Municipal wastewater reuse is an essential strategy to address global water scarcity. However, its expansion is often constrained by reverse osmosis (RO) membrane scaling at high recovery. Achieving high RO recovery is critical for inland facilities to directly reduce the volume of concentrate requiring disposal. Conventional ion exchange (IX) pretreatment removes scaling ions and helps increase RO recovery, yet its reliance on chemicals produces additional salty spent regenerants that add to the RO concentrate burden, further complicating brine management challenges for inland wastewater reuse. In this study, we demonstrated a pressurized CO2-driven hybrid IX process as a sustainable pretreatment to overcome these limitations. Using real and CaSO4-enhanced secondary effluents from a municipal wastewater treatment plant, the IX system consistently removed multiple scaling ions, reduced aqueous pH, and enabled phosphorus recovery over 52 consecutive cycles with CO2 as the regenerant. Regeneration efficiency of IX materials increased systematically with CO2 partial pressure, exceeding 90% above 10 bar, and was unaffected by the presence of nitrogen and oxygen. Comprehensive PHREEQC modeling and bench-scale RO validation confirmed that the pretreatment suppressed carbonate, sulfate, and phosphate scaling due to ion removal and pH reduction. For the CaSO4-enhanced secondary effluent, RO permeate flux was stabilized for over 3 times longer duration than that without pretreatment, and the pretreatment enabled ∼90% water recovery (<30% if without pretreatment for the same water). Additionally, the process reduced reject-side osmotic pressure, thereby lowering operational energy demand. Overall, CO2-driven IX provides a multifunctional pretreatment approach for enhancing RO recovery, promoting sustainable inland wastewater reuse.

In order to explore effect of mechanical stirring and tubular heating on gel crude oil and gel-sol transition characteristics of crude oil in storage tanks, as well as the impact of gel crude oil on the overall physical fields in storage tank, in this paper, porous medium model is adopted to characterize the structural changes during crude oil gelation in storage tank, the changes in physicochemical property near abnormal point and the effect of wax crystal precipitation on the crude oil specific heat capacity during cooling process are considered. The effects of mechanical stirring and tubular heating on eliminating gel crude oil and gel-sol transition characteristics of crude oil are investigated by numerical simulation. Focusing on analyzing heat transfer and flow of crude oil, the volume variations of gel, gel-sol transitional state and sol crude oil are quantitatively compared. Results show that tubular heating only increases crude oil temperature in central region, but the effect in reducing the volume of gel crude oil near boundary of tank is minimal. Increasing heating temperature from 60 degrees C to 80 degrees C elevates average crude oil temperature by 0.71 degrees C, temperature variance by 0.76 degrees C2 and reduces volume of gel crude oil by 2.51 m3. However, increasing heating temperature does not significantly improve heat transfer characteristics or volume reduction of gel crude oil. In a short period, mechanical stirring significantly reduces gel crude oil near the boundary, with reduction being more pronounced closer to agitator. However, the overall oil temperature slightly decreases. When stirring rate is increased from 700 rpm to 1200 rpm, average crude oil temperature remains almost unchanged, both maintaining a slight downward trend, temperature variance decreases by 0.13 degrees C2 and volume reduction of gel crude oil increases by 2.66 m3. Increasing stirring rate does not significantly enhance the stirring effect but instead leads to higher energy waste. In order to eliminate gel crude oil in storage tank during a short time, the widespread use of agitators can produce obvious effects. And the applicable conditions for different engineering methods are proposed. In addition, reasonable combination of tubular heating and mechanical stirring can improve ratio of energy utilization and economic benefits.

Direct air capture (DAC) offers a geographically flexible pathway toward negative emissions, yet its large-scale deployment remains constrained by the high energy demand and operational complexity of sorbent regeneration. While substantial effort has focused on lowering regeneration temperatures, most existing DAC systems remain poorly matched to the largest and most underutilized fraction of industrial waste heat: low-grade (<100 degrees C) liquid heat streams, such as hot water. This mismatch arises because conventional sorbents are primarily designed for gas-phase or dry-state regeneration. Such processes often require vacuum operation, inert sweep gases, or repeated dehydration-rehydration cycles. Here, we systematically evaluate a direct liquid-phase DAC regeneration strategy enabled by a hybrid polymeric ligand exchanger (Poly-LigEx-Cu2+), specifically designed to operate under hydrothermal conditions at ambient pressure. The Cu(II)-chelated ligand exchanger captures CO2 predominantly as bicarbonate, exhibiting a high CO2 capacity (similar to 3-5 mol/kg) under ambient conditions (similar to 420 ppm). Over 600 consecutive sorption-desorption cycles using low-grade hot water (similar to 80 degrees C), the sorbent maintained >90% regeneration efficiency with negligible capacity loss or Cu leaching, demonstrating exceptional durability under aqueous thermal cycling. Mild steam (100 degrees C) was further examined to validate process versatility. Spectroscopic analysis and thermodynamic evaluation confirmed that the reversible bicarbonate-hydroxide chemistry enables efficient CO2 desorption under mild thermal driving forces without vacuum or inert carrier gases. Based on experimental measurements and engineering analysis, the total energy requirement was estimated to be similar to 1.4 MWh/ton CO2, including hot-water regeneration and air-handling demands. Overall, these results establish a mechanistically grounded and energy-efficient DAC pathway that is intrinsically compatible with widespread low-grade liquid waste heat, offering a scalable alternative to conventional gas-phase regeneration strategies.

In this study, the simultaneous rheology and in situ microscopy measurements, as well as the microfluidic technique, were employed to investigate the dynamic formation law of the gelled system in waxy crude oil emulsions, the mesoscopic influencing factors of gel strength, and their corresponding mechanisms under different water cuts, stirring rates, and temperature conditions. The results show that the mesoscopic structural evolution of the emulsion follows a distinct three-stage pathway: wax crystal/water droplet monomers → homogeneous/heterogeneous aggregates → wax crystal-water droplet floc structure, and each evolutionary stage corresponds to the variation of the macroscopic storage modulus. During the structural evolution, emulsified water droplets act as filling units that strengthen the interfacial connection, and their specific surface area is the primary mesoscopic parameter affecting the structural strength of the gelled system, which directly determines the scale of the oil-water interface and the interfacial interaction between wax crystals and water droplets. Wax crystals constitute the continuous network skeleton of the gelled system, and their quantity governs the compactness and continuity of the three-dimensional floc structure, playing a more dominant role in the macroscopic gel strength. Individual regulation of either the specific surface area of water droplets or the quantity of wax crystals can significantly alter the gel strength of the system. The simultaneous optimization of the two parameters produces an obvious synergistic strengthening effect, leading to an exponential rise in gel strength; conversely, the rheological properties of the emulsion can be remarkably improved. The dual-phase synergistic enhancement and weakening model proposed from a topological perspective clarifies that the "small and abundant" mesoscopic morphology featured by high-specific-surface-area water droplets and a large number of wax crystals is the core cause for the strengthened gel structure and deteriorated rheological properties of the emulsion. This model can systematically explain the influence mechanisms of various working conditions on the gel strength of water-in-oil (W/O) waxy crude oil emulsions. The conclusions of this research are well applicable to waxy crude oil emulsions characterized by high saturates, low aromatics, and low heavy polar components, and can provide theoretical references for the rheological regulation and pipeline transportation optimization of waxy crude oil emulsions.

The trend toward concentrated animal feeding operations (CAFOs) has served to concentrate not only livestock animals but the waste they produce to comparatively smaller areas. The point-source nature of this waste is an opportunity for the recovery and valorization of the nitrogen therein. Such a process would be viable on small to intermediate scales and require minimal inputs at the CAFO. In this study, we demonstrate the potential of the biopolymer cyanophycin to serve as a medium for manure-nitrogen recovery. In the first step, genetically modified strains of Escherichia coli produce intracellular cyanophycin from mock manure hydrolysates. Next, cyanophycin is recovered from microbial biomass via acid solubilization and base precipitation using electrochemically generated acids and bases. Finally, to improve both the yield and recoverable fraction of cyanophycin produced, we leverage the tunability of our genetically engineered system to probe the impacts of cyanophycin synthetase solubility, N-domain activity, and cyanophycin molecular weight on cyanophycin recoverability. Collectively, this work serves as a proof of concept for nitrogen recovery from agricultural waste, aligning with global sustainability initiatives. One sentence summary Mock manure-derived substrates can be converted to cyanophycin and recovered, supporting the feasibility of nitrogen recovery at potentially decentralized sites of waste production.

This study aims to address low-temperature dead zones and uneven heating in traditional tubular heating systems of crude oil storage tanks by proposing an optimization scheme based on flow impingement for enhanced heat transfer, involving a newly designed heating tube combined with mechanical stirring. The effects of agitator deflection angle and number on the tank's physical field were investigated. A three-dimensional transient numerical model coupling fluid flow and heat transfer was developed using the finite volume method and turbulence model, and its reliability was verified through scaled experiments. Results show that with only tube-type heaters, flow inside the tank is extremely weak, leading to extensive low-temperature dead zones at the bottom and highly uneven temperature distribution. Introducing mechanical stirring significantly alters the flow field, and forced convection effectively enhances heat transfer. When the new heating tube is combined with an agitator at a 45 degrees deflection angle, the impact flow spatially matches the core heating area, carrying high temperature crude oil to cover most of the bottom and eliminating most low-temperature dead zones, consistent with experimental observations. This configuration achieves a heating efficiency of 81.07% and also helps reduce bottom sedimentation. Increasing the number of agitators further improves heating efficiency and temperature uniformity in the central region of large tanks. Comprehensive energy consumption analysis indicates that this scheme has the lowest energy consumption per unit temperature rise, saving approximately 7.6% energy compared to traditional without agitation configurations. These findings provide a reference for optimizing heating technology in crude oil storage tanks.

In this study, the simultaneous rheology and in situ microscopy measurements, as well as the microfluidic technique, were employed to investigate the dynamic formation law of the gelled system in waxy crude oil emulsions, the mesoscopic influencing factors of gel strength, and their corresponding mechanisms under different water cuts, stirring rates, and temperature conditions. The results show that the mesoscopic structural evolution of the emulsion follows a distinct three-stage pathway: wax crystal/water droplet monomers -> homogeneous/heterogeneous aggregates -> wax crystal-water droplet floc structure, and each evolutionary stage corresponds to the variation of the macroscopic storage modulus. During the structural evolution, emulsified water droplets act as filling units that strengthen the interfacial connection, and their specific surface area is the primary mesoscopic parameter affecting the structural strength of the gelled system, which directly determines the scale of the oil-water interface and the interfacial interaction between wax crystals and water droplets. Wax crystals constitute the continuous network skeleton of the gelled system, and their quantity governs the compactness and continuity of the three-dimensional floc structure, playing a more dominant role in the macroscopic gel strength. Individual regulation of either the specific surface area of water droplets or the quantity of wax crystals can significantly alter the gel strength of the system. The simultaneous optimization of the two parameters produces an obvious synergistic strengthening effect, leading to an exponential rise in gel strength; conversely, the rheological properties of the emulsion can be remarkably improved. The dual-phase synergistic enhancement and weakening model proposed from a topological perspective clarifies that the "small and abundant" mesoscopic morphology featured by high-specific-surface-area water droplets and a large number of wax crystals is the core cause for the strengthened gel structure and deteriorated rheological properties of the emulsion. This model can systematically explain the influence mechanisms of various working conditions on the gel strength of water-in-oil (W/O) waxy crude oil emulsions. The conclusions of this research are well applicable to waxy crude oil emulsions characterized by high saturates, low aromatics, and low heavy polar components, and can provide theoretical references for the rheological regulation and pipeline transportation optimization of waxy crude oil emulsions.

Abstract To address the issues of extensive low-temperature dead zones and insufficient gelled-oil conversion efficiency associated with traditional heating methods in waxy crude oil storage tanks, this study proposes an improved scheme coupling localized concentrated heating with mechanical agitation at a specific deflection angle (45°). Distinct from previous passive heat transfer approaches that solely focus on improving the geometric structure of heating elements, this work reveals the mechanism of “spatial synergistic matching between flow paths and localized fixed heat sources.” By introducing an inclined impinging flow, the mechanical scouring and stripping effects of the fluid on the gelled oil at the side wall are enhanced, breaking the thermal resistance barrier formed by the extremely low thermal conductivity of the crude oil gel layer. This mechanism is systematically demonstrated by establishing a broad-temperature-range mathematical model that characterizes the nonlinear thermophysical property variations during the gel–sol transition of waxy crude oil, combined with computational fluid dynamics simulations and laboratory-scale experiments. Field synergy analysis confirms that, under the 45° deflection condition, the proportion of regions with a synergy angle below 90° reaches 19.41%, significantly improving the coordination between the velocity field and the temperature gradient field. Benefiting from this synergistic effect and the intense wall scouring, the gelled crude oil achieves nearly complete sol-state conversion within 4 h, with the final conversion rate leaping to 99.75%, overcoming the disadvantages of standalone tubular heating, which yields a conversion rate of less than 35% and severe edge accumulation. Furthermore, compared to traditional global heating, the novel coupled process reduces the energy consumption per unit temperature rise by 12.78%. This study provides a new theoretical perspective and engineering guidance for energy conservation and solidification response strategies in high-pour-point crude oil storage and transportation systems.

Traditional tubular heating systems using water as the heat transfer fluid suffer from high energy consumption and uneven heating. This study proposes an innovative approach: employing nanofluids as a novel heat transfer fluid and developing a comprehensive numerical model capable of accurately describing the complex gel-sol transition behavior of waxy crude oil. The model characterizes the temperature-dependent viscosity of waxy crude oil using a hybrid Arrhenius + power law + Herschel-Bulkley model, accounts for phase change latent heat through the apparent heat capacity method, and calculates the thermal conductivity of waxy crude oil in different states using a weighted average method. Focusing on a floating roof tank equipped with a tubular heating system, nanofluids were prepared in-house and an indoor experimental system was constructed. The study investigated the temperature field, flow field, and gel-sol transition behavior of waxy crude oil during the tubular heating process within a small-scale model. Results indicated a relative deviation between experimental and simulation data within 4.61%. The findings demonstrated that CuO-water nanofluid significantly enhanced heating efficiency: it increased the heating rate of crude oil at the model bottom by 32% and at the top by 25%, reduced the thermal lag time by 15%, decreased the radial temperature difference by 1.2 °C, and accelerated the transition of crude oil from gel state through an intermediate state to sol state. Experiments also show that nanofluids exhibit significant heat transfer enhancement for crude oils with different properties, demonstrating good universality. Subsequently, the validated model and algorithm were employed to simulate the heating process in an actual size storage tank using different nanofluids. The simulations revealed the synergistic heat transfer enhancement mechanism of the nanofluid. Benefiting from superior thermal conductivity and a moderate specific heat capacity, it retards its own temperature drop and thins the thermal boundary layer inside the tube (CuO-water nanofluid reduced the thickness by 25%), and enhanced natural convection outside the tubes, achieving synergistic heat transfer enhancement on both sides. CuO-water nanofluid exhibited the best heat transfer enhancement performance. Although it did not alter the macroscopic structure of the temperature field, it increased the average heating rate of the crude oil by 16%, improved heating efficiency by 3.88%, and is projected to reduce heating energy consumption by 3.1% and carbon emissions by 4.9%. Simulations further reveal that optimized heating tube layout combined with nanofluids yields a synergistic enhancement effect, further elevating the overall tank temperature and reducing the low-temperature zone.This study provides not only a validated optimization methodology but also delivers fundamental insights and a theoretical framework for the technological innovation of tank heating systems. Furthermore, it extends the application of nanofluid-enhanced heat transfer technology to media including crude oil, which exhibits a range of rheological properties from Newtonian to non-Newtonian behavior, thereby broadening its scope of engineering applications.

The hybrid Subtractive-Laser Cladding shows great potential for repairing and enhancing the wear resistance of low-alloy high-strength steel (LAHSS) to prolong its operational life. LAHSS has a nominal service life of 1000 h, with a wear rate limited to 0.00528 & micro;m/s under a safe wear depth threshold of 1.9 mm. To evaluate the tribological performance of laser-directed energy deposition (L-DED)-repaired structures, two distinct wear testing protocols, e.g., a 300 s interval wear test repeated six times (cumulative damage duration: 1800 s) and a continuous 1800 s wear trial, were implemented. This work investigated the use of Fe-Cr-Ni as a fill material for repairing 16Mn through subtractive and additive hybrid method, focusing on the room-temperature dry intermittent wear properties of the repair samples. Post-manufacturing, the Fe-Cr-Ni alloy comprised y, & ouml;, and M23C6carbides with a well-bonded interface. Microstructural features varied across regions: near-interface (planar and cellular, 7.25 +/- 3.89 & micro;m), middle (columnar and dendritic, 1.17 +/- 0.59 & micro;m), core (equiaxed dendritic, 1.27 +/- 0.53 & micro;m), and heat-affected zone (HAZ)(lower bainite, ferrite, pearlite). Microhardness differed among substrates, HAZ, and L-DEDed layer. The coefficient of friction showed distinct patterns over 300 s and 1800 s intervals. Wear loss rates varied, with the disc and substrate having relatively higher rates compared to the Si3N4 side, and ejection contributions differed across intervals. Over six wear intervals, the L-DEDed region and substrate exhibited different wear depth and increment trends, with the |lg(Wdepth/Thickness)| metric indicating distinct degradation behaviors. The substrate maintained stable mixed wear, while the L-DEDed region shifted to pure abrasion due to thermal degradation, showing specific wear-related phenomena.

Nitrate (NO3-) persistence in water poses severe ecological and health risks. Electrochemical reduction of nitrate to ammonia (ENRA) offers a promising route for simultaneous nitrate remediation and ammonia (NH3) production. Nevertheless, its real-world application is hindered by cathode fouling, energy inefficiency, and poor performance in complex water matrices. Nitrate-selective anion exchange resins (NAERs) effectively separate and enrich nitrate from complex water, which may mitigate inorganic scaling and boost energy efficiency of ENRA, yet require chemical regeneration with substantial reagent consumption. To address these issues, we developed a hybrid innovative extraction-electrocatalysis-recovery-system (EERS) that integrates ENRA with NAERs. In simulated wastewater, EERS maintained a stable nitrate desorption efficiency of 76.5 ± 1.3% over three cycles, markedly outperforming chemical regeneration, which declined from 73.5 to 56.2%. In real nitrate-polluted groundwater, EERS achieved ∼9.5-fold nitrate enrichment and a NO3- removal efficiency of 86-100% over three cycles. Moreover, EERS yielded >900 mg L-1 ammonia over each cycle. Notably, the integrated system minimizes reagent consumption by enabling continuous desorbent regeneration and electrochemical conversion, substantially reducing chemical demand and on-site storage requirements. Lastly, we confirmed the structural integrity of the resin and the Cu2O@CF electrode, validating EERS's robustness in complex aqueous environments. These results demonstrate a scalable and sustainable platform for decentralized nitrate remediation with ammonia production in real water systems.

This study investigates multiphase flow and crude oil adhesion in near-wellbore pipelines during mechanical recovery, using a visual experimental setup to analyze water blending mechanisms. A composite constitutive equation and a VOF-based multiphase flow model were developed to describe crude oil rheology during the sol-gel transition and to track phase distribution and velocity field changes over a pump stroke cycle. Results show that periodic pump operation induces significant unsteady flow. The oil phase evolves sequentially from a continuous layer into segmented layers, elongated masses, discrete aggregates, and fine droplets, forming strip-like, block-like, spot-like, and dispersed film-like adhesion structures. Water blending improves flow through multiple pathways: it entrains and dilutes the oil phase, disrupting continuity and reducing viscosity. Doubling the blending volume reduces the gelled oil adhesion area by 39.5%. It also maintains flow continuity, lowering the gelled oil adhesion growth rate by 30.7%. Increased flow velocity enhances wall shear stress, detaching gelled oil and reducing its volume fraction from 1.9% to 0.65%. A 5°C rise in blending temperature reduces crude oil viscosity by about 20% and the gelled oil adhesion growth rate by 12.5%. Water blending alleviates gas blockage, reducing its volume from 25.8% to 13.5% and cutting the gelled oil adhesion rate by 51.9%. Local high-water-cut pulses and enhanced shear further suppress deposition. In summary, water blending mitigates adhesion through dilution, flow continuity, shear enhancement, and temperature effects, significantly improving pipeline safety and efficiency.

Jet heating is a widely employed technique for waxy crude oil storage tanks. To enhance heating efficiency and promote efficient gel-sol transition of gelled crude oil, this study optimizes jet heater nozzle structures, taking a 1000 m3 floating roof crude oil tank as the research object. First, wide-temperature-range mathematical characterization of waxy crude oil's physical property changes during gel-sol transition is conducted. Then, the finite volume method is adopted to numerically simulate the heat transfer, flow behavior and phase transition during jet heating with four nozzle structures (conical, baffle-type, double-head, multi-orifice) under uniform and non-uniform initial temperature fields. Results indicate that the high-speed low-temperature jet outperforms high-temperature low-speed condition, with the double-head nozzle achieving the highest in-tank average temperature rise rate of 0.97 °C/h. Under non-uniform initial field (initial gelled oil 15.2 m3, 2.7% of tank volume), the baffle-type nozzle reaches 86.1% gelled oil melting rate within 30 s, the fastest among all nozzles. In terms of energy efficiency and low-carbon performance, however, the double-head nozzle presents the highest heating efficiency (89.8%) and the lowest carbon emission per unit effective temperature rise (110.88 kg/°C).Comprehensive evaluation indicates that the double-head nozzle is the optimal scheme, realizing uniform tank heating while reducing operation energy consumption and carbon emissions.

As a promising new energy storage device, low-temperature adaptability and slow reaction kinetics have become a restriction to flexible zinc-air batteries (FZABs) serviced in extreme environments. The research on electrocatalysts rich in oxygen vacancies (OV) to drive low-temperature FZAB performance still faces significant challenges. Developing high-entropy spinel oxides (HESOs) rich in OV is critical to improving the low-temperature FZAB performance. Herein, (FeCrCuNiMn)3O4 is synthesized using a five-metal element via a hydrothermal calcination method and loaded with three-dimensional graphene (3D-G), revealing the key role of OV in synergistically enhancing the performance of FZABs through dual active sites and interfacial charge transfer to drive electrocatalysis. The prepared electrocatalysts exhibit enhanced oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalytic activity, which drives FZABs at -25 degrees C, with a peak power density of up to 60.1 mW cm-2, a stable voltage gap of 0.74 V, and remarkable low-temperature cycling stability. This work effectively solves the low-temperature limitations of the FZABs by using a high-entropy strategy to improve the ORR/OER, providing a new approach for advanced green and sustainable energy conversion and storage.

Adsorption presents an interesting alternative to traditional phosphorus removal technologies because it excels at achieving low levels of phosphorus (P). One leading adsorption technology is called HAIX (Hybrid Anion Exchanger) and is made from ferric oxide nanoparticles impregnated in a strong base anion exchange resin. This adsorption media, marketed as FerrIX A33E, offers great performance in terms of P removal, but requires substantial quantities of sodium hydroxide (NaOH) and sodium chloride (NaCl) to regenerate. A new version of HAIX (named WBA-2) was previously synthesized using a weak base anionic resin. It showed better regeneration abilities under lower concentrations of NaOH and no NaCl. In this study, breakthrough curves of WBA-2 and FerrIX were compared over three adsorption/regeneration cycles with 0.1 M NaOH as the regenerant solution. FerrIX was able to treat 1630 bed volumes in the first cycle, but only managed to treat 800 bed volumes in the third cycle. WBA-2 was able to keep its full treatment capacity with 1470 bed volumes treated in the first cycle and 1500 for the third. To push the regeneration efficiency of WBA-2 even further, its regeneration was evaluated at 24 degrees C, 50 degrees C and 80 degrees C. Higher temperature during regeneration yielded higher performance with 79 %, 85 % and 91 % +/- 1 % of regeneration efficiency for the three temperatures in increasing order. Finally, this study discusses the possibility of using onsite electrolysis to provide the consumables needed for the regeneration of HAIX, and demonstrates how using higher temperatures during electrolysis and regeneration of HAIX can improve overall operational performance.

The emerging use of ion exchange for resource recovery has repositioned spent regenerant from "waste" to the desired "product". This transition requires a high purity regenerant for pure product recovery (e.g., ammonium recovery from urine) because the long-lasting direct contact regeneration directly mixes the eluted target ions with the regenerant. Direct contact regeneration prevents using impure regenerants such as electrochemically produced acid (containing electrolyte salts) from making a pure product, hindering the advancement of electrified ammonium recovery via ion exchange. We demonstrated a new concept of indirect contact regeneration leveraging the "proton leakage" from an anion exchange membrane to achieve tandem proton separation and resin regeneration, which enabled the recovery of pure ammonium by an impure acid. A weak acid cation exchange resin enabled multicycles over 80% regeneration efficiency by the limited proton leakage from mild acids with pH 2-3. Investigating the effects of acid purity, pH, and resin dosage revealed the critical role of aqueous pH and the dynamic balance of proton leakage and consumption in governing regeneration efficiency and kinetics. Critical insights on salt types and target pH were provided to minimize the trade-off between electrochemical acid production energy and regeneration efficiency.

This paper focuses on the static cooling process for waxy crude oil stored in dome roof tanks. For the three phases of gas on top, liquid crude oil, and bottom water in storage tank, the VOF method is used to describe the evolution of physical quantities at the "oil-water"/"oil-gas" interface. The porous medium method is used to quantitatively characterize the sol-gel conversion process for waxy crude oil. A physical and mathematical models are established to describe the flow-heat transfer coupling behavior of the three-phase medium of crude oil, gas on top, and water at the bottom of the dome roof tank. In terms of the overall cooling process,The gas at the top of the tank has the simplest and fastest physical field evolution. It has the most uneven distribution (average temperature variance of 4 degrees C2), the strongest flow (average flow velocity of 0.4 m/s), the highest cooling rate (0.632 degrees C/h), and the lowest temperature (14.84 degrees C at the end). Its physical field is influenced by both the atmosphere and crude oil. The evolution of the physical field of crude oil is the most complex. It lags behind the gas at the top of tank and is directly effectted by it. Based on the evolution characteristics of the flow field of crude oil, the cooling process is divided into three stages: Stage I (0---10 h) is the stage of convection generation and evolution in the crude oil region; Stage II (10 h - 34 h) is the stage of convection stability in the crude oil region; Stage III (after 35 h) is the stage of flow field transformation of crude oil. In stages I and II, the flow and momentum exchange at the oil-gas interface are significant. Crude oil is jointly influenced by the natural convection of the gas at the top of the tank and its own natural convection, forming a counterclockwise large vortex structure. The low-temperature area is near the central axis boundary of storage tank, oil-gas interface, and tank wall. The high-temperature area is within a range of 0.1 m - 3.3 m from the tank wall. After entering stage III, the flow and momentum exchange at the oil-gas interface weaken. The flow field of crude oil is only controlled by its own natural convection and transforms into a clockwise large vortex dominated. The lowtemperature area is concentrated in the enclosed area of "oil-gas interface - tank wall" and "oil-water interface - tank wall". The temperature field changes accordingly. Eventually, the high-temperature area is concentrated in the area slightly above the center of the tank. The physical field evolution of bottom water lags behind crude oil and is most unstable. Its cooling rate is 0.164 degrees C/h, slightly higher than crude oil's 0.157 degrees C/h. The temperature is always slightly lower (33.47 degrees C at the end), and the physical field is the most uniform (average temperature variance of 0.0003 degrees C2), affected by the tank bottom environment and liquid crude oil.

Perovskite and spinel oxides are promising non-precious metal catalysts for the oxygen reduction and evolution reactions (ORR/OER). In this work, a LaNiO3/FeCo2O4 composite catalyst is synthesized via a two-step sol-gel and hydrothermal method. The catalyst exhibits a high specific surface area (51.66 m(2) g(-1)) and excellent bifunctional catalytic activity. Its OER activity (overpotential of 339 mV) surpasses that of commercial RuO2, while the ORR performance is 1.89 and 2.37 times greater than that of pristine LaNiO3 and FeCo2O4, respectively. When applied in Zn-air batteries, it delivers superior open-circuit voltage (similar to 1.54 V), energy density (877 Wh.kg(-1)), and cycling stability (>650 h) compared with Pt/C + RuO2. Experimental and DFT analyses indicate that enhanced performance arises from optimized e(g) orbital occupancy, abundant redox couples, and increased oxygen vacancy concentration, which together facilitate oxygen intermediate adsorption and activate the lattice oxygen mechanism (LOM). This work provides an effective strategy for rational design of perovskite/spinel nanocomposite catalysts.

By using the Volume of Fluid (VOF) method to capture the phase interface, the porous media method to characterize the gelling structure of waxy crude oil, the physical and mathematical models have been constructed to simulate the tubular heating process in a vault tank where gas, crude oil and bottom water coexist. The finite volume method were used to obtain insights into heat transfer behaviors and interphase interactions during the heating process. It is found that the tubular heating process can be categorized into three stages: (R) Thermal diffusion stage, (R) Global thermal response stage and (R) Stable heating stage. During the thermal diffusion stage, the crude oil in proximity to the heating tube undergoes initial heating, creating a thermal response zone. Subsequently, heat is progressively transferred through a plume - like pathway consisting of the "heating tube -* tank wall -* tank top -* tank center -* the oil - water interface -* heating tube". The gas at the top of the tank is minimally influenced by the heating tube and continuous heat dissipation to the surroundings results in rapid cooling initially at a rate of 8.54 degrees C/h, followed by a slower cooling rate of 0.88 degrees C/h. The bottom water exhibits an evident lag behind crude oil, experiencing a brief period of cooling for 35 min before rapidly heating up at a rate of 0.44 degrees C/h. During the global thermal response stage, the vortex structure in the crude oil region continues to expand, exerting an increasing influence on both the oil - gas and oil - water interfaces. The entire heat transfer process propagate across different regions, leading to a gradual reduction in temperature differences between these regions. The most significant rise observed in proximity to the original cold oil gathering position, which contributes to an increasingly uniform temperature distribution within the crude oil region. The gas region exhibits a rapid temperature rise of 29.2 degrees C/h, followed by a tendency towards stabilization. A dual vortex structure forms in the water region. After reaching the stable heating stage, the crude oil maintaining a higher temperature and consistently maintaining a stable temperature difference of 0.06 degrees C compared to the bottom water. The temperature of gas region exhibits stability after a slight decrease.