The 50 most-cited articles in Industrial & Engineering Chemistry Research, 2018

The electrochemical reduction of carbon dioxide (CO 2 ) has received significant attention in academic research, although the techno-economic prospects of the technology for the large-scale production of chemicals are unclear. In this work, we briefly reviewed the current state-of-the-art CO 2 reduction figures of merit, and performed an economic analysis to calculate the end-of-life net present value (NPV) of a generalized CO 2 electrolyzer system for the production of 100 tons/day of various CO 2 reduction products. Under current techno-economic conditions, carbon monoxide and formic acid were the only economically viable products with NPVs of $13.5 million and $39.4 million, respectively. However, higher-order alcohols, such as ethanol and n -propanol, could be highly promising under future conditions if reasonable electrocatalytic performance benchmarks are achieved (e.g., 300 mA/cm 2 and 0.5 V overpotential at 70% Faradaic efficiency). Herein, we established performance targets such that if these targets are achieved, electrochemical CO 2 reduction for fuels and chemicals…

Pharmaceuticals are environmental contaminants that have been widely detected in aquatic media. In this review, the occurrence of pharmaceuticals in the environment, its major causes, and implications along with effective procedures for their removal from contaminated water have been studied. Adsorption stands out as a promising treatment method, since it offers advantages such as lower energy consumption and simpler operation conditions in comparison to other tertiary treatments. Although commercial activated carbon is extensively studied as an adsorbent of pharmaceuticals, its large-scale application is limited by the high costs. Therefore, different nonconventional low-cost materials have been investigated and adsorbents based on clays, biochars, chitosan, agricultural and industrial wastes, and metal–organic frameworks have been addressed in many studies for pharmaceuticals uptake from water and wastewater. This article reviews key publications on this subject, discussing adsorption performance in terms of kinetics, equilibrium, thermodynamics, continuous fixed-bed process,…

In recent years, the worldwide coating industries and scientific communities have introduced superhydrophobic coatings with exceptional water repellency for marine, automotive, and medical applications. Various research works has been devoted to creating a superhydrophobic surface. This review attempts to highlight the recent development and technical breakthrough on superhydrophobic coatings and its potential application in various fields. Moreover, emphasis has also been on providing insight regarding the recent development in superhydrophobic coatings using nanotechnology focusing both on novel preparation strategies and on investigations of their distinctive properties.

The development of green synthetic approaches is one of the key materials challenges in moving toward semiconductor quantum dots (QDs) for large-scale production and commercial applications. This article presents a comprehensive overview on the synthesis of colloidal QDs prepared via chemical approaches in solution phase, with emphasis on green routes which possess the advantages of environment-friendly raw materials, simple operation process, and robust mass-scale production. The approaches for the synthesis of QDs in batch reactors are summarized, including hot-injection organometallic synthesis, noninjection organometallic synthesis, aqueous synthesis and biosynthesis approaches, with some of the concerns on their limitations for scale-up, followed by some continuous synthetic methods aiming for reproducible and large-scale production. Current advances in continuous synthesis of QDs by microfluidic devices, high-gravity reactors, and spray-based techniques are briefly introduced. We also provide some insights into challenges and opportunities based on our own understanding of…

Abstract Ammonia production currently contributes almost 11% of global industrial carbon dioxide emissions, or 1.3% of global emissions. In the context of global emission targets and growing demand, decarbonization of this process is highly desirable. We present a method to calculate a first estimate for the optimum size of an ammonia production plant (at the process level), the required renewable energy (RE) supply, and the levelized cost of ammonia (LCOA) for islanded operation with a hydrogen buffer. A model was developed to quantitatively identify the key variables that impact the LCOA (relative to a ±10 GBP/tonne change in LCOA): levelized cost of electricity (±0.89 GBP/MWh), electrolyzer capital expenditure (±65 GBP/kW), minimum Haber–Bosch (HB) load (±12% of rated power), maximum rate of HB load ramping, and RE supply mix. Using 2025/2030 estimates results in a LCOA of 588 GBP/tonne for Lerwick, Scotland. The application of the model will facilitate and improve the production of carbon-free ammonia in the future.

Dimensionality reduction is important for the high-dimensional nature of data in the process industry, which has made latent variable modeling methods popular in recent years. By projecting high-dimensional data into a lower-dimensional space, latent variables models are able to extract key information from process data while simultaneously improving the efficiency of data analytics. Through a probabilistic viewpoint, this paper carries out a tutorial review of probabilistic latent variable models on process data analytics. Detailed illustrations of different kinds of basic probabilistic latent variable models (PLVM) are provided, as well as their research statuses. Additionally, more counterparts of those basic PLVMs are introduced and discussed for process data analytics. Several perspectives are highlighted for future research on this topic.

Technological growth in advanced ammunition and weapons has led to development of protective antiballistic composites, which are mostly based on aramid fibers, as they absorb high impact energy, arising from penetrators. Enhanced performance of aramid fibers (modulus ∼ 112,400 MPa) is attributed to their compact molecular structure, hydrogen-bonding, high crystallinity, and high density (∼1.44 g/cm 3 ). Methodologies such as layer-by-layer, shear thickening, yarn pull-out, and surface functionalization via nanomaterials have been reported for modification of aramid fibers, which are widely used with thermosets like epoxy (due to process-friendliness). Recently, researchers are exploring thermoplastics with aramids, due to their higher toughness, chemical resistance, and thermal stability. Modification of aramid fibers is mostly performed using nanomaterials, e.g., carbon nanotubes, graphene, silk fibroins, SiO 2, and ZnO, for enhancing their performance and minimizing fiber buckling under load. This Review presents advances in modification of aramid fibers using nanomaterials with…

Catalyst deactivation by coking is one major problem for propane dehydrogenation (PDH). To develop catalysts with high resistance to coke, the analysis of coke becomes essential. In this work, an analysis procedure is proposed and validated to acquire the detailed locations and compositions of the coke formed on an as-synthesized Pt–Sn/Al 2 O 3 catalyst. This procedure combines high-resolution transmission electron microscopy (HRTEM), FT-IR, Raman, thermogravimetric analysis (TG), and pyrolysis GC-MS; with this procedure, the systematic and quantitative analysis of coke can be achieved. The results show that the coke is located on the metal, in the vicinity of the metal, and on the support. Besides, aliphatics, aromatics, and pregraphite cokes are identified, and they account for 69.0, 4.4, and 26.6 wt %, respectively. Finally, an in situ DRIFT study is performed, and the results show that the aliphatic coke can be transformed into the aromatic coke and this transformation is related to the deep dehydrogenation reactions.

In this research note, we revisit the pseudo-second-order model for adsorption kinetics, its assumptions, and its application to simulated, random, and published data. In particular, a widely used linear form of the pseudo-second-order model—plotting t / q t against t —is shown to result in spurious correlations for typical adsorption experimental data. Depending on the range of data used, data from pseudo-first-order and pseudo-third-order models can also appear to be well-fit by the pseudo-second-order model. Inspection of the residual errors, however, indicates that the errors are not randomly distributed, as they should be. Based on this study, it is recommended to always verify the assumptions of a model, fit the data with the nonlinear form of the model equation, and inspect the residual plot to determine the goodness of fit.

CO 2 hydrogenation can lead to the formation of various products, of which methanol, dimethyl ether (DME) and ethanol have received great attention. In this study, a comprehensive thermodynamic analysis of CO 2 hydrogenation in binary (methanol/CO) and ternary product systems (methanol/CO with DME or ethanol) is conducted in Aspen Plus by the Gibbs free energy minimization method combined with phase equilibrium calculations. It is demonstrated that product condensation can be utilized to circumvent thermodynamic restrictions on product yield. Significant improvements in CO 2 conversion can be achieved by operating at conditions favorable for product condensation, whereas the selectivity is mildly affected. The relevance of the results herein is discussed with regards to recent advances in catalysis and process design for CO 2 hydrogenation. Our study highlights the importance of obtaining a thorough understanding of the thermodynamics of CO 2 hydrogenation processes, which will be critical for developing potential breakthrough technology applicable at the industrial scale.

The petroleum based diglycidyl ether of bisphenol A (DGEBA) epoxy resin is one of the most extensively used epoxy resins for various industrial applications such as paints, coatings, adhesives, and structural applications, owing to its excellent mechanical and thermal properties, low curing shrinkage, and good chemical resistance. However, the serious drawbacks in terms of brittleness or poor fracture energy significantly restricted its extensive utilization. Various renewable resources based flexible chains were used to blend with DGEBA for toughening and to significantly improve the fracture properties without sacrificing the mechanical properties. This review mainly focuses on toughening of DGEBA with various renewable polymers and the effect of its concentration on its toughening mechanism.

The proton exchange membrane fuel cell (PEMFC) converts chemical energy into electrical energy via electrochemical reaction between hydrogen and oxygen, with heat and water as byproducts. When a PEMFC is engineered with polymer electrolyte membrane, e.g., Nafion and polybenzimidazole (PBI), it helps to enhance the performance of the fuel cell under monitored environmental conditions, i.e., high proton conductivity, improved electrode kinetics, and tailoring of properties, along with low tolerance for carbon monoxide. Recently discovered “graphene” has enticed the scientific community, because of its exceptional properties. As per the literature, PEMFCs engineered with graphene can yield high power density, along with 38% enhanced current density, and 257% improved ionic conductivity. In this context, the present review gives the state-of-the-art and progress on polymer electrolyte membranes engineered using graphene and graphene oxide, as well as their synthesis routes and the influence on the performance of PEMFCs.

A copper-based catalyst supported on carbon microspheres prepared by using the spray drying method has exhibited interesting Fenton-like catalytic properties for the degradation of Methyl Orange, Methyl Blue, and Rhodamine B in aqueous solution. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data suggested that the catalyst consisted of copper particles covered by cuprous oxide. The influence of initial pH, reaction temperature, dosage of catalyst, and H 2 O 2 concentration on the catalyst performance were investigated. Under optimum reaction conditions, the Behnajady–Modirshahla–Ghanbery kinetics model was observed to fit well with the experimental data. It was also observed that hydroxyl radical (HO•) formed from the reaction between hydrogen peroxide (H 2 O 2 ) and cuprous (Cu + ) species was responsible for the dye degradation under acidic conditions. This work provides new insights into the mechanism and kinetics of low-valence copper–carbon composite Fenton-like catalyst for degrading organic dyes.

Accident prevention is one of the most desired and challenging goals in process industries. For accident prevention, fault detection and diagnosis (FDD) is critical. FDD has been an active area of research for decades. The focus of the current review is on the data-driven techniques as we are now in a digital era and data analytics is getting more emphasis in all areas including process industries. The analysis is done to address the following fundamental questions: (i) How are the leading areas evolving? (ii) Who are the contributing authors? (iii) What are the key sources and domains of publications? (iv) Which countries are active in this research area? Furthermore, we briefly described four techniques, principal component analysis, partial least-squares, independent component analysis, and the Gaussian mixture model, to represent the state-of-the-art algorithms from different periods. It was observed that significant work in this field is being carried out throughout the world, including both developed and the developing countries. China is emerging as the leading contributor to…

Reactive distillation (RD) is an efficient process intensification technique that integrates chemical reaction and distillation in a single apparatus. The process is also known as catalytic distillation when a solid catalyst is used. RD technology has many key advantages such as reduced capital investment and significant energy savings, as it can surpass equilibrium limitations, simplify complex processes, increase product selectivity, and improve separation efficiency. However, RD is also constrained by thermodynamic requirements (related to volatility differences and heat of reaction), the need to align the reaction and distillation operating conditions, and the availability of catalysts that are active, selective, and with sufficient longevity. This paper is the first to provide an overview and insights into novel integrated reactive distillation technologies that combine RD principles with other intensified distillation technologies—e.g., dividing-wall column (DWC), cyclic distillation, HiGee distillation, heat-integrated distillation column (HIDiC), and membrane-, microwave-,…

Due to the low density, high porosity, three-dimensional (3D) pore structure, high nitrogen content, and excellent mechanical properties, melamine sponge (MS) has been widely used as the main building block to design and obtain 3D porous materials. Moreover, N-doped porous carbon foam can be formed via a simple carbonization of MS, thus making such carbon foam also an ideal carbon material used either directly or as support to load other materials. So far, many studies have been reported on the modification of MS, carbonized MS, and MS-based composite materials in various applications including oil/water separation, water disinfection, adsorption, fire resistance, electrochemistry, strain/stress sensor, catalysis, and so on. In this Review, structure design of such MS-based materials and modification methods are summarized and discussed, and the obstacles and suggestions for how to design and synthesize such materials with better performance are provided, aiming to promote the wide application of MS in various fields.

The insulation characteristics and decomposition components of C 4 F 7 N/N 2 gas mixture, a potential substitute for SF 6, were first explored by breakdown experiments/gas chromatography–mass spectrometer. The structural properties of C 4 F 7 N molecule and the decomposition mechanism of C 4 F 7 N/N 2 gas mixture were analyzed based on the density functional theory calculation and ReaxFF molecular dynamics simulation. We found that C 4 F 7 N/N 2 mixture has great self-recovery performance. The decomposition of C 4 F 7 N in a discharge mainly produces CF 4, C 2 F 6, C 3 F 8, CF 3 CN, C 2 F 4, C 3 F 6, and C 2 F 5 CN, among which the relative content of C 2 F 6, CF 4, and CF 3 CN is higher. ReaxFF-MD simulations show that CF 3, CN, F, and C 3 F 7 are the four main free radicals produced by C 4 F 7 N. The decomposition characteristics of N 2 are better than that of C 4 F 7 N. The addition of N 2 has a certain buffering effect to avoid the massive decomposition of C 4 F 7 N. The global warming potential value of a gas mixture containing 20% C 4 F 7 N decreased by 94.32% compared with SF…

The relatively low density of functional groups of graphene oxide (GO) and the difficulty to completely recover after adsorption limit its application in uranium (U(VI)) removal from aqueous solution. Inspired by a special chemical property, polydopamine (PDA) was first used as a surface modifying agent for GO, and then the as-formed GO@PDA cross-linked with chitosan (CS) to assemble a three-dimensional (3D) porous GO@PDA/CS aerogel for U(VI) adsorption. Morphology and structure of the aerogel were characterized by TEM, SEM, FTIR, XPS, XRD, Raman, and TGA. The results show that compared to GO/CS, the GO@PDA/CS aerogel possesses a more homogeneous and well-organized 3D porous structure as well as the enhanced active sites, which are beneficial for U(VI) removal. According to batch experiments, the adsorption rate of the GO@PDA/CS aerogel was very fast, and the adsorption equilibrium could be reached in 15 min at pH = 6.0. Its maximum adsorption capacity for U(VI) is as high as 415.9 mg g –1 at 298 K calculated from the Langmuir model. In addition, the as-prepared GO@PDA/CS aerogel…

Recycling of discarded polyethylene terephthalate (PET) is an important issue for both environmental protection and resource conservation purposes. In this work, a dissolution-degradation strategy has been developed for recycling PET by adding solvents such as aniline, nitrobenzene, 1-methyl-2-pyrrolidinone (NMP), or dimethyl sulfoxide (DMSO) into the traditional PET glycolysis system. The results show that the conversion of PET reaches 100% and the yield of monomer bis(hydroxyalkyl) terephthalate (BHET) reaches 82% during 1 min with zinc acetate as catalyst in DMSO at 463 K. Importantly, this strategy can be applied to a variety of catalysts. The simulation and in situ IR results indicate that the π–π interaction between PET and aromatic solvents plays a key role in PET dissolution, which leads to fast degradation. This promising dissolution-degradation strategy can improve the glycolysis efficiency of PET dramatically and may be applied to the degradation process of other polyesters.

Ru/CeO 2 catalysts with different amounts of surface oxygen vacancies were prepared by changing the morphology of CeO 2 . The conversion of Ce 4+ to Ce 3+ and the formation of Ru–O–Ce bonds led to enhancement of the amount of oxygen vacancies. Ru species of low crystallinity enriched with Ru 4+ ions exist on the surface of CeO 2 nanorods, while metallic Ru particles exist on CeO 2 nanocubes. The low crystallinity of Ru species and high concentration of oxygen vacancies enhanced the adsorption of hydrogen and nitrogen and also led to desorption of surface hydrogen in the form of H 2 . Therefore, Ru/CeO 2 nanorods showed high ammonia synthesis activities. On the contrary, lower catalytic activity was observed over Ru/CeO 2 nanocubes catalyst because H 2 and N 2 adsorption was less favorable plausibly due to the large particle size of Ru species and low concentration of oxygen vacancies, and most of the hydrogen species were consumed in H 2 O formation.

A series of Cu–Ni/CeO 2 -nanotube catalysts is prepared by an impregnation method for CO 2 hydrogenation to CH 3 OH. Regular CeO 2 nanotubes are perfectly formed with a tube diameter of about 30–50 nm and Cu–Ni alloy is well dispersed on CeO 2 nanotube without nanotube morphology change. There is a synergistic effect between Ni and Cu, promoting the bimetallic Cu–Ni dispersion, reducibility, CO adsorption and hydrogenation. Additionally, a strong interaction is observed between Cu–Ni alloy and CeO 2, and it contributes to partial reduction of Ce 4+ to Ce 3+ and formation of oxygen vacancies which adsorb and activate CO 2 . It is shown that both CO 2 conversion and CH 3 OH space-time yield increase at first, reach their maximum values at a Ni/(Cu+Ni) ratio of 2/3, and then decrease with increasing the Ni/(Cu+Ni) ratio. The CeO 2 -nanotube supported CuNi 2 catalyst gives CO 2 conversion of 17.8% and CH 3 OH space-time yield of 18.1 mmol/(g cat ·h) after preliminary optimization. Furthermore, it exhibits an excellent catalytic performance within a wide range of space velocity.

Machine learning the electronic structure of open shell transition metal complexes presents unique challenges, including robust and automated data set generation. Here, we introduce tools that simplify data acquisition from density functional theory (DFT) and validation of trained machine learning models using the molSimplify automatic design (mAD) workflow. We demonstrate this workflow by training and comparing the performance of LASSO, kernel ridge regression (KRR), and artificial neural network (ANN) models using heuristic, topological revised autocorrelation (RAC) descriptors we have recently introduced for machine learning inorganic chemistry. On a series of open shell transition metal complexes, we evaluate set aside test errors of these models for predicting the HOMO level and HOMO-LUMO gap. The best performing models are ANNs, which show 0.15 and 0.25 eV test set mean absolute errors on the HOMO level and HOMO-LUMO gap, respectively. Poor performing KRR models using the full 153-feature RAC set are improved to nearly the same performance as the ANNs when trained on…

The lower alcohols tend to form azeotropic solution with water which makes the separation challenging. The current work primarily focuses on the synthesis and application of a menthol-based hydrophobic deep eutectic solvent (DES) for the removal of lower alcohols from its aqueous solutions. The DES is synthesized by the addition of DL-menthol and lauric acid (dodecanoic acid) with a molar ratio of 2:1. Liquid–liquid equilibria (LLE) experiments are then performed to evaluate the performance of the synthesized DES for the extraction of lower alcohols such as ethanol, 1-propanol, and 1-butanol. LLE corresponding to the pseudo ternary systems of lower alcohols (1-butanol, ethanol, and 1-propanol) + hydrophobic DES + water are measured at T = 303.15 K and p = 1 atm. The composition of the tie lines were evaluated using 1 H NMR analysis for both extract and raffinate phases. Thereafter, the extraction efficiency of the DES is analyzed and compared by determining the solute distribution coefficients and the selectivity values. Finally, the experimental LLE data for the systems were…

Polymer flooding based enhanced oil recovery (EOR) has been proven to be effective and successful for heavy crude oil systems due to its ability to achieve favorable mobility ratios driven by viscosity alterations. Nanoparticles have the potential to intensify favorable mobility ratios as well as various other mechanisms responsible for EOR. This work addresses the interfacial tension (IFT), emulsification, and rheological and wettability alteration characteristics of silica nanoparticle (SNP) assisted polymer flooding. The stability of the xanthan gum–SNP system was evaluated by a particle size analyzer and zeta potential method. The rheological behavior of the system in addition to IFT and the emulsification mechanism at variant temperatures were also investigated. Wettability alteration studies involved contact angle measurements for oil drops with respect to a nanoparticle saturated rock surface. SNP assisted polymer flooding enabled higher oil recovery of 20.82% at 30 °C and 18.44% at 80 °C due to IFT reduction, higher viscosity, better emulsion stability, and wettability…

Lignin nanospheres/poly(vinyl alcohol) (LNS/PVA) nanocomposite films were prepared through solvent casting approach. Compared with lignin/PVA blend film, LNS could be evenly dispersed in PVA matrix, and the nanocomposite films did not generate macroscopic phase separation. Maximum decomposition temperature ( T max ) and glass transition temperature ( T g ) of pure PVA film were 264.7 and 104.2 °C, while the T max and T g of the nanocomposite film containing 1 wt % LNS increased to 272.1 and 116.8 °C, respectively. Moreover, with increasing of LNS content in PVA matrix, the T max and T g of the nanocomposite films gradually increased. Adding a certain amount of LNS in PVA could improve mechanical strength of the films under the condition of elongation at break in a small amount of loss. The nanocomposite films outperformed the lignin/PVA blend film in UV-absorbing and transparency, which are a promising candidate for medicine bottles and food packaging.

Carbon dioxide capture, utilization, and storage (CCUS) has been identified as an effective method of mitigating anthropogenic CO 2 emissions. To date, most research and development has centered on capturing CO 2 emitted from coal power plants, as they are the largest point source emitters globally. However, cement and steel plants also emit large amounts of CO 2 and are potentially easier targets for a CO 2 capture process because the CO 2 in their flue gas tends to be more concentrated. In this paper, the feasibility of capturing CO 2 from cement and steel plants is examined using currently available membrane technology. Coal power plant flue gas contains 13–15% CO 2; cement and steel plant flue gas contains 20–30% CO 2; this higher CO 2 concentration is useful for all separation technologies, but especially for membranes where separation is strongly dependent on the partial pressure driving force. Membrane-based systems can capture 80% of the CO 2 emitted from cement or steel production processes at costs of $40 to $50/tonne of CO 2 captured. Lower costs are possible if lower…

This paper investigates the spatial resolution of computational fluid dynamics–discrete element method (CFD-DEM) simulations of a bubbling fluidized bed for seven different void fraction schemes. Fluid grids with cell sizes of 3.5, 1.6, and 1.3 particle diameters were compared. The particle velocity maps from all of the void fraction schemes were in good qualitative agreement with the experimental data collected using magnetic resonance imaging (MRI). Refining the fluid grid improved the quantitative agreement due to a more accurate representation of flow near the gas distributor. The approach proposed by Khawaja et al. [ J. Comput. Multiphase Flows 2012, 4, 183−192] provided the closest match to the exact void fraction though only the particle centered method differed significantly. These results indicate that the fluid grid used for CFD-DEM simulations must be sufficiently fine to represent the inlet flow realistically and that a void fraction scheme such as that proposed by Khawaja be used.

In the past few decades, natural gas has attracted worldwide attention as one of the most desired energy sources owing to its more efficient and cleaner combustion process compared to that of coal and crude oil. Due to the presence of impurities, raw natural gas needs to be upgraded to meet the pipeline specifications. Membrane-based separation is a promising alternative to conventional processes such as cryogenic distillation and pressure swing adsorption. Among the existing membranes for natural gas upgrading, polymeric membranes and inorganic membranes have been extensively explored, but each type has its own pros and cons. The development of mixed matrix membranes (MMMs) by incorporating organic/inorganic fillers into the polymer matrix provides a good strategy to combine the merits of each material and fabricate novel membranes with superior gas separation performance. In this review, we first discuss the recent advances in MMMs showing potentials in natural gas upgrading. Special attention is paid to a detailed evaluation on the polymer and filler choices for acidic gas…

This paper reports on Fe–Cu bimetallic catalysts supported on γ-alumina for selective CO 2 hydrogenation to olefin-rich C 2 + hydrocarbons. A strong synergetic promoting effect on C 2 + hydrocarbon synthesis was observed over Fe–Cu bimetallic catalysts when the Cu/(Cu + Fe) atomic ratio was 0.17. Compared to monometallic Fe catalyst, the Fe–Cu bimetallic catalyst significantly enhances C 2 –C 7 hydrocarbon formation and suppresses the formation of undesired CH 4 . The addition of K into Fe–Cu bimetallic catalysts inhibits the methanation and further enhances the formation of C 2 + hydrocarbons in the meantime. The synthesis of olefin-rich C 2 –C 4 hydrocarbons from CO 2 /H 2 was achieved by using K-promoted Fe–Cu/Al 2 O 3 catalysts with higher K/Fe atomic ratios (e.g., K/Fe ≥ 0.5), where the selectivity of C 2 –C 4 olefin contents was even higher than K-promoted Fe–Co catalysts under the same reaction conditions.

Porous carbon with both high CO 2 uptake and CO 2 /N 2 selectivity is desired for reducing the cost of carbon capture. Here, we report the preparation of N-enriched porous carbons (NPCs) derived from the low-cost triazine-based porous organic polymers using KOH as the activating agent under N 2 . The results indicate that the nitrogen content and textural properties of the NPCs can be effectively adjusted by the polymer precursors and the carbonization temperature. Impressively, the NPCs have an enriched N content (5.56–11.33 wt %) and abundant porosity (BET surface area: 394–1873 m 2 /g, pore volume: 0.27–1.56 cm 3 /g), endowing them with high CO 2 uptake (120–207 mg/g at 273 K and 1.0 bar) and acceptable CO 2 /N 2 selectivity (Henry’s law: 14.3–16.8). In particular, the ultra micropore volume ( d ≤ 0.8 nm) is proven a key factor for the CO 2 uptake, while both the ultra micropore volume and N content contribute the CO 2 /N 2 selectivity. Our described work will provide a strategy to initiate developments of rationally designed porous carbons for various potential applications.

Developing inexpensive and highly efficient CO 2 air capture technologies is an important solution for solving the greenhouse problem. In this work, we used the low-cost quaternized chitosan (QCS)/poly(vinyl alcohol) (PVA) hybrid aerogels with quaternary ammonium groups and hydroxide ions to reversibly capture CO 2 from ambient air by humidity swing. The CO 2 capture capacity and adsorption rate of the aerogels were investigated over the temperature range 10–30 °C. The CO 2 capture capacity of the aerogels was measured to be about 0.18 mmol/g, which is 38% higher than the state-of-the-art commercial membrane. In addition, we proposed a modified pseudo-first-order kinetic model considering both the CO 2 adsorption and the H 2 O desorption, which describes the experimental results very well. For the first time, the moisture-swing CO 2 adsorbent is built by low-cost biomass material, which opens up a new approach for the design of the moisture-swing CO 2 adsorbent.

Revolutionary shale gas production has resulted in increasing interest in the use of methane for producing various types of high-value chemicals and among them is aromatics via methane dehydroaromatization (MDA). Progresses achieved in the area of MDA during the last 6 years are significant. However, a review in this area is lacking. This review is designed to fill the gap. The review not only discusses he development of MDA catalysts, including conventional molybdenum (Mo)-based catalyst and non-Mo-based catalysts and novel catalysts. Also, the insights for the associated reaction mechanisms and catalyst regeneration methods and applications of various types of reactors are provided.

The effect of nanoparticle size and structure on XRD and SAXS patterns was investigated using modeling with the Debye scattering equation for a series of nanoparticles (NP) with the positions of atoms kept according to the bulk lattice and after structure relaxation. The purpose of research was to determine if the changes in XRD peak positions for NP are entirely due to the well-known effects of lattice parameter change or if additional effects can arise from the size itself. It was found that for very small NPs with sizes below 5 nm, the size itself influences the XRD patterns. This effect can be caused by interference fringes and is not taken into account when considering XRD patterns in standard software. The research demonstrates that new methods for XRD pattern treatment of very small nanoparticles should be developed.

Highly resilient lignin-containing polyurethane (PU) foam was synthesized via using alkali lignin as a partial substitute for the petrochemical polyols. The flexible polyethylene glycol chains were first grafted onto alkali lignin, converting the phenolic hydroxyls on lignin to aliphatic hydroxyls and enhancing the reaction activity of lignin. The influence of the modified-lignin on the structure, mechanical properties and thermal stability of PU foams were analyzed. The grafted polyethylene glycol chains provided flexibility to the lignin-containing PU foams. All lignin-containing PU foams exhibited large elastic recovery higher than 93%. The compression strength of the PU foams increased with the lignin content while maintaining excellent resilient performance. This work gives a new approach for the application of biopolymer lignin in flexible and highly resilient polyurethane foams.

A series of supported TiO 2 /CeO 2 catalysts were synthesized to investigate the morphology and crystal-plane effects of CeO 2 on these TiO 2 /CeO 2 catalysts for selective catalytic reduction by ammonia (NH 3 -SCR). The experiment results show that TiO 2 /CeO 2 -NC, TiO 2 /CeO 2 -NP, and TiO 2 /CeO 2 -NR catalysts present nanocubes (mainly exposed {100} facet), nanopolyhedrons (mainly exposed {111} and {100} facets), and nanorods (mainly exposed {110} and {100} facets), respectively. Furthermore, TiO 2 /CeO 2 -NR catalyst exhibits the best dispersion of TiO 2 species, the most excellent reduction behavior and surface acidity, and the largest amount of Ce 3+ ions and chemisorbed oxygen, which is due to the largest specific surface area and pore volume of CeO 2 -NR support, as well as the strongest interaction between the surface dispersed TiO 2 species and the {110} facet of CeO 2 -NR support. All of them result in the best denitration performance of TiO 2 /CeO 2 -NR catalyst during NH 3 -SCR reaction.

For profit-oriented stakeholders techno-economic assessment (TEA) is the most important basis for decisions about research, development, and deployment (RD&D). Two key challenges are, first, the rating of RD&D progress which is closely linked to data availability and, second, the selection of TEA methods that adequately fit the available data in order to achieve the best possible decision basis. Technology readiness levels (TRLs) are a popular concept for rating the maturity of RD&D according to available data. Since existing TRL scales remain unspecific to technologies, an understanding of TRL in the chemical industry is presented. TRLs are subsequently used in a framework for TEA. Cost estimation is structured (with focus on capital expenditure), and estimation methods are sorted by TRL. Appropriate profitability indicators for the assessment of economic prospects are discussed for each TRL. Static indicators are favored in earlier TRLs, while dynamic calculations are preferred for detailed forecasts later on.

Wastewater treatment is in a dilemma: more energy and efforts have to be put forth to obtain an effluent with better quality, while a significant amount of sludge is generated and the treatment or disposal expenses are high. Even if the sludge is disposed of properly, the components can be released and pollute the environment again. Therefore, conversion and recovery of the contaminants to resources is the way out of the dilemma. An ion exchange membrane (IEM) is a special type of membrane, which allows charged solutes to pass through it while retaining uncharged components. Attributed to this character, IEMs are taking more important roles in separation and conversion processes recently. They act as key elements in many resource recovery systems, such as in separation and concentration, salt valorization, energy conversion, and even in microbial systems. This review summarizes the important processes for waste conversion and resource recovery from wastewaters by using IEMs. Drawbacks and perspectives are summarized in view of the development of the processes and the membranes.

The free-surface flows with particles are widely found in chemical engineering, and numerical modeling is a strong computing tool for in-depth understanding of the local and macrocharacteristics. In this study, a discrete element method–volume-of-fluid (DEM–VOF) model is extended to turbulent free-surface flows with particles, by means of Reynolds stress model. Also, we adopt a novel virtual dual-grid porosity model to calculate the fluid porosity. The simulated results of single particle sedimentation, the falling of sinking particles, and the floating of buoyant particles agree well to analytical and literatures, which validate the proposed DEM–VOF model. Furthermore, the DEM–VOF model developed in this paper is applied to the simulation of free surface flow with particles in solid–liquid mixing system for the first time. It is found that elliptical-head vessel is preferred to a flat-bottomed vessel for solid–liquid mixing by comparing the simulation results of four different stirred tanks, which agrees well to the related content of the book Handbook of Industrial Mixing (Paul,…

This work focuses on the study of a pressure swing adsorption (PSA) process for biogas upgrading using a carbon molecular sieve adsorbent. Adsorption equilibrium and diffusion data of pure components were used to predict the multicomponent behavior. To validate the prediction of multicomponent adsorption at different concentrations, breakthrough curve experiments were performed for a gas mixture at different pressures (0.25, 0.5, 1, and 5 bar). Based on basic information, a model was used to predict the performance of a two-column PSA unit. The mixture used as feed was 60% CH 4 and 40% CO 2 with pressure swings between 5 bar in adsorption mode to 0.1 bar in blowdown. Experimental data demonstrated that the model could describe the PSA performance with good accuracy. We have evaluated the influence of different feed times in the biomethane recovery and purity. Biomethane purity higher than 97.5% with recovery higher than 90% was obtained.

Hierarchical spinel NiCo 2 O 4 nanowires were synthesized by a facile hydrothermal method followed by an annealing treatment. The prepared NiCo 2 O 4 nanowires presented a hierarchical mesoporous structure. Moreover, the effects of precipitant and solvent on morphologies of NiCo 2 O 4 were researched. The results reveal that the hierarchical mesoporous structured NiCo 2 O 4 exhibited corking supercapacitor performance with a high specific capacitance of 2876 F·g –1 at a current density of 1 A g –1, even increased to 10.0 A g –1, the specific capacitance could still remain 1290 F g –1, what’s more, the capacitance retention reached 84.7% after 500 cycles, which indicates an excellent electrochemical performance. The results demonstrate hierarchical mesoporous NiCo 2 O 4 potential to be a promising supercapacitor electrode materials and inspire furthered research on binary metal oxides as charge storage materials and offer a new route for the large-scale production of high-performance supercapacitor electrode materials.

This study proposes a simple model for viscosities, based on entropy scaling, for real substances and mixtures. The residual entropy is calculated with the perturbed chain polar statistical associating fluid theory (PCP-SAFT). The model requires two or three pure component parameters, noting, however, that an entirely predictive group contribution approach as proposed in our previous work [Loetgering-Lin O.; Gross J. Ind. Eng. Chem. Res. 2015, 54, 7942–7952] gives also very good results. Overall, 140 real substances are considered with relative mean deviations from experimental data of about 5% (without excluding “outliers”). We performed molecular simulations for mixtures of simple model fluid in order to determine a suitable mixture model. A completely predictive approach for viscosities of real mixtures is thereby obtained. The model is evaluated for 566 mixtures with about 34,500 experimental data points of various complexity (i.e., nearly ideal systems as well as highly asymmetric mixtures). Mixtures of nonpolar substances and mixtures with at least one polar, but…

Abstract Inspired by unparalleled adhesion of mussels, bioinspired poly(dopamine) (PDA) has been used to functionalize the surface of aluminum oxide (Al2O3) nanoparticles aiming at improving the thermal conductivity of silicone rubber (SR). The successful and effective preparation of PDA modified Al2O3 nanoparticles (Al2O3–PDA) was confirmed by XPS, HR-TEM, and XRD. The PDA coating on the Al2O3 nanoparticles improved its interfacial interaction between polymeric matrix and facilitated the uniform-dispersion of filler, leading to the 30 vol % Al2O3–PDA/SR composite that exhibited a high thermal conductivity (0.585 W/((m·K))), which was almost 400% of pure silicone rubber (0.147 W/(m·K)). In addition, the 30 vol % Al2O3–PDA/SR composite displayed a relatively low dielectric constant (4.06 at 1 kHz), which was a bit higher than that of pure SR (2.59 at 1 kHz), a big advantage for the electronic or electrical engineering application. With advantages of efficient, easy handling, controllable, and eco-friendly, this modification method provides a new universal route to improve the thermal…

Visible-light-responsive ZnO/NiO/In 2 O 3 mixed metal oxide (ZNI-MMO) photoelectrocatalysts with different Ni/In molar ratios were derived from corresponding ternary hydrotalcite-like precursors followed by calcination at 600 °C. The as-obtained samples were characterized by XRD, TGA, BET, XPS, SEM, TEM, and UV–vis spectra techniques. The optimal molar ratio of Ni/In was found to be 1:1, where the sample (ZNI-1-MMO) was formed by the aggregation of nanospheres with an average diameter of about 50 nm and a BET specific surface area of 33.80 m 2 /g. With a 1.5 V bias potential, the ZNI-1-MMO photoelectrode exhibited high photoelectrocatalytic activity toward methylene blue (MB) degradation. The photoelectrocatalytic degradation of MB followed pseudo-first-order kinetics. Radical trapping experiments were conducted to probe the reactive species in the degradation processes. Results indicated that h + and • OH may be responsible for the efficient MB removal. The photoelectrodegradation mechanism of MB by ZNI-1-MMO-1.5 V photoelectrode was also discussed.

We report herein the upscaled synthesis and shaping of UiO66-COOH for NH 3 air purification. The synthesis of the zirconium-based MOF was carried out in a batch reactor in an aqueous suspension with a yield of 89% and a space-time yield of 350 kg/day/m 3 . Neither toxic chemicals nor organic solvents were used, allowing this MOF to be employed in individual or collective air purification devices. Freeze-granulation and extrusion shaping techniques were investigated. The NH 3 air purification performances of UiO66-COOH in bead, tablet and extrudate forms were compared to those of commercial carbon based materials (type K adsorbents from3M and Norit). Testing conditions were chosen to reflect current standards for ammonia concentration (600–1200 ppm) and velocity. In addition, the breakthrough measurements were carried out at three different relative humidity levels (0%, 40%, and 70%). Pellets and extrudates of UiO66-COOH outperformed commercial benchmark adsorbents in all conditions, especially in dry conditions, for which the commercial adsorbents suffered impaired ammonia uptake…

This work deals with the coupling between high temperature steam electrolysis using solid oxide cells (SOEC) and carbon dioxide methanation to produce a synthetic natural gas (SNG) directly injectable in the natural gas distribution grid via a power-to-gas (P2G) pathway. An intrinsic kinetics obtained from the open literature has been used as the basis for a plug flow reactor model applied to a series of cooled multitube fixed bed reactors for methane synthesis. Evaporating water has been considered as coolant, ensuring a high heat transfer coefficient within the shell side of the reactor. A methanation section has been designed and optimized in order to moderate the maximum temperature within the catalytic bed and to minimize the catalyst load. Then, process modeling of a plant coupling high temperature electrolysis and methanation is presented: the main goal of this analysis is the calculation of overall plant efficiency (in terms of electricity-to-SNG chemical energy). Plant size has been set considering a 10 MW el SOEC-based electrolysis unit; heat produced from the exothermal…

Herein, we have fabricated a series of immiscible blend nanocomposites based on polycarbonate/polypropylene (PC/PP) by uniformly dispersing multiwall carbon nanotubes (MWCNTs) via a melt mixing technique. The effect of polypropylene-grafted maleic anhydride (PP- g -MA) as a compatibilizer has played a pivotal role in reducing the interfacial tension and thereby enhancing the attenuation performance of PC/PP blends. The substantial effect of compatibilization on the dispersion of MWCNTs has resulted in higher conductivity values of 0.33 S cm –1, which is a major requirement for designing EM shields. Nevertheless, both the uncompatibilized and compatibilized blend nanocomposites have shown viscoelastic phase separation processes. The percolation networks of MWCNTs in compatibilized PC/PP blends were clearly observed using a high resolution transmission electron microscope. There was also a remarkable 5-fold decrease in the percolation threshold and 2.5 fold increase in total shielding effectiveness (54.78 dB) of compatibilized PC/PP blends when compared to that of immiscible PC/PP…

Abstract Although steam cracking is a mature technology, mitigation of coke formation remains one of the main challenges in the petrochemical industry. To increase the olefin output of existing plants, coil materials that can withstand higher temperatures are desired. This work reviews material technologies that were developed and tested in the past three decades to minimize the rate of coke deposition and extend the furnace run length. The material not only determines the mechanical properties of the coil but also affects the coking rate substantially. In some cases, differences in coking rates by more than a factor 10 have been observed. SiC materials could be operated at significantly higher temperatures, and this leads to higher olefin selectivity if one includes acetylene hydrogenation; however, the mechanical joints make it currently impossible to take advantage of their superior temperature resistance. On the industrial scale, operational improvements have been reported with advanced reactor surface technologies such as high-performance alloys and coatings during the past…

Hyperbranched polymers (HPs) are a subclass of dendritic polymers, having globular and highly branched structure, containing a number of functional groups emerging from a core. The core contains more than two functional sites where the growing branches are connected, resulting in the formation of a 3D macromolecule comprising a large number of peripheral groups. Their versatile properties and facile structural modifications have attracted considerable attention of researchers. HPs have been used in various applications such as coatings, drug delivery, nanotechnology, additives, sensors, solar cells, an so forth. Thus, this review emphasizes recent structural modifications of HPs that result in enhancement of existing or newly emerging properties. In addition, these modifications have broadened the use of HPs in various advanced technologies such as biological applications, storage devices, energy convertors, catalysis, and so forth, which have not been covered in earlier reviews. Furthermore, this article discusses the limitations associated with their fabrication and application in…

Pyrolysis experiments between 25 and 800 °C for three main components (cellulose, hemicellulose, and lignin) mixed in different proportions were conducted on a thermogravimetric analyzer (TGA) and pyrolysis–gas chromatography/mass spectrometer (Py-GC/MS). The interactions between the three main components during the pyrolysis of biomass were explored from two aspects, namely thermogravimetric properties and pyrolysis products. The results indicate that interactions existed among the three biomass components in the co-pyrolysis process. The presence of lignin significantly reduces the pyrolysis rate of cellulose and inhibits the formation of sugars (mainly levoglucosan) in the pyrolysis of cellulose and hemicellulose. However, the existence of cellulose or hemicellulose greatly promotes the pyrolysis of lignin to produce phenolic compounds. This finding is meaningful for the application of biomass pyrolysis.

In the petrochemical industry, ethane/ethylene (C 2 H 6 /C 2 H 4 ) separation is one of the most important processes. Herein, we reported an iron-based metal–organic framework MIL-142A for efficiently trapping C 2 H 6 from C 2 H 6 /C 2 H 4 mixture, exhibiting preferential adsorption of C 2 H 6 over C 2 H 4 . After various characterization techniques to confirm the successful preparation of MIL-142A, the C 2 H 6 and C 2 H 4 adsorptive separation performance was systematically investigated. Results showed that MIL-142A had remarkably higher C 2 H 6 adsorption capacities than that of C 2 H 4 at 298, 288, and 278 K, such as C 2 H 6 and C 2 H 4 adsorption capacities of 3.8 and 2.9 mmol/g at 298 K and 100 kPa, respectively. In addition, the C 2 H 6 and C 2 H 4 adsorption heats were relatively low and in the corresponding ranges 27.3–25.1 and 26.2–23.8 kJ/mol, which is a favorable property for the regeneration of MIL-142A with less energy penalty. Furthermore, it was inferred that the difference between the adsorption heat for C 2 H 6 and C 2 H 4 with the MIL-142A framework governed the…