Extractant Concentration Research Articles

Soil Organic Carbon Stabilization Is Dominated by Non‐Sorptive Process Among the Subsoils From Different Parent Material

AbstractSoil parent material can strongly influence soil's physical and chemical properties, significantly affecting soil organic carbon (SOC) stabilization. However, the importance of different soil parent materials on the amount and composition of subsoil carbon in subtropical soils remains poorly qualified. Subsoil SOC (below A horizon) is chosen for this study because of its higher proportion of stable carbon than surface soils in A horizon. Here, we investigated the dependence of soil mineral‐associated organic carbon (MAOC) and its three mineral‐stabilized fractions on soil physical and chemical parameters (clay content, cation exchange capacity (CEC) and metal oxides) in the subsoil soil (B and C horizons) originating from three contrasting parent materials (sandshale, granite, limestone). The results showed that MAOC accounts for an average of 88% of total SOC, of which organo‐metal complexes (extracted with sodium pyrophosphate) are the dominant form at all three sites. MAOC and its three fractions were significantly correlated with soil clay, CEC, sodium pyrophosphate extractable Fe and oxalate extractable Fe concentrations (P < 0.05), which varied significantly with soil parent material. Since the sodium pyrophosphate plus oxalate‐ extracted mineral‐associated carbon accounted for more than 70% of MAOC, and the molar ratio between sodium pyrophosphate or oxalate‐ extracted mineral‐associated carbon and Fe (C:Fe) ranged from 2.7 to 17.1. The formation of Fe‐associated organic complex is dominated by co‐precipitation when C:Fe is >1. Therefore we conclude that non‐sorptive interactions with the mineral phase through co‐precipitation are the dominant mechanism for SOC stabilization in subtropical forest soils.

Continuous ingestion of sodium chloride solution promotes allergen absorption and may exacerbate allergy symptoms on ovalbumin-induced food allergy in mice.

Various studies have reported relationships between salt intake and diseases, such as hypertension, cardiovascular disease, stroke, gastric cancer, and bronchial asthma. However, no reports exist on the relationship between salt intake and food allergies. In this study, we investigated the effect of continuous ingestion of sodium chloride (NaCl) on allergy symptoms using a mouse model of food allergy. BALB/c mice were divided into four groups of 6-8 animals each. The control-water group (CW) and sensitization-water group (SW) groups were provided free access to water, and the control-1% NaCl group (CS) and sensitization-1% NaCl group (SS) groups were provided a 1% NaCl solution. The SW and SS groups were sensitized with 50 µg ovalbumin (OVA) at 2 timepoints by intraperitoneal injection. After oral administration of OVA, anaphylactic response was measured and blood was collected. The mice were sacrificed, and serum levels of OVA and anti-OVA immunoglobulin (Ig)E and IgG1 were measured by enzyme-linked immunosorbent assays. The sodium ion (Na+) concentrations in duodenal and jejunal extracts were measured using a Na+ ion meter. The results suggested that continuous ingestion of a 1% NaCl solution for 36 days promoted allergen absorption and may have aggravated allergy symptoms in the mice. However, NaCl ingestion did not affect Na+ concentrations in the small intestine or OVA-specific antibody production.

Anchoring Au on UiO-66 surface with thioglycolic acid for simultaneous SERS detection of paraquat and diquat residues in cabbage

SERS sensors based on metal-organic frameworks (MOFs) have garnered considerable attention in trace pesticide residue detection. UiO-66/AuNPs suspension substrates were fabricated by introducing thioglycolic acid (TGA) as a binder to modify the surface of AuNPs to facilitate their electrostatic assembly with UiO-66 prepared through hydrothermal reaction. The proposed substrates were used for quantitative and simultaneous analysis of paraquat and diquat in cabbage. Diquat and paraquat in actual cabbage samples were individually analysed with detection of limits (LOD) of 6 μg/L and 3 μg/L, respectively, and validated with recoveries ranging from 92.65 to 118.34%. Furthermore, the UiO-66/AuNPs substrate was able to differentiate between paraquat and diquat mixtures, even for the concentrations in the cabbage extracts differed by a factor of 100. The proposed UiO-66/AuNPs substrate provides a potentially useful tool for the trace determination of pesticide residues in the practical food safety analysis

Improvement of ultrasound-assisted extraction of polyphenolic content of the plant Cytisus triflorus L'Her as a natural resource using artificial neural network modeling and multi-objective optimization

The improvement of environmental performance of production processes is a critical problem right now. Processes that are effective in terms of productivity and environmental effects are the center of interest of researchers. This study established such a method for an ultrasound-assisted extraction procedure. The plant Cytisus triflorus L'Her was used to extract polyphenolic chemicals using ultrasound-assisted extraction as a quick, less energy consuming, high-yield technology. This work offers a new experimental planning approach using Artificial Neural Networks, that enables the extraction process to be optimized using multi-objective optimization in order to identify the best extraction conditions to obtain the maximum polyphenolic compounds possible. Advanced modeling using Artificial intelligence and statistical optimization techniques was used to determine the best combinations of ethanol concentration, extraction temperature and time for the maximum extraction of total phenols, total flavonoids, total flavonols, and total tannins. An artificial neural network (ANN) was used to build the models for each of the four goals, then they were multi-objectively optimized using a genetic algorithm technique. The maximum polyphenolic contents including TPC (4.986 ± 0.006 mg GA/g DE), TFC (14.026 ± 0.070 mg Q/g DE), TFolC (5.225 ± 0.010 mg R/g DE), and TTC (6.240 ± 0.021 mg C/g DE) were obtained using an extraction process under optimal conditions, which included a solvent concentration of 78%, an extraction temperature of 52 °C, and an extraction time of 55 min which were obtained using the MOO Pareto optimum solution selection approach Gray Relational Analysis GRA.

Quantitative chemical assay of nanogram-level particulate matter using aerosol mass spectrometry: characterization of particles collected from uncrewed atmospheric measurement platforms

Abstract. Aerosol generation techniques have expanded the utility of aerosol mass spectrometry (AMS) for offline chemical analysis of airborne particles and droplets. However, standard aerosolization techniques require relatively large liquid volumes (e.g., several milliliters) and high sample masses that limit their utility. Here we report the development and characterization of a micronebulization AMS (MN-AMS) technique that requires as low as 10 µL of sample and can provide the quantification of the nanogram level of organic and inorganic substances via the usage of an isotopically labeled internal standard (34SO42-). Using standard solutions, the detection limits for this technique were determined at 0.19, 0.75, and 2.2 ng for sulfate, nitrate, and organics, respectively. The analytical recoveries for these species are 104 %, 87 %, and 94 %, respectively. This MN-AMS technique was applied successfully to analyze filter and impactor samples collected using miniature particulate matter (PM) samplers deployable on uncrewed atmospheric measurement platforms, such as uncrewed aerial systems (UASs) and tethered balloon systems (TBSs). Chemical composition of PM samples collected from a UAS field campaign conducted at the Department of Energy's (DOE) Southern Great Plains (SGP) observatory was characterized. The offline MN-AMS data compared well with the in situ PM composition measured by a co-located aerosol chemical speciation monitor (ACSM). In addition, the MN-AMS and ion chromatography (IC) agreed well for measurements of sulfate and nitrate concentrations in the PM extracts. This study demonstrates the utility of combining MN-AMS with uncrewed measurement platforms to provide quantitative measurements of ambient PM composition.

Extraction of active, contaminant degrading enzymes from soil

Soil microorganisms play critical roles in the degradation of micro-and nano-pollutants, and the corresponding proteins and enzymes play roles in pollutant recognition, transportation, and degradation. Our ability to study these pathways from soil samples is often complicated by the complex processes involved in extracting proteins from soil matrices. This study aimed to develop a new protein soil extraction protocol that yielded active, intracellular enzymes from the perchlorate degradation pathway, particularly perchlorate reductase. An indirect method, which focused on first separating the cells from the soil matrix, followed by cell lysis and enzyme extraction, was evaluated. The optimized indirect method achieved a final extraction efficiency of the active enzyme and total protein of 15.7 % and 3.3 %, respectively. The final step of separating enzymes from residual soil components resulted in the highest activity and protein losses of 67.7 % ± 14.8 % and 91.8 % ± 1.8 %, respectively. Five buffers, each at different concentrations (0.01 M, 0.05 M, and 0.1 M), were tested to enhance enzyme extraction efficiency. The best extractant requires careful consideration between the highest activity and the quality of the recovered enzymes. Coextraction of humic substances could be minimized by using 0.1 M as compared to 0.01 M and 0.05 M of sodium pyrophosphate; however, this resulted in less recovered activity compared to lower extractant concentrations.

Uji Aktivitas Antibakteri Ekstrak Etanol Daun Matoa (Pometia Pinnata J. R & G.Forst.) terhadap Pertumbuhan Staphylococcus Aureus dan Escherichia Coli

This study aims to determine the antibacterial activity, effective concentration, and secondary metabolites in the ethanol extract of matoa left against the test bacteria Staphylococcus aureus and Escherichia coli. The research method extracts matoa leaf samples by maceration using 70% ethanol solvent, testing the antibacterial activity using the paper disk diffusion method. The results of the antibacterial activity test were then analyzed using the One way ANOVA method. The results showed that the diameter of the inhibition zone of the ethanol extract of matoa leaves on the growth of Staphylococcus aureus appeared to have a clear area at a concentration of 1%, 1.5%, and 2%, respectively, of 12.88 mm, 13.15 mm, 11.36 mm. In comparison, the results of measuring the diameter of the inhibition zone of the ethanol extract matoa leaf on the growth of Escherichia coli bacteria were seen to have a clear area at a concentration of 1%, 1.5%, and 2% of 9.5 mm, 10.23 mm, 12.1 mm respectively. This activity is thought to be due to the effects of alkaloid compounds, flavonoids, tannins, saponins, and steroids in the ethanol extract of matoa leaves. Based on the ANOVA test, a significance value of 0.000 <0.05 was obtained, so the results were significant. In conclusion, there are substantial differences in the use of various concentrations of matoa leaf extract on the growth of Staphylococcus aureus and Escherichia coli bacteria.
 Keywords: Antibacterial Activity, Matoa Leaves, Secondary Metabolites

Copper Concentrations Found from Drinking Water, Soils, and Vegetables

Humans, animals, and plants need copper for growth and development, but it can be an irritant to humans. The daily maximum limit of copper for humans is 10-12 µg day^-1 and excess concentrations of copper can cause nausea, diarrhea, and anorexia. In plants, excess copper concentrations cause chlorosis, stunted growth, and denaturing of macromolecules. Only 10 mg kg^-1 of copper can be accumulated by plants. The maximum allowable concentration in agricultural soils is 6.6 mg kg^-1. The concentration of copper in drinking water should not exceed 1 mg L^-1. When copper concentrations exceed an action level of 1.3 ppm in more than 10% of customer taps sampled, several additional controlling measures must be undertaken. In waste, the allowable concentration is 16 mg kg^-1. The hypothesis of the study was that copper would be found in the vegetables grown from the agricultural soils. Cabbage, green pepper, spinach, and tomato were grown for thirteen weeks. The soil and vegetables were digested, and the copper concentrations were measured using an Atomic Absorption Spectroscopy (AAS). The highest total and extractable copper concentrations found in the soil were 73 mg kg^-1 and 26 mg kg^-1, respectively. More than 20 and 32 mg kg^-1 of copper was found in the shoot and roots of the vegetables, respectively. More than 11 mg L^-1 of copper was found in the tap water. The results indicated that the copper concentrations from the soil, water, and vegetables exceeded the allowable concentrations.

Color, Antioxidant Capacity and Flavonoid Composition in Hibiscus rosa-sinensis Cultivars

Hibiscus rosa-sinensis plants are mainly cultivated as ornamental plants, but they also have food and medicinal uses. In this work, 16 H. rosa-sinensis cultivars were studied to measure their colorimetric parameters and the chemical composition of hydroethanolic extracts obtained from their petals. These extracts were characterized using UHPLC-ESI+-Obitrap-MS, and their antioxidant activity was evaluated using the ORAC assay. The identified flavonoids included anthocyanins derived from cyanidin, glycosylated flavonols derived from quercetin and kaempferol, and flavan-3-ols such as catechin and epicatechin. Cyanidin-sophoroside was the anthocyanin present in extracts of lilac, pink, orange, and red flowers, but was not detected in extracts of white or yellow flowers. The total flavonol concentration in the flower extracts was inversely proportional to the total anthocyanin content. The flavonol concentration varied according to the cultivar in the following order: red < pink < orange < yellow ≈ white, with the extract from the red flower presenting the lowest flavonol concentration and the highest anthocyanin concentration. The antioxidant activity increased in proportion to the anthocyanin concentration, from 1580 µmol Trolox®/g sample (white cultivar) to 3840 µmol Trolox®/g sample (red cultivar).

Toxicity of emerging contaminant antibiotics in soil to Capsicum annuum L. growth and their effects on it accumulating copper

Antibiotics are a kind of emerging contaminant in soil. Tetracycline (TC) and oxytetracycline (OTC) in soil are often detected, even with very high concentration in the soils of facility agriculture due to their good effect, low price and large usage. Copper (Cu) is common heavy metal pollutant in soil. The toxicity roles of TC, OTC and/or Cu in soil on a commonly consumed vegetable Capsicum annuum L. and its Cu accumulation were not clear till now. The results of pot experiment showed that the TC or OTC added in soil alone didn't produce poison effects for C. annuum after 6 weeks and 12 weeks growth reflected by some physiological index like SOD, CAT and APX activities changes, while the biomass changes affirmed them either. Cu contaminated soil significantly inhibited the growth of C. annuum. Furthermore, combined pollution of Cu with TC or OTC was with more serious suppression of C. annuum growth. The suppression role of OTC was heavier than TC in Cu and TC or OTC contaminated soil. Such phenomenon was relevant with the role of TC or OTC increased Cu concentration in C. annuum. The improvement role of TC or OTC on Cu accumulation in C. annuum caused by the increased extractable Cu concentration in soil. The study demonstrated that TC or OTC added in soil alone was without any toxicity to C. annuum. But they may aggravate the hurt of C. annuum caused by Cu through increased its accumulation from soil. Thus, such combine pollution should be avoided in safe agricultural product.

Optimization of Supercritical Carbon Dioxide Extraction of Polyphenols from Black Rosehip and Their Bioaccessibility Using an In Vitro Digestion/Caco-2 Cell Model.

The fruits of Rosa pimpinellifolia are rich sources of (poly)phenols, however they are underutilized due to the limited information available. The influence of the pressure, temperature, and co-solvent concentration (aqueous ethanol) of the supercritical carbon dioxide extraction (SCO2-aqEtOH) on the extraction yield, total phenolic-, total anthocyanin-, catechin-, cyanidin-3-O-glucoside contents, and total antioxidant activity of black rosehip was investigated simultaneously. The maximum obtained total phenolic and total anthocyanin contents under the optimized extraction conditions (280 bar, 60 °C and 25% ethanol, v/v) were 76.58 ± 4.25 mg gallic acid equivalent and 10.89 ± 1.56 mg cyanidin-3-O-glucoside equivalent per g of the dry fruits, respectively. The optimal extract obtained by SCO2-aqEtOH was compared to two other extraction procedures: ultrasonication using ethanol as solvent (UA-EtOH) and pressurized hot water extraction (PH-H2O). The bioaccessibility and cellular metabolism of the phenolic compounds in the different black rosehip extracts were assessed using an in vitro digestion coupled with a human intestinal Caco-2 cell model. The in vitro digestive stability and cellular uptake of the phenolic compounds had no significant difference among the different extraction methods. The results of this study confirm the efficiency of SCO2-aqEtOH extraction for phenolic compounds and, in particular, for anthocyanins, and could be used to produce new functional food ingredients from black rosehip with high antioxidant power containing both hydrophilic and lipophilic compounds.

Investigation of Sterile Mining Dumps Resulting from Ore Exploitation and Processing in Maramures County, Romania

Abandoned sterile dumps can be a significant source of environmental pollution, therefore the distribution of trace elements throughout mining is vital. Monitoring environmental factors in closed mining perimeters aims to track the quality of discharged waters in the emissary and assess acid mine drainage, the quality of the soil and vegetation, stability, and the condition of the land surfaces within the perimeter of the sterile deposits. One of the primary sources of land, water and air pollution is sterile mining dumps. Knowing the source of pollution is the first step in adequately managing the affected areas. This paper investigates the physical–chemical properties and the concentrations of heavy metals in sterile dumps resulting from mining. We studied one sterile dump that was the result of ore processing and whose surface was covered with abandoned mixed ore concentrate (Pb, Zn), located in the Băiuț mining area (Romania), and a second sterile mining dump that was the result of exploration and exploitation work in the Ilba mining area (Romania). In order to determine the physicochemical characteristics of the studied sterile dumps and to determine the concentration of heavy metals, 27 sterile samples and one soil sample were taken from the Băiuț dump. Additionally, 10 sterile samples and one soil sample were collected from the Ilba dump. Aqua regia extractable concentrations of heavy metals were determined by inductively coupled plasma optical emission spectrometry. At the same time, using a portable XRF, we analyzed selected samples from each site for total metal concentrations. Furthermore, from each site, one sample was analyzed by FT–IR spectrometry. The pH values in both sterile dumps were highly acidic (≤3.5) and the content of heavy metals was generally increased.

The Effect of Extraction Methods on Phytochemicals and Biological Activities of Green Coffee Beans Extracts.

The objectives of the present study consisted of identifying the impact of extraction methods and parameters held over the phytochemistry and biological activities of green coffee beans. Extraction processes belonging to two categories were performed: classical methods-maceration, Soxhlet extraction, and such innovative methods as turboextraction, ultrasound-assisted extraction, and a combination of the latter two. Total polyphenolic and flavonoid content, as well as in vitro antioxidant activity of the resulted extracts were spectrophotometrically determined. Extracts displaying the highest yields of bioactive compounds were subjected to High Performance Liquid Chromatography-Mass Spectrometry analysis. The extracts with the best phytochemical profiles were selected for biological activity assessment. In vivo, a model of plantar inflammation in Wistar rats was used to determine antioxidant activity, by evaluating the oxidative stress reduction potential, and anti-inflammatory activity. In vitro antimicrobial activity was also determined. The Soxhlet extraction and ultrasound-assisted extraction gave the highest bioactive compound yields. The highest total polyphenolic content was 2.691 mg/mL gallic acid equivalents and total flavonoid content was 0.487 mM quercetin equivalents for the Soxhlet extract subjected to 60 min extraction time. Regarding the antioxidant activity, ultrasound-assisted extraction reached the highest levels, i.e., 9.160 mg/mL Trolox equivalents in the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay and 26.676 mM Trolox equivalents in the FRAP (Ferric Reducing Antioxidant Power) assay, at a 30 min extraction time and 50 °C extraction temperature. The 60 min Soxhlet extract reached the highest level for the ABTS+ (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay, 16.136 mM Trolox equivalents, respectively. Chlorogenic acid was present in the highest concentration in the same Soxhlet extract, 1657.179 µg/mL extract, respectively. Sterolic compounds were found in high concentrations throughout all the analyzed extracts. A proportional increase between yields and extraction parameter values was observed. Increased inhibition of Gram-negative bacteria was observed. The finally selected Soxhlet extract, that of 60 min extraction time, presented a significant in vivo antioxidant activity, with a slight anti-inflammatory activity. Antioxidant levels were elevated after 2 h of extract administration. Pro-inflammatory cytokine secretion was not influenced by the administration of the extract.

Assessment of phytochemical screening and antioxidant potential of Heteropogon contortus (L.) whole plant

Heteropogon contortus (L.) belongs to the family Poaceae, which is known to have bioactivities like anti-inflammatory, antioxidant, membrane and mast cell stabilization, antimicrobial and many more. The aim of the present study is to explore occurrence of phytochemicals and antioxidant activity by using the whole plant (including leaf, stem, and root) crude extract in three different solvents (methanol, hydroethanol, and aqueous). Using standard methods, presence of various bioactive compounds was determined. Quantitative evaluation of total phenol, flavonoid and tannin content were done by using the spectrophotometric techniques. For antioxidant property analysis, in-vitro techniques like ferric reducing antioxidant potential (FRAP) assay, diphenyl1-2-picrylhydrazyl (DPPH) and metal chelation assay were used. In plant extract preparation, the green colour extract of methanol with solid consistency observed to have highest % yield of 4.46 %, followed by hydroethanolic (3.86 %), and aqueous extract (2.95 %). Various phytocompounds (e.g., alkaloids, steroids, phenols, flavonoids, glycosides, carbohydrates, and resins) were observed in higher concentration in methanol, hydroethanol, and aqueous extract. Out of all extracts, the methanol extract observed to have highest flavonoid (30.07 ± 0.09 mg Quercetin equivalent (QE)/g), phenol (34.12 ± 0.028 mg of the Gallic acid equivalent (GAE)/g), and tannin (26.61 ± 0.008 mg of the Tannic acid equivalent (TAE)/g) content. In DPPH and metal chelation assay, the effective inhibitor was the methanol extract (42.94 ± 0.0061 µg/ml, 100.57 ± 0.085 µg/ml) in order of potency inhibitory concentration (IC50) while the FRAP value was observed maximum in the hydroethanol extract (258.41 ± 0.0085 mg/g). Thus, overall investigation of the plant extracts shows that the occurrence of variety of phytochemicals having antioxidant properties makes the plant a promising candidate for usage in the traditional medicine.

Study and Application of High-Level Directional Extraction Borehole Based on Mining Fracture Evolution Law of Overburden Strata

The technical principle of gas drainage using high-level directional extraction boreholes was analyzed. A range of overburden strata was stimulated for pressure relief during mining, the effects of different borehole parameters on gas flow in the goaf and gas concentration in the upper corner were compared, and a field test was conducted to analyze the effect and peculiarities of gas drainage. With the mining of the work plane, overburden mining fissures gradually develop forward and upward, showing a “saddle” shape along the coal seam. The fissures in the middle zone of the goaf are gradually compacted, and a gas accumulation zone is formed around the goaf. High-level directional extraction boreholes arranged in an ellipsoidal belt at the side of the air return can achieve efficient gas extraction in the roof fissure belt. Numerical simulation results showed that the height of the fully depressurized area was 65 m from the roof of the coal seam. In addition, three high-level directional extraction boreholes were drilled in the roof of the coal seam. The gas extraction concentration and gas extraction pure volume of these three boreholes first increased, then decreased, and finally tended to be stable. The sequence of their average values was borehole No.2 &gt; No.3 (twice as much) and &gt; No.1 (2.7 times as much), which are closely related to the evolution law of overburden mining fissures. The research results can provide a reference for the further study of gas extraction technology using high-level directional extraction boreholes in coal and gas outburst seams.

Phytostabilization of trace elements and 13C isotope composition of Atriplex atacamensis Phil. cultivated in mine tailings treated with organic amendments.

Mining generates large quantities of mineral processing wastes that are typically stored in mine tailings (MT) ponds. Long-term exposure of the surrounding areas to the material from the tailings ponds has been reported to have adverse effects on both human health and the environment. The purpose of this study was to evaluate the ability of Atriplex atacamensis Phil. to phytostabilize metals (Cu, Fe, Mn, and Zn) and sulfur (S) when grown directly on mine tailings with and without compost (C) and humic substance (HS). The stress status of A. atacamensis Phil. was also evaluated through the 13C isotopic composition of bulk leaves. A 120-day greenhouse experiment was conducted and three treatments were evaluated: (i) MT without any amendments (control), (ii) MT + C (dose: 89 ton ha-1), and (iii) MT + HS (0.72 ton ha-1). Mine tailings material exhibited low salinity, alkaline pH, high extractable S-SO4 concentrations, and low fertility; total Fe, Mn, and Zn concentrations were within the reference range for mine tailings, but total Cu concentrations were high at 1860 ± 236mgkg-1. The HS had higher pH, EC, CEC, and available concentrations of N, P, and K than compost, while S-SO4 concentrations were similar in both amendments. 13C NMR analysis showed that the HS contained more alkyl, aromatic, and phenolic groups, while the compost was dominated by O-alkyl and carboxyl groups. At the end of the experiment, the MT + C treatment achieved a significant decrease in Cu, Fe, and Mn concentrations in the roots and aboveground parts of A. atacamensis Phil. and an increase in Zn values in both tissues. Both amendments increased the sulfur content in the aboveground parts, while metal concentrations under the HS treatment proved similar to control. Furthermore, the δ13CV-PDB values obtained in this study indicate that the organic amendments did not cause additional physiological stress to the plants compared to the MT treatment. Overall, A. atacamensis Phil. was shown to have the ability to phytostabilize metals and sulfur, making it a potential candidate species for in situ evaluation of the phytostabilization process on mine tailings.

Study on liquid–liquid two-phase mass transfer characteristics in the microchannel with deformed insert

In this work, the liquid–liquid two-phase mass transfer characteristics in the microchannel with deformed insert were studied. The experiment used di-(2-ethylhexyl) phosphoric acid/kerosene-Cu 2+ as the mass transfer evaluation system. The effects of some key factors such as the total flow velocity, channel inner diameter, channel length, insert diameter, extractant concentration on the extraction efficiency and mass transfer coefficient were systematically investigated. Compared with a simple microreactor, the liquid–liquid mass transfer enhancement effect of the insert was quantitatively analyzed. The study found that the regular deformation of insert could cause fluid interface deformation and promote flow state chaos, effectively increasing the mass transfer rate. And the enhancement effect of the insert was more significant at high flow velocities. The highest mass transfer coefficient in the microchannel with deformed insert was 7.886 s –1 , the enhancement factor could reach 4.17. And only needed 0.095 s to approach the extraction equilibrium. The deformed center insert exhibited an effective liquid–liquid mass transfer enhancement effect, which can be used as a micro-chemical process enhancement method to be applied in the fields of higher throughput mass transfer and chemical synthesis, and at the same time provide ideas for development and structural optimization of microreactors.

Phytoremediation of Potentially Toxic Elements from Contaminated Saline Soils Using Salvadora persica L.: Seasonal Evaluation.

Plants in coastal ecosystems are primarily known as natural sinks of trace metals and their importance for phytoremediation is well established. Salvadora persica L., a medicinally important woody crop of marginal coasts, was evaluated for the accumulation of metal pollutants (viz. Fe, Mn, Cu, Pb, Zn, and Cr) from three coastal areas of Karachi on a seasonal basis. Korangi creek, being the most polluted site, had higher heavy metals (HM's) in soil (Fe up to 17,389, Mn: 268, Zn: 105, Cu: 23, Pb: 64.7 and Cr up to 35.9 mg kg-1) and S. persica accumulated most of the metals with >1 TF (translocation factor), yet none of them exceeded standard permissible ranges except for Pb (up to 3.1 in roots and 3.37 mg kg-1 in leaves with TF = 11.7). Seasonal data suggested that higher salinity in Clifton and Korangi creeks during pre- and post-monsoon summers resulted in lower leaf water (ΨWo) and osmotic potential at full turgor (ΨSo) and bulk elasticity (ε), higher leaf Na+ and Pb but lower extractable concentrations of other toxic metals (Cr, Cu, and Zn) in S. persica. Variation in metal accumulation may be linked to metal speciation via specific transporters and leaf water relation dynamics. Our results suggested that S. persica could be grown on Zn, Cr and Cu polluted soils but not on Pb affected soils as its leaves accumulated higher concentrations than the proposed limits.

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.

Extraction of Cerium (III) by a Solvent Extraction Technique Using Diaminododecylphosphonic Acid (DADTMTPA): Experimental, Density Functional Theory and Molecular Dynamic Studies

AbstractThis paper aims to present the recent results progress on diaminododecylphosphonic acid (DADTMTPA) as an extractant of cerium (III) from Ce(NO3)3.6H2O solution medium. Different parameters including pH, temperature, extractant concentration, and foreign ions present in the aqueous phase were examined to investigate the extractional mechanism. The optimum conditions of solvent extraction of Ce(III) are as follows: under experimental conditions of 298 K and the initial concentration of Ce(III) being kept at 10−4 M at pH 3.50. The agitation duration of 5 min for a volume ratio equal to 2, and the best yield is 77 % in one‐step. An increase in the temperature reduced the extraction process. The DADTMTPA extracts Ce(III) after the second cycle with a yield of 95 %. The extraction thermodynamic parameters such as ΔG, ΔH and ΔS are also determined and reported. On the other hand, density functional theory (DFT) based on B97D3 functional with 6‐311++G(d,p) basis set analysis and molecular dynamics simulations were used to extremely fast methods at calculating the non‐bonded interactions and to understand its properties of molecular interactions, which have proved to be an adopted and useful tool to predict and describe the chemical behavior of the evolution of the system.