Direct air capture of CO2 (DAC) has been increasingly recognized as a promising carbon-negative technology. The challenge in deploying energy-efficient DAC lies in effective sorbent materials. In this research, we comprehensively investigated the DAC behavior of LTA zeolites exchanged with different metal cations (Na+, K+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Y3+, La3+, Ce3+, Eu3+, Tb3+, and Yb3+) by both static single-component gas adsorption and dynamic mixture gas adsorptive separation tests. We found that a large charge-to-size ratio of cations is critical to imparting a high DAC capacity of LTA zeolites, which is ascribed to the enhanced electrostatic interaction and/or π-back bonding toward CO2. Meanwhile, a detrimental effect is associated with an excessively large charge-to-size ratio, that is, a significant “shielding effect” of (pre-) adsorbed contaminants (e.g., H2O and CO2) on cations (e.g., Mn2+ and Mg2+) reduce the accessible CO2 capacity. Ca-LTA featuring Ca2+ with an appropriate charge-to-size ratio exhibits the highest DAC capacity (350 ppm CO2 in the air, 1.20 mmol/g) with fast kinetics and good reusability. These results provide valuable insights for the design of zeolites-based physisorbents for DAC.

Traditional supply chains usually follow fixed facility designs which coincide with the strategic nature of supply chain management (SCM). However, as the global market turns more volatile, the concept of mobile modularization has been adopted by increasingly more industrial practitioners. In mobile modular networks, modular units can be installed or removed at a particular site to expand or reduce the capacity of a facility, or relocated to other sites to tackle market volatility. In this work, we formulate a mixed-integer linear programming (MILP) model for the closed-loop supply chain network planning with modular distribution and collection facilities. To further deal with uncertain customer demands and recovery rates, we extend our model to a multistage stochastic programming model and efficiently solve it using a tailored stochastic dynamic dual integer programming (SDDiP) with Magnanti-Wong enhanced cuts. Computational experiments show that the added Magnanti-Wong cuts in the proposed algorithm can effectively close the gap between upper and lower bounds, and the benefit of mobile modules is evident when the temporal and spatial variability of customer demand is high.

The construction of high-performance MOF-based hollow fiber composite membrane (HFCM) modules is a significant, yet challenging task for the biofuel production industry. In this study, a novel approach was taken to fabricate PDMS@ZIF-8/PVDF HFCMs in modules through a facile ZIF-8 self-crystallization synthesis followed by pressure-assisted PDMS infusion for pervaporation ethanol-water separation. The as-prepared HFCMs exhibited an ultrathin separation layer (thickness, 370 ± 35 nm), which was achieved through precise regulation of the ZIF-8 membrane and defect repair by PDMS infusion. Moreover, the strategy utilized in this study resolved the defect issues arising from MOF agglomeration in conventional composite membranes. Impressively, at the optimal packing density, the prepared membrane demonstrated a remarkable ethanol flux (1.11 kg m−2 h−1) with an PSI value (26.59 kg m−2 h−1) and showed promising long-term stability for the pervaporation of 5 wt% ethanol aqueous solution at 40°C.

The commercialization of cellulose nanocrystals (CNCs) is currently limited by its environmental impact of high water consumption and brine wastewater generation. Here, a combined process integrating the production of CNCs and calcium sulfate whiskers (CSWs) was proposed to achieve complete utilization of the waste acid, and the corresponding environmental performance was evaluated by life cycle assessment (LCA). Accordingly, we prepared fibrous CSWs with an average length of 309 μm and an average aspect ratio of 57 under optimum conditions. The LCA results demonstrated the superior environmental performance of the combined process, especially for CNC production, and the impact values reduced by 45.6% on average. Moreover, the cost of producing 20 g of CNCs decreased from 3.04 CNY (traditional process) to 1.66 CNY (combined process). Therefore, this combined production process is eco-efficient and economically scalable for the industrial production of CNCs.

High tunability of both ionic liquids (ILs) and metal organic frameworks (MOFs) enables great opportunity in the rational designation of IL/MOF composites for physical adsorption and separation. Traditionally, cations and anions of ILs as an entirety are combined with MOFs either inside or outside the microchannels. Herein, organic cations of ILs were confined into Cu-BTC and the champion adsorbent is obtained by using 1-propionic acid-3-vinylimidazole bromide as the precursor with a moderate loading amount, exhibiting higher CO2 uptakes of 8/5 mmol g−1 than Cu-BTC (6.0/3.5 mmol g−1) at 273/298 K and 100 kPa, associating with significantly improved CO2/N2(CH4) selectivities. The organic cations are interacted with two adjacent CuII2(CRO2)2 paddle wheel units of Cu-BTC, expanding the CuO bond to strengthen the CO2 affinity of open Cu sites and also serving as an additive CO2 adsorptive site. The promotion of CO2 capture ability is further reflected in the dynamic column breakthrough experiment.

A new micro-kinetic model of the enzyme-catalyzed synthesis of fructo-oligosaccharides (FOS) was developed. A commercial enzyme mixture Pectinex® Ultra SP-L derived from Aspergillus aculeatus was used. A variety of initial enzyme concentrations (1–5 vol%) and sucrose concentrations (400–600 g/L) were experimentally investigated and included in kinetic modeling. Several variations of kinetic mechanisms and corresponding models have been examined. A hybrid genetic algorithm was used to predict the kinetic parameters simultaneously for all experimental data. The best fitting model has been adopted, and with an average error of 13.34%, it describes the experimental data very well. The influence of initial concentrations on the conversion of sucrose and production of FOS is being carefully investigated. It was shown that the initial sucrose concentration significantly affects the highest level of FOS concentration, but the enzyme concentration controls the time at which maximum is reached as well as the rate of FOS decomposition.

The constant molar overflow (CMO) framework, while useful for shortcut distillation models, assumes that all components have the same latent heats of vaporization. A simple transformation, from molar flows to latent-heat flows, allows shortcut models to retain the mathematical simplicity of the CMO framework while accounting for different latent heats, resulting in the constant heat transport (CHT) framework for adiabatic distillation columns. Although several past works have already proposed this transformation in the literature, it has not been well utilized in recent times. In this article, we show the utility of this transformation in upgrading various applications such as identifying energy-efficient multicomponent distillation configurations based on heat duty rather than surrogate vapor flow. The method transforms the V min $$ {V}^{\mathrm{min}} $$ diagram to a Q min $$ {Q}^{\mathrm{min}} $$ diagram. Furthermore, we derive new and insightful analytical results in distillation, such as cumulative latent-heat stage fractions having monotonic profiles within a distillation column under the CHT framework.

A new methyl chloride (CH3Cl) capture and dehydration process using two ionic liquids (ILs) was designed and systematically studied. ILs [EMIM][Ac] and [EMIM][BF4] were screened out as CH3Cl capture and drying absorbents through the COSMO-RS model. The result of solubility experiment suggests [EMIM][Ac] has an excellent solvent capacity for CH3Cl at mild operation conditions. The bench-scale CH3Cl absorption experiments further confirmed the outstanding CH3Cl capture ability of [EMIM][Ac]. Besides, the water content of outlet gas can be decreased to 452 ppm (ma's fraction) using [EMIM][BF4] in the dehydration experiment. The industrial-scale CH3Cl capture and dehydration process was simulated and optimized. Compared to the benchmarked triethylene glycol process, IL process has higher product purity (99.99 wt%), and lower energy consumption. The quantum chemical calculations clearly revealed the relationship between hydrogen bond and separation performance. This study provides a decision-making basis for designing green process associated with volatile organic compounds.

Developing highly active, selective, and stable electrocatalysts for the CO2 reduction reaction (CO2RR) is essential to relieve the greenhouse effect and the energy crisis. Traditional catalytic electrodes require ionomer binders, which inevitably impose undesired high CO2 transport resistance and block the active sites. Herein, Ni single atoms anchored on nitrogen-doped carbon nanoarrays (denoted as Ni-SAC-NA) were developed as the electrode without additional ionomers for efficient CO2RR. The unique nanoarray structure provided a higher specific surface area, more exposed active sites, and enhanced electron/mass transport due to its short diffusion pathway and ionomer-free nature. As a result, the Ni-SAC-NA electrode exhibited enhanced activity of CO2RR and selectivity towards CO with Faradaic efficiency of 96.7%, turnover frequency of 27,504 h−1, and cathodic energy efficiencies of 54.9% at −0.88 V (vs. RHE). Our findings provide a rational design strategy for CO2RR electrocatalysts by constructing ionomer-free electrodes.

Aluminum-based lithium adsorbent (Li/Al-LDH) is the only industrialized adsorbent for Li+ extraction from salt lake brines. The inherent mechanism of declined Li+ adsorption performance was revealed to explain the feebleness in sulfate-type brines. SO42− in brines could replace interlayer Cl− by a stronger electrostatic attraction with laminates, significantly altering the stacking structure and interlayer spacing, while Cl K-edge of XAFS showed intercalated SO42− would not obviously change the chemical environment of interlayer Cl−. Experiments as well as DFT and FEM simulations indicated the intercalated SO42− regulated Li+ adsorption of Li/Al-LDHs at different ionic strength under a combined effect of expanded interlayers, close packing, and electrostatic repulsion. Although sufficient SO42− contents in brines might promote the single Li+ adsorption by offering ionic strength as a driving force, the long-term usability would be severely impaired as SO42− intercalation in interlayers reduced the subsequent Li+ adsorption capacity and increased the desorption difficulty.

The exploration of efficient and environmentally friendly oxidation method is highly desirable to overcome the critical problems of poor selectivity and heavy metal contamination for the fine chemicals industry. Herein, a self-supported three-dimensional (3D) SeNi5P4 nanosheet electrocatalyst was rationally designed and fabricated. Benefiting from the synergistic effect of aminoxyl radical and mesoporous SeNi5P4/graphite felt (GF), an excellent performance of ≥98% selectivity and 33.12 kg (m−3 h−1) space–time yield was obtained for sterol intermediate oxidation with the enhanced mass transfer effect of the continuous flow system. The doping of anionic selenium and phosphorus modulated the electronic structure of SeNi5P4, and the oxyhydroxides generated by surface reconstruction accelerated the turnover of 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO), thereby enhancing the intrinsic electrocatalytic activity. A scale-up experiment was conducted with stacked-flow electrolyzer demonstrated the application potential. This work provided an efficient synergistic electrocatalytic strategy to facilitate rapid electron and mass transfer for electrochemical alcohol oxidation and highlighted the potential for practical electrosynthesis applications.

With the aim of lowering energy consumption for gas regeneration, rational design of absorbents with low absorption enthalpy changes while retaining good gas solubility is of both scientific and practical significance. Herein, we demonstrated that acidic protic ionic liquid (APIL)-based deep eutectic solvents (DESs), which comprise N-ethylimidazole hydrochloride ([EimH]Cl) and ethylene glycol (EG), were able to reversibly absorb SO2 with high solubility (11.60 mol kg−1) and SO2/CO2 selectivity (655) at 293.2 K and 101.3 kPa. Meanwhile, [EimH]Cl/EG DESs exhibit very low enthalpy changes (ΔrHm) ranging from −27.1 to −25.6 kJ mol−1, and thus ease of desorption at very mild temperature conditions (303.2 K) with desorption ratios up to 99.6%. Recycling experiments showed that no obvious loss in capacity was found after six absorption–desorption cycles, suggesting good regeneration performance of [EimH]Cl/EG DESs. Moreover, spectroscopic analysis revealed the charge-transfer interaction between [EimH]Cl/EG and SO2.

Describing spatiotemporal evolution and characteristics of dispersed systems using the population balance equation (PBE), examples including sectional and moment methods are fraught with numerous issues. Hence, this study develops an accurate method by combining computational fluid dynamics and population balance-Monte Carlo method (CFD-PBMC) with a moderate computational cost. An efficient sub-model for particle migration was proposed to simulate the convection and diffusion processes of particulate flows. A graphics processing unit (GPU)-based parallel computation was performed to accelerate the high-dimensional CFD-PBMC. Several classical cases with analytical or benchmark solutions were simulated, and a comprehensive comparison was made using the classical weighted random walk method. Good agreements were obtained, except in the case of radial migration, the reasons for which are explained in detail. The measured speedups on the GPU showed a factor of ~450 for pure migration and ~50 for the CFD-PBMC method when compared with a standard high-performance computer.

Renewable energy accommodation entails extensive use of modular devices, whose performance degrades remarkably from the lab scale to the industrial scale. This work presents a multi-objective design optimization approach for modular devices scale-up as exemplified by hierarchical numbering-up of reverse water-gas shift microreactors. The optimization objectives cover a wide span of competing system performance metrics, including the reaction performance, energy efficiency, space occupation, environmental impact, and costs. The decision variables involve the hierarchical geometry, branching, and inter-stack connection schemes of the microreactor stacks. The obtained Pareto-optimal designs suggest that multiple short stacks with small intra-stack distribution channels and large inter-stack connection tubes can well balance cost and performance. Meanwhile, single-stack structures with large distribution channels are more suitable for portable applications. The methodology not only can be extended to the numbering-up of various types of microreactors but also has essential guidance for the integration design of other modular devices.

The enhancement of catalytic activity is always limited by the dilemma in activation and desorption due to Sabatier principle. Locating the Sabatier optimum by manipulating catalyst electronic structure has been a long-standing challenge in heterogeneous catalysis. Herein, we presented a generic strategy to continuously tailor the Pt 5d state occupancy via tuning the PtOMn electronic linkage over Al2O3-confined MnOx islands, aiming at accommodating the CH cleavage and product desorption capabilities in dehydrogenation of liquid organic hydrogen carriers (monocyclic/bicyclic hydrides). Rising Mn valence can decrease the Pt 5d state occupancy through more electron transfer from Pt 5d to O 2p due to the strong π-donation of O 2p to Mn 3d. This will lead to the lower initial CH activation energy barrier while higher product desorption energy barrier. An intermediate Pt 5d filling of ~8.4 in PtMn2O3/Al2O3 enables the balanced level of product desorption and CH activation, thus ensuring a superior dehydrogenation activity. The electron structure-adsorption-performance modulation mechanism described herein provides a benchmark to locate the Sabatier optimum for the metal catalyst design.

A predictive mathematical model for tablet dissolution was developed and implemented in an end-to-end integrated continuous manufacturing pilot plant. The tablets were produced for immediate release with a proprietary extrusion-molding-coating (EMC) unit operation. Besides the mass balance of API solute in the buffer solution, the model consisted of the dissolution, diffusion, and population balance of API particles in the swollen tablet, which was mainly controlled by the swelling and erosion of the polymeric excipient matrix. An equivalence study was investigated by comparing the model prediction to the experiments that were conducted according to USP42-NF37 General Chapter <711> Dissolution, during which the drug dose level was varied in a range from 60 to 80 wt%. Consistent equivalence was demonstrated with the similarity factor f2 > 50 for all sampled tablets. Concluding remarks and industrial perspectives on model predictive in vitro dissolution testing are provided.

We report a plasma-assisted CO2 hydrogenation to CH3OH over Fe2O3/γ-Al2O3 catalysts, achieving 12% CO2 conversion and 58% CH3OH selectivity at a temperature of nearly 80°C atm pressure. We investigated the effect of various supports and loadings of the Fe-based catalysts, as well as optimized reaction conditions. We characterized catalysts by X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), CO2 and CO temperature programmed desorption (CO2/CO-TPD), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), x-ray photoelectron spectroscopy (XPS), Mössbauer, and Fourier transform infrared (FTIR). The XPS results show that the enhanced CO2 conversion and CH3OH selectivity are attributed to the chemisorbed oxygen species on Fe2O3/γ-Al2O3. Furthermore, the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and TPD results illustrate that the catalysts with stronger CO2 adsorption capacity exhibit a higher reaction performance. In situ DRIFTS gain insight into the specific reaction pathways in the CO2/H2 plasma. This study reveals the role of chemisorbed oxygen species as a key intermediate, and inspires to design highly efficient catalysts and expand the catalytic systems for CO2 hydrogenation to CH3OH.

Uranium is a key element to improve nuclear energy demands, and thereby the extraction of uranium from seawater is a strategic way to address uranium sustainability. Herein, a novel two-dimensional porous aromatic framework (AO-PAF), which possesses an ultra-microporous architecture with an ordered structure, excellent stability and selectivity of uranium extraction from a liquid phase. AO-PAF shows excellent uranium adsorption capacities of 637 (mg/g) and 3.22 (mg/g) in simulated and natural seawater attributable to the selective uranium coordinating groups on highly accessible pores on the walls of open channels. In addition, benefiting from the super-hydrophilicity due to the presence of amidoxime groups attributes high selectivity and ultrafast kinetics with an uptake rate of 0.43 ± 0.03 (mg/g·day) and allowing half-saturation within 1.35 ± 0.09 days. This strategy demonstrates the potential of PAF not only recovery of uranium and can be extended for other applications by sensible planning of target ligands.

A novel and efficient α-MnO2-N/C@active carbon (AC) catalyst was proposed and synthesized through a surface modification method based on imprinting process. Uniformly dispersed α-MnO2 and N/C sites were constructed simultaneously and the competitive adsorption of metal precursors with nonmetal precursors was avoided. Conformational relationship of α-MnO2-N/C@AC revealed that α-MnO2 and graphite N were the main active sites, cleverly forming synergistic catalytic effect, which results in a good degradation effect for two actual printing and dyeing wastewater. The removal rate of chemical oxygen demand (COD) could reach 78% and 58% within 60 min, respectively, and it maintained stable after 20 repetitions without leaching of metal ions. Mechanistic investigation demonstrated that N/C sites rapidly adsorbed ozone to generate ·O2− and synergistically catalyzed with adjacent α-MnO2 sites to further produce ·OH, significantly facilitating the generation of ·OH. This work provides a promising strategy to synthesize novel and efficient catalysts for ozone catalytic oxidation process.

The zero-length column (ZLC) method has been frequently used to measure the effective diffusivity of guest molecules in nanoporous crystalline materials. Recent studies unveiled that the mass transport of guest molecules could originate from either intracrystalline diffusion and/or surface barriers. Directly quantifying the intracrystalline diffusivity and surface permeability of guest molecules. therefore, is essential for understanding the mass transfer and thus optimizing the design of nanoporous crystalline materials. In this work, we extended the ZLC method, based on a derived theoretical expression of the desorption rate, to decouple the surface barriers and intracrystalline diffusion from effective diffusion of guest molecules in nanoporous materials. The diffusivities of ethane, propane and n-pentane in SAPO-34 and Beta zeolites have been experimentally measured to verify the effectiveness of this method.