Dilute organic wastewater is a common challenge in the chemical and petroleum industries due to its complexity and low organic concentration, making the recovery of valuable components both difficult and energy-intensive. In ship-washing operations, where chemicals are cleaned from tanks before loading new cargo, several streams of dilute wastewater with simple and sole organic component are generated. Efficient treatment of such wastewater is both urgent and necessary. This work reports an energy-efficient process that integrates distillation with catalytic cracking oxidation for the cost-effective treatment of dilute organic wastewater. The distillation unit concentrates the organic components, while the catalytic cracking oxidation breaks down large molecules into small ones, which are subsequently oxidized into carbon dioxide and water. The process achieves competitive net energy performance through effective heat integration, making it a promising solution for industrial applications. Several case studies simulated by using Aspen Plus V14 are employed to demonstrate the effectiveness and economic advantages of the reported process.

Polycyclic Aromatic Hydrocarbons (PAHs) are typical persistent organic pollutants in soil, and their efficient and green remediation is a major challenge in the environmental field. This study addresses the problems of easy agglomeration and limited active sites of goethite (FeOOH) catalysts, and the FeOOH was innovatively loaded onto the surface of montmorillonite (Mt) by ultrasonic co-precipitation method, constructing the FeOOH/MtH2O2 advanced oxidation system. Through XRD, FT-IR, SEM/EDS, BET and XPS characterization, it is confirmed that FeOOH is highly dispersed on the surface of Mt. (no agglomeration even at a loading amount of 200 wt%), and the Fe3+ active sites have significantly increased; the layered structure of Mt. effectively promotes the enrichment of pollutants and electron transfer. The optimized degradation conditions for pyrene (Pyr) are: catalyst dosage of 0.2 g/L, H2O2 concentration of 0.8 M, pH of 6, temperature of 45 degrees C, and Pyr degradation rate reaches 91.08 % within 6 h. Compared with the pure FeOOH system, this catalyst shows a 29.47 % increase in activity under a lower oxidation dose (reduced by 73 %) and a wider pH range (2-6). Soil simulation experiments further verified that under the conditions of 0.4 g/kg catalyst, 1 mol/kg H2O2, water-to-soil ratio of 3:1, pH of 6, and 50 degrees C, the Pyr degradation rate is 85.73 %. This system provides a low-cost, efficient, and environmentally benign technical solution for the remediation of actual contaminated soil.

The pressure-swing distillation traditionally used in the industry for separating dimethyl carbonate/methanol (DMC/MeOH) commonly suffers from high energy consumption and challenges in achieving high-purity separation due to the existence of pinch zone. Our recently proposed extractive distillation for the separation of DMC/ MeOH offered significant energy savings, but confronts challenges such as unclear splits in both columns and high bottoms temperature. Hence, an energy-saving heterogeneous azeotropic distillation system is explored for the mild and high-purity separation of the azeotrope, featuring two-phase decanter temperature reduction, preconcentrator addition, and heat pump integration. Upon analysis of ternary diagrams and residue curve maps, cyclohexane (CYCL) was selected as the most suitable entrainer, and a heterogeneous azeotropic distillation process was analyzed, synthesized and optimized for the production of 10 ktpy 99.9 wt% DMC. Furthermore, heat pump and heat integration technologies are integrated into the optimal basic heterogeneous azeotropic distillation to gain additional energy conservation, bringing about several improved processes. It is revealed that the heat-pump heterogeneous azeotropic distillation process with heat integration (HP-HI-HAD) possesses the best economic and environmental advantages, offering marked reductions of 20.09 % and 39.19 % in TAC and COQ emissions compared with the conventional extractive distillation (ED) one. This work provides a feasible and promising approach to energy-saving, mild and high-purity separation of DMC/MeOH azeotrope.

Dimethyl carbonate (DMC) and methanol (MeOH) form a binary minimum-boiling homogeneous azeotrope, and thus conventional distillation cannot achieve complete separation. The extractive distillation (ED) with o-xylene as a heavy entrainer in our recent work possesses significant energy saving and achieves a high purity of 99.9% DMC compared with the pressure-swing distillation (PSD). For a fair comparison, both ED and PSD were evaluated against the same minimum product specifications (DMC ≥ 99.5 wt% and MeOH ≥ 98.0 wt%), noting that the recovered MeOH stream was recycled to the reactive distillation column rather than treated as a final product. However, the dynamic performance of this ED is still unclear, and all the benefits of the ED are reasonable only under good dynamic controllability. In this work, the dynamic controllability of the ED process was compared with that of the PSD one. Both processes were evaluated under a unified temperature-control philosophy, including conventional fixed R. Closed-loop dynamic simulations were performed under ±10% step disturbances in feed flowrate and composition. It was revealed that under the tested disturbances, DMC purity was maintained close to the high-purity target (≈99.9 wt%) in the ED process, whereas larger deviations and a lower attainable DMC purity were obtained in PSD. The results provide a control-oriented basis for the selection and further development of special distillation schemes for MeOH/DMC azeotropic separation.

Catalytic oxidation is a promising technology for the deep cracking of chlorinated organic compounds (COCs) in pharmaceutical waste salts. The critical challenge lies in the development of catalysts that can synergistically activate C-Cl bonds and promote highly efficient oxidation. Herein, this study employed a B-site doping strategy to develop a series of perovskite-type catalysts that successfully achieved the synergy of acidic and redox sites. Among them, the LaMn0.8Cr0.2O3/ZSM-5(25) catalyst exhibited the optimal performance in the catalytic cracking-oxidation of the model pollutant 1-chloro-3-phenylpropane. It achieved a T-90 of 260 degrees C, representing a significant reduction of 48 degrees C compared to the undoped catalyst. Moreover, it retained around 90% conversion over 60 h. In-depth mechanism study indicated that the pronounced electron transfer between Cr and Mn ions (3Cr(2+)+3Mn(4+) -> 2Cr(3+)+Cr6++3Mn(2+)) not only increased the oxygen vacancy concentration but also significantly enhanced the activity of both chemisorbed oxygen (0.37 mmol.g(cat)(-1)) and lattice oxygen (0.23 mmol.g(cat)(-1)). Concurrently, the metal doping effectively exposed the inherent Si-OH-Al acidic sites in the ZSM-5 framework without altering their intrinsic nature. This synergistic mechanism drives the efficient cracking-oxidation of COCs by accelerating the steps of C-Cl bond cleavage and deep oxidation of intermediates, rather than altering the reaction pathway. This work provides a solid theoretical basis and profound insights for designing multi-site synergistic catalysts for the purification of COCs.

A series of CeMnCrx/H(3 catalysts were synthesized, and their performance for the complete catalytic oxidation of chlorobenzene (CB) in air was evaluated. The results showed that the incorporation of Cr significantly enhanced catalytic activity, improved water-vapor resistance, and strengthened long-term stability. The underlying reason for this improvement via various characterization indicated that Cr doping increased both the density and strength of Lewis acid sites, as well as the fraction of lattice oxygen, which facilitated the dissociation of C-Cl bond and the ring-opening, and accelerated the deep oxidation of CB. Meanwhile, synergistic interactions between Cr and Ce/Mn species stabilized the catalyst structure and promoted rapid oxygen migration. Kinetics equation of the CB oxidation based on the Mars-van Krevelen (MvK) model was modeled and established, which was competent in describing the experimental data with relative deviations of <= 10 %, confirming the rational of the lattice oxygen oxidation mechanism. With the help of In-situ FTIR, XPS, and O2-TPD results, a CB oxidation mechanism was further proposed, which involves CB adsorption on Br & oslash;nsted acid sites, cleavage of the C-Cl bond, formation of phenolic/carboxylate/maleate intermediates and subsequent oxidation to CO2, H2O, and HCl by lattice oxygen. These findings highlight the dominant role of lattice-oxygen dynamics in governing catalytic performance, suggesting the excellent performance of CeMnCr0.06/H(3 in CB oxidation.

5-Hydroxymethylfurfural (HMF) is a central platform molecule linking plant biomass to renewable fuels and chemicals, yet its scalable production is hindered by instability and costly separation. Here we present a temperature-responsive, phase-switchable acetone/betaine hydrochloride (BHC) aqueous system that unifies catalysis, product stabilization, and catalyst/solvent recycling in one platform. The system behaves as a liquid-liquid biphasic medium during fructose dehydration, enabling in situ extraction of HMF into acetone, and switches to a solid-liquid state upon cooling, allowing quantitative BHC recovery. Molecular simulations reveal that BHC accelerates dehydration via directional hydrogen bonding, while acetone selectively solvates HMF to suppress degradation. The system achieves up to 86.7% HMF yield at a high concentration of 30 wt% fructose, sustains >75% yield at 60 wt%, and remains robust over multiple cycles. A 1000-fold scale-up validates kilogram-scale production, and techno-economic analysis projects cost competitiveness with all reported routes. This phase-switchable concept establishes a broadly applicable catalytic strategy for catalyst/solvent recovery and product stabilization in biomass valorization.

Ethanol is used to produce various value-added chemicals and as automobile fuel. Acetic acid hydrogenation to ethanol is of practical significance to meet the increasing market. However, limited engineering research for reactor and crude separation process for the acetic acid hydrogenation to ethanol despite the increasingly mature catalyst system. Moreover, the traditional approach of industrial reactor design mainly relies on point data and inadequately quantifies the strong coupling between reaction rate and transfers within the reactor, which is prone to local and loose design and optimization. In this work, a coupled design approach that combines kinetics with transfers is proposed for designing and optimizing the multi-tubular fixed-bed reactor for the acetic acid hydrogenation to ethanol. To efficiently achieve the products crude separation, staged cooling/flash/absorption/ desorption units featuring with N-methyl-2-pyrrolidone as an absorbent is proposed, numerically designed and optimized. Further heuristic heat integration is also investigated to conserve extra energy of the preliminary process, which features that a by-product steam generated from ethanol synthesis reactor is utilized to drive the reboiler of the desorption. It is demonstrated that the heat-integrated process presents significant economic and emission advantages compared with the preliminary process, specifically with 36.5 % and 10.9 % reductions in operating cost and total annual cost respectively, as well as 58.1 % reductions in CO2 emissions. The cost of synthesizing ethanol with 100 ktpy production is as low as 14.25 $/t. This work could provide a feasible and promising reactor and crude separation process for acetic acid hydrogenation to ethanol, which features economic, high-efficient, energy-saving, and low-carbon.

The one-step methanol oxidation to dimethoxymethane (DMM) is a promising method for value-added chemical synthesis. However, vanadium cerium (VCe) catalysts commonly exhibit insufficient DMM selectivity in spite of its moderate high-temperature methanol conversion. In this work, titanium dioxide (TiO2) with relatively strong acidity was introduced into VCe catalyst to improve the catalysis performance of VCe. The results showed that the addition of TiO2 enhanced the oxidation reduction and surface acidity of the catalyst, and effectively improved the selectivity and yield of DMM. Furthermore, a scaled-up conceptual process for the one-step oxidation of methanol to DMM was explored, designed and economically evaluated based on the TiO2 modified catalysts. The entire conceptual process featured that multiple condensation-separation/absorption units offered a complete collection of the DMM. Through the optimization of the process, the generated products and unreacted methanol can be directly stripped from N2 and O2, and complete separation of DMM-methanol azeotrope was achieved with only one vacuum distillation unit. The entire process at what catalysis performance (methanol conversion, DMM selectivity, etc.) could bring profit was revealed and discussed. This study emphasizes the interaction between catalyst design, conceptual process design and economic evaluation, providing new ideas for the development of efficient industrial catalysts.

Industrial production and transportation of n-butanol generate a substantial volume of wastewater, which poses significant treatment challenges because of the tendency of n-butanol to form an azeotrope with water. Adsorption, a promising method for treating n-butanol wastewater, still faces limitations such as the low adsorption capacity and desorption efficiency of conventional commercial adsorbents. This study systematically screened commercial adsorbents and identified ZSM-5-300 as a suitable candidate. The 7.5Cu-ZSM-5 adsorbent was developed to overcome the limitations of commercial adsorbents in terms of adsorption capacity, presenting an exceptional n-butanol adsorption capacity of 114 mg g-1 with a 53% improvement over unmodified ZSM-5. Adsorption kinetics and isotherm studies indicated that n-butanol is adsorbed as a monolayer on 7.5Cu-ZSM-5, with physical adsorption being predominant. Thermodynamic analysis further revealed that this adsorption process is spontaneous and exothermic. Additionally, the adsorbent showed excellent adsorption-desorption cycling stability, with a low adsorption capacity loss of 17.72% after 20 cycles. This work reveals that metal-modified ZSM-5, with enhanced performance and moderate reusability, is a promising alternative to conventional commercial adsorbents for the sustainable recovery of n-butanol from wastewater.

The transesterification of propylene carbonate (PC) or ethylene carbonate (EC) to dimethyl carbonate (DMC) by using catalytic reactive distillation (RD) is a promising approach for carbon dioxide utilization. However, there is still scarcity of comprehensive comparison between the two RD processes. Hence, using the UNIQUAC model and kinetics calibrated by literature and our experiments, we conduct an extensive comparison of the two RD processes. Based on the kinetic insights, laboratory RD processes for both reactions are modeled, analyzed, and experimentally validated. Consequently, two RD processes designed to produce 60 ktpy of DMC are optimized and compared. The interplay and control factors between reaction and separation are elucidated and clarified via investigating variations of the actual chemical equilibrium constant profile compared with theoretical values along the reactive section at various pressures, liquid holdups, etc. The results reveal that the optimized EC RD process achieves almost 50 % reductions in both total annual cost and carbon dioxide emission compared to the PC RD process. This work facilitates the carbon neutrality and provides an essential guide for quantitatively assessing the two routes.

Direct autothermal methane reforming is an energy-efficient way of hydrogen production. However, significant hot spot is always encountered near the reactor inlet, causing catalyst sinter and even reactor damage. Hence, bed temperature regulation by oxygen distributed feeding was numerically investigated using a one-dimensional heterogeneous model. Simulation results show oxygen feeding along full length of reactor leads to low methane and oxygen conversion despite avoiding hot spot. Elevating feeding temperature solves this problem, but requires extra heat. Shortening feeding length to 1/10 of reactor reduces maximum bed temperature by 100 K; Half oxygen fed into reactor inlet and the other along the length further reduces maximum bed temperature and avoids the transient runaway. Optimization results show that oxygen parabolically and totally fed along the front part of the reactor length shows better performance than that feeding half along reactor length and the other into reactor inlet.

The impressive water stability demonstrated by MIL-101(Cr) highlights its considerable potential for the effective elimination of organic contaminants from wastewater. Nevertheless, the limited availability of adsorption sites within MOFs leads to an unsatisfactory capacity for tetracycline (TC) adsorption. In this case, the lanthanum modified MIL-101(Cr) porous adsorbents, termed as nLa-MIL-101(Cr), were successfully synthesized using a post-synthetic modification method. Through various characterization analyses, it was confirmed that lanthanum exists in the form of La(OH)3 within the adsorbents, and all adsorbents also preserved the original structure as MIL-101(Cr). The results of static adsorption experiments demonstrated that, compared to the original material, the adsorption capacity of 1La-MIL-101(Cr) for TC increased by 3.5 times. Further experiments demonstrated that the adsorbent exhibits remarkable ion interference resistance and cycle stability. Finally, based on X-ray photoelectron spectroscopy, the adsorption mechanism was primarily attributed to the coordination between TC molecules and metals active site, while electrostatic interactions also played a significant role in the process. This study has developed a highly efficient adsorbent for the treatment of TC-contaminated wastewater, which reflects promising practical application prospects.

The pressure-swing distillation traditionally used in the industry for separating dimethyl carbonate/methanol (DMC/MeOH) commonly suffers from high energy consumption and challenges in achieving high-purity separation due to the existence of pinch zone. Hence, energy-saving extractive distillation system is explored to achieve the high-purity separation of DMC/MeOH azeotrope. With the analyses of isovolatility and residue curve maps based on Wilson model calibrated by vapor-liquid equilibrium experimental data, an extractive distillation process using O-Xylene (OX) as the most suitable entrainer were modeled and experimentally validated. Furthermore, design, optimization, and comparison of an extractive distillation process and a pressure-swing distillation process for producing 10000 t DMC/a are investigated. It is demonstrated that the extractive distillation process presents significant economic and emission advantage, specifically with 34.66 % and 26.95 % reductions in operating cost (OC) and in total annual cost (TAC) respectively, as well as 42.53 % reduction in CO2 emissions. This work should provide a feasible and promising approach to energy saving, low-carbon, and highpurity separation of DMC/MeOH azeotrope.

The industrialization of solid amine adsorbents requires the molding of the adsorbents, and the blockage or collapse of the pore structure caused by the molding process will inevitably affect the CO2 adsorption performance. Herein, the structured solid amine adsorbent SA-Tx/My pellets were fabricated basing on the crosslinking of alginate and Ca2+ under mild conditions. The pelletized SA-Tx/My well preserved the pore structure of the original support, with only a 26.8% reduction in specific surface area, which profited to a more uniform loading and dispersion of amine. Benefitting from the influence of pore structure on amine dispersion, SA-Tx/My pellets achieved a pretty CO2 adsorption capacity of 2.49 mmol·g-1. The hydroxyl group of alginates can form hydrogen bonds with TEPA, which greatly improved the amine stability of the adsorbent and enabled SA-Tx/My pellets to exhibit excellent cyclic stability. After 30 adsorption-desorption cycles, the adsorption capacity of SA-T0.8/M0.18 merely decreased by 11.6%. Considering the adsorption capacity and stability of structured adsorbents, the molding strategy with the assistance of alginate provides a potential path for the industrial application of solid amine adsorbent molding technique.

Hydrogen is being considered as a possible large-scale carbon-free industrial combustion and transportation fuel. Steam methane reforming (SMR) reaction is the most dominant industrial hydrogen production method. This paper develops comprehensive models and delves into the influences of the multi-dimensional reactor and catalyst domains in SMR. Several single-scale or multi-scale SMR packed-bed reactor models are developed with the Aspen Custom Modeler and solved by the built-in finite difference method. These models are categorized into pseudo-homogeneous and heterogeneous models. This study thoroughly compares and discusses the effects of axial and/or radial mixing due to mass/heat dispersion as well as interfacial and intraparticle mass/heat transport phenomena across various types of reactor-catalyst configurations. Furthermore, insights into the prediction accuracy of each model under various operating conditions are provided. This research fills a gap in the existing literature by developing rigorous dynamic models for SMR reactors to investigate their profiles and performances, offering a clearer understanding of the relative importance of different modeling approaches in predicting the behavior of SMR reactors. The findings provide valuable guidelines for researchers and industry professionals in selecting the appropriate model for their design, analysis, optimization, and control tasks.

Studying the relationship between electronic structure and activity helps to understand the catalytic mechanism since the catalytic combustion is a redox reaction dominated by electron transfer. Herein, we regulated the electron energy and O p-band center of La-based perovskite catalysts by a facile method of changing the B-site ion (B = Co, Mn, Fe). The crystal structure, morphology, reducibility, element valence distribution, and catalytic properties of prepared catalysts were characterized. Combining with DFT calculation, it was found that the low electron energy in (110) facets of LaCoO3/SiO2 catalyst contributes to the formation of reactive oxygen species and high-valence Co3+ ions. The highest oxygen adsorption activation capacity of LaCoO3/SiO2 originates from a moderate location of the O p-band center with respect to the Fermi level. As expected, the LaCoO3/SiO2 sample shows higher n-butylamine oxidation activity than that of LaMnO3/SiO2 and LaFeO3/SiO2. This work provides different insights into understanding the activity of La-based perovskite catalysts for oxidation reactions.

Bioethanol is regarded as a sustainable alternative to fossil fuels; however, large-scale production is challenging owing to high energy consumption. In this study, some existing side-stream processes are analyzed and optimized to demonstrate their suitability; consequently, binary side-stream processes are proposed. Two types of sidestream processes are considered: a two-column process with a vapor sidestream (VSP) and that with a liquid sidestream (LSP). The merits and demerits are compared, and a novel three-column distillation process with binary vapor and liquid sidestreams (LVSP) is presented. LVSP incorporates heat integration (LVSP-HI) and combines vapor and liquid sidestreams; the vapor sidestream provides heat to concentrate the liquid sidestream, thus conserving energy. Upon eliminating the liquid sidestream, LVSP is simplified to VSP, whereas eliminating the vapor sidestream results in LSP. This approach offers the most substantial energy-saving performance, as energy consumption is decreased by 28.4-37.3% compared to the other processes. Furthermore, dynamic control simulations confirm that the proposed control strategy within LVSP-HI ensures stable flow, concentration, and temperature control. The results of this study are expected to be applied industrially to bioethanol concentration processes.

Intrinsic kinetic experiments were performed in a wide range of process conditions over an industrial Fischer-Tropsch Synthesis (FTS) cobalt-based catalyst to obtain the kinetic models, aiming at the process/engineering design and the elucidation of the reaction mechanism. A hybrid kinetic model including the CO consumption model based on the Langmuir Hinshelwood Hougen Watson (LHHW) reaction mechanism and the lump-type product distribution model-C19+ selectivity model was developed. The obtained model, through parameters' evaluation and optimization, could provide an excellent prediction of CO conversion and C19+ selectivity in a wide process condition range. Furthermore, it was inferred that CO activation follows direct dissociation mechanism with the hydrogenation of the dissociated C* and O* to CH* and OH* respectively as the rate determining step; and the activation energy for CO consumption rate model was obtained as 80.26 kJ mol- 1.