Volume Of Aqueous Phase Research Articles

Smart self-assembled polymeric-MMT/Moringa Oleifera L. particles by solvent replacement method

Obesity, stemming from metabolic syndrome and energy imbalance, is a common health concern characterized by excess energy consumption and fat buildup. Moringa Oleifera L. (MO), known for its anti-obesity properties, is extracted via Soxhlet extraction. MO is extracted using the Soxhlet extraction method. To evaluate the antioxidant properties of MO powder, several analyses were conducted, including the assessment of total phenolic content (TPC), total flavonoid content (TFC), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity. The TPC and TFC, DPPH activity, and ABTS activity values were determined to be 386.7 mg GAE/g and 82.33 mg QE/g, 32.86 %, and 49.4 % respectively. To improve drug delivery, the freeze-dried MO powder was encapsulated within a polymeric carrier, poly(e-caprolactone) (PCL). Moreover, the incorporation of montmorillonite (MMT) into the MO-loaded PCL nanoparticles enhanced the encapsulation efficiency and drug loading of MO. Nanoprecipitation was employed as a method to produce the nanoparticles, and the effects of four key parameters were studied: the ratio of aqueous phase volume to organic volume (1.5 – 10), stirring speed (400 rpm – 1200 rpm), mass weightage of MO (1 % -5 %), and mass weightage of MMT (2 % - 5 %). Design Expert was utilized for full factorial analysis to assess the impact of these parameters on encapsulation efficiency and drug loading. The optimal formulation was achieved at the ratio of aqueous phase volume to the organic volume of 1.5, stirring speed of 400 rpm, mass weightage of MO at 1 %, and mass weightage of MMT at 5% The expected encapsulation efficiency is 91.33 % and drug loading is 6.49 %.

Solvent extraction of lithium from brines with high magnesium/lithium ratios: investigation on parameter interactions.

Solvent extraction of lithium from brine with a high Mg/Li ratio was investigated. Tributyl phosphate (TBP), ferric chloride (FeCl3), and kerosene were used as the extractant, co-extractant, and diluent, respectively. The mechanism of the extraction process was studied by LC-MS, UV-VIS, and FT-IR analyses. Effects of organic to aqueous phase volume ratio (O/A) on the extraction efficiency and separation factor were optimized. The effects of major parameters including Fe/Li molar ratio, hydrochloric acid concentration, and TBP volume percent as well as their interactions on the lithium extraction efficiency were evaluated using central composite design. These major parameters represent interactions within their selected ranges. While the lithium extraction efficiency as the response value in the experimental design showed the most sensitivity to the acid concentration, the separation factors were more affected by alteration in the TBP volume percent with the fixed optimum values of the other major parameters. The highest one-stage extraction efficiency of 76.3% and Li/Mg separation factor of 304 were obtained at the optimum conditions of Fe/Li = 2.99, HCl = 0.01 M, and TBP = 55%. The Mg/Li mass ratio could be significantly reduced from 192 in the feed to 1.5 in the stripping solution. Based on the findings, a schematic diagram of the process including extraction, stripping, and saponification steps was proposed.

Identification and Characterization of Critical Processing Parameters in the Fabrication of Double-Emulsion Poly(lactic-co-glycolic) Acid Microparticles.

In the past several decades, polymeric microparticles (MPs) have emerged as viable solutions to address the limitations of standard pharmaceuticals and their corresponding delivery methods. While there are many preclinical studies that utilize polymeric MPs as a delivery vehicle, there are limited FDA-approved products. One potential barrier to the clinical translation of these technologies is a lack of understanding with regard to the manufacturing process, hindering batch scale-up. To address this knowledge gap, we sought to first identify critical processing parameters in the manufacturing process of blank (no therapeutic drug) and protein-loaded double-emulsion poly(lactic-co-glycolic) acid MPs through a quality by design approach. We then utilized the design of experiments as a tool to systematically investigate the impact of these parameters on critical quality attributes (e.g., size, surface morphology, release kinetics, inner occlusion size, etc.) of blank and protein-loaded MPs. Our results elucidate that some of the most significant CPPs impacting many CQAs of double-emulsion MPs are those within the primary or single-emulsion process (e.g., inner aqueous phase volume, solvent volume, etc.) and their interactions. Furthermore, our results indicate that microparticle internal structure (e.g., inner occlusion size, interconnectivity, etc.) can heavily influence protein release kinetics from double-emulsion MPs, suggesting it is a crucial CQA to understand. Altogether, this study identifies several important considerations in the manufacturing and characterization of double-emulsion MPs, potentially enhancing their translation.

STUDY OF EXTRACTION OF SORBIC AND BENZOIC ACIDS USING BLOCK COPOLYMER “PLURONIC”

characterized by the use of harmless, environmentally friendly reagents. The relevance of the work is due to the increasing requirements for extractants capable of ensuring almost complete extraction of sorbic and benzoic acids from food objects for the purpose of their subsequent quantitative determination. The work is devoted to studying the extracting ability of the Pluronic block copolymer in relation to sorbic and benzoic acids and establishing the patterns of interphase distribution in the studied systems. Nonionic surfactant block copolymers of ethylene oxide and propylene oxide provide high quantitative indicators of interfacial distribution of a wide class of organic substances. In small quantities, sorbic and benzoic acid in food products do not have a negative effect on human health, but high levels of preservatives cause pathologies in the body. Therefore, the development of new methods for the extraction and determination of sorbic and benzoic acids in aqueous media with the aim of further monitoring their content in food objects is an urgent task of analytical chemistry. The article presents the calculated distribution coefficients and the degree of extraction of sorbic and benzoic acids using the Pluronic block copolymer and ammonium sulfate as an extractant. The concentrations of analytes and extractant, as well as the ratio of the volumes of aqueous and organic phases at which maximum extraction characteristics are achieved, have been established. Еlectrophoretic analysis of the aqueous phase after extraction is used in the work. Parameters for the quantitative determination of sorbic and benzoic acids were established. Schemes for the interaction of the block copolymer with analytes due to hydrogen bonds are proposed, taking into account the structural features of Pluronic and the extracted substances. For citation: Pakhomova O.A., Polteva A.V., Mokshina N.Ya. Study of extraction of sorbic and benzoic acids using block copolymer “Pluronic”. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 41-47. DOI: 10.6060/ivkkt.20246707.7020.

Process Optimization of Scaled-Up Production and Biosafety Evaluation of the Dimethyl-Dioctadecyl-Ammonium Bromide/Poly(lactic acid) Nano-Vaccine.

Nano-adjuvant vaccines could induce immune responses and enhance immunogenicity. However, the application and manufacturing of nano-adjuvant is hampered by its challenging scale-up, poor reproducibility, and low security. Therefore, the present study aimed to optimize the preparation nanoparticles (NPs) using FDA-approved biopolymer materials poly(lactic acid) (PLA) and cationic lipid didodecyl-dimethyl-ammonium bromide (DDAB), develop the scale-up process, and evaluate the stability and biosafety of it. The optimum preparation conditions of DDAB/PLA NPs on a small scale were as follows: DDAB amount of 30 mg, aqueous phase volume of 90 mL, stirring rate at 550 rpm, and solidifying time of 12 h. Under the optimum conditions, the size of the NPs was about 170 nm. In scale-up preparation experiments, the vacuum rotary evaporation of 6 h and the Tangential flow ultrafiltration (TFU) method were the optimum conditions. The results suggested that DDAB/PLA NPs exhibited a uniform particle size distribution, with an average size of 150.3 ± 10.4 nm and a narrow polydispersity index (PDI) of 0.090 ± 0.13, coupled with a high antigen loading capacity of 85.4 ± 4.0%. In addition, the DDAB/PLA NPs can be stored stably for 30 days and do not have side effects caused by residual solvents. For biosafety, the acute toxicity experiments showed good tolerance of the vaccine formulation even at a high adjuvant dose. The local irritation experiment demonstrated the reversibility of muscular irritation, and the repeated toxicity experiment revealed no significant necrosis or severe lesions in mice injected with the high-dose vaccine formulation. Overall, the DDAB/PLA NPs exhibit potential for clinical translation as a safe candidate vaccine adjuvant.

Mechanical and Thermal Properties of Porous Nanocellulose/Polymer Composites: Influence of the Polymer Chemical Structure and Porosity.

The excellent emulsifying capacity of nanocellulose allows for the preparation of porous nanocellulose/polymer composites through the emulsion templating process. However, the effects of the polymer chemical structure and porosity on the material properties have not been extensively explored. Here, we discuss the effects of these two factors on the thermal and mechanical properties of the composites. Two types of porous nanocellulose/polymer composites were fabricated with styrene-divinylbenzene (poly(St-co-DVB)) or styrene-poly(ethylene glycol) dimethacrylate (poly(St-co-EGDMA)) copolymers as the polymer phases. The porosity of the composite was changed up to ∼50% v/v by varying the aqueous phase volume fraction in the original nanocellulose-stabilized w/o emulsions. As the porosity increased, the thermal conductivity of the composite decreased. The mechanical properties were strongly influenced by the polymer type; the nanocellulose/poly(St-co-DVB) composite showed stiff but brittle behavior, whereas the nanocellulose/poly(St-co-EGDMA) composite showed higher strength and toughness. In both types of composites, the nanocelluloses served as reinforcing agents, contributing to the improvement of the mechanical properties.

Tannic acid coated nanosuspension for oral delivery of chrysin intended for anti-schizophrenic effect in mice

Chrysin is a flavonoid drug with numerous therapeutic activities. It suffers from low intestinal absorption owing to its hydrophobicity. Therefore, the aim of this study is to exploit the efficient technique of nanosuspension (NSP) to formulate chrysin-NSP coated with tannic acid (TA) to improve the solubility and anti-schizophrenic activity of chrysin. A 23 full factorial design was constructed where the independent factors were type of polymer, surfactant concentration (0.5 or 1 %) and the aqueous phase volume (5 or 15 mL), while the dependent responses were the particle size (PS) of the obtained formulation as well as the % chrysin dissolved after 2 h (Q2h). The optimum formulation (NSP-4) composed of 1 % PEG 400 and 1 % Cremophor RH40 in 15 mL aqueous phase. It achieved a PS and Q2h values of 108.00 nm and 38.77 %, respectively. NSP-4 was then coated with TA (TA-coated NSP-4) for further enhancement of chrysin solubility. TA-coated NSP-4 revealed PS and zeta potential values of 150 ± 14 nm and –32.54 ± 2.45 mV, respectively. After 6 h, chrysin dissolved % were 53.97 and 80.22 for uncoated NSP-4 and TA-coated NSP-4, respectively, compared with only 9.47 for free chrysin. The developed formulations and free chrysin were assessed regarding their effect on schizophrenia induced in mice by cuprizone (CPZ). Treatment with the developed formulations and free chrysin ameliorated demyelination and behavioral deficit induced by CPZ via elevating MBP and PI3K/PKC activities as well as reducing GFAP expression levels. The developed formulations and free chrysin inhibited Galactin-3 and TGF-β expressions and stimulated GST antioxidant enzyme. Furthermore, they maintained the balances in glutamatergic and dopaminergic neurotransmission via modulation on neuregulin-1 and alleviated nuclear pyknosis and degeneration in the neurons. The order of activity was: TA-coated NSP-4 > NSP-4 > free chrysin.

Encapsulation of mRNA in lipid nanoparticles by membrane micromixing

Messenger RNA encapsulated in lipid nanoparticles (mRNA-LNPs) are successfully used worldwide for vaccination against COVID-19. mRNA-LNPs are manufactured by mixing an ethanolic phase (containing an ionizable lipid, a phospholipid, a PEGylated lipid and cholesterol) and an aqueous phase (citrate buffer at pH 4.5 containing mRNA). The characteristics of the mRNA-LNPs obtained (size, internal structure, mRNA functional delivery in vivo, etc) depend on several parameters and among them are the mixing conditions of the ethanolic and aqueous phases. While the impact of these parameters is well-recognized for small scale preparations (some microliters), their effect at a larger scale is less well-known. The purpose of this study is to investigate the production of some hundreds of millilitres of mRNA-LNP suspension using a ceramic membrane (SPG Technology) as a new mixing device. Summarily, in this technique, the ethanolic phase permeates through the membrane pores and mixes with the aqueous phase flowing in a small annular pipe between the tubular membrane and an inside rod. First, empty LNPs were prepared to determine the effect of membrane pore size, flow rate, and the ratio between the ethanolic and aqueous phase volumes. The experimental conditions tested did not change the characteristics of the LNPs obtained. Second, mRNA-LNPs were prepared and the suspensions obtained were then submitted to buffer exchange/concentration/ sterile filtration dialysis. The resulting mRNA-LNPs had a particle size of 103 ± 5 nm, a polydispersity index of 0.15 ± 0.005, and encapsulation efficiency of 96 ± 0.0 %. mRNA-LNPs with similar characteristics were obtained using ethanol ratios of 1/4 (20 % ethanol in the final preparation) and 1/6 (14 % ethanol). Overall, membrane micromixing using a ceramic membrane was shown to be a suitable technology for the preparation of mRNA-LNP suspensions.

A greener sample preparation procedure using reverse-phase dispersive liquid–liquid microextraction for multielement determination of inorganic species in petroleum-derived samples

This study describe the development and first application of reverse-phase dispersive liquid–liquid microextraction (RP-DLLME) sample preparation for the determination of Ca, Cd, Cu, Fe, K, Mg, Mn, Ni, Pb, and Zn in petroleum-derived samples using inductively coupled plasma optical emission spectroscopy (ICP OES). Some factors inherent to RP-DLLME were optimized using multivariate statistical analysis through the 24 full factorial design followed by the Doehlert matrix. The established RP-DLLME procedure employs 5.0 g of samples, 1600 µL of the 3.75% (v/v) HNO3:isopropyl alcohol [3:1 (v/v)] extractive solution, 10 min of thermostatic bath at 80 °C, 60 s of vortexing, 3 min of sonication at 55 °C, and 15 min of centrifugation at 3500 rpm. The resulting aqueous phase volume was adjusted up to 15 mL with ultrapure water, and ICP OES carried out the measurements. Relative standard deviations (RSD) less than 3.5%, linear correlation coefficients better than 0.9985, and limit of detection (LOD) in the range of 0.57 ng g−1 (Mn) to 107.6 ng g−1 (K) were obtained for the determination of the analytes. Accuracy of the RP-DLLME using ICP OES was evaluated by analysis of the V21 + K metallo-organic standard, and recovery percentages within the 89.4–98.3% interval with RSD less than 6.4% were obtained. The accuracy and precision were also evaluated through a recovery test, and the results were in the range of 87.1–95.7% with RSD less than 4.9% for all analytes. Therefore, the RP-DLLME-ICP OES methodology was successfully applied to gasoline, diesel oil, JET-A1 (jet fuel), Avgas (aviation gasoline), lubricant oil, and vaseline samples, and the contents were obtained for almost all analytes. Although there are no regulatory resolutions for all petroleum-derived samples, the content of the analytes determined in JET-A1 and Avgas samples complied with ANP Resolution No. 856/2021 and 901/2022 legislation, respectively. Furthermore, the relative simplicity of the RP-DLLME combined with the accurate and precise measurements carried out by ICP OES can be a viable alternative in routine analysis.

Extraction and separation studies of Nd/Fe and Sm/Co by deep eutectic solvent containing Aliquat 336 and glycerol

AbstractBACKGROUNDIn today's technologically developed society, the demand for materials with enormous applications in electrical and electronic devices has been sharply increasing. Rare earths, like neodymium and samarium, are two of these high‐demand materials. Their widespread use as permanent magnets in association with some transition metals (like iron and cobalt) has created the need to design novel and environmentally benign pathways for their extraction and separation.RESULTSThe present work demonstrates the use of a novel deep eutectic solvent (DES) synthesized from Aliquat 336 and Glycerol diluted in kerosene for the solvent extractive separation studies of Nd/Fe and Sm/Co from nitrate medium. The variations in thermophysical attributes (like density, dielectric permittivity, and refractive index) provide insight on their extraction behavior, DES efficiency, and separation feasibility. Effects of variable experimental conditions, like pH, mixing time, temperature, DES molarity, nitrate concentration, and phase volume ratio, on separation have been examined. Complete separations of Nd(III)/Fe(III) and Sm(III)/Co(III) were achieved under multiple extraction conditions. Using the organic to aqueous phase volume ratio (O/A) ratio = 2:1 (pH = 2, [NaNO3] = 3.5 M, [DES] = 0.2 M, T = 298 K), the highest extraction percentage of Nd(III) was found to be 93.8%, and with O/A = 4:1(pH = 2, 2 M NaNO3, 0.2 M DES, 298 K), that of Sm(III) was 93.6%. Stripping was 100% for Nd and Sm using 0.6 M HCl.CONCLUSIONAli‐Gly DES diluted in kerosene showed the highest selectivity for Nd, then for Sm, followed by Fe. It did not extract cobalt under the considered conditions. A lower time consumption, room temperature separation, and the low concentration of DES used are the major findings of the present research work. © 2023 Society of Chemical Industry (SCI).

Modelling the partitioning equilibria of nonionic surfactant mixtures within the HLD framework

Commercial non-ionic surfactants are usually blends of species differing in the degree of ethoxylation, characterised by a distribution of surfactants with different affinity for the oil and the aqueous phases. This leads to an unexpected concentration dependence of the phase behaviour and the rationalization of such deviations is necessary for their exploitation in surfactant-based formulations. In this work, the phase behaviour of commercial Novel® nonionic surfactants in presence of brine and oil was studied fixing equal volumes of organic and aqueous phases and changing the amount of surfactant and brine salinity (fish cut). The conditions for the balanced state (microemulsion solubilizing equals amount of water and oil) have been determined for different alkanes. The phase behaviour of the surfactant mixture was described, without a priori information about its actual chemical composition, in terms of two pseudo-components: one hydrophilic, entirely at the interface, and the other lipophilic, able to partition itself between the interface and the oil bulk according to a partition constant P. The pseudo-components effect on the interface is quantified through surfactant characteristic parameters (SCPs), according to the Hydrophilic-Lipophilic-Difference (HLD) model. SCPs and P can be experimentally determined by fitting the dependence of the balanced state on the surfactant concentration. The model is successfully applied to the tested surfactants and can quantitively predict the behaviour of their mixtures.

Characterization of chemical and carbon isotopic compositions of gases during thermochemical sulfate reduction and implications for gas origin and content

For identifying the occurrence and extent of thermochemical sulfate reduction (TSR) reaction of natural gas and better understanding the chemical and carbon isotopic variations in natural gas reservoirs, high-pressure hydro-pyrolysis with a special designed apparatus was performed using natural gas and various amounts of MgSO4·7H2O at up to 360 °C. The yields, chemical and isotopic compositions of the gases produced during TSR and thermal cracking were measured. As the extent of TSR reaction increased, the concentrations of CH4, CO2 and H2S increased in a nonlinear way, while those of C2H6 and C3H8 decreased. According to the variation of gas content, the TSR reaction of alkane gases can be divided into an uncatalyzed and a catalyzed stage, which is different from previous studies that treated the TSR reaction of alkane gases as a non-autocatalytic reduction process. As the concentration of MgSO4·7H2O increased, the rate of TSR reaction with hydrocarbon gases increased. The concentrations of HSO4− and volume of aqueous phase could be responsible for the different TSR reaction rates in the catalyzed stage. The co-variation of ln(C1/C2) and ln(C2/C3) could be related to the TSR reaction of alkane gases. Our study provides clues for understanding the compositional variations in natural conditions.

Ultrathin polyamide membranes enabled by spin-coating assisted interfacial polymerization for high-flux nanofiltration

While nanofiltration (NF) membranes have much potential for precise molecule/ion separations, the thick nanofilms fabricated via rapid and irreversible interfacial polymerization (IP) result in low water permeance. The distribution and location of aqueous monomers play a pivotal role in the IP reaction and thus in the polyamide films, yet are rarely reported to improve the performance. In this study, a one-step spin-coating procedure was utilized to deposit diamines atop porous polysulfone substrates followed by IP reaction for construction of ultrathin polyamide membranes. Direct spin-coating of aqueous diamines onto a porous substrate allows for a uniform diamine deposition, demonstrated by confocal laser scanning microscope analysis. In addition to the uniform distribution, this procedure is able to enrich the diamines beyond the surface pores, contributing to the formation of ultrathin polyamide layers based on Freger’s theory. Importantly, rational regulation of spinning speed, aqueous phase volume, and IP reaction parameters allows to optimize the membrane microstructure and separation performance. The optimal TFC membranes with 9.7-nm-thick polyamide nanofilm evince a remarkably high water permeance of 36.1 L m-2 h−1 bar−1, and an acceptable divalent Na2SO4 rejection of 96.2%. An extended use of spin-coating assisted IP onto other substrates also yields high-flux polyamide NF membranes (TFC-Kevlar: 37.9 L m-2 h−1 bar−1, 97.5%, TFC-polyacrylonitrile: 41.7 L m-2 h−1 bar−1, 96.2%), confirming the applicability and high efficiency of this approach. In contrast with established methods, spin-coating assisted IP (SCIP) features distinct superiorities in economizing diamine dosage, ease of control, and attaining an excellent sieving performance, which paves the way of constructing high-performance NF membranes.

1D magnetic resonance imaging and low-field nuclear magnetic resonance relaxometry of water-based silica nanofluids

The purpose of this research is to investigate 1-D Magnetic Resonance Imaging (MRI) and low-field Nuclear Magnetic Resonance (NMR) relaxation characteristics of silica nanofluids. The results show that presence of silica nanoparticles increases the MRI signal intensity and influences the NMR relaxation by shifting the relaxation peaks toward faster times compared to deionized water (DIW). Additionally, inversion recovery sequences show that nanoparticles reduce longitudinal relaxation time. For the tested nanofluid of EOR-12, signal intensity, longitudinal relaxation rate and transverse relaxation rate show a strong linear dependence on nanoparticle concentration with the highest enhancement of 1.75-fold, 2.57-fold and 3.20-fold, respectively compared to DIW. Additionally, investigation of the effect of nanoparticle size shows that below an optimal size, the MRI signal intensity and the NMR relaxation rates show a positive correlation with nanoparticle size but above the optimal size, the behavior reverses. For the nanoparticle with the optimal diameter, signal intensity, longitudinal relaxation rate and transverse relaxation rate enhancement was 2.21-fold, 4.44-fold and 4.45-fold, respectively compared to DIW. Application of the observed improvement in signal intensity to obtain the profile of the aqueous phase volume fraction in a Pickering emulsion shows a maximum error of 8% which indicates that the proposed technique can be applied for emulsion characterization with good accuracy.

Reverse Micellar Extraction of Copper Ions from Wastewater: Modelling and Simulation

The waste streams from various agencies like textile, leather, electroplating, and process industries are generating pollutants in the form of effluents or by products. These waste streams consist of various carcinogenic pollutants such as dyes and heavy metals above the permissible limits. Numerous effluent treatment techniques have been implemented for the removal of these pollutants before their discharge into the water body. In this work, reverse micellar extraction was used for the removal of copper ions (heavy metal ions) from the waste stream. Mathematical models namely, the ion exchange reaction model and electrostatic model were developed in order to compare the experimental data with model predictions with regard to the effect of process parameters such as initial metal ion concentration, sodium bis-2-ethyl hexyl sulphosuccinate (AOT) concentration, and organic to aqueous phase volume ratio on final copper ion concentration in the aqueous phase. The ion exchange reaction model was based on chemical and electrostatic interactions between heavy metal ions and the surfactant head groups at the reverse micellar interface, whereas the electrostatic model was based on the adsorption of metal ions on the reverse micellar interface due to electrostatic force of attraction with no chemical bonding. The developed mathematical models were found in close agreement with the experimental data. Atomic absorption spectroscopy (AAS) was used to measure the metal ion concentration in the aqueous phase.

Fabrication of ultrastable water-in-oil high internal phase emulsion as versatile delivery vehicle through synergetic stabilization

Bioactive substances possess superior antioxidant, anti-hypertensive, and anti-tumor activities. However, their susceptibility to degrade at low pH often limit their application. Compare with the conventional oil-in-water (W/O) emulsions, the lack of natural hydrophobic stabilizers resulted in difficulties in fabricating water-in-oil (W/O) high internal phase emulsion (HIPE). Further, the instability of W/O HIPE also limit its industrial application in food industry. In the present study, a natural, conventional, eco-friendly, and structured W/O HIPE was developed using glyceryl monostearate (GMS) as emulsifier and beeswax and gellan gum as structurant. The system with the synergetic effect of emulsifier and structurant, accounted for 0.25 wt % of GMS and hydrogel, and 1.25 wt % of beeswax in total system endowed the W/O HIPE with biphasic rigid network and impressive storage stability. The microstructures of these newly developed W/O HIPEs could be controlled by the beeswax concentration (cb), GMS concentration (cg), and aqueous phase volume (Φ). Moreover, the GMS-based emulsion encapsulation improved the retention rate of betanin by 36.68% after 7 days of storage. Meanwhile, this emulsion gel could prevent the nucleophilic attack of hydrogen ions against betanin at room temperature under a low pH environment, which greatly improved the stability of betanin under highly acid conditions. Furthermore, the GMS stabilized W/O HIPE possessed pH-sensitive, which could achieve controlled-release of both hydrophilic and hydrophobic functional compounds in an in vitro simulated release assay.

Separation-preconcentration and ultra trace lead determination in the environmental sample by a combination of ion-imprinted polymer and solidification of floating organic drop microextraction

ABSTRACT The ion-imprinted polymer combined with the solidification of floating organic drop microextraction has been developed as an ultra-pre-concentration technique to determine lead ions in real samples. In ion-imprinted polymer – solidification of floating organic drop microextraction, lead was adsorbed from a large volume of aqueous samples (500 mL) into 100 mg of the ion-imprinted polymer sorbent. After the elution of lead ions from the sorbent by using nitric acid, the solidification of floating organic drop microextraction technique was performed on the obtained solution. Several important extraction parameters, such as weight of ion-imprinted polymer (mg), pH, uptake time (min), desorption time (min), HNO3 desorption volume (mL) aqueous-phase volume (mL), were studied and optimised. The ion–imprinted polymer particles were characterised by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). The new method (SPE–SFODME) provided an ultra-enrichment factor (5000) for lead. The calibration graphs were linear in the range of 5–200 ng L−1. The optimum conditions for the method were as follows: pH of solution, 7.5; weight of ion-imprinted polymer, 100 mg; type and concentration of eluent, HNO3 1 M; volume of eluent, 1 mL; sorption time, 25 min; desorption time, 15 min. Under optimum conditions, the limit of detection (LOD) was 1 ng L−1 for lead and relative standard deviation (RSD %) for five replicate determinations of 10 ng L−1 for lead was 6.5%. The results for the determination of lead ions in reference materials, tap water, ground vegetables, butter and flour wheat demonstrated the accuracy, recovery and applicability of the presented method.

Solvent extraction and separation of zinc-iron from spent pickling solution with tri-n-octylamine

Studies on the effective extraction and separation of zinc-iron from spent pickling solution using tri-n-octylamine (TOA) with solvent extraction were investigated. Single extraction efficiency of 83.75% is obtained under the optimal conditions (organic phase consisting of 30% (v/v) extractant TOA, 20% (v/v) modifier iso-octanol, and 50% (v/v) diluent sulfonated kerosene, organic phase volume: aqueous phase volume of 2:1, and extraction time 10 min), while only 1.8% iron is co-extracted. McCabe-Thiele diagram is employed to analyze the number of theoretical stages needed for the effective extraction of zinc, and it is found that under five-stage counter-current extraction, almost all the zinc ions are extracted. A stripping efficiency of more than 90% from the loaded organic phase is achieved by 2.0 mol/L NH3·H2O and organic phase volume: aqueous phase volume of 1:2. Furthermore, the extraction mechanism of zinc with TOA accompanied by anion exchange is demonstrated by FT-IR spectra analysis and ESI-MS analysis, and the structure of the extracted complex is confirmed as [R3NHZnCl3].

In-Vitro kinetic release study of illicium verum (Chakraphool) polymeric nanoparticles

In traditional medicine, Illicium verum is regarded as the most important plant as it possesses a variety of active components which are responsible for medicinal characteristics such as antifungal, antibacterial, and anti-carminative effects. Nanoparticles have been synthesized from illicium verum employing biodegradable polymer like poly (lactic-co-glycolic acid) PLGA which is widely used as a drug delivery system owing to its two significant properties such as biocompatibility and controlled drug release characteristics. Earlier synthesis, characterization, and antimicrobial studies on these biocompatible nanoparticles were carried out, however, kinetic release models need more instigation. The objective behind this work is to formulate illicium verum loaded PLGA nanoparticles employing solvent evaporation technique and to study kinetic release patterns of the synthesized biocompatible nanoparticles. This work considers the effects of some preparation variables on the size and shape of synthesized nanoparticles and the results show that sonication time, polymer content, the ratio of organic to aqueous phase volume, and the amount of drug have a significant effect on the size of nanoparticles. Polymeric nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) which shows nanoparticles with a size range below 270 nm was successfully prepared. The drug release from drug-loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by using various kinetic models. The release profile corresponds to first-order kinetics, specifying that the delivery phase is directly proportional to the absorption of therapeutics in the nanoparticulate, and corresponds to the Higuchi model, indicating medication released by diffusion. The effectiveness of various dosage kinds is controlled by studying the drug's release pattern.

Separation of niobium and tantalum using continuous multistage counter-current solvent extraction with trioctyl amine

Niobium and tantalum are valued for their uses in nuclear, steel, aviation and electronics industries. This paper elucidates the development of a multistage counter-current separation process for obtaining pure niobium and tantalum from the hydrofluoric acid solution of Coumbite-Tantalite ore (leach liquor), with trioctyl amine (TOA) as the extractant solvent. Contrary to the conventionally used multistage process this novel route does not use any other acid in addition to hydrofluoric acid, resulting in the elimination of the generation of mixed fluoride waste. Reaction equilibrium constants for the reactions involving the extraction of hydrofluoric acid, niobium and tantalum have been determined and were used to generate equilibrium distribution curve of niobium and tantalum in the organic and aqueous phase. The number of counter-current stages required for an appropriate organic to aqueous phase volume (O/A) ratio was determined using McCabe-Thiele calculations. Selective extraction of 99% of tantalum from the leach liquor was achieved using 5 v/v% TOA and two counter-current stages for an O/A ratio of four. The tantalum lean raffinate was treated with commercial grade hydrofluoric acid to form the niobium feed solution having 16 M free acidity. Near complete extraction of niobium was achieved using a three stage counter-current process with O/A ratio of two and 10 v/v% TOA as the organic extractant. The calculations for the stage-wise variation of concentrations were validated by batch experimental simulation of counter-current processes.