Solution Flow Rate Research Articles

The Effect of Electrospinning Parameters on Morphological and Mechanical Properties of PAN-based Nanofibers Membrane

The electrospun nanofibers membranes (ENMs) have gained great attention due to their superior performance. However, the low mechanical strength of ENMs, such as the rigidity and low strength, limits their applications in many aspects which need adequate strength, such as water filtration. This work investigates the impact of electrospinning parameters on the properties of ENMs fabricated from polyacrylonitrile (PAN) solved in N, N-Dimethylformamide (DMF). The studied electrospinning parameters were polymer concentration, solution flow rate, collector rotating speed, and the distance between the needle and collector. The fabricated ENMs were characterized using scanning electron microscopy (SEM) to understand the surface morphology and estimate the average fiber sizes. The membrane porosity percentage was measured using the dry-wet weight method. Also, a dynamic mechanical analyzer was used to determine the mechanical strength properties (tensile strength and Young's modulus) (DMA). The obtained results revealed that the polymer concentration and flow rate mainly affect the porosity and fiber size in ENMs. Increasing the polymer concentration improves the strength and flexibility, while the flow rate did not show a clear effect on the mechanical strength of ENMs. Both fibers collecting speed and spinning distance did not clearly impact the membrane morphology. ENMs flexibility significantly increased with increasing the collector speed and decreasing the spinning distance. Strong and flexible ENMs with small fibers can be fabricated using 10% PAN/DMF at a flow rate of 1 mL/h, collector speed of 140 rpm, and spinning distance of 13 cm.

Experimental investigation of the mixing efficiency via intensity of segregation along axial direction of a rotating bar reactor

As a significant index to evaluate the mixing efficiency, studying the concentration distribution is directly related to the intensity of segregation (Is). In this work, the Is of the mixture composed of NaCl solution-water was investigated experimentally in a rotating bar reactor (RBR) by the conductivity method. The results showed that the mixing efficiency was improved along the axial direction from the bottom to the top in the RBR. The concentration distribution at the bottom section was more uneven, and Is was higher compared with the top section, which decreased from 6.53 × 10−5 to 1.57 × 10−7. With the increase of rotational speed from 0 to 700 r·min−1, Is at the bottom and top sections decreased from 4.27 × 10−3 to 7.10 × 10−5 and from 1.93 × 10−3 to 7.29 × 10−7, respectively. The increases flow rate of solution A, and the decreases of concentration of NaCl and flow rate of solution B gave rise to the reduction of Is, signifying an improved mixing efficiency. The results revealed that the conductivity method used in this paper has high efficiency and low cost to measure the Is, which indicates a promising prospect for estimating reactors’ mixing performance.

Esterification of Acetic Acid by Flow-Type Membrane Reactor with AEI Zeolite Membrane.

AEI-type zeolite membrane for dehydration was prepared, and a flow-type membrane reactor for the esterification of acetic acid and ethanol by AEI membrane was developed. A synthesized AEI membrane had suitable molecular sieving property for gas separation (H2/i-butane and CO2/CH4) and pervaporation (H2O/acetic acid). AEI membrane showed H2O permeance of 6.2 × 10-7 mol m-2 s-1 Pa-1 with a separation factor of 67 at 363 K for the equimolar mixture of H2O/acetic acid. AEI membrane maintained stable performance under acidic conditions. The yield of ethyl acetate at 363 K in a flow-type membrane reactor with AEI membrane successfully exceeded the equilibrium of 69.1%, reaching 89.0%. The flow rate of feed solution strongly affected the conversion of acetic acid and the space-time yield (STY) of ethyl acetate. Due to the more significant proportion of water selectively removed from the reaction system at a lower feed flow rate, the thermodynamic equilibrium shifted significantly, resulting in higher conversions. In contrast, STY increased with increasing feed flow rate. Our flow-type membrane reactor exhibited a relatively large STY of 430 kg m-3 h-1 compared with the batch-type membrane reactor previously reported.

Experimental studies on absorption-compression hybrid refrigeration system using 1,1,1,2-tetrafluoroethane/tetraethylene glycol dimethyl ether as working pair

The feasibility of combining novel halogenated hydrocarbon-based working pairs with low-pressure compression-assisted absorption refrigeration system (LCARS) was proved for the first time from the experimental perspective. An experimental prototype of the absorption-compression hybrid refrigeration system with a 1 kW cooling capacity was designed and tested to explore actual performances of selected R134a-DMETEG and performance improvements from compression in LCARS. At an evaporation temperature of approximately 5 °C, as the hot water inlet temperature and the solution flow rate change from 75 to 95 °C and 1.2–2.7 L/min, respectively, the coefficient of performance (COP) in the single-stage absorption refrigeration system (SSARS) varies from 0.211 to 0.412. At an increased evaporation temperature of approximately 10 °C, as the hot water inlet temperature and flow rate increase from 70 to 80 °C and 1.18–2.89 L/min, respectively, the COP in the SSARS varies from 0.238 to 0.552, while the COP in LCARS is improved and varies from 0.470 to 0.617. The LCARS increases the COP by a maximum of 91.04 % and can utilize a lower-grade heat source more efficiently due to its higher optimal COP at reduced hot water inlet temperatures. This study provided one feasible technical approach of combined use of R134a-DMETEG and LCARS to make up for the application limitations of traditional working pairs, contributing to application promotions of absorption systems, especially for the occasions with high requirement on safety and lightweight.

Dynamics of the State of the Eye Fundus of a Patient with Proliferative Diabetic Retinopathy and End-Stage Chronic Renal Failure after Hemodialysis (Clinical Case)

Purpose. To analyze a clinical case on the study of the dynamics of the state of the fundus of a patient with proliferative diabetic retinopathy (PDR) and end-stage chronic renal failure (CRF) on the background of hemodialysis (HD).Patient and methods. A clinical case of the study of the state of the organ of vision against the background of HD in patient S., 36 years old, is presented. Hemodialysis was performed for 4 months using the Artis Surdial-55 device (Nipro, Japan) for 3.5–4 hours with a blood flow rate of 250 ml/min and a dialysis solution flow rate of 500 ml/min. The severity of PDR was assessed using standard methods based on ultrasound (Opticon 2000, Italy), photographic recording of the state of the eye fundus (Carl Zeiss Visucam 500, Germany) and OCT of the macular region (on an RTVue-100 tomograph, OptoVue, USA).Results and conclusion. Studies before and after a course of HD indicate no changes in the fundus, which is confirmed by the data of an objective examination.

Fabrication of 1-octane sulphonic acid modified nanoporous graphene with tuned hydrophilicity for decontamination of industrial wastewater from organic and inorganic contaminants.

This research work is based on the fabrication of a graphene oxide-based composite (GOBC) to remove the maximum number of contaminants from different industrial effluents. The GO was first intercalated with 1-octanesulphonic acid sodium salt and subjected to microwave irradiation to produce GOBC. Fixed-bed column tests and Jar-tests were performed for removal of the most harmful endocrine disrupting compounds (EDCs) such as bisphenol A, bisphenol S, endosulphan, beta-estradiol, dyes (methylene blue and violate) and toxic metal ions such as Pb2+, Li+, Ni2+, Co2+, Cr6+, Zn2+, Cd2+, Hg2+, Cu2+, and As5+via adsorption. The prepared material was thoroughly characterized for its unique functional and structural properties. The results obtained from Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, scanning electron microscopy, Raman spectroscopy, water contact angle and X-ray diffraction analysis confirmed the successful preparation of GOBC using the proposed intercalation/microwave method. The water contact angle results showed decreased hydrophilicity of GOBC as compared to GO as the contact angle of GOBC (77.75°) was higher than that of GO (53.98°). The effects of main column parameters such as bed height, initial analyte concentration and solution flow rate were investigated. The results revealed that shorter breakthrough time, and high adsorption capacity were obtained at high flow rates of 1 mL min-1, while longer breakthrough time and lower adsorption capacity were obtained at lower flow rates of 0.5 mL min-1. The effect of bed depth on the breakthrough curve of analyte adsorption was a steep breakthrough curve; or a shorter breakthrough time occurring at lower bed height. The adsorption data obeyed the Yoon-Nelson and Thomas models very well. The adsorption capacity for BPA, BPS, endosulphan, beta-estradiol, methylene blue and violate was found to be 307, 305, 260, 290, 230 and 195 mg g-1, respectively. The adsorption capacity of GOBC for toxic metal ions such as Pb2+, Li+, Ni2+, Co2+, Cr6+, Zn2+, Cd2+, Hg2+, Cu2+, and As5+ was found to be 156, 136, 126, 124, 118, 114, 82, 82, 72 and 72 mg g-1, respectively with excellent kinetics. The adsorption data obtained using Jar-tests revealed that GOBC obeys a Langmuir isotherm and a pseudo second order kinetics model. The analysis of industrial wastewater samples showed good removal efficiency of GOBC.

СОРБЦИОННО-ХРОМАТОГРАФИЧЕСКОЕ РАЗДЕЛЕНИЕ ФОСФОРНЫХ ЭФИРОВ ТИАМИНА НА СОРБЕНТАХ РАЗЛИЧНОЙ СТРУКТУРЫ

The paper presents the results of studies on the selection of parameters for the sorption-chromatographic isolation of cocarboxylase (thiamine diphosphate) from a mixture of thiamine esters method development. The use of sulfonic cation exchanger KU-2-20 with the solution flow rate 0.2 ml/min during the release of thiamine triphosphate and 1.5 ml/min during the release of thiamine diphosphate is shown to be promising.

Effect of perforation shear on viscosity of polymer solution

Polymer flooding is a tertiary oil recovery technology that is very suitable for the characteristics of China’s reservoirs. However, due to the fast flow rate of polymer solution in near-well zone, the shear effect of perforation blasthole and the compacted zone results in serious loss of polymer viscosity. In this paper, the polymer used in Dagang Oilfield is studied by simulation experiment through the shearing process of perforating holes, and the influence of different perforating parameters on polymer viscosity loss is analyzed, so as to provide theoretical basis for the optimization design of perforating technology in field test. The experimental results show that, the shear effect of perforation blasthole on polymer is not obvious, and the viscosity retention rate of polymer solution is greater than 96%. The size and shape of perforation blasthole have no effect on viscosity loss of polymer solution. The shear effect of compacted zone on polymer is obvious, and the viscosity retention rate of polymer solution is lower than 64% for the target block. The viscosity loss of polymer solution increases with flow rate at compacted zone, and the decrease of permeability can increase viscosity loss of polymer solution. The higher the polymer concentration is, the stronger the shear resistance is, while the higher the molecular weight is, the weaker the shear resistance is. It is suggested that perforation gun and perforation method with deep perforation depth and low compaction degree be chosen to reduce the flow rate at compacted zone and viscosity loss of polymer solution.

Evaluation of the Effect of the PMMA Dialysis Membrane on the Level of Inflammation in Patients on Hemodialysis

Introduction: The inflammation syndrome is typical for chronic kidney disease (CKD) and increases with the progression of CKD. It is extremely important to monitor the markers of inflammation in patients with CKD, as there is a clear relationship between the level of inflammation and mortality in these patients. Currently, there is no single approach to the treatment of chronic inflammation in patients with CKD. Methods: This was a prospective open cohort study. We studied 31 patients on hemodialysis from March 1, 2020, to August 1, 2021, in 2 Moscow clinics (No. 7 and S.P. Botkin). Inclusion criteria for patients in the study were an adequate dialysis according to the KT/V index ≥1.4, absence of an active inflammatory process or infections, age over 18 years, standard hemodialysis regimen of 3 times per week, at least 4 h, levels of interleukin-6 (IL-6), IL-8, and C-reactive protein (CRP) above the reference values. Patients were transferred from hemodialysis performed using a standard polysulfone (PS) membrane to a polymethylmethacrylate (PMMA) membrane (Filtryzer BK-2.1F). For dialysis treatment in patients, blood flow rates of 250–350 mL/min were used, and the flow rate of the dialysis solution was set at 500 mL/min. The control group consisted of 19 patients, with similar inclusion parameters, who continued their treatment with hemodialysis using a PS membrane. The aim of the research was to study the effect of the dialysis membrane (Filtryzer BK-2.1F) on the level of inflammation in routine practice compared to a PS membrane. Adverse events were monitored. Results: By the end of the study, after 12 months, the levels of cytokines significantly decreased only in patients who had treatment with PMMA membrane, starting from the 3rd month of treatment, and became close to normal levels: IL-6 from 16.9 ± 8.0 to 8.5 ± 4.8 pg/mL (p ≤ 0.0001); IL-8 from 78.5 ± 11.4 to 43.6 ± 11.6 pg/mL (p ≤ 0.0001); and CRP from 10.33 ± 2.83 to 6.15 ± 1.57 mg/L (p ≤ 0.0001). Values of inflammation markers did not change in control group. Conclusion: In our study, we demonstrated for the first time a significant reduction in the level of inflammation in patients on standard hemodialysis in routine practice due to the use of PMMA membranes.

Solar Photocatalysis of A Pesticide in A Tubular Reactor on Titaniferous Sand as A New Semi-Conductor

This present study comes in addition to overcome the problems of separation of fine particles of TiO2 in heterogeneous photocatalysis after treatment. It aims to show the potential for using titaniferous sand as a new semiconductor under solar irradiation. The photocatalytic efficiency of this titaniferous sand was tested on a pesticide (Azadirachtin). A tubular photocatalytic reactor with recirculation of the polluting solution was designed for the elimination of the pesticide in an aqueous solution. Before its use as a photocatalyst, the titaniferous sand has undergone a specific treatment that consists of calcination at 600℃ followed by extraction of the calcined natural organic materials, which can interfere with the measurement of analytical parameters such as COD. The titaniferous sand was also characterized by X-ray fluorescence spectroscopy (XRF). XRF analyses have shown that TiO2 is predominant in the titaniferous sand with a percentage that has been estimated at 46.34%. The influence of various experimental parameters such as the flow rate of the polluting solution, the concentration of titaniferous sand, the presence of oxygen and the intensity of the overall rate of sunshine, was studied to optimize the photocatalytic degradation of the pesticide. The results showed that the highest removal rate (70%) was observed under the following conditions: a pH of 6, a titaniferous sand concentration of 150 g/L, a flow rate of 0.3 mL/min, and a sunshine rate of 354 W/m2 and in the presence of atmospheric oxygen. Under these experimental conditions, the rate of photodegradation of the pesticide follows the pseudo first order kinetic model of Langmuir Hinshelwood with a coefficient of determination R2 of 0.9869 and an apparent rate constant of 0.0029 min-1. The results clearly demonstrated the potential of titaniferous sand as a photocatalyst sensitive to sunlight for the effective removal of pesticides in the aquatic environment.

Simultaneous detection of dopamine and ascorbic acid by using a thread-based microfluidic device and multiple pulse amperometry.

This study presents a novel approach for the simultaneous detection of ascorbic acid (AA) and dopamine (DA) using an affordable and user-friendly microfluidic device. Microfluidic devices, when combined with electrochemical detectors like screen-printed electrodes (SPEs), offer numerous advantages such as portability, high sample throughput, and low reagent consumption. In this study, a 3D-printed microfluidic device called a μTED was developed, utilizing textile threads as microfluidic channels and an unmodified SPE as the amperometric detector. The method employed multiple pulse amperometry (MPA) with carefully selected potential values (+0.65 V and -0.10 V). The reduction current signals generated by dopamine o-quinone were used to calculate a correction factor for the oxidation signals of ascorbic acid, enabling simultaneous quantification. The developed microfluidic device ensured a stable flow rate of the carrier solution at 1.19 μL s-1, minimizing the consumption of samples and reagents (injection volume of 2.0 μL). Under the optimized experimental conditions, a linear range from 50 to 900 μmol L-1 was achieved for both DA and AA. The obtained sensitivities were 2.24 μA L mmol-1 for AA and 5.09 μA L mmol-1 for DA, with corresponding limits of detection (LOD) of 2.60 μmol L-1 and 1.54 μmol L-1, respectively. To confirm the effectiveness of the proposed method, it was successfully applied to analyze AA and DA in a commercial blood serum sample spiked at three different concentration levels, with a medium recovery rate of 70%. Furthermore, the MPA technique demonstrated its simplicity by enabling the simultaneous determination of AA and DA without the need for prior separation steps or the use of chemically modified electrodes.

Fabrication and compatibility evaluation of polycaprolactone/hydroxyapatite/collagen-based fiber scaffold for anterior cruciate ligament injury.

Knee injuries are musculoskeletal system injuries, including the Anterior Cruciate Ligament (ACL). ACL injuries are most common in athletes. This ACL injury necessitates biomaterial replacement. It is sometimes taken from the patient's tendon and a biomaterial scaffold is used. The use of biomaterial scaffolds as artificial ACLs remains to be investigated. The purpose of this study is to determine the properties of an ACL scaffold made of polycaprolactone (PCL)-hydroxyapatite (HA) and collagen with various composition variations of (50 : 45 : 5), (50 : 40 : 10), (50 : 35 : 15), (50 : 30 : 20), and (50 : 25 : 25) wt%. The scaffold was created using the electrospinning method with a voltage of 23 kV, a needle-collector distance of 15 cm, and a solution flow rate of 2 mL h-1. The average fiber diameter in all samples was less than 1000 nm. The model with the best characterization was PCL : HA : collagen with a weight-to-weight (wt%) ratio of 50 : 45 : 5 and an average fiber diameter of 488 ± 271 nm. The UTS and modulus of elasticity for braided samples were 2.796 MPa and 3.224 MPa, respectively, while the non-braided samples were 2.864 MPa and 12.942 MPa. The estimated time of degradation was 9.44 months. It was also revealed to be non-toxic, with an 87.95% viable cell percentage.

Degradation of methylene blue aqueous solution using atmospheric pressure dielectric barrier discharge

Methylene blue (MB) is toxic to humans and aquatic animals, and its removal from aqueous solutions requires high power consumption and long processing times. To improve the effect of dielectric barrier discharge (DBD) treatment of methylene blue and increase the energy utilization rate. In this study, we employed a novel approach, using a cylindrical DBD reactor, to treat MB in aqueous solutions. We found several factors, including input voltage, aqueous solution flow rate, number of high voltage electrodes, electrode size, and inside diameter of the dielectric tube influenced the MB removal rates with DBD. Our experimental results indicate that the change of electrode parameters can effectively improve the removal rate of methylene blue in DBD plasma treatment. At the same time, electrode parameters can lead to medium layer change of energy consumption; hence, the influence of electrode parameters on energy utilization efficiency also has an optimal value.

Features of the use of growth regulators in the cultivation of corn for grain in Western Siberia

The results of three-year studies (2020-2022) on the effectiveness of the use of various growth regulators in the cultivation of corn hybrids for grain in the forest-steppe zone of Western Siberia are presented. The studies were carried out on leached chernozem of the Novosibirsk region of the Novosibirsk region and on gray forest soil of the forest-steppe zone of the Novosibirsk Ob region. It is shown that in the forest-steppe of Western Siberia it is effective to use modern innovative growth regulators and chelate fertilizers in the process of corn grain production. It has been shown that on soil types it is effective to apply growth regulators Ecofus 0.001%, Epin-Extra 0.04% l/ha and chelated organosilicon fertilizer Siliplant 0.01% with a working solution flow rate of 300 l/ha in the phase of four to six maize leaves on six hybrids. It was statistically determined that the yield of corn grain depended on the element of technology by 33, genotype - 27 and the conditions of the year 23% and green mass, respectively, 35, 29 and 25%. It was shown that growth regulators and chelate fertilizers improved the parameters of the yield structure of corn hybrids.

Efficient nitrate reduction in water using an integrated photocatalyst adsorbent based on chitosan-titanium dioxide nanocomposite.

Globally, there exists a huge concern on the increased discharge of nitrates to the natural water resources out of various anthropogenic activities as it causes serious environmental pollution and associated harmful effects. In the present work, sol-gel-derived functional nanocomposites based on silver (Ag) and nitrogen (N)-doped titanium dioxide (TiO2)-coated chitosan nanocomposites were successfully synthesized in the form of beads, and their application for the reduction of nitrates in water was studied. The synthesized nanocomposite beads were characterized for their structural, textural, and morphological features using X-ray diffraction analysis, Fourier transform infrared spectroscopy, UV-visible spectroscopy, BET surface area analysis, Scanning electron microscopy, Transmission electron microscopy, and X-ray photoelectron spectroscopy. A uniform coating of doped titania species on the chitosan porous structure was achieved through electrostatic interaction. Adsorption/photocatalytic reduction of nitrates was further carried out using functional nanocomposite beads by monitoring the nitrate concentration of the model contaminated water, in an adsorption study under dark condition and photocatalytic study under UV/sunlight for a definite time period. Drying conditions of the nanocomposite beads were found to have a significant effect on the adsorption cum photocatalytic efficiencies of the nanocomposite. The freeze-dried chitosan-titania nanocomposite beads containing 0.5mol% Ag exhibited an adsorption efficiency of ~ 43.5% (under dark for 30min) and photocatalytic reduction capability of ~ 95% (under sunlight for 2h), whereas the oven dried beads of the same composition exhibits adsorption and photocatalytic efficiencies of 40% (under dark for 30min) and 70% (under UV light for 2h) respectively, towards the reduction of nitrate ions in an aqueous solution. Continuous flow adsorption cum photocatalytic study using the oven-dried nanocomposite beads was also carried out with the help of an experimental setup fabricated in-house and under varying experimental conditions such as flow rate, bed height, and concentration of feed solution. Nitrate reduction efficiency of 87.6% and an adsorption capacity of 7.9mgg-1 were obtained for the nanocomposite beads in the continuous flow adsorption cum photocatalysis experiment for up to 8h when using an inlet concentration of 100ppm, bed height 12cm, and flow rate 5.0mLmin-1. A representative fixed-bed column adsorption experiment performed with oven dried nanocomposite beads in a real groundwater sample collected from the Palakkad District of Kerala shows promising results for nitrate reduction (85.9% efficiency) along with a significant removal rate for the other anions as well. Thus, the adsorption cum photocatalytic nitrate reduction efficiency of the functional nanocomposite material makes them suitable for the reduction of nitrates from water/wastewater through an integrated nanocomposite approach.

Particle preparation of pharmaceutical compounds using supercritical antisolvent process: current status and future perspectives.

The low aqueous solubility and subsequently slow dissolution rate, as well as the poor bioavailability of several active pharmaceutical ingredients (APIs), are major challenges in the pharmaceutical industry. In this review, the particle engineering approaches using supercritical carbon dioxide (SC CO2) as an antisolvent are critically reviewed. The different SC CO2-based antisolvent processes, such as the gas antisolvent process (GAS), supercritical antisolvent process (SAS), and a solution-enhanced dispersion system (SEDS), are described. The effect of process parameters such as temperature, pressure, solute concentration, nozzle diameter, SC CO2 flow rate, solvent type, and solution flow rate on the average particle size, particle size distribution, and particle morphology is discussed from the fundamental perspective of the SAS process. The applications of the SAS process in different formulation approaches such as solid dispersion, polymorphs, cocrystallization, inclusion complexation, and encapsulation to enhance the dissolution rate, solubility, and bioavailability are critically reviewed. This review highlights some areas where the SAS process has not been adequately explored yet. This review will be helpful to researchers working in this area or planning to explore SAS process to particle engineering approaches to tackle the challenge of low solubility and subsequently slow dissolution rate and poor bioavailability.

Fabrication and characterization of polycaprolactone/cellulose acetate blended nanofiber mats containing sericin and fibroin for biomedical application

Polycaprolactone/cellulose acetate blended nanofiber mats containing sericin and fibroin were fabricated by electrospinning process to study the effect of sericin and fibroin on the physical and structural properties, wettability, degradability, elastic modulus, cell adhesion, and cell cytotoxicity of the electrospun nanofibers. Polycaprolactone/cellulose acetate solution was prepared with different percentage ratio of sericin and fibroin to be the running solution. Nanofibers were spun at fixed solution flow rate, flying distance, and operating voltage. The diameter of the obtained nanofibers linearly increases with the increasing of the sericin ratio. The derivative structures of polycaprolactone, cellulose acetate, sericin, and fibroin of the obtained nanofibers were confirmed by FTIR analysis. All acquired nanofibers show superhydrophilicity with adequate time of degradation for L-929 cell adhesion and growth. More elasticity is gained when the sericin ratio decreases. Moreover, all fibers containing sericin/fibroin reveal more elasticity, cell adhesion, and cell growth than that with only polycaprolactone/cellulose acetate. Greater cell adhesion and growth develop when the sericin ratio is lower. All the fabricated nanofibers are low toxic to the cells. Fibers with a mixture of sericin and fibroin at 2.5:2.5 (% w/v) are the most promising and suitable for further clinical development due to their good results in each examination. The novelty found in this study is not only making more value of the sericin, silk industrial waste, and the fibroin, but also getting the preferable biomaterials, scaffold prototype, with much greater mechanical property and slower degradation, which are required and appropriate for cell attachment and proliferation of cell generation process, compared to that obtaining from polycaprolactone/cellulose acetate or sericin/fibroin nanofibers.

Electrodialysis desalination: The impact of solution flowrate (or Reynolds number) on fluid dynamics throughout membrane spacers

The incorporation of a spacer among membranes has a major influence on fluid dynamics and performance metrics. Spacers create feed channels and operate as turbulence promoters to increase mixing and reduce concentration/temperature polarization effects. However, spacer geometry remains unoptimized, and studies continue to investigate a wide range of commercial and custom-made spacer designs. The in-depth discussion of the present systematic review seeks to discover the influence of Reynolds number or solution flowrate on flow hydrodynamics throughout a spacer-filled channel. A fast-flowing solution sweeping one membrane's surface first, then the neighboring membrane's surface produces good mixing action, which does not happen commonly at laminar solution flowrates. A sufficient flowrate can suppress the polarization layer, which may normally require the utilization of a simple feed channel rather than complex spacer configurations. When a recirculation eddy occurs, it disrupts the continuous flow and effectively curves the linear fluid courses. The higher the flowrate, the better the membrane performance, the higher the critical flux (or recovery rate), and the lower the inherent limitations of spacer design, spacer shadow effect, poor channel hydrodynamics, and high concentration polarization. In fact, critical flow achieves an acceptable balance between improving flow dynamics and reducing the related trade-offs, such as pressure losses and the occurrence of concentration polarization throughout the cell. If the necessary technical flowrate is not used, the real concentration potential for transport is relatively limited at low velocities than would be predicted based on bulk concentrations. Electrodialysis stack therefore may suffer from the dissociation of water molecules. Next studies should consider that applying a higher flowrate results in greater process efficiency, increased mass transfer potential at the membrane interface, and reduced stack thermal and electrical resistance, where pressure drop should always be indicated as a consequence of the spacer and circumstances used, rather than a problem.

Energetic evaluation of phenol wastewater treatment by reverse electrodialysis reactor using different anodes

Efficient electrode materials are essential to convert salinity gradient energy into oxidative degradation energy and electrical energy by reverse electrodialysis reactor (REDR). In this context, comparative experiments of REDR using different anodes (Ti/IrO2–RuO2, Ti/PbO2 and Ti/Ti4O7) were conducted. The effects of output current and electrode rinse solution (ERS) flowrate on mineralization efficiency and energy output were discussed. Results demonstrated that the COD removal rate(ηCOD) rose almost linearly with output current and ERS flowrate when using Ti/Ti4O7 anode, but excessive operating conditions caused a slow increase or even decrease of ηCOD when using Ti/IrO2–RuO2 or Ti/PbO2 anodes. The order of electrode system potential loss (Eele) for the three anodes was Ti/Ti4O7> Ti/PbO2> Ti/IrO2–RuO2. High Eele was beneficial to ηCOD but had a negative effect on the net output power (Pnet) of REDR. Regardless of the applied anodes, increasing the current and decreasing the ERS flowrate was detrimental to Pnet due to higher Eele. Based on these findings, four energy efficiency parameters were defined to evaluate energy recovery from multiple perspectives by linking energy output with mineralization capacity. They were electrode efficiency (ηele), energy efficiency (EE), general current efficiency (GCE) and energy consumption (EC), respectively. Results showed that REDR with Ti/Ti4O7 anodes and suitable operating conditions achieved the optimal energy indicators and mineralization efficiency, which provided an efficient and economical option for wastewater treatment and energy recovery.

Highly efficient activation of peroxymonosulfate by novel CuO-Chrysotile catalytic membrane for degradation of p-nitrophenol

A novel CuO-Chrysotile thin membrane catalyst was prepared by simple impregnation-calcination route, which provided new insights of catalytic membranes by natural mineral fiber for the degradation of organic contaminants in wastewater treatment. Through intermittent and continuous catalytic degradation experiments, peroxymonosulfate (PMS) was efficiently activated by the membrane to degrade p-nitrophenol (PNP), and the effects of experimental parameters (including initial solution pH value, PMS dosage, catalyst dosage, reaction temperature, membrane mass and flow rate) on PNP degradation were systematically studied. The results showed that the catalytic membrane had great catalytic performance and long-term stability, it could completely degrade 10 mg/L of PNP within 60 min and its degradation ratio could remain above 90 % after 5 cycles. Meanwhile, it was worth noting that 0.15 g of CuO-Chrysotile catalytic membrane used as fixed bed could continuously degrade 12.5 L of PNP solution with gratifying performance, which proved that the catalytic membrane had convenient use method and great application effect. The mechanism study found that 1O2 produced in this process played a key role in the degradation of PNP. From the aspects of manufacturing cost, catalytic performance and service life, the novel CuO-Chrysotile catalytic membrane has excellent industrial application potential.