Low Mass Transfer Research Articles

MXene Membranes Inserted with Tannic Acid Etched MOF Nanocrystals for Ultrafast Water Permeation: Elucidating the Water Transport Mechanism in Nanoconfined Interlaminar Channels.

Utilizing pore and interlayer engineering within nanoconfined interlaminar channels represents an ingenious approach to design highly permselective MXene (Ti3C2TX) membranes. Herein, the tannic acid (TA) etched ZIF-8 (TZIF-8) nanocrystals with hollow structures were effectually inserted into the interlayer spacing of MXene membranes. First, the density functional theory (DFT) results demonstrated the reaction mechanism between TA and ZIF-8. Then, the underlying mechanism of enhanced water-adsorptive properties for MXene/TZIF-8 membrane was due to the higher binding energy of water/TZIF-8 system than that of water/ZIF-8 system, elucidated by molecular dynamic simulation. Furthermore, the low mass transfer resistance and abundant mass transfer pathways of the MXene/TZIF-8 membrane were comprehensively proved by various experimental conclusions, characterizations and simulation calculations. As a result, the optimal MXene/TZIF-8 membrane exhibited high water permeance and concurrently satisfactory separation efficacy toward various oil/water emulsions. This work is anticipated to deepen the comprehension of high-efficiency water transport along interbedded nanochannels in MXene membranes.

High performance ozone nanobubbles based advanced oxidation processes (AOPs) for degradation of organic pollutants under high pollutant loading.

Advanced Oxidation Processes (AOPs) have proven to be an effective solution for chemical wastewater treatment, particularly for degradation of organic pollutants, especially dyes. Ozonation is recognized as one of the most prevalent AOPs. Nevertheless, some cases show a lowered efficiency of O3 utilization which is attributed to its inadequate distribution in the treated water causing low residence time, low mass transfer coefficient as well as shorter half-life. This study demonstrates the application of ozone nanobubbles to enhance the degradation of organics under high pollution load conditions. We propose an integrated method that utilizes bulk nanobubbles to enhance the reactivity of ozone for the degradation of organics. We examined the degradation of organic pollutants under parameters such as varying pH levels, ozone concentrations and presence of salts and surfactants. The degradation of the organic pollutant by ozone nanobubbles (0.177 L mg-1min-1) demonstrated a threefold increase in reaction rate constants compared to microbubbles (0.025 L mg-1min-1). The plausible reason for these findings is (i) higher mass transfer coefficient (ii) higher ozone solubility (iii) NBs may act as a surface for chemical reaction (iv) NBs may increase the half-life of ozone. The presence of reactive oxygen species was verified using scavenging tests. This part of the studies revealed contribution of reactive oxygen species (ROSs) such as hydroxyl radical (•OH), superoxide radical anion (O2•-) and singlet oxygen (1O2) in the degradation process. The conditions that provide total degradation of 100% in 300s for both organic pollutants (Green rit and methylene blue dye) are: 5 LPM (Litre per minute) ozone flow rate, acidic pH, monovalent salts (NaCl, 2mM) and lower concentration of surfactants (CTAB and SDS, 0.3 CMC). A degradation mechanism has been outlined based on intermediates identified by LC-MS. This work presents a new method that combines AOPs with nanobubbles, which should lead to increased environmental sustainability and efficiency.

2D monolayer electrocatalysts for CO2 electroreduction.

The electrocatalytic carbon dioxide reduction reaction (CO2RR) is an attractive method for converting atmospheric CO2 into value-added chemicals and fuels. In order to overcome the low efficiency and durability that hinder its practical application, a significant amount of research has been dedicated to designing novel catalysts at the nanoscale and even the atomic scale. Two-dimensional (2D) monolayer materials inherit the merits of both 2D materials and single-atom materials. Through bridging the gap between heterogeneous and homogeneous catalysis, 2D monolayer materials exhibit great potential in the CO2RR due to their unique structural/electronic properties, high atom utilization, low mass transfer resistance and uniform active sites. Here, we systematically overview the development and application of 2D monolayer catalysts for the electrocatalytic CO2RR. First, an overview of the CO2RR technology is presented. Subsequently, a comprehensive discussion is undertaken on various types of 2D monolayer electrocatalysts, such as 2D graphene-based materials, 2D monolayer metal-organic frameworks (MOFs), 2D monolayer covalent organic frameworks (COFs) and 2D monolayer metal-based materials. Their respective electrocatalytic performances are also systematically analyzed. More importantly, novel perspectives on the primary challenges and opportunities associated with the utilization of 2D monolayer materials in the CO2RR are presented. Achieving high-quality 2D monolayer materials and producing highly selective multi-carbon products remain the two major challenges in the design, synthesis and application of 2D monolayer electrocatalysts. Addressing these synthesis-related and performance-related issues is significant for the progression and practical utilization of 2D monolayer materials in the CO2RR.

Gallium Electrowinning in Complex Solutions Produced by a Zinc Hydrometallurgy System.

Gallium metal is scattered within Fankou lead-zinc ore, and the existing zinc hydrometallurgy process includes a leaching-extraction-electrowinning sequence to recover the gallium metal. However, impurities from lead-zinc ore have many adverse effects on the gallium electrowinning process such as strong hydrogen evolution reaction and low mass transfer rate, which lead to low current efficiencies and poor quality cathode gallium during gallium electrowinning process. In order to achieve efficient separation and recovery of gallium from zinc hydrometallurgy system, the effects of Al, Zn, and OH- impurities on gallium electrowinning were systematically investigated in this study. The research results indicate that the Al impurity did not affect the cathode gallium product, but do affect the current efficiency of the gallium electrowinning process. The Zn impurity had a greater impact on the gallium electrowinning process than the other impurities, and deposition of Zn at the cathode led to a low current efficiency and directly affected the quality of the cathode gallium product. When the Zn concentration exceeded 1 g/L, the purity of the cathode gallium product was reduced to approximately 99%. Both excessively low and high OH- concentrations had negative effects on the gallium electrowinning process, and the maximum value of current efficiency of gallium electrowinning is 54.14% when the alkali concentration was 120 g/L NaOH. The optimized main conditions for gallium electrowinning provide suggestions for realization of gallium production in zinc hydrometallurgy system.

Novel cobalt-doped CuFe2O4 spinel catalyst for enhanced peroxymonosulfate activation to achieve rapid degradation of tetracycline hydrochloride: Dominant roles of O2[rad]- and 1O2 in the oxidation process

Heterogeneous peroxymonosulfate (PMS) catalysis is a promising method for water pollution treatment. CuFe2O4 spinel can activate PMS, but its application is limited by its tendency to agglomerate and its low-mass transfer efficiency. In this study, a cobalt-doped CuFe2O4 (CuFeCoO4, CFCo-1) was successfully synthesized, achieving a degradation efficiency of 98.36 % for tetracycline hydrochloride (TCH) within 21 min, with a high degradation rate corresponding to a kinetic constant of 0.2041 min−1. CFCo-1 demonstrated strong resistance to interference from inorganic ions and organic compounds. It maintained over 90 % TCH removal efficiency with negligible leaching of metal ions after five cycles, indicating that the catalyst had strong cyclic stability. Mechanistic analysis revealed that cobalt doping improved the electron transfer efficiency of the catalyst, enabling CFCo-1 to activate PMS and degrade the pollutant through both radical (OH, SO4- and O2-) and non-radical (1O2) pathways, with O2- and 1O2 being the dominant species. The potential degradation pathways of TCH were proposed based on theoretical calculation and the identification of degradation products. In conclusion, cobalt doping is an effective strategy for enhancing the catalytic performance of spinel for efficient degradation of pollutants in water.

Immobilized chitosan as an efficient adsorbent for columnar adsorption of Cr (VI) from aqueous solution

The current effort focuses on creating an effective adsorbent for Cr (VI) adsorption due to the growing need to address Cr (VI) pollution in aqueous solutions. Chitosan, a biopolymer and polysaccharide with several functional sites, is immobilized on alginate using the ion exchange technique. Both prior to and following Cr (VI) adsorption, the material's shape, crystallinity, and functional groups are reported. Immobilized chitosan was employed to adsorb Cr (VI) in a fixed bed column with variable operational parameters (flow rate, initial chromium content, and bed height). The analysis of breakthrough curves showed that at a flow rate of 10 mL/min, Cr (VI) concentration of 50 mg/L and a bed height of 18 cm, a maximum adsorption of 78.41 % was achieved. The adsorption system and the breakthrough curves were thoroughly understood by using Thomas, Yoon-Nelson and Adams-Bohart kinetic models. There is promise for the large-scale use of synthesized immobilized chitosan because the current adsorption process fits the Thomas and Yoon-Nelson model well and confirms the homogenous bed, low mass transfer resistance, and constant operating conditions throughout the experiment. Furthermore, an exploration of the adsorption mechanism is undertaken and the outcomes are compared with existing literature. The regeneration and reuse tests up to four cycles provided insight into the immobilized chitosan's stability, dependability, and potential for scaling up.

Fibrillated Films for Suspension Catalyst Immobilization-A Kinetic Study of the Nitrobenzene Hydrogenation.

The immobilization of suspension catalysts in flexible, fibrillated films offers a promising solution to the mass transfer limitations often encountered in three-phase hydrogenation reactions. This study investigates the catalytic performance and mass transfer properties of fibrillated films in the hydrogenation of nitrobenzene to aniline, comparing them to free-flowing powdered catalysts. Fibrillated films were prepared from Pd/C catalysts with varying thicknesses (100-400 µm), and their performance was evaluated through kinetic studies in both batch reactors and microreactors. The specific activity of the films was significantly influenced by film thickness with thinner films demonstrating lower mass transfer limitations. However, mass transfer limitations were observed in thicker films, prompting the development of alternative film designs, including enhanced macro-porous films and sandwich structures. These modifications successfully minimized diffusion limitations, achieving similar specific activity to the powder catalysts while maintaining the mechanical stability of the films. This work demonstrates the feasibility of using fibrillated films for continuous catalytic processes and highlights their potential for efficient catalyst reuse, avoiding filtration steps and enhancing process sustainability. Furthermore, while PTFE remains indispensable for producing such films due to its mechanical and thermal stability, ongoing research focuses on identifying more environmentally friendly alternatives without compromising performance.

Enhancement of H2-water mass transfer using methyl-modified hollow mesoporous silica nanoparticles for efficient microbial CO2 reduction

Inorganic-microbial hybrid catalysis is an emerging technology that uses electrical energy to drive microorganisms to reduce CO2 into high value-added compounds, and it has broad application prospects in CO2 reduction. However, the low current density (production yield) limits its practical application. Hydrogen-mediated inorganic-microbial hybrid catalysis system can achieve higher current density, but it is limited by low H2 mass transfer. Here, silica nanoparticles were used to enhance the hydrogen mass transfer for highly efficient CO2 reduction. Solid silica (SN), mesoporous silica (MSN), hollow mesoporous silica (HMSN), and methyl-modified hollow mesoporous silica (MHMSN) were firstly prepared and tested for the enhancement of hydrogen mass transfer. Of these, MHMSN nanoparticles at a concentration of 0.3 wt% were the best at enhancing gas-liquid mass transfer, the volumetric mass transfer coefficient (KLa) and saturated dissolved hydrogen concentration of H2 are 0.53 min-1 and 1.81 mg l-1, respectively. Compared with the control group without added nanoparticles, MHMSN significantly increased the solubility and KLa of H2. This can be attributed that the addition of MHMSN promoted the detached process of hydrogen bubbles from the electrode surface, which made the diameter of hydrogen bubbles smaller, increased the gas-liquid mass transfer area, and strengthened the mass transfer process of H2. Furthermore, it was added to the inorganic-microbial hybrid catalysis system to effectively promote the microbial carbon reduction process, achieving a polyhydroxybutyrate (PHB) yield of up to 700 mg l-1, and the electron utilization rate and CO2 conversion rate were 51 % and 58 % higher than the control group, respectively. These results demonstrated that the addition of MHMSN is an effective approach to enhancing the performance of H2-mediated inorganic-microbial hybrid catalysis system.

Hydrodynamics of liquid–liquid parallel flow in novel microextractors: Review

Parallel flows on microfluidic platforms enable continuous liquid–liquid operations and inline separation of effluent streams, bearing immense scope in integration of miniaturized separation processes. However, these flows face major challenges including low mass transfer efficiency due to lack of transverse convection and flow instability at low flow rates, which undermine their operating range and utility. The limitations have inspired dedicated research, delving into the fundamentals of fluid flow and transport mechanism and exploring novel configurations of microextractors. The current article summarizes the hydrodynamics of parallel flows and relevant process intensification strategies in microfluidic extractors, evolving from the use of straight to curved and helical geometries, besides elucidating unique secondary flow patterns observed in-state-of-the-art designs. It includes exclusive sections addressing various aspects of parallel flows: (i) flow inception and theoretical modeling of flow fields and phase hold up, (ii) challenges concerning interfacial stability and flow intensification, (iii) curvature effects in planar curved geometries, and (iv) curvature cum torsional effects in unique multi-helical configurations. The theoretical perspective of this review presents a roadmap that can provide further insights into design modifications for developing improved integrated microextractors based on parallel flows.

Creating CoRu Dual Active Sites Codecorated Stable Porous Ceria Support for Enhanced Li-CO2 Batteries Cathodes.

Lithium-carbon dioxide (Li-CO2) battery represents a high-energy density energy storage with excellent real-time CO2 enrichment and conversion, but its practical utilization is hampered by the development of an excellent catalytic cathode. Here, the synergistic catalytic strategy of designing CoRu bimetallic active sites achieves the electrocatalytic conversion of CO2 and the efficient decomposition of the discharge products, which in turn realizes the smooth operation of the Li-CO2 battery. Moreover, obtained support based on metal-organic frameworks precursors facilitates the convenient diffusion and adsorption of CO2, resulting in higher reaction concentration and lower mass transfer resistance. Meanwhile, the optimization of the interfacial electronic structure and the effective transfer of electrons are achieved by virtue of the strong interaction of CoRu at the support interface. As a result, the Li-CO2 cell assembled based on bimetallic CoRu active sites achieved a discharge capacity of 19,111mAhg-1 and a steady-state discharge voltage of 2.58V as well as a cycle life of >175 cycles at a rate of 100mAg-1. Further experiments combined with density-functional theory calculations achieve a deeply view of the connection between cathode and electrochemical performance and pave a way for the subsequent development of advanced Li-CO2 catalytic cathodes.

Novel rate-based modeling and mass transfer performance of CO2 absorption in rotating spiral contactor

For the process of CO2 absorption, existing gas-liquid contactors suffer from low mass transfer performance and low gas-liquid ratios. In this study, a rotating spiral contactor was developed to overcome these drawbacks and a novel rate-based model was developed to predict the CO2 absorption performance. The effective interfacial area (ae), overall volumetric mass transfer coefficient (KGae) and CO2 absorption efficiency (η) were investigated. The results showed that the ae was 913–1125 m2/m3 superior to the conventional contactor. In the range of gas–liquid ratio of 200–1800, the KGae and η were 1.4–10.1 kmol.m-3.h-1.kPa-1 and 40.5–99.6 %, respectively. The rate-based model predicted the KGae and η with the AARD of 6.71 % and 1.90 %, respectively. Also, it has better robustness even in highly nonlinear temperature and composition distributions. This study provides a potential contactor and a new modeling tool for CO2 capture and other gas-liquid separation.

Flow characteristics and mass transfer performance of phosphoric acid extraction in a T-type central plug-in microreactor

In recent years, the demand for phosphoric acid, a key raw material for lithium iron phosphate batteries, has surged. However, current phosphoric acid extraction equipment faces challenges such as low mass transfer efficiency and difficulty in phase separation, leading to reduced production efficiency, bulky equipment, and scaling issues. To address these problems, this study introduces a T-type central plug-in microreactor (TCPM) designed to enhance mass transfer efficiency and facilitate rapid phase separation. The extraction of phosphoric acid from the water phase to the organic phase (volume ratio of tributyl phosphate to kerosene is 4:1) was chosen as the experimental system. We investigated the effects of various parameters on liquid-liquid flow and mass transfer characteristics in the TCPM. Visualization techniques identified slug and parallel flow as the primary liquid-liquid flow patterns within the TCPM. Notably, the central plug-in promotes the formation of parallel flow, improving phase separation compared to conventional T-type microreactors. The volume mass transfer coefficient of the TCPM ranges from 0.023 to 0.074 s-1, and the optimal phosphoric acid extraction efficiency and volume mass transfer coefficient can reach up to 90.5% and 0.074 s-1, respectively, outperforming conventional T-type microreactors. Predictive model for extraction efficiency was developed, showing deviations within 10%. These findings demonstrate the TCPM's potential as an efficient phosphoric acid extraction device with rapid phase separation, holding significant promise for liquid-liquid extraction applications.

Water-retaining slurry washcoat for high-loading and robust CuMnOx structured catalyst toward durable monoxide oxide purification from real flue gas

Structured catalysts play key roles in many industries with the advantages of low pressure drop and efficient mass transfer. The copper-manganese oxide (CuMnOx) as a cost-effective catalyst has been widely applied in gas purification, but still lack efficient structured catalyst due to the challenge in controlling its slurry and coating quality. In this work, this challenge was addressed by introducing the water-retaining agent (WRA) into slurry with sophisticatedly designed conditions. The effects of the type and dosage of WRA, pH value, and temperature on slurry properties including viscosity, stability, and water-retention were systematically studied, and the slurry property-coating quality relationship was correlated. The preferred slurry and coated layer could be segregated into sub-millimeter-sized water-retaining regions where catalyst and binder particles were well dispersed and connected. After slow release of water and organic during drying and calcination, the CuMnOx structured catalyst with uniform, defect-free and dense coating was obtained, showing high loading (>160 kg/m3), great mechanical strength (powder shedding rate < 1 wt%), and no blockage for practical use. The robustness of the structured catalysts was validated by a scale-up preparation of 2 m3 volume amount for CO purification from real ore-sintering flue gas in a steel plant, which achieved the CO catalytic efficiency maintaining over 90 % for more than 1440 h. This work showcases an efficient strategy for structured catalyst preparation and expands the gas purification application of the industrially-favored CuMnOx.

The effect of swirling shear blade on gas-liquid flow pattern and mass transfer performance in Venturi injector

To address the challenge of low mass transfer efficiency of gas-liquid reaction in traditional reactors, this study proposes a new method to improve the gas-liquid mass transfer efficiency by integrating swirl shear blades (SSB) into Venturi injectors. The gas-liquid flow patterns in the mixing and diffusion sections between the Swirl Venturi Injector (SVI) and the Traditional Venturi Injector (TVI) was compared, and it was found that the SSB significantly reduced the proportion of annular flow while increased the proportion of mist flow. The enhancement factor αE and the acceleration factor αA are applied to evaluate the mass transfer performance. Compared to TVI, the maximum αA of SVI was 29%, and the maximum αE was 43%. This work shows great potential in efficiently capturing gas components with low solubility in the liquid phase, thereby helping to achieve the goal of green chemical engineering.

Hierarchical biocatalytic membranes embedded with trypsin–inorganic hybrid nanoflowers for effective β-lactoglobulin hydrolysis

β-lactoglobulin (β-LG) is a significant allergen in milk. Enzymatic hydrolysis of β-LG produces peptides with low allergenicity and improved functionality. The biocatalytic membranes combine enzyme function and membrane separation in one step, but is still challenging for proteolysis. Herein, the biocatalytic membranes embedded with trypsin-inorganic hybrid nanoflowers are developed by a facile and green method for β-LG hydrolysis. Ethylene vinyl alcohol copolymer (EVAL) nanofibers are fabricated as 3D scaffolding on the membrane surface and trypsin-copper phosphate nanoflowers are in-situ grown in the porous structure of membranes. The nanoflowers are uniformly entrapped in the EVAL nanofiber layer and preferentially grow in the EVAL nanofibers layer, leading to the hierarchical structure of membranes. The trypsin loading of the nanoflowers membrane is approximate to 282.1 µg/cm2. Lower Michaelis-Menten constants Km prove the better affinity of Cu3(PO4)2-TR nanoflower membrane with substrates during filtration than that in static mode, even than free trypsin. The hierarchical structure of the membranes ensures both the enhanced trypsin-substrate contacts and low mass transfer resistance during the β-LG filtration. This work not only presents a novel concept of enzyme immobilized biocatalytic membranes, but also offers a sustainable solution for high-performance proteolysis.

Facile fabrication of eccentric hollow molecularly imprinted polymers microspheres via miniemulsion one-step seed swelling polymerization

Molecular imprinting technique has been increasingly concerned for preparing tailor-made specific recognition materials. In this work, the molecularly imprinted polymers (MIP) microspheres with eccentric hollow structure were prepared by miniemulsion one-step seed swelling polymerization for specific recognition of bisphenol A (BPA), a typical endocrine disrupter. The obtained MIP microspheres were investigated by TEM and SEM, respectively. The images show that the MIP microspheres are of unique eccentric hollow structure with the average diameter of 210 nm. Due to the presence of hollow structure, most of imprinted sites were distributed in the internal and external surfaces of MIP microspheres and the mass transfer resistance of template molecule decreases significantly. The successful building of imprinted sites was validated by a series of adsorption experiments. The experimental results indicate that the MIP microspheres present fast adsorption rate and could reach adsorption equilibrium within 90 min because of low mass transfer resistance resulted from the hollow structure. Additionally, the MIP microspheres also appear considerable binding capacity, binding selectivity (the imprinting factor of 2.06) and renewability. The binding capacity of MIP could remain at a high level after 5 binding-unbinding cycles. Furthermore, the MIP microspheres present excellent water compatibility and could rebind BPA selectively from aqueous medium because of the adoption of hydrophilic functional monomer and aqueous polymerization environment. Due to these unique characteristics, the MIP microspheres show the application prospect in the fields of environmental protection and detection.

Enhanced solvent extraction of rare earth elements in ultra-high phase ratio with pore-throat microchannels

To enrich and recover low-concentration (101–102 ppm) rare earth elements from ores and industrial wastes, high phase-ratio solvent extraction is favored. However, high phase-ratio solvent extraction is limited by low mass transfer efficiency in the continuous phase due to the insufficient contact between large volume continuous phase and sparse droplets. To realize efficient solvent extraction of rare earth ions from low concentrations (100 ppm) aqueous phase to oil phase with high phase ratio, we introduce a type of microchannel with sequential pore-throat geometry. This sequential pore-throat geometry creates capillary barriers and effectively retains dispersed droplets, leading to a reduction of apparent water–oil volume ratio and thereby major mass transfer enhancement in the continuous phase. We experimentally highlight its advantage over classic uniform microchannel for solvent extraction of rare earth ions under high phase ratios: in a double pore-throat microchannel, extraction equilibrium can be reached within 30 s under high phase ratios of 50–250; for an extreme phase ratio of 500:1, extraction efficiency can achieve 77 % within a quadruple pore-throat channel, while that within a uniform microchannel is only below 40 %. The superiority of sequential pore-throat microchannel for extraction at a high phase ratio is reproduced using different types of rare earth ions. We thus conclude that sequential pore-throat geometry can drastically promote the performance of microfluidic-based solvent extraction at extreme phase ratios, for rare earth enrichment and potentially for other relevant applications.

Hollow porous organic framework nanotube for efficient photocatalytic H2O2 generation by promoting H2O oxidation

The hydrogen peroxide (H2O2) generation by photocatalytic O2 reduction coupling H2O oxidation is a promising alternative to the traditional anthraquinone method. However, the low mass transfer and weak water oxidation are still the major responsible for the low efficiency of photocatalytic H2O2 production. Herein, we present a porous organic framework (BPTEE-POF) with hollow nanotube structure containing 2,2′-bipyridine active center of H2O oxidation, which was synthesized by template-free Sonogashira cross-coupling reaction of 5,5′-dibromo-2,2′-bipyridine (BP) and 1,1,2,2-tetrakis(4-ethynylphenyl)ethene (TEE). The 2,2′-bipyridine moieties can effectively weaken HO bond and facilitate H2O oxidation to generate O2 and H+, which can be subsequently employed as reactants for non-sacrificial H2O2 production. Meanwhile, the throughout hollow structure of BPTEE-POF is conducive to mass transfer/diffusion of substrate and product by siphoning, which promotes O2 and H2O molecules to contact with catalytic active sites and causes the quick dissociation of H2O2 from active sites, thereby boosting the overall reaction kinetic and efficiency.

Cu quantum dots anchored core-shell submicrosphere catalyst for electro-enhanced degradation of diclofenac sodium

The low mass transfer efficiency, sluggish redox cycles of metal ions, and poor recycling rate of S2O82-→SO42-→S2O82- greatly limit the application of two-dimensional (2D) electrodes and persulfate (PS) techniques. In this study, an interface engineering strategy was developed to anchor Cu quantum dots (CuQDs) onto a novel Cu-CoO@NC (N-doped carbon) core-shell submicrosphere catalyst. The 3D electrochemical system (2D electrodes combined with Cu-CoO@NC particle electrodes) exhibited excellent catalytic behavior with 99.1 % removal of diclofenac sodium in 30 min. The Cu-CoO@NC catalyst presented effectiveness and strong environmental adaptability in a broad pH range, in actual water bodies, and for multiple PPCPs. Based on the results analyses of experiments and density functional theory (DFT) calculations, the excellent performances of Cu-CoO@NC/PS during electrochemical oxidation (EO) result from the effective mass transfer, efficient interfacial charge transport, rapid redox cycling of bimetallic ions promoted by cathode, repetitive cycle of S2O82- → SO42- → S2O82- caused by anode and multiple active sites of PS.

Development of an Apple Snack Enriched with Probiotic Lacticaseibacillus rhamnosus: Evaluation of the Refractance Window Drying Process on Cell Viability.

The objective of this study was to develop a dried apple snack enriched with probiotics, evaluate its viability using Refractance Window (RWTM) drying, and compare it with conventional hot air drying (CD) and freeze-drying (FD). Apple slices were impregnated with Lacticaseibacillus rhamnosus and dried at 45 °C using RWTM and CD and FD. Total polyphenol content (TPC), color (∆E*), texture, and viable cell count were measured, and samples were stored for 28 days at 4 °C. Vacuum impregnation allowed for a probiotic inoculation of 8.53 log CFU/gdb. Retention values of 6.30, 6.67, and 7.20 log CFU/gdb were observed for CD, RWTM, and FD, respectively; the population in CD, RWTM remained while FD showed a decrease of one order of magnitude during storage. Comparing RWTM with FD, ∆E* was not significantly different (p < 0.05) and RWTM presented lower hardness values and higher crispness than FD, but the RWTM-dried apple slices had the highest TPC retention (41.3%). Microstructural analysis showed that RWTM produced a smoother surface, facilitating uniform moisture diffusion and lower mass transfer resistance. The effective moisture diffusion coefficient was higher in RWTM than in CD, resulting in shorter drying times. As a consequence, RWTM produced dried apple snacks enriched with probiotics, with color and TPC retention comparable to FD.