Concentration In Aqueous Phase Research Articles

Synthesis and study of organo-modified silica based hydrogels: Rheological properties and drug release kinetics.

The method of synthesis of unmodified and organo-modified silica hydrogels and their composites with orotic acid as a model drug was developed. The hydrogels had a pH of 6.5-7.8. The particulate nature and highly porous structures of the hydrogel materials were revealed using scanning electron and optical microscopy methods. The content of aqueous phase in the hydrogels was 99% or more. In order to evaluate the possibility of their application as a basis for development of novel soft drug formulations and cosmetic compositions, rheological properties of the hydrogels and in vitro release kinetics of the drug were studied. The effects of synthesis conditions (increasing concentration of catalyst of silica sol formation, drug loading) and the silica matrix modification with various organic groups on the indicated properties were investigated. It was found that all synthesized hydrogels exhibited pseudoplasticity, thixotropy and controlled release of the drug, which are important for their potential application. However, in general, the indicated effects led to worsening the properties of the hydrogel materials in comparison with the unmodified silica hydrogels.

Photo-Oxidation of α-Pinene Oxidation Products in Atmospheric Waters - pH- and Temperature-Dependent Kinetic Studies.

The atmospheric α-pinene oxidation leads to three carboxylic acids: norpinonic acid (NPA), pinic acid (PA), and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA). In this study, the OH radical kinetics in the aqueous phase of these carboxylic acids were investigated at different temperatures and pH values of solutions. Activation parameters and the corresponding atmospheric lifetimes of the acids in the troposphere were derived. The overall second-order rate constants for the individual speciation forms of the acids (AH and A- for NPA; AH2, AH- and A2- for PA; and AH3, AH2-, AH2- and A3- for MBTCA) were determined. At 298 K, the rate constants for reactions of protonated forms (AHx) of NPA, PA, and MBTCA with •OH, were (1.5 ± 0.2) × 109 L mol-1 s-1, (2.4 ± 0.1) × 109 L mol-1 s-1, and (4.1 ± 0.6) × 108 L mol-1 s-1, respectively. For the fully deprotonated forms (Ax-) of studied acids, the second-order rate constants were (2.2 ± 0.2) × 109 L mol-1 s-1, (2.8 ± 0.1) × 109 L mol-1 s-1, and (10.2 ± 0.7) × 108 L mol-1 s-1 at 298 K, respectively. It was found that the reactions of NPA and PA with OH radicals are faster than with MBTCA. For MBTCA, the reaction rate depends on pH more strongly at elevated temperatures (>298 K). The atmospheric lifetimes of the acids considered due to their reactivity with •OH were calculated for different model scenarios at a temperature of 283 K and pH = 2 in the aqueous phase. For this purpose, liquid water content (LWC) was used for aerosols and clouds under storm conditions and at various aqueous-phase concentrations of OH radicals. The lifetimes decreased with increasing LWC (from 10-12 m3 m-3 in aerosol to 10-5 m3 m-3 in storms), indicating that the acids undergo significant aqueous processing under realistic atmospheric conditions. Besides, the aerosol systems appeared less effective in removing PA and NPA, with lifetimes ranging from hundreds of days to tens and hundreds of hours, respectively. Clouds were more effective, with lifetimes ranging from tens of hours to a single second or less. MBTCA, which dissolves better in water, was effectively removed in all systems, with the longest lifetime of approximately 90 min.

Utilization of the waste aqueous phase from tea residue hydrothermal carbonization for preparing active food packaging films

Hydrothermal carbonization (HTC) is an effective strategy for high-value utilization of tea residue (TR), and it was noticed the aqueous phase (AP) has not been extensively studied. This study aimed to investigate the chemical components and characteristics of the AP, and applied it in active food packaging films. The results showed that the total phenolic content of AP was 1.86 mg GAE/mL, and the main compounds in AP were organic acids, alcohols, and amino acids. The AP showed excellent antibacterial activity and antioxidant capacity. The active films were prepared using the casting method. The 4:7-AP/PVA film showed outstanding mechanical properties (tensile strength = 34.18 MPa, elongation at break = 458.67%), antioxidant ability (DPPH scavenging capacity 92.01%), antibacterial activity, water resistance and biocompatibility. The banana preservation test showed the AP/PVA films could successfully prolong the shelf-life of bananas and have the potential to be food packaging films.

Multicomponent steady-state modeling, performance optimization and prediction of cleaning frequency for treatment of cellulosic manmade fibre industry stream using polysodium 4- styrenesulfonate (PSS) incorporated nanofiltration membrane

Effect of polysodium 4-styrenesulfonate (PSS) in the skin layer on performance of nanofiltration (NF) membrane was analyzed for treatment of saline stream from manmade fiber industry. The NF membrane with 0.05 % (w/w) PSS concentration in aqueous phase had better hydrophilicity (contact angle: 330) and water flux of 27 L.m−2.h−1 along with significant salt rejection (Na2SO4: 90 %, CaSO4: 85 % and NaCl: 80 %) at transmembrane pressure 8.3 bar and crossflow rate 100 L.h−1. A long-term study with the wastewater showed that the intermittent cleaning of the membrane every 6 h led to 16 L.m−2.h−1 average permeate flux and sulfate rejection above 95 %.A two-component, steady-state model was used to quantify the performance of the selected membrane. Based on the fouling study, a semi-empirical theory was proposed to identify the cleaning frequency. The theory developed is useful for the operation, maintenance and recovery of the divalent salts from reject stream of such industry.

Creating and Evaluating Herbal Anti-Ageing Cream Contains Pomegranate Seed Oil

 Introduction: The skin is the most important exposed a part of the body, is crucial in establishing social bonds and defending against environmental harm. In the present scenario to look attractive is a primary concern for the growing population in order to maintain social integrity and well being. However cell death is a natural process but due to highly stressful environmental conditions now a day’s skin aging is a primary concern for dermatologists. In the present research work we aim to develop a novel anti-ageing cream for the prevention and treatment of unnatural skin ageing by utilizing pomegranate seed oil.  Method: The pomegranate seed oil was purchased from Amarnath export Bangalore Karnataka. The preparation of anti-aging cream was accomplished through conventional method by taking pomegranate seed oil as an oily phase and stearic acid as an emulsifying agent. The formulation was optimized by varying the concentration of aqueous and oily phase.  Result and Discussion: The pH of the developed cream was found to be 7.2 ± 1.2 and viscosity was found to be 5639±2.51cps. Furthermore the spreadibility of the developed cream was found to be 26.6 ±0.2 gm*cm/sec. The developed formulation showed no skin irritation or erythema and also it was easily washable from skin. The stability study of the formulation was studied for 3 month at room temperature (25oC) which suggests high stability as no indication of cracking, phase separation or any other visual change was observed. Furthermore the developed formulation was analyzed through in vivo animal model(Albino wistar rat) which suggest high biocompatibility and potential in the management of skin ageing.  Conclusion: In conclusion we have developed a novel pomegranate seed oil based anti-aging cream for the prevention and treatment of unnatural skin ageing caused by the vulnerable environmental conditions. The developed formulation was analyzed through extensive in vitro and in vivo characterization which proves the potential of the developed cream in the management of unnatural skin ageing.

Synthesis of AuNPs in microemulsion and nano-emulsion systems using aqueous extract of C. chayamansa leaves as reducing agent

This paper explores the synthesis and characterization of gold nanoparticles using various microemulsion and nano-emulsion systems. The pseudo-ternary system consists of an aqueous phase / Brij O10: 1,2-hexanediol (1:1) / castor oil; the aqueous phases include the aqueous extract of Chaya Maya (Cnidoscolus chayamansa) leaves or aqueous extract of Chaya maya leaves combined with the inorganic gold precursor. Chaya maya extract act as a reducing agent for gold (III) ions. The influence of aqueous phase content and surfactant concentration on gold nanoparticles size, morphology, and stability is investigated. Dynamic Light Scattering, Scanning Transmission Electron Microscopy, and UV-Vis spectroscopy are employed to analyze the synthesized gold nanoparticles. The sizes of the gold nanoparticles obtained were influenced by the system composition and are within the range of 19–40 nm. Results indicate that increasing the aqueous phase content generally leads to larger nanoparticle sizes, while higher surfactant concentrations yield smaller nanoparticles. A transition from microemulsion to nano-emulsion is observed at a specific aqueous phase content, marking a shift in nanoparticle size distribution and growth behavior. Additionally, microemulsion and nano-emulsion systems provide stability to gold nanoparticles, as evidenced by measured Zeta potentials indicating negatively charged surfaces conducting to colloidal stability. Also, remark that the use of organometallic precursors is no needed to obtain very good results on nanoparticle size and shape when O/W systems are used to this end. These findings highlight the potential of tailored microemulsion and nano-emulsion systems formulated with low-toxic components for controlling gold nanoparticles properties under mild conditions, contributing to the development of advanced gold nanoparticles-based materials with enhanced functionalities, with implications for diverse applications.

Solvent Extraction with Cyanex 923 to Remove Arsenic(V) from Solutions.

The removal of harmful arsenic(V) from aqueous solutions using Cyanex 923 (solvation extractant) was investigated using various experimental variables: equilibration time, the acidity of the aqueous phase, temperature, extractant and arsenic concentrations, and O/A ratio. Cyanex 923 extracted As(V) (and sulfuric acid) from acidic solutions; however, it could not be used to remove the metal from slightly acid or neutral solutions. The extraction of arsenic is exothermic and responded to the formation of H3AsO4·nL species in the organic phase (L represents the extractant, and the stoichiometric factor, n = 1 or 2, depends on the acidity of the aqueous phase). Extraction isotherms are derived from the experimental results. Both arsenic and sulfuric acid loaded onto the organic phase can be stripped with water, and stripping isotherms are also derived from the experimental results. The selectivity of the system against the presence of other metals (Cu(II), Ni(II), Bi(III), and Sb(III)) is investigated, and the ability of Cyanex 923 to extract As(V) and sulfuric acid compared to the use of other P=O-based solvation reagents, such dibutyl butylphosphonate (DBBP) and tri-butyl phosphate (TBP), is also investigated.

Electrochemical Oxidation of Hydrothermal Liquefaction-Derived Aqueous Phase for Simultaneous H2 Production

Hydrothermal liquefaction (HTL) is a thermochemical process in which high water containing feedstocks (95%-75%) such as food waste or sewage sludge is converted into fuels. There are four different phases generated during HTL, namely biocrude (oil phase), biochar (solid phase), aqueous phase and gaseous phase. The biocrude phase needs to be processed with hydrogen (H2) via catalytic hydrotreating to produce gasoline, diesel, jet oil. The aqueous phase (AP) contains up to 5 wt% organic compounds mostly in the form of carboxylic acids and amines and inorganics (e.g., Na, K) and cannot be treated with traditional wastewater treatment technologies (e.g., anaerobic digestion). Hence, it is necessary to treat this wastewater so it can be released safely.Electrocatalysis represents a novel approach to treat this AP waste stream while simultaneously generating the H2 needed for hydrotreating. Instead of using traditional water electrolysis (H2O → 2 H+ + 2 e- + ½ O2, E° = − 1.18 V, ∆H° = 275 kJ/mol H2), we explore electrocatalytic oxidation (ECO) of organic molecules (e.g., CH3COOH + 2 H2O → 2 CO2 + 8 e- + 8 H+, E° = − 0.02 V, ∆H° = 53 kJ/mol H2) to simultaneously remove organics from the HTL-derived AP while simultaneously producing H2. The HTL-derived AP can have different concentration and composition of both organics as well as inorganics, which depend on the source feedstock. The ECO of different HTL-derived wastewaters was evaluated in this study. It was studied, how the concentration and source of AP as well as the electrochemical reaction conditions affect the organic removal as well as the H2 production in both batch cell and continuous flow-cell configuration. Our results show that the presence of organics decreases the current density as well as causes anode deactivation after 40 h of operation in the continuous flow cell. However, the cathode performance and stability remained unaffected for more than 1,000 h. Different strategies were evaluated to enhance the life of the electrode and running the system under alkaline conditions improved the anode stability 5 folds References Andrews, E.; Lopez-Ruiz, J. A.; Egbert, J. D.; Koh, K.; Sanyal, U.; Song, M.; Li, D.; Karkamkar, A. J.; Derewinski, M. A.; Holladay, J.; Gutiérrez, O. Y.; Holladay, J. D., Performance of Base and Noble Metals for Electrocatalytic Hydrogenation of Bio-Oil-Derived Oxygenated Compounds. ACS Sustainable Chemistry & Engineering 2020, 8 (11), 4407-4418.Lopez-Ruiz, J. A.; Qiu, Y.; Andrews, E.; Gutiérrez, O. Y.; Holladay, J. D., Electrocatalytic valorization into H2 and hydrocarbons of an aqueous stream derived from hydrothermal liquefaction. Journal of Applied Electrochemistry 2021, 51 (1), 107-118.Lopez-Ruiz, J. A.; Andrews, E.; Akhade, S. A.; Lee, M.-S.; Koh, K.; Sanyal, U.; Yuk, S. F.; Karkamkar, A. J.; Derewinski, M. A.; Holladay, J.; Glezakou, V.-A.; Rousseau, R.; Gutiérrez, O. Y.; Holladay, J. D., Understanding the Role of Metal and Molecular Structure on the Electrocatalytic Hydrogenation of Oxygenated Organic Compounds. ACS Catalysis 2019, 9 (11), 9964-9972. Figure 1

Geospatial and co-occurrence analysis of antibiotics, hormones, and UV filters in the Chesapeake Bay (USA) to confirm inputs from wastewater treatment plants, septic systems, and animal feeding operations

Previous studies have reported select contaminants of emerging concern (CECs) in limited areas of the Chesapeake Bay (USA), but no comprehensive efforts have been conducted. In this work, 43 antibiotics, 9 hormones, 11 UV filters, and sucralose, were measured in matched water, sediment, and oyster samples from 58 sites. The highest sucralose concentration was 3051 ng L-1 in a subwatershed with 4.43 million liters of wastewater effluent per day (MLD) and 4385 septic systems. Although antibiotic occurrence was generally low in subwatersheds located in less populated areas, 102 ng L-1 ciprofloxacin was detected downstream of 0.58 MLD wastewater effluent and 10 animal feeding operations. Hormones were not regularly detected in water (2%) or oysters (37%), but the high detection frequencies in sediment (74%) were associated with septic systems. UV filters were ubiquitously detected in oysters, and octisalate exhibited the highest concentration (423 ng g-1). Oyster-phase oxybenzone and aqueous-phase sucralose concentrations were significantly correlated to wastewater effluent and septic systems, respectively. Toxicity outcomes were predicted for homosalate and octisalate throughout the Bay, and antimicrobial resistance concerns were noted for the Chester River. The geospatial and co-occurrence relationships constitute crucial advances to understanding CEC occurrence in the Chesapeake Bay and elsewhere.

Efficient zinc extraction with novel phenyl phosphate PTOPP in sulfuric acid system

Traditional acidic phosphate extractants (D2EHPA and HEH/EHP) exhibit poor extraction performance under high-acid conditions and require saponification pretreatment to maintain the pH stability of the aqueous phase during the solvent extraction. However, saponification pretreatment produces a large amount of saline wastewater, resulting in high treatment costs and difficulty of the industrial waste salts utilization. Thus, we synthesized an efficient p-tert-octyl phenyl phosphate (PTOPP) extractant suitable for a high-acid system based on phenyl substitution and carbon-chain design. The structure and content of the synthesized products were confirmed to be [(CH3)3CCH2C(CH3)2C6H4O]2P(O)OH (diphenyl phosphate, P10B4, 88.26%) and (CH3)3CCH2C(CH3)2C6H4OP(O)(OH)2 (monophenyl phosphate, DHP10B4, 10.68%) via HRMS, LCMS, and NMR characterization combined with potentiometric titration. After three-stage countercurrent extraction and two-stage countercurrent stripping, the zinc extraction efficiency of PTOPP reached 85%, and the zinc concentration of aqueous phase increased from 20 g/L to 66.53 g/L with a 3.3 enrichment multiple. In comparison, the enrichment multiples of D2EHPA and HEH/EHP under the same conditions were only 1.5 and 1.1, respectively. The zinc extraction mechanism with PTOPP was determined by the slope method and structural characterization of the extracted compound (PTOPP-Zn). During the zinc extraction process, the P-OH and P=O groups in PTOPP interacted with Zn2+ to form Zn–O bonds through proton exchange and coordination reactions, and the molecular formula of the extracted compound was ZnA2·HA. The novel PTOPP significantly improves the zinc extraction performance and achieves a remarkable enrichment effect without saponification pretreatment, thereby avoiding the consumption of NaOH and the discharge of Na2SO4 wastewater. It has promising applications in the fields of low-grade zinc mineral resource recovery and heavy-metal wastewater disposal.

Improving the design and conduct of aquatic toxicity studies with oils based on 20 years of CROSERF experience

Laboratory toxicity testing is a key tool used in oil spill science, spill effects assessment, and mitigation strategy decisions to minimize environmental impacts. A major consideration in oil toxicity testing is how to replicate real-world spill conditions, oil types, weathering states, receptor organisms, and modifying environmental factors under laboratory conditions. Oils and petroleum-derived products are comprised of thousands of compounds with different physicochemical and toxicological properties, and this leads to challenges in conducting and interpreting oil toxicity studies. Experimental methods used to mix oils with aqueous test media have been shown to influence the aqueous-phase hydrocarbon composition and concentrations, hydrocarbon phase distribution (i.e., dissolved phase versus in oil droplets), and the stability of oil:water solutions which, in turn, influence the bioavailability and toxicity of the oil containing media. Studies have shown that differences in experimental methods can lead to divergent test results. Therefore, it is imperative to standardize the methods used to prepare oil:water solutions in order to improve the realism and comparability of laboratory tests. The CROSERF methodology, originally published in 2005, was developed as a standardized method to prepare oil:water solutions for testing and evaluating dispersants and dispersed oil. However, it was found equally applicable for use in testing oil-derived petroleum substances. The goals of the current effort were to: (1) build upon two decades of experience to update existing CROSERF guidance for conducting aquatic toxicity tests and (2) to improve the design of laboratory toxicity studies for use in hazard evaluation and development of quantitative effects models that can then be applied in spill assessment. Key experimental design considerations discussed include species selection (standard vs field collected), test substance (single compound vs whole oil), exposure regime (static vs flow-through) and duration, exposure metrics, toxicity endpoints, and quality assurance and control.

Compound-Specific Carbon, Hydrogen, and Nitrogen Isotope Analysis of Nitro- and Amino-Substituted Chlorobenzenes in Complex Aqueous Matrices.

Compound-specific isotope analysis (CSIA) is an established tool to study the fate of legacy groundwater contaminants but is only emerging for nonconventional contaminants, e.g., nitro- and amino-substituted chlorobenzenes that are widely used as industrial feedstock and the target of this work. To date, CSIA of the target compound groups used special combustion interfaces and the potential matrix interferences in environmental samples has not been assessed. We validated CSIA methods for δ13C, δ2H, and δ15N of four analytes from each chemical group and developed a solid-phase extraction (SPE) method to minimize matrix interferences during preconcentration of complex aqueous samples. The SPE recovery was >80% and the method quantification limits of SPE-CSIA for δ13C, δ2H, and δ15N were 0.03-0.57, 1.3-2.7, and 3.4-10.2 μM aqueous-phase concentrations, respectively, using 2 L of spiked MQ water. The SPE-CSIA procedure showed negligible isotope fractionation for δ13C (≤0.5‰), δ15N (≤0.5‰), and δ2H (≤5‰ for nitroaromatics and ≤10‰ for aminoaromatics). In addition, solvent evaporation, water sample storage up to 7 months, and SPE extract storage for 1.5 years did not change analytes' δ13C signatures beyond ±0.5‰. However, to avoid significant δ2H and δ15N fractionation of aminoaromatics, cartridge breakthrough should be avoided and SPE preconcentration must be conducted at pH > pKa + 2. Application of the method at a contaminated site showed excellent precision, at ≤0.3‰ for C and N, and ≤1.5‰ for H. The methods validated here now allow the use of multielement CSIA to track the environmental fate of nitro- and amino-substituted chlorobenzenes in complex aqueous samples.

Rheology of gel-containing water-in-crude oil emulsions

The rheological properties of gel-containing emulsions have been studied. Emulsions have been obtained from well production facilities after the use of demulsifiers based on oxyethylated high molecular weight surfactants. Today the properties of such emulsions are poorly understood, they are practically not destroyable by commonly used methods and ranked as oil waste. The studied emulsions were highly flocculated water-in-oil emulsions with aqueous phase concentrations of 53–62 wt% and “gel” contents of 8–25 wt%. The average diameter of water droplets varied from 40 to 50 μm. The gel-like behaviour of the studied emulsions has been confirmed by the dynamic rheological analysis using oscillatory techniques at 20 and 60 °C. The storage modulus G′ was higher than loss modulus G″ in a wide range of frequencies without a crossover. The gel-containing emulsions demonstrated the characteristics of non-Newtonian flow of the pseudoplastic type at 20 and 60 °C. Besides that, the emulsion with “gel” content of 25 wt% exhibited higher viscosity at 60 °C than at 20 °C due to the dehydration of oxyethylated surfactant molecules and additional stabilization of the water-in-oil emulsion. The rheological behaviour of the studied emulsions has been approximated by the Bingham model. The yield strength increased sharply with an increase in the “gel” concentrations because the “gel” networks in these emulsions were stronger. The results of rotational and oscillatory tests carried out at different “gel” concentrations, temperatures and shear rates can be useful in understanding and predicting their subsequent processing and demulsification.

Advances in sensory science: From perception to consumer acceptance

Advances in sensory science: From perception to consumer acceptance

Stability and release of peach polyphenols encapsulated by Pickering high internal phase emulsions in vitro and in vivo

In this work, Pickering high internal phase emulsions (HIPEs) were employed to protect peach polyphenols in vitro and vivo. Firstly, HIPEs stabilized by zein nanoparticles and gum Arabic (GA) with corn oil volume fraction of 76% were prepared. The effects of pH in aqueous phase (pH 3–7) and GA concentration (0 %–4%) on the creaming index (CI), particle size, potential, microstructure and rheology of HIPEs were analyzed. Results indicated that after GA concentration reached 2%, the stability of HIPEs kept relatively steady. With the decrease of pH in aqueous phase, the stability of HIPEs improved. Consequently, the pH 3 and 2% GA concentration were selected to prepare the stable HIPEs. Secondly, the HIPEs with corn oil dissolved peach polyphenols (PP-HIPEs) were obtained and the encapsulation rate of peach polyphenols reached 74.25%. Compared to polyphenols dissolved in water and corn oil, the stability of peach polyphenols in PP-HIPEs during UV irradiation, storage and heating significantly improved. Bioaccessibility of peach polyphenols in PP-HIPEs during simulated gastrointestinal digestion obviously enhanced and reached 60.49%. The content of polyphenols in stomach, small intestine, colon and feces in PP-HIPEs were higher, suggesting the better protection, higher adsorption and stronger potential biological activity during digestion. Meanwhile the peach polyphenols could prevent the increase of body weight caused by HIPEs. Thus, the HIPEs could be used as an excellent protective and effective delivery method for peach polyphenols during digestion.

Enantioseparation of amino acid and mandelic acid enantiomers using Josiphos-metal complexes as chiral extractants.

The development of new and efficient chiral extractants has always been the research hotspot and difficulty in the field of chiral extraction. Josiphos, a famous ferrocene derivative catalyst, is employed as a chiral extractant in enantioseparation of amino acid and mandelic acid enantiomers. The influences of metal ions, organic solvents, pH of the aqueous solution, extractant concentrations, and extraction temperature on enantioselectivities are systematically studied. The result reveals that Josiphos-Pd has good capabilities to enantioseparate 4-nitro-phenylalanine (Nphe), 3-chloro-phenylglycine (Cpheg), and mandelic acid (MA) with separation factors (α) of 3.30, 2.65, and 2.18, respectively. The pH of the aqueous phase and Josiphos-Pd concentration affect the extraction significantly, whereas extraction temperature shows little influence. After optimizing by response surface method, the mathematical models for extractions are established. And the highest experimental performance factors (pf) for Nphe, Cpheg, and MA are 0.1843, 0.1335, and 0.08884, respectively.

The secret of reversed-phase/weak cation exchange retention mechanisms in mixed-mode liquid chromatography applied for small drug molecule analysis

Resolving complex sample mixtures by liquid chromatography in a single run is challenging. The so-called mixed-mode liquid chromatography (MMLC) which combines several retention mechanisms within a single column, can provide resource-efficient separation of solutes of diverse nature. The Acclaim Mixed-Mode WCX-1 column, encompassing hydrophobic and weak cation exchange interactions, was employed for the analysis of small drug molecules. The stationary phase's interaction abilities were assessed by analysing molecules of different ionisation potentials. Mixed Quantitative Structure-Retention Relationship (QSRR) models were developed for revealing significant experimental parameters (EPs) and molecular features governing molecular retention. According to the plan of Face-Centred Central Composite Design, EPs (column temperature, acetonitrile content, pH and buffer concentration of aqueous mobile phase) variations were included in QSRR modelling. QSRRs were developed upon the whole data set (global model) and upon discrete parts, related to similarly ionized analytes (local models) by applying gradient boosted trees as a regression tool. Root mean squared errors of prediction for global and local QSRR models for cations, anions and neutrals were respectively 0.131; 0.105; 0.102 and 0.042 with the coefficient of determination 0.947; 0.872; 0.954 and 0.996, indicating satisfactory performances of all models, with slightly better accuracy of local ones. The research showed that influences of EPs were dependant on the molecule's ionisation potential. The molecular descriptors highlighted by models pointed out that electrostatic and hydrophobic interactions and hydrogen bonds participate in the retention process. The molecule's conformation significance was evaluated along with the topological relationship between the interaction centres, explicitly determined for each molecular species through local models. All models showed good molecular retention predictability thus showing potential for facilitating the method development.

Diverse sorption capacities and contribution of multiple sorptive sites on illitic clays to assess the immobilization of dissolved cesium in subsurface environments

The multiple sorptive sites on illitic clays (e.g., frayed edge [FES], type II [TS], and planar sites [PS]) are related to variable 137 Cs immobilization in subsurface environments. This study investigated the diverse Cs + sorption using 10 illitic clays under various competing K + (distilled water−10 −1 mol/L) and Cs + concentrations (10 −7 −10 −3 mol/L). In addition, the multisite cation exchange model was simulated the best-fit sorption models compared to experimental datasets, and subsequently, optimized the sorption capacities of multiple sorptive sites on the illitic clays. The best-fit sorption model exhibited that diverse Cs + sorption of 10 illitic clays was closely linked to the individual sorption capacities at the FES (1.76 × 10 −5 to 1.12 × 10 −4 eq/kg), TS (1.59 × 10 −3 to 9.76 × 10 −3 eq/kg), and PS (2.14 × 10 −2 to 1.51 × 10 −1 eq/kg). The FES predominantly sorbed Cs + at low aqueous-phase concentrations, whereas the TS and PS contributed to Cs + sorption at relatively high concentrations. These sorption capabilities were correlated to illite contents and crystallinity of 10 illitic clays so that such parameters could be significant factors to predict the Cs + sorption for illitic clays. Finally, the 1-D transport simulations showed significantly diverse Cs + retardation ( R d ≈ 20 to 100) at low dissolved Cs + , implying that the various FES capacities of illitic clays could play an important role on Cs + distribution in actual radioactive contamination sites. • 10 illitic clays had diverse Cs + sorption capacities at multiple sorptive sites. • Multisite cation exchange model was optimized to evaluate Cs + sorption to illitic clays. • Statistical relationship between Cs + sorption and mineralogical data was evaluated. • Selectivity coefficients of Cs + were affected by competing cation concentrations.

Pickering high internal phase emulsions with excellent UV protection property stabilized by Spirulina protein isolate nanoparticles

Herein, we reported the use of natural, renewable, and food-grade Spirulina protein isolate nanoparticles (SPI NPs) as effective particle stabilizers for Pickering high internal phase emulsions (Pickering-HIPEs). SPI NPs were prepared using a straightforward antisolvent technique and characterized using dynamic light scattering (DLS), and zeta potential measurement as well as scanning electron microscopy (SEM). SPI NPs were afterward used as sole stabilizers to prepare the oil-in-water (O/W) HIPEs, the effects of oil content, particle concentration, and pH of aqueous phase on the microstructure, stability, and rheological behaviors of the resulting Pickering-HIPEs were investigated. The Pickering-HIPEs generated showed a self-supporting gel network, a high oil content (up to 85 vol%), and extraordinary storage stability after prolonged storage and UV exposure. Concurrently, the Pickering-HIPEs provided good UV protection for a variety of photosensitive compounds, including β-carotene, vitamin E, and limonene. These findings would not only advance the development of biocompatible particle stabilizers for Pickering-HIPEs in cosmetic, food, and pharmaceutical industries, but they would also provide a guidance for the protection of photosensitive compounds.

Efficient extraction of phenol from wastewater by ionic micro-emulsion method: Anionic and cationic

Phenolic wastewater is one of the priorities in the field of wastewater treatment, which poses a serious threat to the human health and nature environment. In this paper, cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium oleate (NaOL) microemulsions were utilized to extract phenol from the wastewater. The optimal extraction factors were investigated by exploring the effects of microemulsion composition ratio and extraction conditions on the phenol extraction performance. Furthermore, the enhanced extraction mechanism of phenol by cations microemulsions is illustrated by studying the extraction process of cationic and anionic microemulsions in the extraction of phenol. The optimum components were obtained: surfactant concentration of 0.2 mol·L–1, isoamyl alcohol volume of 30%, internal aqueous phase concentration of CTAB microemulsion of 0.05 mol·L–1, and internal aqueous phase concentration of NaOL microemulsion of 0.09 mol·L–1. The extraction efficiencies were 96.44% and 82.0% when using CTAB and NaOL microemulsions under optimal conditions (water–emulsion ratio of 5, contact time of 9 min, extraction temperature of 298.15 K, and pH of 9), confirming the enhanced extraction of phenol by CTAB cationic microemulsion. It was analyzed that the enhanced extraction of CTAB microemulsion was due to the electrostatic adsorption of cations with phenol root ions.