Exploring the impact of polyvinylidenefluoride membrane physical properties on the enrichment efficacy of microfluidic electro-membrane extraction of acidic drugs

Membrane technology has revolutionized various fields with its energy efficiency, versatility, user-friendliness, and adaptability. This study introduces a microfluidic chip, comprised of silicone rubber and polymethylmethacrylate (PMMA) sheets to explore the impacts of polymeric support morphology on electro-membrane extraction efficiency, representing a pioneering exploration in this field. In this research, three polyvinylidenefluoride (PVDF) membranes with distinct pore sizes were fabricated and their characteristics were assessed through field-emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). This investigation centers on the extraction of three widely prescribed non-steroidal anti-inflammatory drugs: aspirin (ASA), naproxen (NAP), and ibuprofen (IBU). Quantitative parameters in the extraction process including voltage, donor phase flow rate, and acceptor phase composition were optimized, considering the type of membrane as a qualitative factor. To assess the performance of the fabricated PVDF membranes, a comparative analysis with a commercially available Polypropylene (PP) membrane was conducted. Efficient enrichment factors of 30.86, 23.15, and 21.06 were attained for ASA, NAP, and IBU, respectively, from urine samples under optimal conditions using the optimum PVDF membrane. Significantly, the choice of the ideal membrane amplified the purification levels of ASA, NAP, and IBU by factors of 1.6, 7.5, and 40, respectively.

Improved structure of Zr-BTC metal organic framework using NH2 to enhance CO2 adsorption performance

Modified mesoporous NH2-Zr-BTC mixed ligand MOF nanocomposites were synthesized via the hydrothermal method as a novel adsorbent for CO2 capture. The newly modified MOF-808 with NH2 demonstrated a similar mesoporous morphology as MOF-808, whereas the specific surface area, pore volume, and average particle size, respectively, increased by 15%, 6%, and 46% compared to those of MOF-808. The characterization analyses exhibited the formation of more active groups on the adsorbent surface after modification. In addition, a laboratory adsorption setup was used to evaluate the effect of temperature, pressure, and NH2 content on the CO2 adsorption capacity in the range of 25-65 °C, 1-9 bar, and 0-20 wt%, respectively. An increase in pressure and a decrease in temperature enhanced the adsorption capacity. The highest equilibrium adsorption capacity of 369.11 mg/g was achieved at 25 °C, 9 bar, and 20 wt% NH2. By adding 20 wt% NH2, the maximum adsorption capacity calculated by the Langmuir model increased by about 4% compared to that of pure MOF-808. Moreover, Ritchie second-order and Sips models were the best-fitted models to predict the kinetics and isotherm data of CO2 adsorption capacity with the high correlation coefficient (R2 > 0.99) and AARE% of less than 0.1. The ΔH°, ΔS°, and ΔG° values were - 17.360 kJ/mol, - 0.028 kJ/mol K, and - 8.975 kJ/mol, respectively, demonstrating a spontaneous, exothermic, and physical adsorption process. Furthermore, the capacity of MH-20% sample decreased from 279.05 to 257.56 mg/g after 15 cycles, verifying excellent stability of the prepared mix-ligand MOF sorbent.

Stability, optimum ultrasonication, and thermal and electrical conductivity estimation in low concentrations of Al12Mg17 nanofluid by dynamic light scattering and beam displacement method

The thermal conductivity and stability of nanofluids pose challenges for their use as coolants in thermal applications. The present study investigates the heat transfer coefficient (HTC) of an Al12Mg17 nanofluid through the utilization of a novel beam displacement method. The study also examines the nanofluid's stability, particle size distribution (PSD), TEM micrograph, and electrical conductivity. From three distinct categories of surfactants, a particular surfactant (CTAB) was chosen to disperse Al12Mg17 nanoparticles in DI water, and subsequently, a two-step method was employed to generate the nanofluid. Dispersion stability is visually monitored and quantified with a zeta potential test. HTC and PSD are measured using optical setups. To evaluate the results, the HTC obtained from the beam displacement method is compared with that of the KD2 Pro apparatus, and the PSD findings are analyzed through TEM micrographs. The results show that a 0.16 vol.% CTAB is the maximum stability for 0.025 vol.% Al12Mg17 nanofluid properly. The optimum ultrasonication period is 2 h, yielding a peak PSD of 154 nm. Increasing nanoparticle concentration enhances HTC up to 40% compared to the base fluid at 0.05 vol.%. Electrical conductivity increases linearly from 155 to 188 μ[Formula: see text] with nanoparticle concentration. Optical methods for measuring HTC in nanofluids offer the advantage of early results, prior to bulk motion. Thus, the application of nanofluids in thermal systems necessitates the development of optical techniques to improve accuracy.

An experimental investigation on the oxidative desulfurization of a mineral lubricant base oil

In the present study, the oxidative desulfurization (ODS) of Sn 650 base oil with total sulfur content of 10,000 ppmw has been investigated experimentally. The response surface methodology (RSM) considering Box-Behnken design (BBD) was applied to examine the impacts of the oxidation temperature (30-70˚C), hydrogen peroxide to sulfur molar ratio (2-8), and formic acid to sulfur molar ratio (20-60) on the sulfur removal. In the next step, the appropriate values of the independent variables such as stirrer speed (750-1250 rpm), reaction time (60-180 min), and the number of extraction stages (1-4) were determined based on the optimal result obtained from the BBD. The best performance of the ODS process was found at a reaction temperature of 58˚C, an oxidant to sulfur molar ratio of 7.35, a formic acid to sulfur molar ratio of 58.5, a reaction time of 150 min, and a stirrer speed of 1250 rpm for the oxidation reaction. The achieved sulfur removal after oxidation followed by liquid-liquid extraction was 32 %, and 60 % for one extraction and three extraction stages, respectively. The changes in the base oil specifications after the ODS treatment were also investigated.

A novel multi-probe continuous flow ultrasound assisted oxidative desulfurization reactor; experimental investigation and simulation

In this work, a cylindrical multi-probe continuous flow system with different injection strategies was exploited to study ultrasound assisted oxidative desulfurization process. The effects of nozzle number, nozzle diameter, ultrasonic power and volumetric flow rate (residence time) on the desulfurization efficiency of the diesel fuel were investigated. It was found that the sulfur removal increases by increasing the nozzle diameter when the flow rate is fixed. Sulfur removal was increased by increasing the residence time, for all types of the nozzles. Injection of the aqueous phase below the horn tip in the active zone provides the conditions by which the higher interfacial area between the phases and thus greater conversion rate can be obtained. The results indicated that over 97% sulfur removal was achieved using the double-nozzle injection with nozzle diameter of 1.5 mm, residence time of 15 min, electrical power of 277.2 W and volumetric flow rates of the aqueous and oil phases 48.89 and 244.44 mL/min, respectively. The simulation results showed that choosing a proper injection strategy has an impact on the hydrodynamic and flow pattern induced by ultrasonic field and in turn could effectively influence the mixing of the two-immiscible phases. A more uniform distribution of the aqueous-phase volume fraction was observed in the system with double-nozzle injection in comparison with the single nozzle injection.

Hydrodynamic and mass transfer investigation of oxidative desulfurization of a model fuel using an ultrasound horn reactor

Ultrasound assisted oxidative desulfurization (UAOD) is a promising technology, which can result in ultra-low sulfur fuels in order to reduce the environmental crisis. Most of the researches have been conducted with the experimental approaches. In the present study, a computational fluid dynamic (CFD) model has been developed to investigate the hydrodynamics as well as the reactions involved in a sonoreactor. The results indicate that the physical and chemical effects associated with the ultrasonic field can contribute to the enhancement of the reaction and sulfur removal rates. However, the physical effects are predominant as compared to the chemical effects. Indeed, homogenous mixing and fine micro-emulsification caused by the physical effects lead to increase the interfacial area and mass transfer rate between the immiscible aqueous and oil phases. The dibenzothiophene concentration predicted by the simulation was in a reasonably good agreement with the corresponding experimental data. Another key hydrodynamic parameter induced by ultrasonic field was turbulent kinetic energy, which can play an important role in the sulfur removal rate. The results indicate the higher desulfurization efficiency has been attained at the regions with the higher velocity fluctuations.

Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase

A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images.

Investigation of Salt and precipitating agent effect on the specific surface area and compressive strength of alumina catalyst support

Nowadays, catalyst supports are extensively used to decrease the costs and increase the contact surface area in chemical reactions. Specific surface area, compressive strength, pore volume and pore size are some of the most important characteristics of a catalyst support. In this work, Sol-gel and peptization methods were applied to produce alumina catalyst support. Also the roles of aluminum salts and precipitating agents on the specific surface area and compressive strength of alumina catalyst support were investigated. In addition, various additives and common methods in the increasing surface area, compressive strength and adjusting the porosity and pore size are used in this study. The results show that using caustic soda as precipitating agent and aluminum chloride salt yields catalyst supports with the best compressive strength. Also, using aluminum nitrate and ammonia as precipitating agent produced alumina catalyst support with the highest specific surface area.

CFD study of the flow pattern in an ultrasonic horn reactor: Introducing a realistic vibrating boundary condition

Recently, great attention has been paid to predict the acoustic streaming field distribution inside the sonoreactors, induced by high-power ultrasonic wave generator. The focus of this paper is to model an ultrasonic vibrating horn and study the induced flow pattern with a newly developed moving boundary condition. The numerical simulation utilizes the modified cavitation model along with the "mixture" model for turbulent flow (RNG, k-ε), and a moving boundary condition with an oscillating parabolic-logarithmic profile, applied to the horn tip. This moving-boundary provides the situation in which the center of the horn tip vibrates stronger than that of the peripheral regions. The velocity field obtained by computational fluid dynamic was in a reasonably good agreement with the PIV results. The moving boundary model is more accurate since it better approximates the movement of the horn tip in the ultrasonic assisted process. From an optimizing point of view, the model with the new moving boundary is more suitable than the conventional models for design purposes because the displacement magnitude of the horn tip is the only fitting parameter. After developing and validating the numerical model, the model was utilized to predict various quantities such as cavitation zone, pressure field and stream function that are not experimentally feasible to measure.

Chemical absorption of CO2 into an aqueous piperazine (PZ) solution: development and validation of a rigorous dynamic rate-based model

Carbon dioxide (CO₂) chemical absorption into reactive solvents, is regarded as a proven technology to mitigate global warming aversive effects.

Using maximum entropy approach for prediction of drop size distribution in a pilot plant multi-impeller extraction contactor

In this study, the maximum entropy principle is used to predict the drop size distributions in a multi-impeller column extractor.

CFD Investigation of Hydrodynamic and Heat Transfer Phenomena around Trilobe Particles in Hydrocracking Reactor

In this work, computational fluid dynamics (CFD) has been employed to compute local convection heat transfer coefficient (h) that is the key parameter in calculation of heat transfer rate between the particle and fluids in packed bed reactors. In addition, the relation between Reynolds number and Nusselt number for spherical and trilobe catalyst particles have been investigated. Moreover, the parameters of Ranz-Marshall (R-M) correlation have been estimated in order to use it for trilobe catalyst particle. The heat transfer coefficients of the spherical and trilobe particles were compared and the effect of particle shape and configuration on heat transfer rate has been investigated. Eulerian-Eulerian approach was employed in order to investigate gas-liquid hydrodynamic especially liquid film formation around trilobe particles. The effects of liquid film around a trilobe particle and liquid volume fraction on heat transfer coefficient have also been studied. The CFD simulation results indicate that increasing inlet liquid volume fraction raises the liquid film thickness around the particles leading to reduction of heat transfer coefficient. In addition, the results revealed that flow field and temperature profiles around the particles became more complicated as a result of liquid film formation and gas-liquid interactions.

Evaluation of an 18F-labeled oligonucleotide probe targeting p21(WAF1) transcriptional changes in human tumor cells

The ability to image gene expression using 18F-labeled antisense oligonucleotides (asODNs) directed to specific mRNA transcripts during, or immediately following, radio- or chemotherapy would be a valuable clinical tool to monitor the early tumor response to treatment. Imaging of upregulated p21 mRNA postirradiation using 18F-labeled asODNs could offer insights into early tumor responses by detecting signs of accelerated cellular senescence. Thus, the aim of this work was to evaluate the uptake and distribution of a (radio)-fluorinated asODN in vitro in HCT116 p21(+/+) human colon carcinoma cells, asODN and a random sequence oligonucleotide (rsODN) were conjugated with a (radio)fluorine prosthetic group. Irradiated HCT116 cells were treated with naked or liposome-transfected ODNs. Cell fractionation, confocal microscopy, immunofluorescence, and Western blot studies were performed to observe uptake, distribution, and antisense activity of the probes. [F]asODN demonstrated similar antisense binding ability as the unlabeled asODN to p21 mRNA. Liposomal-transfected 18F-labeled asODNs and rsODNs exhibited a three-to fivefold increase in uptake at 2.5 h compared to the naked [18F]ODNs. Distribution of transfected [18F]asODN in the cytoplasm and endosomes increased over time whereas no change in intracellular distribution was observed with transfected [18F]rsODN or naked ODNs. Antisense activity was not compromised with the addition of a fluorine moiety on asODN. The cellular accumulation and distribution of the (radio)fluorinated ODNs was not altered by the addition of the prosthetic group. Radiolabeled ODNs were able to penetrate the cell with preferential uptake observed with the liposome-transfected probes. Increased distribution of [18F]asODN in the cytoplasm suggests the probe is available for targeting its transcript mRNA. This warrants further investigations into the potential of [18F]asODN to image accelerated senescence postirradiation.