In an effort to estimate the feasibility of heat recuperation from an internal combustion engine (ICE) by steam reforming (SR) or by decomposition of the fuel, we study here the required size of a reformer heat exchanger in order to power a 3.7 kW engine. To that end, we experimentally test the heat transfer in a structured commercial reactor with ∼0.39 m2 of heat transfer area in an ∼1 L unit. We then simulate the required length for evaporation and reforming of several fuels, using published kinetics with a highly active catalyst, under a fixed exhaust temperature of 973 K, and study the effect of pressure and steam-to-fuel ratio. Both co- and counter-current schemes are considered. Methanol decomposition is probably the best solution from the energy point of view. However, it is known to lead to deactivation. Methanol SR (with S/M = 1) requires about 2 L of reformer-HE and seems to be a reasonable solution, yielding a chemical energy gain of ∼16%, a value close to the asymptotic thermodynamic value. Moreover, the presence of CO2 in the reformate is known to mitigate to NOx emissions down to zero-impact levels. Ethanol SR (with S/E = 1 or 3) yields poor results since CH4 is an intermediate, which requires high temperatures for reforming; operating ESR requires exhaust temperatures of ∼1250 °K or higher. While such high temperatures may be attained and may yield an energetic gain of more than 20%, it will require modification of the process. Methylal SR (S/MA = 1) yields good results as well.

The by-products generated from the whiskey distillation process consist of organic liquids with a high chemical oxygen demand (COD) and residues with a high solid content. Low-carbon strategies that repurpose and valorize such by-products are now imperative to reduce the carbon footprint of the food and beverage industries. The operation of a two-phase anaerobic digester to produce volatile fatty acids (VFAs) and biogas may enable distilleries to transition toward a low-carbon bioeconomy. An example of such a system is a leach bed reactor connected to an expanded granular sludge bed (LBR-EGSB) which was designed, commissioned, and conceptually validated in this paper. Several design improvements progress the LBR-EGSB beyond previous reactor designs. An external gas–liquid–solid separator in the EGSB was used to capture any residual gases produced by the effluent and may reduce the amount of methane slippage and biomass washout. The implementation of a siphon-actuated leachate cup is a low-cost alternative that is less prone to actuation malfunction as compared to electrically actuated solenoid valves in previous reactor designs. Furthermore, replacing fresh water with distillery’s liquid by-products as leachate promotes a circular repurpose and reuse philosophy. The system proved to be effective in generating VFAs (10.3 g VFAs L–1Leachate), in EGSB COD removal (96%), and in producing methane-rich biogas (75%vol), which is higher than the values achieved by traditional anaerobic digestion systems. The LBR-EGSB could ultimately provide more by-product valorization and decarbonization opportunities than traditional anaerobic digestion systems for a whiskey distillery.

Froth flotation is the most versatile process in mineral beneficiation, extensively used to concentrate a wide range of minerals. This process comprises mixtures of more or less liberated minerals, water, air, and various chemical reagents, involving a series of intermingled multiphase physical and chemical phenomena in the aqueous environment. Today’s main challenge facing the froth flotation process is to gain atomic-level insights into the properties of its inherent phenomena governing the process performance. While it is often challenging to determine these phenomena via trial-and-error experimentations, molecular modeling approaches not only elicit a deeper understanding of froth flotation but can also assist experimental studies in saving time and budget. Thanks to the rapid development of computer science and advances in high-performance computing (HPC) infrastructures, theoretical/computational chemistry has now matured enough to successfully and gainfully apply to tackle the challenges of complex systems. In mineral processing, however, advanced applications of computational chemistry are increasingly gaining ground and demonstrating merit in addressing these challenges. Accordingly, this contribution aims to encourage mineral scientists, especially those interested in rational reagent design, to become familiarized with the necessary concepts of molecular modeling and to apply similar strategies when studying and tailoring properties at the molecular level. This review also strives to deliver the state-of-the-art integration and application of molecular modeling in froth flotation studies to assist either active researchers in this field to disclose new directions for future research or newcomers to the field to initiate innovative works.

The effects of co-feeding CO2 and methane on the performance of La0.8Sr0.2FeO3 (LSF) were studied with different CO2 concentrations. The reaction was conducted in chemical looping mode at 900 °C and a weight hourly space velocity (WHSV; g methane/g catalyst/h) of 3 h–1 during 15 min reduction (10 mol % methane with 0–1.8% CO2 in nitrogen) and 10 min oxidation (10 mol % oxygen in nitrogen) cycles. Analyses of X-ray diffraction and X-ray photoelectron spectroscopy data of spent materials indicated that CO2 reacts with the oxygen vacancies on the LSF surface during methane reduction, increasing CO selectivity in POM. As the CO2 feed concentration increased to an optimal value (1.6% CO2), the CO selectivity increased to 94%. Under those conditions, the EOR (extent of reduction) of LSF, defined as the amount of oxygen depleted from the lattice, was 0.18–0.15 mmol/min·gcat. Reducing the EOR to 0.09–0.08 mmol/min·gcat (1.8% CO2) led to partial methane combustion. These results were confirmed by altering the operating conditions (WHSV = 2 and 1 h–1, T = 950 °C) and CO2 feed concentrations while extending the reduction time. Operation in an optimal EOR range (0.17–0.10 mmol/min·gcat) that enabled optimal CO selectivity (>90%) was obtained without oxidative regeneration for the 18 h reduction time.

Cellulose pyrolysis is reportedly influenced by factors such as sample size, crystallinity, or different morphologies. However, there seems to be a lack of understanding of the mechanistic details that explain the observed differences in the pyrolysis yields. This study aims to investigate the influence of particle size and crystallinity of cellulose by performing pyrolysis reactions at temperatures of 673–873 K using a micropyrolyzer apparatus coupled to a GC × GC-FID/TOF-MS and a customized GC-TCD. Over 60 product species have been identified and quantified for the first time, including water. Crystalline cellulose with an average particle size of 30–50 × 10–6 m produced 50–60 wt % levoglucosan. Predominantly amorphous cellulose with an average particle size of 10–20 × 10–6 m resulted in remarkably low yields (10–15 wt %) of levoglucosan complemented by higher yields of water and glycolaldehyde. A detailed kinetic model for cellulose pyrolysis was used to obtain mechanistic insights into the different pyrolysis product compositions. The kinetics of the mid-chain dehydration and fragmentation reactions strongly influence the total yields of low-molecular weight products (LMWPs) and are affected by cellulose chain arrangement. Levoglucosan yields are very sensitive to the activation of parallel cellulose decomposition reactions. This can be attributed to the mid-chain reactions forming smaller chains with the levoglucosan ends, which remain in the solid phase and react further to form LMWPs. Direct quantification of water helped to improve the description of the dehydration, giving further indications of the dominant role of mid-chain reaction pathways in amorphous cellulose pyrolysis.

Atmospheric carbon poses an existential threat to civilization via global climate change. Hundreds of gigatonnes of carbon dioxide must be removed from earth’s atmosphere in the next three decades, necessitating a low-cost, energy-efficient process to extract low concentrations of carbon dioxide for conversion to a stable material permanently stored for thousands of years. In this work, the challenge of removing gigatonnes of CO2 is described via the scale of effort and the thermodynamics of collecting and reducing this diffuse chemical, the accumulation of which imparts a substantial entropy penalty on any atmospheric carbon capture process. The methods of CO2 reduction combined with upstream direct air capture (DAC) including absorption, membrane separation, and adsorption are compared with biomass torrefaction and permanent burial (BTB). A Monte Carlo model assesses the mass, energy, and economics of the full process of biomass torrefaction from biomass collection and transport to stable carbon burial to determine that 95% of scenarios could remove carbon for less than $200 per CO2-tonne-equivalent. Torrefied carbon is further discussed for its long-term stability and availability at the scale required to substantially mitigate the threat of climate change.

The objective of this study was to optimize the pectin extraction from industrial quince biowaste using citric acid as a hydrolytic agent and assisting the process with ultrasound technology. For this, the process was modeled using the Box–Behnken design (BBD) to find the factors’ optimum values and their interactions. The quince pectin extraction was carried out by adding to the biowaste a citric acid solution at different pH values (2.0, 2.5, and 3.0) in mass volume ratios of 1/25, 1/20, and 1/15 g/mL and immersing it in an ultrasound bath for 30, 45, and 60 min at controlled temperatures of 70, 80, and 90 °C. Pectin yield, process cost, and CO2 emission were calculated under different conditions according to the BBD model, and a polynomial function was adjusted for each dependent variable. A multiobjective optimization technique known as “Genetic algorithms” was used to find the proper extraction conditions that would maximize the pectin yield and minimize the process cost. The optimal extraction conditions obtained were as follows: pH = 2.12, mvr = 0.04 g/mL, time = 48.98 min, and temperature = 85.20 °C, with response variables of pectin yield = 12.78%, cost = 1.501 USD/kg of pectin, and calculated CO2 emission = 0.565 kg of CO2/kg of pectin.

CuOx/CeO2 is emerging as an effective catalyst for CO oxidation due to its unique redox properties; however, its activity and stability still need to be enhanced compared with supported platinum group metals. Here, an approach is demonstrated to increase the CO oxidation performance and resistance to hydrocarbon inhibition through the K+ modification of the CuOx/CeO2 catalyst. The K+ can improve the electron transfer at the metal–oxide interface, shifting the redox equilibrium (Cu2+ + Ce3+ ↔ Cu+ + Ce4+) to be right to accelerate the formation of highly active Cu+ species. The reaction activity of the K+-modified CuOx/CeO2 catalyst was in the same order of magnitude as the noble metal of Pt and Pd catalysts. In addition, the K+-modified catalyst showed significantly improved resistance to hydrocarbon inhibition. This work demonstrates a facile way to tune the redox properties of binary transition metal oxides.

The diversification of coal for its sustainable utilization in producing liquid transportation fuel is inevitable in countries with huge coal reserves. Gasification has been contemplated as one of the most promising thermochemical routes to convert coal into high-quality syngas, which can be utilized to produce liquid hydrocarbons through catalytic Fischer–Tropsch (F-T) synthesis. Liquid transportation fuel production through coal gasification could help deal with environmental challenges and renewable energy development. The present study aims to develop an equilibrium model of a downdraft fixed-bed gasifier using Aspen Plus simulator to predict the syngas compositions obtained from the gasification of high-ash low-rank coal at different operating conditions. Air is used as a gasifying agent in the present study. The model validation is done using published experimental and simulation results from previous investigations. The sensitivity analysis is done to observe the influence of the major operating parameters, such as equivalence ratio (ER), gasification temperature, and moisture content (MC), on the performance of the CL-RMC concerning syngas generation. The gasification performance of CL-RMC is analyzed by defining various performance parameters such as syngas composition, hydrogen-to-carbon monoxide (H2/CO), molar ratio, syngas yield (YSyngas), the lower heating value of syngas (LHVSyngas), cold gas efficiency (CGE), and carbon conversion efficiency (CCE). The combined effects of the major operating parameters are studied through the response surface methodology (RSM) using the design of experiments. The optimized condition of the major operational parameters is determined for a target value of a H2/CO molar ratio of 1 and the maximum CGE and CCE using the multiobjective optimization approach. The high-degree accurate regression model equations were generated for the H2/CO molar ratio, CGE, and CCE using the variance analysis (ANOVA) tool. The optimal conditions of the major operating parameters, i.e., ER, gasification temperature, MC for the H2/CO molar ratio of 1, and the maximum CGE and CCE, are found to be 0.5, 655 °C, and 16.36 wt %, respectively. The corresponding optimal values of CGE and CCE are obtained as 22 and 16.36%, respectively, with a cumulative composite desirability value of 0.7348. The findings of the present investigation can be decisive for future developmental projects in countries concerning the utilization of high-ash low-rank coal in liquid fuel production through the gasification route.

A systematic comparison is demonstrated for the predictions of frontier orbital energies─highest occupied molecular orbital (HOMO) (EH), lowest unoccupied molecular orbital (LUMO) (EL), and energy gap (ΔEHL) of the molecules in the QM9 dataset, where it contains 120k-plus three-dimensional organic molecule structures determined by first-principles simulations. The target molecular properties (EH, EL, and ΔEHL) are predicted using linear regression (LR), machine learning (random forest, RF), and continuous-filter convolutional neural network (SchNET) approaches. LR and RF models built upon various knowledge-based descriptors, being derived from SMILES of the molecules, can provide predictivity of the target properties with the mean absolute errors (MAEs) 4–6 times the chemical accuracy (0.043 eV). The best approach, SchNET, using the graph representation derived from molecular Cartesian coordinates, is confirmed to provide MAEs of EH, EL, and ΔEHL at 0.051, 0.041, and 0.076 eV, respectively. With the introduction of bond-step matrix representation with the SchNET model, the computational cost of dataset preparation can be substantially reduced, and the corresponding MAEs increase moderately to 2–3 times the chemical accuracy. The chemical interpretation of the important descriptors identified in the LR and RF models appears to align with the chemical knowledge of describing these molecular electronic properties but is accompanied with tolerable prediction errors. The combination of bond-step representation and the SchNET model can provide an assessable and balanced option for the high-throughput screening of organic molecules and the development of the data science approach.

The authors discuss the opportunities for achieving rapid innovation cycles in the chemical manufacturing space, a field that is traditionally slow to evolve compared to other industries like automotive, aerospace, and IT industries. The main reason is the enormously complex heterogeneous multiphase, multiscale, reactive mixtures that are handled in such manufacturing facilities. Hence, the flow structure changes with increasing scales of equipment, making it difficult to develop new technologies without extensive pilot-scale testing and without the use of empirical correlations for scaleup. In other industries, the adoption of standards and interoperability has made the incremental adoption of devices (like storage devices as an example) improve the performance in existing equipment. Computers, in particular, have experienced orders of magnitude improvement in performance in a highly heterogeneous environment from tablets to supercomputers and are still able to communicate with each other due to the adoption of standards. The modularization and development of standards for interconnectivity can help accelerate the introduction of innovation to process industries. We discuss some of the possibilities.

Thermal control devices like diodes, regulators, and switches are essential to achieve directional heat flow for numerous applications, such as electronic systems, energy conversion or storage systems, and equipment for buildings. These devices exhibit a controllable thermal conductance that can be manipulated to allow preferential thermal transport. While several design concepts have existed for decades, they are rarely deployed due to some basic practical limitations related to scalability, cost, operating temperature, and/or requirements for external excitation. In this study, we achieved a fundamental breakthrough in developing a passive thermal switch, which has a simple and scalable design, is thermally driven (thus does not require an external stimulus), and exhibits a rectification ratio of 17.5, which is among the highest value reported for passive switches in the literature. Notably, the switch transitions from an effective thermal conductivity of ∼1.6 W/m-K (insulator) in the OFF state to ∼28 W/m-K (conductor) in the ON state near 50 °C. To demonstrate the cost-effective implementation of our technology at a large scale, we developed a self-regulating insulation panel that automatically varies its thermal resistance by using just a few thermal switches occupying less than 10% of the total surface area. Lastly, using a parametric analysis, we establish a promising pathway to further improve the performance and versatility of the proposed technology.

Plasma-surface coupling has emerged as a promising approach to perform chemical transformations under mild conditions that are otherwise difficult or impossible thermally. However, a few examples of inexpensive and accessible in situ/operando techniques exist for observing plasma-solid interactions, which has prevented a thorough understanding of underlying surface mechanisms. Here, we provide a simple and adaptable design for a dielectric barrier discharge (DBD) plasma cell capable of interfacing with Fourier transform infrared spectroscopy (FTIR), optical emission spectroscopy (OES), and mass spectrometry (MS) to simultaneously characterize the surface, the plasma phase, and the gas phase, respectively. The system was demonstrated using two example applications: (1) plasma oxidation of primary amine functionalized SBA-15 and (2) catalytic low temperature nitrogen oxidation. The results from application (1) provided direct evidence of a 1% O2/He plasma interacting with the aminosilica surface by selective oxidation of the amino groups to nitro groups without altering the alkyl tether. Application (2) was used to detect the evolution of NOX species bound to both platinum and silica surfaces under plasma stimulation. Together, the experimental results showcase the breadth of possible applications for this device and confirm its potential as an essential tool for conducting research on plasma-surface coupling.

Air pollution is a central problem faced by industries during the production process. The control of this pollution is essential for the environment and living organisms as it creates harmful effects. Biofiltration is a current pollution management strategy that concerns removing odor, volatile organic compounds (VOCs), and other pollutants from the air. Recently, this approach has earned vogue globally due to its low-cost and straightforward technique, effortless function, high reduction efficacy, less energy necessity, and residual consequences not needing additional remedy. There is a critical requirement to consider sustainable machinery to decrease the pollutants arising within air and water sources. For managing these different kinds of pollutant reductions, biofiltration techniques have been utilized. The contaminants are adsorbed upon the medium exterior and are metabolized to benign outcomes through immobilized microbes. Biofiltration-based designs have appeared advantageous in terminating dangerous pollutants from wastewater or contaminated air in recent years. Biofiltration uses the possibilities of microbial approaches (bacteria and fungi) to lessen the broad range of compounds and VOCs. In this review, we have discussed a general introduction based on biofiltration and the classification of air pollutants based on different sources. The history of biofiltration and other mechanisms used in biofiltration techniques have been discussed. Further, the crucial factors of biofilters that affect the performance of biofiltration techniques have been discussed in detail. Finally, we concluded the topic with current challenges and future prospects.

The energy required to heat, cool, and illuminate buildings continues to increase with growing urbanization, engendering a substantial global carbon footprint for the built environment. Passive modulation of the solar heat gain of buildings through the design of spectrally selective thermochromic fenestration elements holds promise for substantially alleviating energy consumed for climate control and lighting. The binary vanadium(IV) oxide VO2 manifests a robust metal─insulator transition that brings about a pronounced modulation of its near-infrared transmittance in response to thermal activation. As such, VO2 nanocrystals are potentially useful as the active elements of transparent thermochromic films and coatings. Practical applications in retrofitting existing buildings requires the design of workflows to embed thermochromic fillers within industrially viable resins. Here, we describe the dispersion of VO2 nanocrystals within a polyvinyl butyral laminate commonly used in the laminated glass industry as a result of its high optical clarity, toughness, ductility, and strong adhesion to glass. To form high-optical-clarity nanocomposite films, VO2 nanocrystals are encased in a silica shell and functionalized with 3-methacryloxypropyltrimethoxysilane, enabling excellent dispersion of the nanocrystals in PVB through the formation of siloxane linkages and miscibility of the methacrylate group with the random copolymer. Encapsulation, functionalization, and dispersion of the core─shell VO2@SiO2 nanocrystals mitigates both Mie scattering and light scattering from refractive index discontinuities. The nanocomposite laminates exhibit a 22.3% modulation of NIR transmittance with the functionalizing moiety engendering a 77% increase of visible light transmittance as compared to unfunctionalized core─shell particles. The functionalization scheme and workflow demonstrated, here, illustrates a viable approach for integrating thermochromic functionality within laminated glass used for retrofitting buildings.

Inclusion of van der Waals (vdW) interactions in density functional theory (DFT) calculations improves the accuracy of the calculations of molecular structures, solid structures, and molecular adsorption configuration and energy. However, it remains unclear how vdW approximations affect calculations of activation barriers of surface reactions, which is valuable for evaluating the reaction kinetics. In this work, we choose a prototype reaction─cyclohexene hydrogenation on a Pd surface─as an example to compare different approaches to include vdW interactions in the calculation of activation barriers of surface elementary steps. We find that the adsorption of cyclohexene and desorption of the product, cyclohexane, are very sensitive to the approaches used to incorporate vdW interactions, while the intrinsic barrier of hydrogenation only varies by about 10%. As a result, the apparent activation barrier also varies to a large extent (from −1.90 to 0.28 eV). The rate-determining transition state was found to be the first hydrogenation step, independent of the vdW approximation used. These calculations indicate that the comparison of intrinsic (true) activation barriers between experimentally measured activation barriers and calculated values is more straightforward, while the comparison for the apparent activation energy may be less reliable. Therefore, simultaneous measurement of intrinsic and apparent activation barriers could serve as a potential way to benchmark the most reliable vdW approximation for molecular adsorption and reaction.

We wish you a very happy 2022 and welcome you to the first issue of Volume 2 of ACS Engineering Au. Our inaugural editorial (DOI: 10.1021/acsengineeringau.1c00024) introduced ACS Engineering Au and its mission. We also announced our Editors and Editorial Advisory Board and the scope of ACS Engineering Au as a fully open access journal for researchers and engineers working on chemicals, materials, and energy, which are essential for almost all human endeavors. In particular, advances in these areas improve resource efficiency and facilitate decarbonization throughout the value chain and across the economy. ACS Engineering Au held its first Editorial Advisory Board meeting on the second of December 2021. We had an excellent discussion on matters concerning the journal, including the need to expand the journal’s scope. Specifically, we decided that ACS Engineering Au should aim to bring an enhanced focus on technological and engineering aspects of research on chemicals, materials, and energy. Additionally, the journal is now looking to provide a platform for sharing new research methods and results to facilitate the translation of basic research to practice and application, highlighting work with advanced technology readiness levels. In light of this new focus, we have expanded and updated the scope of ACS Engineering Au to include:“Process technologies for chemicals and materials,” to specifically include engineering and technology-focused manuscripts from chemistry, biology, and materials researchers;specific topics such as decarbonization, electrification, microwave utilization, cavitation for emphasizing alternative energy sources based on electricity, and other relevant ideas for clean energy and mitigating CO2 emissions;manuscripts featuring new methods, models, and tools (real-time data analytics, multiscale models, physics-informed machine learning models, machine learning-enhanced physics-based models, soft sensors, high-performance computing). “Process technologies for chemicals and materials,” to specifically include engineering and technology-focused manuscripts from chemistry, biology, and materials researchers; specific topics such as decarbonization, electrification, microwave utilization, cavitation for emphasizing alternative energy sources based on electricity, and other relevant ideas for clean energy and mitigating CO2 emissions; manuscripts featuring new methods, models, and tools (real-time data analytics, multiscale models, physics-informed machine learning models, machine learning-enhanced physics-based models, soft sensors, high-performance computing). Please see the full revised journal scope online at http://pubs.acs.org/page/aeacb3/about.html. As we are committed to developing ACS Engineering Au with our community of authors, reviewers, and readers, we invite you to share your suggestions on our scope and other aspects of the journal. We will consider all feedback carefully and may implement and include your input and suggestions in subsequent editorials. We want ACS Engineering Au to become the premier fully open access community-based chemical engineering journal. We are also pleased to introduce the first issue of Volume 2 of ACS Engineering Au, which contains a perspective and four primary research articles:“Perspectives on Manufacturing Innovation in Chemical Process Industries” by Krishnaswamy Nandakumar and co-workers (DOI: 10.1021/acsengineeringau.1c00009)“Effect of Nickel Active Site Density on the Deactivation of Ni-Beta Zeolite Catalysts during Ethene Dimerization” by Rajamani Gounder and co-workers at Purdue University, USA (DOI: 10.1021/acsengineeringau.1c00014)“A Hybrid Modeling Approach for Catalyst Monitoring and Lifetime Prediction” by Linh Bui, Daniel Hickman, and co-workers at The Dow Chemical Company, USA (DOI: 10.1021/acsengineeringau.1c00015)“The Effect of Si/Al Ratio on the Oxidation and Sulfur Resistance of Beta Zeolite-Supported Pt and Pd as Diesel Oxidation Catalysts” by Louise Olsson and co-workers at Chalmers University of Technology, Sweden (DOI: 10.1021/acsengineeringau.1c00016)“Sonochemical Synthesis of Poly(lactic acid) Nanocomposites with ZnO Nanoflowers: Effect of Nanofiller Morphology on Physical Properties” by Vijayanand S. Moholkar and co-workers at the Indian Institute of Technology Guwahati, India (DOI: 10.1021/acsengineeringau.1c00018) “Perspectives on Manufacturing Innovation in Chemical Process Industries” by Krishnaswamy Nandakumar and co-workers (DOI: 10.1021/acsengineeringau.1c00009) “Effect of Nickel Active Site Density on the Deactivation of Ni-Beta Zeolite Catalysts during Ethene Dimerization” by Rajamani Gounder and co-workers at Purdue University, USA (DOI: 10.1021/acsengineeringau.1c00014) “A Hybrid Modeling Approach for Catalyst Monitoring and Lifetime Prediction” by Linh Bui, Daniel Hickman, and co-workers at The Dow Chemical Company, USA (DOI: 10.1021/acsengineeringau.1c00015) “The Effect of Si/Al Ratio on the Oxidation and Sulfur Resistance of Beta Zeolite-Supported Pt and Pd as Diesel Oxidation Catalysts” by Louise Olsson and co-workers at Chalmers University of Technology, Sweden (DOI: 10.1021/acsengineeringau.1c00016) “Sonochemical Synthesis of Poly(lactic acid) Nanocomposites with ZnO Nanoflowers: Effect of Nanofiller Morphology on Physical Properties” by Vijayanand S. Moholkar and co-workers at the Indian Institute of Technology Guwahati, India (DOI: 10.1021/acsengineeringau.1c00018) We hope you enjoy this first issue of Volume 2 of ACS Engineering Au and wish to thank all of our authors and reviewers for their contributions, assistance, and expertise in making it possible. This article has not yet been cited by other publications.

In the efforts to corroborate safer environmental CO2 mitigation strategies, herein, we elucidate engineered practices that convert the absorbed CO2 in a solid material and its utilization in the path of product synthesis. In this way, the cheaper lime material, the primary calcium resource, when exposed to CO2 capture, and the storage material (CO2CSM) prepared by using 1,2-ethylenediamine and 1, 4-butanediol resulted in the formation of controlled vaterite and aragonite CaCO3 polymorphs in their respective pure forms mediated by the functionalized CO2CSM. The investigation studies demonstrated that the obtained CO2CSM under the supercritical CO2 state has a higher uptake and release efficiency of CO2 equivalent to 3.730 and 3.17 mmol/g, respectively. Therefore, the conversion of raw materials depended on the amount of CO2CSM availed in the reaction and would be complete at the expense of supercritical CO2CSM in the solid-type reaction. The mechanism study explains the fundamental formation of products correlating to the amount of CO2CSM supplied in the reaction which would initiate the reaction, while the amine functional group of the material could stabilize and effectively control the transition of vaterite to aragonite phases of CaCO3. The so-obtained CaCO3 phases were tested for their antiwear and friction stability of the lubricant 500SN; vaterite and aragonite demonstrated good reinforcement of the mechanical properties of lubricants compared to the calcite type. Therefore, this system proposes a validation platform of using sequestrated CO2 to generate products with industrial commercialization benefits in the reinforcement of organic-based lubricants.

Solid flow in a Geldart’s group B circulating fluidized bed (CFB) riser is complex, and it exhibits backflow and recirculation in the riser. A single radioactive tracer particle is used to measure the overall and sectional residence time distribution in a CFB riser at a gas velocity of 7.6–9.2 m/s and a solid flux of 100–200 kg/m2s. At the same time, radioactive particle tracking (RPT) data are used to measure the trajectories of the tracer particle and its length distribution at the bottom and middle sections of the riser. Both residence time distribution (RTD) and trajectory length distribution data obtained from RPT and RTD experiments are processed and compared. Results show that the bottom section has higher back mixing than the middle section. The results also show that back mixing in both the sections reduces with an increase in the gas inlet velocity and reduces marginally with an increase in the solid flux. Results confirm that RPT and RTD data are highly correlated and can be used with the same accuracy to quantify the macromixing behavior of any process vessel/reactor.

Non-thermal plasma (NTP) catalysis is a promising technology for CO2 valorization with renewable H2, in which catalyst design is one of the key aspects to progress the hybrid technology. Herein, bimetallic NiCo supported on CeO2 catalysts, that is, NiCo/CeO2, were developed with less metal loading of ∼2 wt % using mechanochemical synthesis for NTP-catalytic CO2 methanation. During the synthesis, different addition orders of Ni and Co precursors were investigated, and the results show that the NiCo1/CeO2-I catalyst (which was prepared by the simultaneous addition of Ni and Co precursors, protocol I) exhibited the highest CO2 conversion (∼60%) and CH4 selectivity/yield (∼80%/∼50%), whereas the NiCo1/CeO2-II and NiCo1/CeO2-III catalysts (prepared by sequential addition protocols of II and III) showed very poor catalytic performance. Characterization results suggested that in protocol I, Ni and Co prefer to alloy, and concentrated oxygen vacancies on the CeO2 surface and high surface basicity are retained as well. Such properties of NiCo1/CeO2-I were responsible for CO2 activation and hydrogenation under NTP conditions, which was explained by the proposed mechanisms.