of comparable, successful technologies, a capital investment of several hundred million dollars could buy down the cost of DAC. This buy-down effort at a relatively low cost will quantify the learning potential of DAC and show whether its costs can be reduced (like solar photovoltaic modules) or whether despite the investment it remains expensive (like nuclear power generation).

This review discusses the recent application of artificial intelligence (AI) algorithms in five aspects of computational fluid dynamics: aerodynamic models, turbulence models, some specific flows, and mass and heat transfer. Currently, there are three main coupling models. The first is the data-driven model to obtain the input–output relationship without involving any physical mechanisms. The second is the physical model to optimize the existing models by AI algorithms. The third is the hybrid model involving both data and physical mechanisms. Among various AI algorithms, artificial neural network is usually applied to build data-driven models and has been successfully employed in the mentioned five fields. Other AI algorithms such as recursive neural network, support vector machine, and naive Bayes are mainly used for the physical models. Finally, the development tendency of coupling models and how to choose an appropriate model are given in the conclusions and prospects.

Hydrogen is one of the cleanest energies with potential to have zero carbon emission. Hydrogen storage is a challenging phase for the hydrogen energy application. The safety, cost, and transportation of compressed and liquified hydrogen hinder the widespread application of hydrogen energy. Chemical absorption of hydrogen in solid hydrogen storage materials is a promising hydrogen storage method due to its high storage and transportation performance. Hydrogen storage density, dehydrogenation temperature, and dehydrogenation dynamics are the main challenges for the hydrogen storage materials. The ultimate goal of the system gravimetric capacity was set by the Department of Energy to be 6.5 wt % with a working temperature from −40 to 60 °C. The theoretical densities of most present hydrogen storage materials are even lower than 6.5 wt %, which make it impossible to reach the system gravimetric capacity goal. Only hydrogen storage materials with high theoretical density (≥10 wt %) with further modification have the possibility to reach the goal. However, most of the reviews focus on the…

Low-temperature methane dry reforming (MDR) over supported Ni catalysts is a more economical way to convert greenhouse gases than high-temperature MDR. However, sintering from Ni aggregation and carbon deposition from deep cracking of CH 4 caused catalyst deactivation. In this study, we synthesized a supported Ni/SiO 2 -E catalyst by strong electrostatic adsorption for low-temperature MDR (673–773 K). Experimental results showed that the Ni/SiO 2 -E catalyst exhibited higher performance on using low-temperature MDR than the Ni/SiO 2 -I catalyst prepared by the conventional impregnation method. From characterizations of X-ray diffraction (XRD), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H 2 -TPR), etc. in fresh catalysts and used catalysts, the excellent stable performance of MDR over the Ni/SiO 2 -E catalyst was associated with the smaller Ni size and the stronger Ni–SiO 2 interaction. The former contributed to less formation of carbon deposits and the latter resulted in hardly any sintering of Ni nanoparticles.

The amount of CO 2 in the atmosphere is rising due to the combustion of fossil fuels to fulfill the energy demand. The need to build cleaner and more efficient energy systems is motivated by the introduction of chemical looping combustion (CLC) as an alternative to conventional combustion by transferring oxygen. The transfer of oxygen from the air to fuel is carried out by a metal oxide known as an oxygen carrier (OC). For high fuel conversion and oxygen transport capacity, many efforts have been made for the preparation of an OC with minimal material cost. This review aims to summarize the recent advances and development of various types of OCs; particularly those developed within the previous five years are critically discussed in this paper. The main criteria for the selection of the OCs for CLC include their oxygen vacancies, oxygen transport capacities, costs, and tendencies over coke deposition, agglomeration, and attrition. OCs for CLC can be generally divided into single oxides, mixed oxides, natural mineral, spinel from mixed metal oxides, and perovskite. These have been…

Modeling the interactions between CO 2 uptake and different parameters of activated carbon (AC) adsorbent synthesis in biomass types can be a way to create efficient adsorbents for CO 2 capture. In the present work, several AC syntheses experiments, from 35 publications, have been used for the development of operability simulations, based on an artificial neural network (ANN). Four ANN structures were developed by multilayer perceptron (MLP) and radial-based function (RBF) algorithms to predict the specific surface area (BET) of the adsorbents and their CO 2 adsorption capacity. The precursors, activators, pyrolysis temperatures, pour volumes, adsorption pressure, adsorption temperature, BET, and CO 2 adsorption capacity have been considered as input and output variables. The Bayesian Regularization backpropagation algorithm has been chosen for the two hidden layers from the MLP and compared with the RBF algorithms. The number of neurons in the MLP and RBF algorithms was 35 and 45 for BET prediction, and 130 and 240 for CO 2 adsorption capacity prediction, respectively, after an…

Polysulfone (PSF)-based mixed-matrix membranes (MMMs) were developed through incorporation by solvent casting of poly(ethylene glycol)-grafted carbon nanotubes (PEG-g-CNTs) into the polymer matrix. Single-gas permeability and the respective perm-selectivity values of the resulting MMMs for CO2, CH4, and N2 along with mixed-gas selectivities were determined at various temperatures and pressures. The performance was further analyzed by obtaining gravimetrically gas adsorption isotherms and interpreting the results to determine the solubility and diffusivity coefficients of the prepared membranes. Simultaneous improvement in CO2 permeability, selectivity, and mechanical robustness was achieved. Indicatively, an increase in CO2 permeability by 52.4% at 1.5 bar was discerned for the MMM containing 5 wt % PEG-g-CNTs along with enhancements of 81 and 74% in CO2/N2 and CO2/CH4 perm-selectivities, respectively, while an up to 43.4% increase in tensile modulus and a 12.5% increase in tensile strength were achieved as well. This performance, in conjunction with the stability of the fillers,…

Utilizing Li-ion conductors as solid electrolytes is essential in solid-state lithium (Li) batteries (SSLBs), which is a promising solution for the next-generation electrochemical energy storage systems that require high energy and high levels of safety. Among various Li-ion conductors, Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 (LATP), a NASICON-type ceramic, has attracted intensive attention due to its advantages of air stability and fast Li + conductivity. However, to reach a decent ionic conductivity and reduce grain boundary resistance, LATP requires high temperatures for densification, which is time-consuming and expensive for large-scale applications. Herein, we report a simple solution-casting synthesis for new composite solid electrolytes by embedding LATP ceramic into a PVdF–HFP matrix. In the LATP/PVdF–HFP composite solid membranes, the NASICON-type crystal structure of LATP is well maintained. Without taking any additional liquid electrolyte absorption, the prepared composite solid electrolytes with 10 wt % LATP show the highest ionic conductivity of 2.3 × 10 –4 S cm –1 at room…

High Resolution Image Download MS PowerPoint Slide In this study, a systematic investigation on Dual Functioning Materials (DFMs) for the capture and methanation of CO 2 is carried out. The attention is focused on the nature of the CO 2 adsorbent component (storage material, SM) varying between alkaline (Li, Na, K) and alkaline-earth (Mg, Ca, Ba) metal oxides in combination with Ru, both supported on an Al 2 O 3 support. Combining gas phase reactivity analysis and FT-IR characterization, the samples are characterized in terms of CO 2 storage capacity. It is found that all the SM-containing samples adsorb significant amounts of CO 2 as carbonate species, with the higher amounts being adsorbed when the more thermally stable species are formed, i.e., when Ca, Ba, or K are employed as SMs. In all cases, the hydrogenation of the adsorbed carbonates to CH 4 occurs at lower temperature, if compared to their thermal desorption. However, in the case of Ca- and Ba-based DFMs, resilient carbonates are present on the material surface. It was found that the SMs able to form the more thermally…

In order to systematically understand the hydrothermal carbonization reactions and kinetics of glucose at 180 °C, the structures of intermediate and final chemical products were identified, the conversion paths were clarified, and the conversion rates and yields were calculated. By comparing the hydrothermal reaction paths and kinetics of 5-hydroxymethylfurfural (HMF), fructose, and glucose, it is proven that HMF is the most important intermediate and the sole precursor of hydrothermal carbon. The degradation of glucose, fructose, and HMF follows the first-order reaction, and the formation of hydrothermal carbon linearly depends on the conversion of HMF. Approximately 28% of HMF is converted from fructose and ∼72% is from glucose. Also, the hydrothermal reaction time-dependent morphologies and structures of the resulting hydrothermal carbon are compared, and their structures before and after heat treatment are characterized.

The design of novel nanocomposite films based on hydroxypropyl cellulose (HPC) and wax/halloysite hybrid microspheres has been reported. In particular, we first prepared wax/clay Pickering emulsions which were characterized by thermogravimetric analysis and microscopy. SEM images allowed more detailed insights on the nanotubes disposition at the wax/water interface, acting as an outer stabilizing shell. Therefore, the cellulosic biopolymer was added, and it was found that HPC enhances the colloidal stability of the particles, preventing their coalescence and sedimentation. The preparation of the composite films was carried out by the solvent casting method, which enabled the development of very homogeneous materials. Contact angle and sliding angle measurements showed that the increasing amount of wax/halloysite microparticles into the biopolymeric matrix is responsible for an enhanced hydrophobic nature of the films and, at the same time, it facilitates the rolling process of droplets on the surfaces, thus making the prepared materials promising protective coatings. These findings…

Sulfur hexafluoride (SF 6 ), which has a greenhouse effect of 228 000 times more terrible than carbon dioxide, has attracted increasing attention. Its efficient capture, especially from the mixtures with low SF 6 concentrations, is urgently needed while challenging. Herein, we use a calcium (Ca)-based metal–organic framework (MOF; SBMOF-1) with multiaromatic ring-functionalized channels to achieve a record selectivity as high as 727 for an industrially relevant SF 6 /N 2 mixture (volume concentration of SF 6: 0.03%) at 298 K and 1 bar. Grand canonical Monte Carlo simulations and density functional theory calculations identified that SF 6 molecules were energy-favorably trapped in the functionalized MOF channels by the strong interactions between the channel walls and six fluorine atoms on SF 6 . Excellent breakthrough results accompanied with good stability and regenerability recommend its promising application for practical SF 6 capture from low-concentration SF 6 mixtures, which also provides a new benchmark for SF 6 /N 2 separation.

Concerning the environmental and health problems related to SO x emission, the environmental protection agencies are incessantly tightening the permissible sulfur level in fuels such as gasoline and diesel. This gives a greater challenge for the traditional hydrodesulfurization (HDS), which is quite inefficient for removing refractory sulfur (RS) compounds (e.g., 4,6-dimethyldibenzothiophene). Consequently, the new efficient HDS catalysts for substituting the industrial HDS catalysts (Ni(Co)Mo/Al 2 O 3 ) have received much attention. Zeolite-containing HDS catalysts are of particular importance because zeolites could alleviate the HDS of RS compounds via isomerization and cracking abilities of their Brønsted acid sites. The microporous zeolites slow down the diffusion of reactants and products, leading to uncontrolled cracking reactions that promote the coke formation and thus deactivate the HDS catalysts. Therefore, the application of zeolite-based catalysts was limited for HDS reactions in the early years. But, due to the introduction of hierarchical porous structure in zeolites,…

The autothermal reforming (ATR) process for hydrogen production saves considerable energy for the reaction compared with endothermic steam methane reforming (SMR). However, it requires a supply of pure oxygen, for which an air separation unit (ASU) is needed; this hinders the adoption of ATR in industrial applications because of both the high capital and operating costs. At the same time, in liquefied natural gas (LNG) regasification terminals, the cold energy from the regasification process is typically wasted. Coincidentally, the temperature of this waste cold energy matches that required for ASU operation. Thus, in this paper, a novel ATRprocess is proposed in which an ASU and LNG regasification are integrated in order to make use of the cold energy as an operating utility and achieve hydrogen production from the LNG. For the sake of comparison, the proposed system and a conventional SMR process are optimized using a genetic algorithm to evaluate and benchmark its performance. With an LNG feed stream of 827.5 kmol/h, the optimal case of the proposed system produces 2508.0 kmol/h…

Metal-doping is an efficient strategy to develop high-activity composite metal oxides catalysts for VOCs abatement. Herein, MnNbO x composite oxides were prepared using niobium element as a modification additive, finding that niobium addition presented a promotional effect on boosting the catalytic activity of MnO x for propane combustion. It was demonstrated that niobium insertion into manganese oxides was in favor of the formation of Mn 3 O 4 crystalline phase and concurrently caused higher redox ability, more abundant surface oxygen species, and acid sites. All these properties were considered to be crucial parameters for catalytic activity enhancement. Among all, the catalyst of Mn 0.85 Nb 0.15 O x (simply designated as M 0.85 N 0.15 ) showed the highest propane conversion efficiency and relatively good catalytic durability under CO 2 -containing atmospheres. Moreover, the in situ DRIFTs analysis highlighted the important role of surface acidity in the surface catalytic pathways of propane adsorption, activation, and oxidation.

The new generation of glucose biosensors has gained immense research interest owing to its cost effectiveness, quick response, good stability, reproducibility, and low detection limit. The enzymatic glucose sensor suffers from numerous intrinsic disadvantages; therefore, there is a need to develop a new biosensor which can overcome the disadvantages of enzymatic glucose biosensors. In that context, metal oxide-based nanostructures and their compostites exhibit properties that can overcome the drawbacks of enzymatic glucose sensors. This review discusses recent developments in some of the metal oxides (CoO, NiO, CuO, and ZnO) along with their composites as well as their applications toward nonenzymatic glucose sensors. The metal oxide composites possess excellent features which signify the potential commercial applications of metal oxide-based composites for nonenzymatic electrochemical glucose sensing.

High Resolution Image Download MS PowerPoint Slide Despite the rapid development and enormous success of organic–inorganic hybrid halide perovskites ( AB ′ X 3 ), such as CH 3 NH 3 PbI 3 as absorbers for perovskite-based solar cells (PSCs), the commercial applications of photovoltaic techniques still face several challenges, such as decomposition when exposed to light and moisture, and lead toxicity. On the other hand, the double perovskites ( A 2 B ′ B ″ X 6 ) are derived from the AB ′ X 3 when half of the octahedrally coordinated B ′-cations are partially replaced by the suitable B ″-cations. They are attracting attention due to a new design strategy to replace Pb 2+ ions with the couple of a monovalent M + ion and a trivalent M 3+ ion, leading to a new family of quaternary double perovskites. In this way, we aim to synthesize and characterize Cs 2 AgSbCl 6 powdered samples, designed for solar cell applications. The crystalline phase and morphological features are investigated by X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), scanning electron microscopy (SEM)…

Kenics static mixers enhance mixing under laminar flow conditions. The ideal static mixer achieves efficient mixing at a low pressure drop. A modified design of the Kenics static mixer is analyzed, featuring gaps between the mixing elements, which can achieve the same level of mixing as the conventional design but with fewer mixing elements and a substantially lower pressure drop. The mixing effects at the entrances and exits of the mixing elements are enhanced by the introduction of gaps between the elements. The performances of mixers based on the right–left and right–right configurations with different gap lengths are characterized in terms of pressure drop, coefficient of variance of concentration, residence time distribution, and extensional efficiency with computational fluid dynamics simulations. Furthermore, the coefficient of variance of concentration is measured experimentally with several three-dimensional (3D) printed devices. The gaps reduce the mixing length when the design is based on the right–right configurations, and the gap-to-diameter ratio is 0.5 or 1.0 compared…

The unique geometry of screw extruders allows handling very viscous media; thus, they can be used as continuous reactors to conduct polymerization reactions without using any solvents. This is called reactive extrusion polymerization. It is an intensified process as it maximizes reaction rates upon maximizing the concentrations of monomers and an initiator/catalyst (if there is any). It also allows conducting polymerization reactions at higher temperatures, without having to take measures to prevent solvents from evaporating or to work under pressure. However, screw extruders are not suitable for the early stage of polymerization in which the viscosity of the polymerization system may not be high enough for the rotation of the screws to generate a steady flow. A combination of continuously stirred tank reactors and a twin-screw extruder or several in series is preferred for the polymerization process. This review shows how reactive extrusion may intensify different types of polymerization processes under the constraint of no solvents, such as free-radical polymerization, anionic…

Herein, an efficient adsorbent based on an activated carbon and metal–organic framework was developed for the adsorption of heavy metals from an aqueous solution. The structural and morphological characterizations of the Cr-MOF/AC composite were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), exhibiting the formation of crystalline cubic-shaped particles. The Cr-MOF/AC composite showed 3-fold higher specific surface area (2440 m 2 /g) than AC. The response surface methodology was employed to find the optimum adsorption conditions for the fast and efficient removal of lead and cobalt ions. The study of the kinetics of adsorption showed that the metal ions adsorption followed the pseudo-second-order model. The resultant composite was proved to be an excellent and highly efficient adsorbent with the adsorption capacity as high as 127 and 138 mg/g for lead and cobalt, respectively, under optimal conditions (pH = 5, an adsorption time of 40 min, adsorbent content of 25 mg, and metal ion concentration of 70…

Boron nitride (BN) presented enormous potential in the fabrication of novel membranes with superior separation efficiency. Researchers try to produce membranes with high solvent permeability and good rejection performance in industrial applications. In this review, the recent progress in the fabrication of BN-based membranes with different fabrication techniques and various applications is reviewed. Representative studies on applying BN-based membranes in gas separation, proton exchange, electrodialysis, and water filtration membranes to develop their performance and stability, induce antifouling characteristics, and decline the trade-off between selectivity and permeability, together with the explanation of their mechanisms, are discussed. Moreover, various methods of synthesis of BN allotropes are introduced. In addition, a brief review of simulation studies (molecular dynamic and density function theory) on theoretical studies of BN nanosheet membranes was performed. The authors hope that this review will arouse the active interest of many researchers in the further development…

A key concept for hydrogen-fueled internal combustion engines is reducing NO x emissions with direct H 2 -SCR. Besides platinum as an active noble metal component, palladium-based catalysts are attractive for NO reduction with high selectivity. However, reliability of the catalytic activity in the presence of water with persistently low side product formation remains challenging. Therefore, a monolithic 1%Pd/5%V 2 O 5 /20%TiO 2 -Al 2 O 3 model catalyst is studied extensively under different conditions, showing that NO x conversion remains high even in the presence of 5% water, maintaining over 65% selectivity toward N 2 . Additionally, the catalyst remained active in a long-term experiment over 12 h in the absence and presence of water with an NO conversion over 45%. Finally, steady-state measurements and a kinetic analysis reveal overall concentration dependencies alongside trends of the reduction reaction competing with the hydrogen combustion reaction.

Efficient and sustainable separation of metals is gaining increasing attention, because of the essential roles of many metals in sustainable technologies for a climate-neutral society, such as rare earths in permanent magnets and cobalt, nickel, and manganese in the cathode materials of lithium-ion batteries. The separation and purification of metals by conventional solvent extraction (SX) systems, which consist of an organic phase and an aqueous phase, has limitations. By replacing the aqueous phase with other polar solvents, either polar molecular organic solvents or ionic solvents, nonaqueous solvent extraction (NASX) largely expands the scope of SX, since differences in solvation of metal ions lead to different distribution behaviors. This Review emphasizes enhanced metal extraction and remarkable metal separations observed in NASX systems and discusses the effects of polar solvents on the extraction mechanisms according to the type of polar solvents and the type of extractants. Furthermore, the considerable effects of the addition of water and complexing agents on metal…

0.1–3 wt % Ce-promoted MCM-41-supported nickel catalysts were prepared for dry reforming of CH 4 (DRM) and characterized by surface area and pore analyses, powder X-ray diffraction, temperature-programed reduction with H 2, temperature-programed CO 2 desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and scanning transmission electron microscopy using a high-angle annular dark field. Notably, 5Ni0.5Ce/MCM-41 has a bimodal distribution of NiO crystallites inside and outside the pores of MCM-41, the highest number of basic sites inducing profound CO 2 interactions with the surface, and metallic nickel particles interacting with the support for facilitating CH 4 dissociation. In addition, a thin surface layer of ceria provides surface oxygen species for carbon deposit oxidation. All these physiochemical properties ensured >90% conversion (H 2 /CO ∼ 1) over 330 min on stream and >80% conversion over 75 h of time on stream (H 2 /CO = 0.98) over the 5Ni0.5Ce/MCM-41 catalyst. A higher ceria loading than 0.5 wt % masked the active Ni sites with a ceria layer, which…

The catalytic process mediated by solid materials plays an important role in current human wealth and environmental protection. It enables the production of clean fuels and chemical products, and it ultimately allows the mitigation of undesired gas or liquid emissions to the environment. These features are highly recognized by the scientific community, industrial sector, and society. Despite this relevance, the hurdles that must be overcome to become industrially relevant are less known. There are many demanding requirements. This commentary reviews, from an academic point of view, the implementation requirements of a catalytic material. The motivation for this perspective article comes from the existing gap between academic research and industrial application. This account first defines what a catalytic material is, from the structural and application point of views. It then locates the catalytic material in an entire system analysis. This includes active sites, reactor system, the entire plant and the integration with other processes. Subsequently, the properties of an ideal…

Fluidized bed gasification is a promising process technology to manage the growing amount of sewage sludge (SS) requiring disposal.Two samples of SS, produced in different seasons of the year by a municipal wastewater treatment plant, were subjected to gasification at 850 °C in a bench-scale fluidized bed reactor using, as a gasification agent, a nitrogen/air mixture at different values of oxygen/fuel equivalence ratio (ER = 0.1-0.2).The starting materials and the output streams (syngas, tar, and solid residues) were thoroughly characterized.The fate of specific SS constituents and the characteristics of bottom ashes were addressed, so contributing to the problem of a proper SS management approach in the context of the circular economy.Computeraided simulations were also performed, which allowed us to predict the composition of the syngas from SS gasification under operating conditions different from those experimentally investigated (i.e., reactor temperature and ER).