Mineral carbonation is a promising carbon capture, utilization, and storage (CCUS) pathway because it permanently converts CO₂ into thermodynamically stable carbonate minerals while enabling valorization of alkaline industrial residues. Although many studies have examined carbonation chemistry and feedstock reactivity, less attention has been given to reactor configuration and its role in overcoming mass-transfer limitations during scale-up. This review critically evaluates slurry bubble column reactors (SBCRs) as gas–liquid–solid platforms for CO₂ mineralization and scalable carbon sequestration. SBCRs are compared with fixed-bed, fluidized-bed, flow-through, and rotating packed-bed reactors, emphasizing differences in contacting efficiency, operational complexity, solids handling, and scalability. The carbonation performance of fly ash, steel slag, calcium carbide slag, cement and concrete waste, red mud, and lithium-bearing materials is then assessed with focus on how feedstock properties interact with reactor operation. The review shows that carbonation performance depends not only on intrinsic feedstock reactivity but also on gas–liquid–solid contact, CO₂ transfer, particle suspension, and hydrodynamic behavior. Emerging concepts, including microbubble-assisted carbonation and electrochemical mineralization, are discussed as process-intensification pathways. Finally, scale-up challenges related to hydrodynamics, fouling, solids handling, and performance evaluation are identified, highlighting SBCRs as promising reactors for industrial CO₂ mineralization using alkaline residues under practical and scalable operating conditions.
Managing hyperphosphatemia in chronic kidney disease (CKD) and tumor lysis syndrome (TLS) remains challenging due to the kinetic mismatch between rapid dialytic extraction and slow intracellular phosphate mobilization. This study presents the fabrication, characterization, and computational optimization of a lanthanum-doped poly(vinyl alcohol)/chitosan (PVA/CS 315-La) hydrogel film in a microscale continuous-flow device for phosphate capture. Lanthanum-bearing nanoparticles transformed the hydrogel from an isotropic sponge to a dense, aligned fibrous architecture dose-dependently. Characterization indicated lanthanum entrapment without disrupting the network. In dynamic in vitro flow, the lanthanum-functionalized hydrogel (PVA/CS 315-La5) achieved 42.9% phosphate removal (1.47 to 0.84 ± 0.12 mM). Response Surface Methodology (RSM) mapped the coupled effects of flow rate, active site density (Sads), and intra-gel diffusivity (Di,gel) on phosphate depletion time. The validated quadratic model (R² = 0.9957) identified an optimal configuration of 6.05 mL/min flow rate and Sads of 962.6 mol/m³ as the mathematical optimum for 36-hour depletion; however, long-duration sensitivity analysis identified a narrower practical window of Sads ≈ 150–200 mol/m³ at the same flow rate as favorable for a gradual, monotonic clearance profile, avoiding the early quasi-burst extraction observed at higher loadings. These findings establish an integrated framework linking sorbent chemistry, device hydrodynamics, and computational optimization for designing continuous sorbent-based phosphate capture devices.
The top-fired heating furnace serves as critical thermal equipment in the oil shale refining process. Conventional top-fired furnaces typically suffer from unsatisfactory in-furnace temperature uniformity and excessive NOₓ emissions, resulting in inevitable environmental pollution. To enhance the comprehensive combustion performance and mitigate NOₓ pollution, this study proposes a modified top-fired heating furnace configuration, in which the conventional side-mounted gas and air nozzles are rearranged to a top-jet layout. By adopting an orthogonal experimental scheme L16(43), this work systematically investigates the influencing levels of three key structural parameters—air nozzle number (A), gas nozzle number (B), and air nozzle inclination angle (C)—on four combustion evaluation indicators: maximum combustion temperature, average combustion temperature, NOₓ emission concentration, and flue gas heat output. Range and variance analyses are employed to quantify the relative significance of each parameter. The results indicate that the air nozzle number exerts a significant effect on both the maximum cross-sectional temperature and the furnace outlet NOₓ concentration, whereas the gas nozzle number and air nozzle inclination angle produce only insignificant influences. Benefiting from the improved structural design, the NOₓ emission concentration of the novel top-fired heating furnace is reduced to below 50 mg/Nm³ across all 16 tested cases. The parametric trends identified provide directional guidance for nozzle structure improvements within the investigated parameter ranges; the methodology can be readily extended to other furnace configurations, though quantitative conclusions should be revalidated for substantially different design conditions.
Aqueous carbonation of coal fly ash (CFA) has been widely studied for CO2 utilisation, yet its governing limitations remain unclear. This review demonstrates that carbonation performance is controlled by the accessibility of reactive Ca-bearing phases rather than total Ca content or process severity. Carbonation proceeds via a dissolution–precipitation mechanism, in which Ca²⁺ release from accessible phases governs carbonate formation, while progressive passivation limits further reaction. A synthesis of experimental data shows that CO₂ uptake spans a broad range (∼3–196 g-CO2/kg-CFA), reflecting differences in Ca accessibility and reaction extent. Under low-severity conditions, low-Ca CFAs typically exhibit limited uptake (∼19–23 g-CO2/kg), whereas medium- and high-Ca systems display wider variability (∼10–130 g CO2/kg). Higher values are observed only under intensified conditions, but these primarily reflect extended reaction toward the intrinsic carbonation ceiling rather than an increase in the ceiling itself. Carbonation also alters material functionality, shifting CFA from a partially reactive supplementary cementitious material to a predominantly inert or weakly reactive filler. Future progress requires a shift from severity-driven optimisation toward accessibility-driven strategies that enhance reactive Ca availability and align carbonation processes with practical material applications.
The efficiency of mini-micro reactors is often associated with the intensification of transfer processes. The small dimensions of channels and liquid films lead to strong suppression of natural convection and a decrease in reaction rates. Increasing the rate of mixing of two liquids in intersecting microchannels requires high temperatures and heat fluxes, which causes technological challenges. In this work, the mixing of two liquids when a droplet of alcohol falls into a layer of water is experimentally investigated. We propose a new method for significantly intensifying liquid mixing by using rectilinear and curvilinear laser beam movement (continuous movement of the heating point). The movement of a local heating point leads to increased Marangoni convection. The change in the vortex convection pattern over time leads to an increase in heat and mass transfer by 30-40% and a reduction in the mixing time of the liquids compared to a stationary laser beam. The fall of a alcohol droplet into a water layer and the presence of local heating leads to a 60-fold reduction in mixing time, compared to mixing without heating and without alcohol (a colored falling droplet of water).
‘Nanobrachytherapy’ is emerging as an attractive avenue for cancer treatment. In our effort toward developing potent radiolabeled inorganic biomaterials for nanobrachytherapy, we report preparation and evaluation of a single-vial ‘cold kit’ of glucuronic acid-functionalized hydroxyapatite nanoparticles (GAHAnp) for efficient one-step radiolabeling using a plethora of therapeutic radiometals (177Lu, 169Yb, 161Tb, 153Sm and 90Y) having particulate emission with broad tissue penetration range. This approach allowed flexibility in selecting the appropriate radiometal for personalized treatment using a single nanoplatform and ensured reproducibility in achieving high radiolabeling yield. Radiolabeling of GAHAnp with all the radiometals using the cold kit resulted >99% radiochemical purity. The cold kits were found to be useful for preparation of radiolabeled formulations upto six months from the date of manufacturing. Pre-clinical investigations of [177Lu]Lu-GAHAnp in animal model showed excellent retention of the formulation in the tumor. The same formulation was injected intra-tumorally in one female patient suffering from breast cancer and monitored by acquiring SPECT images upto 24 h. The results showed near-complete retention of the formulation in the tumor site. Overall, this study demonstrated that cold kit of GAHAnp can be effectively used for radiolabeling a variety of radiometals, providing a versatile platform for delivering localized radiation therapy.
Waterborne pathogens remain a major public health challenge because of their association with gastrointestinal illness and fatal outcomes. Their detection requires rapid, specific, portable, easy-to-use, and reliable platforms, making microfluidic biosensing a promising strategy. Here, we present a centrifugal microfluidic device that, guided by lumped-element computational modeling, integrates a passive elastic membrane-assisted reciprocating mechanism with a PAMAM dendrimer-aptamer-functionalized PDMS interface for E. coli O157:H7 detection. The model guided device design and evaluated the effects of membrane and fluidic parameters on reciprocation, showing good agreement with experimental liquid reciprocation at 30 rpm/s, with a maximum error of 6.76% and a 1.25 mm deviation in liquid-front position. FTIR analysis supported stepwise PDMS modification with APTMS, PAMAM dendrimers, and DNA aptamers. Using mRuby-expressing E. coli O157:H7 as a viable-cell fluorescence model, bacterial capture increased at lower angular acceleration and with repeated reciprocation. The highest fluorescence response occurred at 1 rpm/s after three cycles, with signal intensity strongly correlated with cycle number (R² = 0.997). The platform detected E. coli O157:H7 with a calculated limit of detection of 8.14 × 10³ CFU/mL. These results demonstrate reciprocation-enhanced whole-cell capture and support future pathogen detection applications in water-quality monitoring.
Curved hydrocyclones are promising for multistage separation, but the coupled effects of structural sequence and split-ratio allocation remain unclear. A spline-curved-cone hydrocyclone (H1) and a Bezier-curved-cone hydrocyclone (H2) were arranged into four two-stage configurations. Response surface models for separation efficiency (η) and pressure drop (Pd) were developed using a Box-Behnken design and optimized using NSGA-II/TOPSIS. A simplified mechanistic framework based on mass balance, two-stage efficiency composition, and hydraulic energy dissipation was introduced to interpret sequence and split-ratio effects. Experiments used hollow glass microspheres (density: 0.80–0.84 g/cm³) dispersed in water (density: ∼1.0 g/cm³) at 250 mg/L, with inlet flow rates of 0.5–1.5 m³/h and stage-wise overflow split ratios (S1 and S2) of 5–15%. S1 exerted a stronger influence on η than S2. H1-H2 achieved higher η than H2-H1 but incurred a higher Pd, confirming a sequence effect. H1-H1 achieved the highest η, H2-H2 minimized Pd, and H1-H2 provided the best overall trade-off. Compared with baseline conditions, TOPSIS compromise solutions increased η by 2–19% while reducing Pd by 75–78%. Relative to Pareto extreme-efficiency solutions, they reduced Pd by 87–90% with a 24–28% reduction in η. These findings provide practical guidance for optimizing two-stage curved-hydrocyclone systems for relevant environmental separation and water-treatment applications.
Widespread presence of the caffeine derivatives in aquatic environment poses a high environmental and health risks due to its persistence and partial removal in conventional treatment processes. This study investigated the degradation of caffeine by electrooxidation in a novel Inclined Electrode Reactor (IER) under varying initial conditions of pH (3-9.5), caffeine concentration (4-20 mg/L), NaCl dosage (50-250 mg/L), and current density (1-5 mA/cm2). Optimal degradation efficiency up to 95.2 ±2.93% was achieved at pH 3, 150 mg/L NaCl, and 5 mA/cm² within 60 min in deionised water. Acidic conditions favoured the stability of reactive chlorine species (HOCl), while elevated pH levels reduced efficiency due to less effective oxidant speciation. A lower pollutant load improved degradation kinetics, whereas higher concentration led to oxidant competition. Initial electrolyte concentration of 150 mg/L NaCl balanced oxidants generated and side reactions. Increasing current density resulted in faster degradation but raised energy consumption, indicating a compromise between efficiency and cost. Further, application to sewage wastewater achieved >95% caffeine removal and a up to 85% in COD removal, demonstrating robustness against matrix interference. Specific energy consumption ranged from 1.42-12.49 kWh/m3, lowest under optimal conditions. The IER showed stable operation with minimal electrode fouling, confirming its potential for scalable, energy-efficient degradation of emerging contaminants in complex wastewater.
Pyruvic acid is an important α-keto acid with broad applications in pharmaceuticals, food, and agrochemicals, yet its recovery from aqueous media remains challenging due to high solubility, instability, and polymerization. Reactive extraction offers a selective, energy-efficient alternative to conventional separations, relying on reversible acid–base complexation with tertiary amines. In this study, the recovery of pyruvic acid was investigated using tri-n-octylamine (TOA) in four diluents 1-octanol, ethyl hexanol, nitrobenzene, and isoamyl alcohol. Distribution coefficients, extraction efficiencies, and equilibrium complexation constants were determined across varying initial acid concentrations (0.02–0.8 kmol/m³) and extractant concentrations (0.1–0.5 kmol/m³). TOA-isoamyl alcohol exhibited the highest extraction efficiency (99.74%) and complexation strength, outperforming other diluents and physical extraction. Comparative analysis demonstrates the critical role of diluent polarity and hydrogen-bonding capacity in stabilizing acid amine complexes. These results provide new insights for solvent selection and reinforce reactive extraction as a robust downstream strategy for efficient pyruvic acid recovery.
A semi-analytical formulation is developed for the periodically driven electromagnetohydrodynamic (EMHD) flow, heat transfer, and entropy generation of a water-Al2O3 Jeffrey nanofluid in a porous circular microchannel. The axial velocity is obtained from the Jeffrey momentum equation, whereas the effective temperature response is evaluated through a Green’s function representation and numerical quadrature. In the steady Newtonian limit, the velocity solution agrees with the analytical result reported in Ref. Zhao et al. (2019), with discrepancies at the level of double-precision round-off. The relaxation and retardation Deborah numbers produce opposite radial redistributions of the velocity. Increasing De1 lowers the velocity in the central region but raises it in the outer radial region, whereas De2 produces the reverse response. Under the conditions examined, a larger De1 makes the wall-referenced dimensionless temperature more negative, decreases the Nusselt number, and increases the cross-sectionally integrated total entropy generation. Increasing De2 produces the opposite thermal and thermodynamic trends. Increasing Ha suppresses the axial velocity but raises Nu and reduces the total entropy generation. A larger K localizes the electroosmotic body force closer to the wall and also increases Nu. Within the range 0.01≤ϕ≤0.04, increasing ϕ slightly reduces the velocity, increases Nu, and decreases both local and total entropy generation. Increasing Da improves the axial flow capacity but lowers Nu and raises the total entropy generation, revealing a trade-off between flow throughput and thermodynamic irreversibility. A larger Br further increases local entropy generation. These findings are specific to the parameter ranges examined and provide guidance for parameter selection rather than establishing a unique optimum.
Rotating Packed Beds (RPB) technology has the potential to capture carbon dioxide emissions from industrial flues. A porous packing in rotation provides an extensive surface area for effective mass transfer between a gas and a solvent. The application of centrifugal force enables counter-current flow of the two fluids, enhancing the efficiency of the process.HiGee contactors present a superior alternative to traditional packed columns. In these systems, the solvent is subjected to acceleration up to a thousand times that of gravity, significantly increasing the mass transfer rates by one to two orders of magnitude. Additionally, these systems are remarkably compact, being ten times smaller than their conventional counterparts. Flooding in RPBs represents a significant operational challenge, characterized by the inability of the solvent to evacuate through the packing. This issue arises due to various resistive forces, such as gravitational and frictional forces, which hinder the solvent’s exit from the packing. Operational RPBs have been documented using a two-camera setup to study flooding. One camera focuses on the solvent injection point to monitor flooding, while the other captures the droplets exiting the packing. Initial results align with literature.Given the extreme challenges posed by the imaging conditions, deep learning with convolutional neural networks for segmentation is essential to extract meaningful information from these images. This deep learning–driven analysis has been pivotal in characterizing the geometric and dynamic properties of the droplets, revealing a previously unrecognized precursor to flooding in RPB systems.
Hydrogen is widely recognized as a clean energy due to its ability to release carbon-free energy through catalytic reactions under suitable thermal conditions. To enhance its conversion, a bimetallic Pt-Cu/Co0.8Fe0.2Al2O4 catalyst is prepared and evenly loaded onto different foam carriers. The main parameters, including carrier type, pore structure, length, loading, inlet flow rate, and temperature, were optimized to maximize low-concentration hydrogen conversion. Among the carriers, SiC exhibited the highest catalytic activity, achieving 62.33% hydrogen conversion within 30 min, compared with 42.63% and 56.58% for ZrO2 and Al2O3, respectively. This superior performance is attributed to its higher thermal conductivity and heat capacity, which promote faster conversion and result in an outlet temperature of 52.37°C. The investigation of catalyst loading and foam length revealed that 2.0 g at 30 mm generated a thermal output of 68.06°C, comparable to that of higher loadings (2.5 and 3.0 g), indicating active site utilization. A moderate flow and inlet temperature of 25°C enable rapid, complete conversion within 37.5 min, demonstrating the critical role of flow and thermal management. These findings emphasize the potential of foam supported spinel catalysts for industrial hydrogen applications, including fuel cell preheating and safe hydrogen utilization systems.
Electric dehydrators are conventional crude oil treatment equipment with inherent drawbacks, including narrow inlet water content adaptability and limited performance improvement potential. To address these issues, a compact electrostatic coalescer (CEC) is developed and be installed at its upstream to enhance the dehydration performance. The separation performance under series connection of a CEC and an electric dehydrator is experimentally studied. The water content at oil outlet of the separator is used as the evaluation indicator. Influence of different parameters such as temperature, inlet water content, demulsifier, electrical field parameters on the dehydration performance for crude oil emulsion are systematically investigated. Presence of CEC enables the electric dehydrator to overcome its limitation of only being able to treat crude oil with water content of less than 30%. The electric dehydrator could still operate normally and achieve good performance even when the inlet water content is 40%. Existence of CEC helps to reduce temperature in electric dehydrator by 10 °C, or the residence time by 10 minutes, as well as reducing the amount of demulsifier by 87.5%. The research results provide guidance and reference for improving the performance of electric dehydrator and the promotion and application of CEC in offshore platform.
To enhance the temperature uniformity and thermal-hydraulic performance of multi-cluster radial fractal microchannel heat sink (MCHS) radiating outward from the center of a disc, two new types of microchannel heat sinks with multiple loops structure are proposed, which are microchannel heat sink with two connected loops (MCHS-TCL) and microchannel heat sink with three discontinuous loops (MCHS-TDL). Results illustrated that the heat transfer enhancement effect of connected loop structure is significantly higher than that of discontinuous loop structure compared to the design without loop structure. The comprehensive performance (FOM) of MCHS-TCL and MCHS-TDL is 1.127 and 1.049 times than MCHS, respectively. However, there is a serious problem of uneven heat transfer flow in the secondary branch channels of MCHS-TCL. Therefore, rectangular fins are embedded in the MCHS-TCL to examine heat transfer performance. Results illustrated that the temperature uniformity of the secondary branch with symmetrical fins (MCHS-TCL-SMF) and staggered fins (MCHS-TCL-SGF) of MCHS-TCL increased by 24.74% and 22.37%, and FOM increased by 23.51% and 21.50% respectively, which enhanced the heat dissipation of the secondary branch flow path. MCHS-TCL-SMF demonstrates a good thermal and hydraulic performance can achieve the best cooling capacity.
Isopropyl palmitate (IPP) is an ester widely used in personal care formulations. This study investigated its catalyst-free synthesis from palmitoyl chloride and isopropanol using computational fluid dynamics (CFD) and experiments in a 3D-printed PLA microreactor containing periodically arranged static elements. The CFD model represented a section of the complete 2632μL device and was used to assess hydrodynamics, species redistribution, reaction progress, volumetric productivity, and hydraulic demand. Reactive simulations were performed at 65 °C using a literature-derived second-order rate constant. Hydrogen chloride was represented as a pseudo-dissolved numerical species to close the stoichiometric mass balance, whereas gas–liquid partitioning was not modeled. Experimentally, temperature and nominal space time were evaluated using a 2² factorial design with triplicate center points. The CFD results showed repeated stream redistribution around the static elements and progressive attenuation of palmitoyl chloride-rich regions along the modeled section. Increasing the prescribed CFD space time increased predicted conversion and reduced pressure drop and hydraulic power, whereas the associated decrease in flow rate reduced volumetric productivity. At 65 °C and a nominal experimental space time of 15 min, the microreactor achieved an apparent conversion of 76.3%, compared with 56.1 ± 3.2% in the batch system, corresponding to approximately 36% on a relative basis. Although the unreplicated microreactor condition and the hydrodynamic differences between the reduced CFD domain and the complete reactor prevented statistical inference and formal numerical–experimental validation, the combined results showed how static elements redistribute the reactant streams and identified the trade-off among conversion, productivity, and hydraulic demand. This integrated assessment provides a mechanistic basis for reaction-specific reactor optimization and supports continuous-flow processing with static elements as a promising catalyst-free route to IPP.
The global transition toward green energy is accelerating. Newly installed wind and solar power capacity is growing faster than conventional thermal power generation. However, the inherent variability and intermittency of renewable electricity pose increasing challenges to grid stability. At the same time, industrial electrolysis is under increasing decarbonization pressure because of its high electricity demand and associated emissions. Against this background, integrating fluctuating renewable electricity into industrial electrolysis provides a practical route to flexible electrolysis. By absorbing variable green electricity and converting it into stable, high-value products, electrolysis systems can serve as a form of “virtual energy storage”. This process also links renewable electricity utilization with industrial emission reduction. Based on recent literature, this review summarizes progress in three representative pathways: flexible hydrogen production, metal electrolysis, and electrochemical synthesis of chemicals. This review also discusses common challenges and possible solutions under flexible operating conditions. The analysis suggests that these pathways are complementary across different timescales. They can be integrated to provide flexible regulation capacity for the power system. This approach provides a feasible route for transforming energy-intensive industries from rigid electricity consumers into active participants in grid flexibility.
Biological methanation in ex situ biotrickling filter reactors (BTFRs) is a promising power-to-gas solution for converting renewable H₂ and CO₂-rich gas streams into biomethane under mild operating conditions. However, cross-study comparison remains difficult because reactor configurations, operating definitions, normalization bases, and performance metrics are reported inconsistently. This review critically synthesizes up-to-date evidence linking gas–liquid–biofilm mass transfer, hydrogenotrophic metabolism, reactor design, and operating conditions to CH₄ productivity, H₂ utilization, CO₂ conversion, product-gas quality, and long-term stability. Quantitative evidence reveals recurring process-intensification trade-offs: shorter gas residence time can increase productivity but reduce substrate utilization, while pressurization can improve conversion at the expense of compression and pressure-rated equipment. Packing architecture and liquid delivery enhance biofilm retention and effective contact but may also increase pressure drop, liquid hold-up, and diffusion resistance. Pilot and field-integrated studies demonstrate real-biogas utilization, recovery after H₂ interruptions, modular operation, and extended production of high-CH₄ gas. Although biological methanation has reached commercial application in other reactor configurations, publicly documented ex situ BTFR biomethanation remains predominantly at pilot scale. By consolidating the latest quantitative evidence and reporting needs, this review provides a knowledge base to guide scale-up and commercial development.
