In the extraction of potassium from salt lakes, Mg is abundant in the form of bischofite (MgCl₂·6H₂O), which is not utilized effectively, resulting in the waste of resources and environmental pressure. Anhydrous MgCl₂ prepared by the dehydration of bischofite is a high-quality raw material for the production of Mg. However, direct calcination of MgCl₂·6H₂O in industrial dehydration processes leads to a large amount of hydrolysis. The by-products are harmful to the electrolysis process of Mg, causing problems such as sludge formation, low current efficiency, and corrosion in the electrodes. To obtain high-purity anhydrous MgCl₂, different advanced dehydration processes have been proposed. In this review, we focus on the recent progress of the dehydration process. Firstly, we discuss the molecular structure of MgCl₂·6H₂O and explain the reason why much hydrolysis occurs in dehydration. Secondly, we introduce the specific dehydration processes, mainly divided into direct dehydration processes and indirect dehydration processes. The direct dehydration processes are classified into gas protection heating and molecular sieve dehydration process. Indirect dehydration processes are classified into thermal dehydration of ammonium carnallite (NH₄Cl·MgCl₂·6H₂O), thermal dehydration of potassium carnallite (KCl·MgCl₂·6H₂O), thermal decomposition of the [HAE]Cl·MgCl₂·6H₂O, organic solvent distillation, ionic liquid dehydration process and ammonia complexation process. In the meanwhile, purity of anhydrous MgCl₂ of each dehydration process, as well as the advantages and disadvantages, is discussed. The characteristics of different processes with a simple economic budget are also given in this paper. Finally, the main challenges are evaluated with suggested directions in the future, aiming to guide the synthesis of high-purity anhydrous MgCl₂.

To improve the ability of diglycolamide extractants for the extraction of Sr(II) from high-level waste liquid, N,N,N',N'-tetracyclohexyldiglycolamide (TCHDGA) was proposed and studied to extract Sr(II) from nitrate media. TCHDGA was prepared and characterized by ¹H nuclear magnetic resonance spectroscopy (NMR), ¹³C NMR, and fourier transform infrared spectroscopy (FT-IR). Various factors affecting extraction were studied systematically. In just 20 s, the extraction rate can reach approximately 98.2%. The extraction capacity of cyclohexyl-substituted extractant TCHDGA is tens of times higher than that with linear or branched chain alkyl. The chemical structure of the complex has been demonstrated to be [Sr 3TCHDGA]·(NO₃)₂, based on FT-IR, X-ray photoelectron spectroscopy (XPS), and crystal structure analysis. The crystal belongs to the monoclinic system, space group P21, and a strontium ion coordinates with nine oxygen atoms, all of which contribute from TCHDGA. The stripping rate can reach over 99% when using distilled water or 0.50 mol·L^-1 oxalic acid as stripping agents.

Simultaneous recovery of Ni and Co from Fe(III) and Al is a critical challenge in hydrometallurgical processes. Recognized solvent extraction systems often struggle with selectivity and effective performance in mixed metal ion environments. Herein, a new synergistic solvent extraction (SSX) system comprised of a novel pyridine analog, N,N-bis(pyridin-2-ylmethyl) dodecan-1-amine (BPMDA), and dinonylnaphthalene sulfonic acid (DNNSA) with tributyl phosphate as phase modifier is introduced. The SSX system demonstrates high extraction performance achieving >90% for Ni and >97% for Co in a single-stage extraction process, with high selectivity. Under optimal conditions, the selectivity sequence is observed as Co²⁺ (>97%) > Ni²⁺ (>90%) > Mn²⁺ (<20%) > Fe³⁺ (<10%) > Mg²⁺ (<5%) > Al³⁺ (<2%) > Ca²⁺ (<1%). Spectroscopic analysis evidences the preferential binding of BPMDA with Ni and Co in the presence of DNNSA, concurrently achieving a significant reduction in the co-extraction of Fe(III) and Al. The selective complexation of Ni and Co using the SSX system offers a highly efficient and selective approach for their extraction, with promising potential for applications in recovery-based processes.

The pyrolysis process of Shendong coal (SD) was first studied by combining the characteristics of thermal gravimetric (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and Gray-King assay (G-K). The results show that the order of coke yields is G-K (76.35% (mass))>TG (73.11% (mass))>Py (70.03% (mass)). G-K coke yield caused by condensation reaction and secondary reaction accounts for 3.08% (mass) and 3.24% (mass), respectively. Compared with slow pyrolysis, fast pyrolysis has stronger fracture ability to coal molecules and can obtain more O-compounds, mono-ring aromatics and aliphatics. Especially, the content of phenolics increases significantly from 15.49% to 35.17%, but the content of multi-ring aromatics decreases from 23.13% to 2.36%. By comparing the compositions of Py primary tar and G-K final tar, it is found that secondary reactions occurred during G-K pyrolysis process include the cleavage of alkane and esters, condensation of mono-ring aromatics with low carbon alkene, ring opening, isomerization of tri-ring aromatics, hydrogenation of aromatics and acids.

In order to analysis the oxygen distribution in the adsorption bed during the hydrogen purification process from oxygen-containing feed gas and the safety of device operation, this article established a non-isothermal model for the pressure swing adsorption (PSA) separation process of 4-component (H₂/O₂/N₂/CH₄), and adopted a composite adsorption bed of activated carbon and molecular sieve. In this article, the oxygen distribution in the adsorption bed under different feed gas oxygen contents, different adsorption pressures, and different product hydrogen purity was studied for both vacuuming process and purging process. The study shows that during the process from the end of adsorption to the end of providing purging, the peak value of oxygen concentration in the adsorption bed gradually increases, with the highest value exceeding 30 times the oxygen content of the feed gas. Moreover, the concentration multiplier of oxygen in the adsorption bed increases with the increase of the adsorption pressure, decreases with the increase of the oxygen content in the feed gas, and increases with the decrease of the hydrogen product purity. When the oxygen content in the feed gas reaches 0.3% (vol), the peak value of oxygen concentration in the adsorption bed exceeds 10% (vol), which will make the front part of the oxygen concentration peak fall in an explosion limit range. As the decrease of product hydrogen content, the oxygen concentration peak in the adsorption bed will gradually move forward to the adsorption bed outlet, and even penetrate through the adsorption bed. And during the process of the oxygen concentration peak moving forward, the oxygen will enter the pipeline at the outlet of the adsorption bed, which will make the pipeline space of high-speed gas flow into an explosion range, bringing great risk to the device. The preferred option for safe operation of PSA for hydrogen purification from oxygen-containing feed gas is to deoxygenate the feed gas. When deoxygenation is not available, a lower adsorption pressure and a higher product hydrogen purity (greater than or equal to 99.9% (vol)) can be used to avoid the gas in the adsorption bed outlet pipeline being in the explosion range.

It is known that salt ions are abundant in the natural environment where natural gas hydrates are located; thus, it is essential to investigate the self-preservation effect of salt ions on methane hydrates. The dissociation behaviors of gas hydrates formed from various NaCl concentration solutions in a quartz sand system at 268.15 K were investigated to reveal the microscopic mechanism of the self-preservation effect under different salt concentrations. Results showed that as the salt concentration rises, the initial rate of hydrate decomposition quickens. Methane hydrate hardly shows self-preservation ability in the 3.35% (mass) NaCl and seawater systems at 268.15 K. Combined the morphology of hydrate observed by the confocal microscope with results obtained from in situ Raman spectroscopy, it was found that during the initial decomposition stage of gas hydrate below the ice point, gas hydrate firstly converts into liquid water and gas molecules, then turns from water to solid ice rather than directly transforming into solid ice and gas molecules. The presence of salt ions interferes with the ability of liquid water to condense into solid ice. The results of this study provide an important guide for the mechanism and application of the self-preservation effect on the storage and transport of gas and the exploitation of natural gas hydrates.

Fabric multifunctionality offers resource savings and enhanced human comfort. This study innovatively integrates cooling, heating, and antimicrobial properties within a Janus fabric, surpassing previous research focused solely on cooling or heating. Different effects are achieved by applying distinct coatings to each side of the fabric. One graphene oxide (GO) coating exhibits exceptional light-to-heat conversion, absorbing and transforming light energy into heat, thereby elevating fabric temperature by 15.4 ℃, 22.7 ℃, and 43.7 ℃ under 0.2, 0.5, and 1 sun irradiation, respectively. Conversely, a hydrogel coating on one side absorbs water, facilitating heat dissipation through evaporation upon light exposure, reducing fabric temperature by 5.9 ℃, 8.4 ℃, and 7.1 ℃ in 0.2, 0.5, and 1 sun irradiation, respectively. Moreover, both sides of Janus fabric exhibit potent antimicrobial properties, ensuring fabric hygiene. This work presents a feasible solution to address crucial challenges in fabric thermal regulation, providing a smart approach for intelligent adjustment of body comfort in both summer and winter. By integrating heating and cooling capabilities along with antimicrobial properties, this study promotes sustainable development in textile techniques.

Herein, the liquid-solid mass transfer characteristics in micropacked bed reactors (μPBRs) operated with immiscible liquid-liquid two-phase flow is experimentally investigated. It is found that the overall volumetric liquid-solid mass transfer coefficient (k_sa) increases with the total flow rate and the channel-to-particle diameter ratio, while decreases with the organic-to-aqueous phase flow rate ratio. A satisfactory correlation model for calculating k_sa of the liquid-liquid μPBRs is developed. The new knowledge obtained would be useful in guiding the design and optimization of the liquid-liquid μPBRs.

This research was performed to investigate the optimization of copper recovery from copper smelting slag (CSS) with a deep eutectic solvent as a green reagent. The effect of important parameters on the leaching efficiency of copper and zinc (as well as dissolution of iron), such as leaching time, leaching temperature, solid/liquid ratio, and particle size was studied. In order to model the copper recovery, an optimization method was used. According to the chemical analysis of CSS, the slag contains 0.9% copper, 3.3% zinc, and 36.7% iron. Also, it was found that the CSS is mainly composed of Fe₂SiO₄, Fe₃O₄ and SiO₂. Copper-containing structures were determined as CuO and CuS. As a result of leaching experiments, 80% copper and 61% zinc recoveries were obtained at 48 h, 95 ℃, 1/25 g·ml^-1, and -33 μm. It is noted that the iron and silicon dissolution remained negligible under the selected conditions. According to the mathematical model, the highest copper leaching efficiency (up to 100%) could be under optimum working conditions as 48.5 ℃ leaching temperature, 40.1 h leaching duration, and 62.3 ml·g^-1 solid/liquid ratio. Also, the proposed model revealed that a wide range of experimental levels can be used as leaching parameter to get desired metal leaching efficiency.

Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission. In this study, the characteristics of corncob CO₂-gasification in molten salt environments is thoroughly investigated, and the approach of introducing Fe₂O₃ as catalyst to enhance the syngas yield is proposed. The results showed that the molten salts significantly promoted the conversion of corncob into gaseous products with very low tar and char yield. Compared to O₂ and H₂O atmospheres, utilizing CO₂ as gasifying agent enhanced the yield of gaseous products during the corncob gasification, especially the yields of CO and H₂. The introduction of Fe₂O₃ as a catalyst could further increase the yield of gaseous products and the cold gas efficiency (CGE), and the yield of syngas was increased into 2258.3 ml·g^-1 with a high CGE of 105.8% in 900 ℃. The findings evidenced that CO₂ gasification in the molten salt environment with Fe₂O₃ addition can promote the cracking of tar, increasing the syngas yield significantly. Moreover, the energy required to drive the gasification process was calculated, and the total energy consumption was calculated as 16.83 GJ·t^-1. The study opened up a new solution for the biomass gasification, exhibiting a great potential in distributed energy or chemical systems.

The effects of internals on liquid mixing and gas—liquid mass transfer have rarely been investigated in bubble columns, and the commonly used measurement method overestimates significantly overall gas holdup. Firstly, gas holdup measurement method is improved by conducting multi-point liquid level measurement and using net fluid volume instead of bed volume to calculate gas holdup. Then, a stable conductivity method for liquid macromixing has been established by shielding large bubbles using #16 nylon mesh. Subsequently, the influences of internal coverage (=12.6%, 18.9% and 25.1%) on macroscopic fluid dynamics in a bubble column with a free wall area are systematically investigated. It is found that the presence of internals has a notable effect on macroscopic fluid dynamics. The overall gas holdup and gas—liquid volumetric mass transfer coefficient decrease, and the macromixing time decreases with the increase of internal cross-sectional area coverage. These are mainly caused by the uneven distribution of airflow due to the low resistance in the free wall area. This design makes maintenance easier, but in reality, the reactor performance has decreased. Further improvements will be made to the reactor performance based on such a configuration through flow guidance using baffles.

Combining the advantages of high efficiency, low-pressure drop, and large throughput, the pore array-enhanced tube-in-tube microchannel (PA-TMC) is a promising microreactor for industrial applications. However, most of the mass transfer takes place in the upstream pore region, while the contribution of the downstream annulus is limited. In this work, helical wires were introduced into the annulus by adhering to the outer surface of the inner tube. Mixing behavior and mass transfer of liquid—liquid two-phase flow in PA-TMC with different helical wires have been systematically studied by a combination of experiments and volume of fluid (VOF) method. The introduction of helical wires improves the overall volumetric mass transfer coefficient K_La by up to 133% and the mass transfer efficiency E by up to 117%. The simulation results show that the helical wire brings extra phase mixing regions and increases the specific interface area, while accelerating the fluid flow and expanding the area of enhanced turbulent dissipation rate. Influences of helical wires in various configurations are compared by the comprehensive index I concerning the pressure drop and mass transfer performance simultaneously and a new correlation between K_La and specific energy consumption ϕ is proposed. This research deepens the understanding of the mixing behavior and mass transfer in the PA-TMCs and provides practical experience for the process intensification of microchannel reactors.

Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas-liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas-liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α₁ and α₂ are influenced by the viscous force. The values of pre-factors m₁ and m₂ are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.

Fault detection and diagnosis (FDD) plays a significant role in ensuring the safety and stability of chemical processes. With the development of artificial intelligence (AI) and big data technologies, data-driven approaches with excellent performance are widely used for FDD in chemical processes. However, improved predictive accuracy has often been achieved through increased model complexity, which turns models into black-box methods and causes uncertainty regarding their decisions. In this study, a causal temporal graph attention network (CTGAN) is proposed for fault diagnosis of chemical processes. A chemical causal graph is built by causal inference to represent the propagation path of faults. The attention mechanism and chemical causal graph were combined to help us notice the key variables relating to fault fluctuations. Experiments in the Tennessee Eastman (TE) process and the green ammonia (GA) process showed that CTGAN achieved high performance and good explainability.

Lignin has been proved to be a promising precursor for producing carbon foam. The thermal and chemistry properties of lignin during its thermal conversion make it quite unique comparing with other precursors, and the conversion parameters can clearly affect the properties of the derived products. Therefore, this study systematically investigated the effects of key carbonization parameters on the properties of the resulting carbon foam materials. The findings demonstrate that the performance of the self-shaping lignin-derived carbon foam is simultaneously influenced by the factors that carbonization temperature, heating rate, and carbonization duration. Specifically, the carbonization temperature and carbonization duration have a significant impact on the mechanical performance, where higher temperatures and long carbonization time improve compressive strength and specific strength. Moreover, the data revealed that elevated temperatures, rapid heating rates, and shortened carbonization periods collectively promoted the development of higher porosities and larger pore diameters within the carbon foam structure. Conversely, lower carbonization temperatures, slower heating rates, and extended carbonization durations facilitated the formation of microporous in the carbon foam. This study provides a scientific foundation for optimizing the production of lignin-derived carbon foam with tailored properties and performance characteristics.

The removal of cesium-137 (¹³⁷Cs) from nuclear wastewater remains crucial due to its radioactivity and high solubility in water, which pose serious risk to human health and the environment. Aiming at selective capture of Cs⁺ from wastewater, a core-shell adsorbent, Prussian blue analog@γ-alumina (PBA@Al₂O₃) pellets were synthesized using the hydrothermal-stepwise deposition method. The core-shell PBA@Al₂O₃ pellets showcased a PBA loading of 25% and demonstrated a maximum adsorption capacity of 15.65 mg·g^-1. The adsorption data was consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model. It effectively reduced bulk Cs⁺ concentrations from an initial 6.62 mg·L^-1 to 2 μg·L^-1, achieving a removal efficiency of 99.97% and distribution coefficient (K_d) of 1.265×10⁶ ml·g^-1, surpassing the performance of other PBA-based materials. The material also indicated good mechanical properties and cesium ion removal rates of 99.7% across a wide pH range (1.82 to 11.12). Furthermore, PBA@Al₂O₃ exhibited consistent removal rate of over 99% and good selectivity (SF=50—1600) towards Cs⁺ even in the presence of interfering ions such as Na⁺, K⁺, Mg²⁺, and Ca²⁺ ions. The K_d(Cs⁺) for PBA@Al₂O₃ in simulated seawater and groundwater were 9.92×10³ and 2.23×10⁴ ml·g^-1, where the removal rates reached 96.1% and 98.2%, respectively. XPS confirms that the adsorption mechanism is the ion exchange between Cs⁺ and K⁺ ions. This study underscores the significant potential of inorganic core-shell pellets adsorbents as promising agents for the selective capture of Cs⁺ from wastewater.

By enhancing surface interaction between metal oxide particles and carbon-based materials, it can effectively improve Faraday capacitance and conductivity, ultimately achieving high energy density with sufficient redox reactions in supercapacitors. Through a gentle biomineralization process and subsequent thermal reduction strategy, we successfully prepared the graphene oxide (GO) wrapping mixed-valence manganese oxides (MnO_x) and S, P self-codoped carbon matrix porous composite (MnO_x@SPC@reduced graphene oxide (RGO)). During the biomineralization process of engineered Pseudomonas sp. (M1) cells, GO nanosheets functioned as the ‘soil’ to adsorb Mn²⁺ ion and uniformly disperse biogenic Mn oxides (BMO). After undergoing annealing, the MnO_x nanoparticles were evenly wrapped with graphene, resulting in the creation of the MnO_x@SPC@RGO3 composite. This composite possesses strong C—O—Mn bond interfaces, numerous electroactive sites, and a uniform pore structure. By optimizing the synergistic interaction between the highly conductive graphene and the remarkable surface capacitance of MnO_x, the MnO_x@SPC@RGO3 electrode, with its intercalation Faraday reactions mechanism of Mn²⁺ ⇌ Mn³⁺ and Mn³⁺ ⇌ Mn⁴⁺ transformations, exhibits an outstanding specific capacity (448.3 F·g^-1 at 0.5 A·g^-1), multiplying performance (340.5 F·g^-1 at 10 A·g^-1), and cycling stability (93.8% retention after 5000 cycles). Moreover, the asymmetric all-solid-state supercapacitors of MnO_x@SPC@RGO3//PC exhibit an exceptional energy density of 64.8 W·h·kg^-1 and power density of 350 W·kg^-1, as well as a long lifespan with capacitance retention of 92.5% after 10000 cycles. In conclusion, the synthetic route utilizing biomineralization and thermal reduction exhibits significant potential for exploiting high-performance electrode materials in all-solid-state supercapacitor applications.

The direct oxidation of methane to methanol (DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane (LCMM) and supplying liquid fuel. Herein, the noble metals (Pt, Pd and Ru) modified Cu/alkalized sepiolite (CuX/SEPA) catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures. The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g^-1·h^-1 and methanol selectivity of 90% under the optimal reaction conditions. Various characterizations demonstrated that the addition of Ru promoted the formation of Cu²⁺ and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs, which facilitated the formation of reactive dicopper species ([Cu₂O]²⁺ or [Cu₂O₂]²⁺). Investigation of the reaction mechanism revealed that [Cu₂O]²⁺ or [Cu₂O₂]²⁺ species could adsorb and activate methane to form CH₃O* species and ultimately generated methanol with the assistance of water.

This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel production. Rubber seed oil, obtained through hexane extraction using the Soxhlet method, contains the major fatty acids of oleic acid (C_18:1), palmitic acid (C_16:0), linoleic acid (C_18:2), and stearic acid (C_18:0), while rubber seed oil primarily consists of linoleic acid (C_18:2), oleic acid (C_18:1), linolenic acid (C_18:3), palmitic acid (C_16:0), and stearic acid (C_18:0). The least acid value of lard oil (0.55 mg KOH/g) can benefit of reducing soap formation of rubber seed oil during transesterification process in biodiesel production due to its substantial-high acid value (16.28 mg KOH/g). Blending at ratios below 80:20 volume ratio produced biodiesel exceeding 85%, utilizing CaO as a catalyst. Lard oil demonstrated a higher reaction rate constant (11.88×10^-3 min^-1) than rubber seed oil (2.11×10^-3 min^-1), indicating a significant difference in performance. High acid value and free fatty acids in rubber seed oil correlated with lower reaction rates. Maintaining a mixture ratio below 80:20 volume ratio optimized reaction rates during biodiesel production. Biodiesel obtained from blends below 80:20 volume ratio met ASTM D6751 and EN 14214 standards, demonstrating suitability for bio-auto fuel. The drawbacks of using rubber seed oil as a raw material for biodiesel production are overcome by blending with lard oil, giving rise to expanding renewable energy options for rural communities, community enterprises, and large-scale biodiesel production.

Poly(4-methyl-1-pentene) hollow fiber membranes (PMP HFMs) are commonly used in gas separation membrane and artificial lung membrane in extracorporeal membrane oxygenation (ECMO), and its porous structure and mechanical properties have a significant impact on the performance of the membrane material. In our work, PMP HFMs were prepared by thermally induced phase separation method. Subsequently, through characterization analysis of powder X-ray diffraction, universal tensile machine, scanning electron microscope and other instruments, the effects of PMP concentration, diluent ratio, quenching temperature, air gap distance and winding speed on the membrane performance were systematically investigated to obtain optimal preparation conditions for PMP HFMs. The results showed that the PMP HFMs prepared under optimal conditions possessed good gas permeability with a nitrogen flux of 10.5 ml·MPa^-1·cm^-2·min^-1, a surface dense layer, and a good tensile strength of 9.33 MPa. We believed that this work could provide useful references for the application of PMP membranes in the medical field.