Isobaric (vapour + liquid) equilibria for sulfolane with toluene, ethylbenzene, and isopropylbenzene at 101.33 kPa

Isobaric (vapour + liquid) equilibrium data have been measured for the (toluene + sulfolane), (ethylbenzene + sulfolane), and (isopropylbenzene + sulfolane) binary systems with a modified Rose-Williams still at 101.33 kPa. The experimental data of binary systems were well correlated by the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phase. All the experimental results passed the thermodynamic consistency test by the Herington method. Furthermore, the model UNIFAC (Do) group contribution method was used. Sulfolane is treated as a group (TMS), the new group interaction parameters for CH₂–TMS, ACH–TMS and ACCH₂–TMS were regressed from the VLE data of (toluene + sulfolane) and (ethylbenzene + sulfolane) binary systems. Then these group interaction parameters were used to estimate phase equilibrium data of the (isopropylbenzene + sulfolane) binary system. The results showed that the estimated data were in good agreement with the experimental values. The maximum and average absolute deviations of the temperature were 4.50 K and 2.39 K, respectively. The maximum and average absolute deviations for the vapour phase compositions of isopropylbenzene were 0.0237 and 0.0137, respectively.     

A review of analytical methods for the determination of sulfolane and alkanolamines in environmental studies

Sulfolane and alkanolamines are used extensively in the processing of sour natural gases. Over many years of operation, there have been inadvertent leaks of these chemicals to groundwater and wetlands surrounding gas processing facilities, leading to uptake by vegetation. Because sulfolane and alkanolamines are extremely water-soluble, their analysis has presented challenges, particularly requirements for suitable extraction from biological matrixes and soil, along with sensitive detection using commonly available instrumentation. Analytical methods usually use gas chromatography or liquid chromatography with a variety of detector systems. Sample preparation techniques may include extraction with organic solvents, water, or a combination of these. In some cases, direct aqueous injections have been used. Derivatization of alkanolamines has been used to improve the chromatographic separations and detection. More recent procedures, using positive-ion electrospray ionization mass spectrometry (MS), have been useful for the confirmation of uptake of the alkanolamines and transformation products by wetland vegetation. Future developments will likely center on further MS analyses for identification of metabolites and transformation products in aquatic environments.     

Foliar uptake of zinc by vascular plants: radiometric study

The aim of this paper was to obtain quantitative data of foliar uptake kinetics and long distance transport of zinc in tobacco (Nicotiana tabacum L.) and hop (Humulus lupulus L.) plants. Zinc was used as a model of microelement and toxic metal, tobacco and hop as a representatives of agriculturally important plants. A tip of leaf blade was immersed in the solution spiked with ⁶⁵ZnCl₂ and foliar uptake and translocation to other parts of the plant grown in nutrient solution was measured by gamma-spectrometry and autoradiography. We found that foliar zinc uptake by both plants is dependent on the initial metal concentration within the range C ₀ = 10–100 μmol dm⁻³ ZnCl₂. Zinc is immobilized mainly in immersed part of the contact leaf and only <1% is transported to non-immersed parts of the leaf. At C ₀ = 0.1 mmol dm⁻³ ZnCl₂ concentrations >2.5 mg/g Zn and 4.8 mg/g Zn (dry wt.) in immersed part of tobacco and hop leaf plant, respectively were found after 5 days of exposure. Low mobility of zinc entering the plant via the leaf surface can be attributed to the immobilization of zinc into Zn–ligand complexes with high stability constants log K at pH 6.0–8.0, such as the reaction products of Zn²⁺ ions with citric acid, histidine or phosphates. Zinc can be extracted from dried leaves by the solutions of inorganic salts, carboxylic acids, amino acids and synthetic complexing ligands such as EDTA. Anionic (SDS) and non-ionic (Tween 40) surfactants causes the decrease of the Zn foliar uptake, but not translocation of Zn from the contact leaf area. Obtained data are discussed from the point of view of possible limited efficiency of liquid formulations designed for practical applications as Zn foliar fertilizers.     

Activity concentration of radium-226 in agricultural soils

Both Indian mustard and sunflower were grown in a hydroponic solution treated with different concentration activities of ¹³⁴Cs or with different amounts of copper or with both in order to investigate the interaction between copper and radiocesium. It was found that ¹³⁴Cs activity concentration applied in the nutrient solution exerted more influence on the uptake and translocation of copper by Indian mustard than by sunflower. Indian mustard grown in hydroponic solution containing certain levels of copper and being treated with higher ¹³⁴Cs activity concentration showed higher uptake of copper than sunflower. However, in the case of root copper concentrations, sunflower showed significantly higher copper immobilization by roots than Indian mustard. It was also found that the presence of copper in the hydroponic solution did modify radiocesium uptake by both species. The application of 1 mg/l in the growth medium could greatly increase the uptake of ¹³⁴Cs by both species. With 3 mg/l concentration of copper amended to the solution, the accumulation of ¹³⁴Cs by both species was decreased compared to the 1 mg/l copper treatment. These lines of evidence show that there is stronger interaction between copper and radiocesium in Indian mustard than in sunflower during the root uptake through nutrient solution.     

Isobaric (vapour + liquid) equilibria for sulfolane with toluene,ethylbenzene, and isopropylbenzene at 101.33 kPa

Isobaric (vapour + liquid) equilibrium data have been measured for the (toluene + sulfolane), (ethylbenzene + sulfolane), and (isopropylbenzene + sulfolane) binary systems with a modified Rose-Williams still at 101.33 kPa. The experimental data of binary systems were well correlated by the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phase. All the experimental results passed the thermodynamic consistency test by the Herington method. Furthermore, the model UNIFAC (Do) group contribution method was used. Sulfolane is treated as a group (TMS), the new group interaction parameters for CH₂–TMS, ACH–TMS and ACCH₂–TMS were regressed from the VLE data of (toluene + sulfolane) and (ethylbenzene + sulfolane) binary systems. Then these group interaction parameters were used to estimate phase equilibrium data of the (isopropylbenzene + sulfolane) binary system. The results showed that the estimated data were in good agreement with the experimental values. The maximum and average absolute deviations of the temperature were 4.50 K and 2.39 K, respectively. The maximum and average absolute deviations for the vapour phase compositions of isopropylbenzene were 0.0237 and 0.0137, respectively.     

Determination of heavy metal concentrations in plants exposed to different degrees of pollution using ICP-AES

Plant samples (Plantago lanceolata – narrow leaf plantain and Cichorium endiviae – endive) were collected in the surroundings of heavy metal emission sources and in other less contaminated areas. After digestion in a closed microwave system using HNO₃, the concentrations of Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn were determined using ICP-AES. Detection limits for all the elements of interest are given. Differences in heavy metal uptake rate between both plant species were observed. The uptake is more intensive for endive than for narrow leaf plantain. High concentrations of some heavy metals were determined in the unwashed plant samples as a result of exposure to aerosols. Tukeys statistical test was used to confirm the discrepancy of Cr concentration in plant samples from various areas. Washing the leaves with water was found to remove a large amount of water-soluble aerosols.     

Selenium transformation studies during broccoli (Brassica oleracea) growing process by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS)

Selenium uptake and transformation was studied in Se-enriched Broccoli (Brassica olearacea). Plants were grown in hydroponic culture and exposed during 40 days to Na₂SeO₃ (1 mg L⁻¹). After growing, the plants were harvested and their different parts (roots, stems and fruit) were analyzed by ICP-MS or LC-ICP-MS.Se-species were identified and quantified after enzymatic extraction by using both an anion exchange (PRP-X100), and a size exclusion/ion exchange (Shodex Asahipak) chromatographic columns. Selenium translocation and transformation Se species in plants was studied through the Se-speciation in root, stem and fruit. After 40 days of exposure, selenomethionine was the major species found in roots, however, Se-methylselenocysteine was the main species found in the fruit, suggesting Broccoli as a source of this important selenoamino acid in human diet. However, the degree of meal processing influences the stability of Se-aminoacids. Speciation studies in boiled Broccoli and in the extraction water were also carried out. This experiment revealed a noticeable degradation of Se-methylselenocysteine in the boiled Broccoli fruit.Proteins soluble in Tris-HCl were analyzed by two-dimensional chromatography coupled to ICP-MS.The results obtained contribute not only to a deeper understanding of Se accumulation mechanisms by plants but also to further functional food complements preparation and the effect of food processing on species stability.     

Transformation of 14C‐Labeled Graphene to 14CO2 in the Shoots of a Rice Plant

This study focused on using carbon‐14‐labeled few‐layer graphene (FLG) to determine its uptake, distribution, transformation, and depuration in rice plants. After 7 d hydroponic exposure to FLG suspension at 250 μg L^?1, roots accumulated 694.8 mg kg^?1 graphene and shoots had 53.7 mg kg^?1 graphene from intra‐plant translocation. FLG could likely pass through the cell wall and membrane and enter the chloroplast in the shoots. After 14 days of depuration, only about 15 % of the accumulated FLG were eliminated into the depuration solution with about 70 % of graphene retained in the plants. About 9 % of the accumulated FLG was degraded to ¹⁴CO₂ and proposed that reaction with OH^. in the leaves may likely contribute to the degradation of FLG, which had structural defects. These findings have an important impact on the long‐term environmental fate of graphene‐related materials in soil–plant systems.     

Measuring the solubility of CO2 and H2S in sulfolane and the density and viscosity of saturated liquid binary mixtures of (sulfolane + CO2) and (sulfolane + H2S)

The density and viscosity of liquid sulfolane saturated (loaded) with single CO₂ and H₂S gases were measured simultaneously with the solubility of the single CO₂ and H₂S gases in sulfolane at temperatures ranging from (303.15 to 363.15) K and pressures of up to about 2.4 MPa using a new experimental set-up developed in our laboratory. The experimental density and viscosity values were correlated using a modified Setchenow-type equation. It was observed that the density and viscosity of mixtures decrease by increasing temperature and acid gas solubility (loading) in sulfolane. Acid gas loading has a much profounder effect on the viscosity of solutions than on their density, i.e. at a concentration of 1 mol CO₂/H₂S per kg of sulfolane the density decreases by less than 3%, but viscosity decreases by more than 30%. Results show that at fixed temperature and pressure H₂S is more than four times as soluble as CO₂ in sulfolane. The measured solubility and density values were respectively used to obtain Henry’s law constants and partial molar volumes at infinite dilution for dissolution of CO₂ and H₂S gases in the liquid sulfolane at the temperatures studied. The Henry’s law constants obtained at different temperatures were used to determine infinite dilution partial molar thermodynamic functions (Gibbs free energy, enthalpy and entropy) of solution. The measured solubility data were correlated by using a model comprised of the extended Henry’s law and the Pitzer’s virial expansion for the excess Gibbs free energy.     

Uptake kinetics of deuteriated water vapor by plants: Experiments of D2O release in a greenhouse as a substitute for tritiated water

Potted plants were exposed to D₂O vapor in a greenhouse and uptake of D₂O by leaf and deposition of D₂O to pot soil were examined. Atmospheric D₂O concentration in the greenhouse increased rapidly after starting the release and reached constant level in a few hours. Although the variation of D₂O concentration in leaf followed that in air with showing a time delay, D₂O concentration in leaf did not become the same level as that in air and vein showed lower concentration that lamina. D₂O concentration in the pot soil increased slowly with diffusing in deeper layer.     

Phytoremediation of lead with green onions (Allium fistulosum) and uptake of arsenic compounds by moonlight ferns (Pteris cretica cv Mayii)

Phytoremediation has been investigated as an alternative to excavation to remediate contamination in soil. In this work, Allium fistulosum (green onions) and Pteris cretica cv Mayii (moonlight ferns) were investigated for phytoremediation. Green onions were planted in lead-spiked soil, and chelating agents were introduced to enhance the uptake of lead by the plants. Lead uptake was low in the absence of chelating reagents. Ethylenediaminetetraacetic acid (EDTA) significantly enhanced the concentration of lead in the stems of green onions, while propylenediaminetetraacetic acid (PDTA) did not induce lead absorption.Moonlight ferns (P. cretica cv Mayii) were planted in a hydroponic system to which arsenic (III), arsenic (V), and monomethylarsenate (MMA) were added with hydroponic solution. Ferns exposed to arsenic (III) showed the highest extraction of arsenic followed by ferns exposed to arsenic (V). The extraction of arsenic by the ferns was higher when arsenic (III) was mixed with arsenic (V) than the combination of arsenic (III) and MMA. These results suggest that inorganic arsenic is phytoextracted preferentially to MMA.     

Kinetics of the Absorption of Pure CO2 by Mixtures of Diisopropanolamine and Triethanolamine in Aqueous Solution

This study analyzes the absorption of pure carbon dioxide in aqueous solutions of mixtures of di‐isopropanolamine (DIPA) and triethanolamine (TEA). A stirred tank batch reactor was used with a known flat interface area. The variables considered were temperature within the range 288–313 K and concentration in the interval 5–20% (in weight), being DIPA/TEA relations 75/25, 50/50, and 25/75. The temperature control for the DIPA/TEA 75/25, 50/50, 25/75 systems in the absorption experiments, at all the concentrations and temperatures assayed, showed no differences between that of the liquid phase with respect to the operation, implying that the processes occurred under isothermal conditions. The results show that for the DIPA/TEA 75/25 CO₂ was absorbed in a moderately fast reaction regime, following a second‐order reaction for the total alkanolamine and a first‐order reaction for the CO₂, whereas for the DIPA/TEA 50/50 and 25/75 systems the process followed first‐order kinetics with respect to CO₂ and the mixture of alkanolamines, in a moderately fast reaction regime.     

Genotoxic Evaluation of Fe3O4 Nanoparticles in Different Three Barley (Hordeum vulgare L.) Genotypes to Explore the Stress-Resistant Molecules

Sustainable agricultural practices are still essential due to soil degradation and crop losses. Recently, the relationship between plants and nanoparticles (NPs) attracted scientists’ attention, especially for applications in agricultural production as nanonutrition. Therefore, the present research was carried out to investigate the effect of Fe₃O₄ NPs at low concentrations (0, 1, 10, and 20 mg/L) on three genotypes of barley (Hordeum vulgare L.) seedlings grown in hydroponic conditions. Significant increases in seedling growth, enhanced chlorophyll quality and quantity, and two miRNA expression levels were observed. Additionally, increased genotoxicity was observed in seedlings grown with NPs. Generally, Fe₃O₄ NPs at low concentrations could be successfully used as nanonutrition for increasing barley photosynthetic efficiency with consequently enhanced yield. These results are important for a better understanding of the potential impact of Fe₃O₄ NPs at low concentrations in agricultural crops and the potential of these NPs as nanonutrition for barley growth and yield enhancement. Future studies are needed to investigate the effect of these NPs on the expression of resistance-related genes and chlorophyll synthesis-related gene expression in treated barley seedlings.     

Essential oil composition,antioxidant activity and phenolic content of endemic Teucrium alyssifolium Staph. (Lamiaceae)

The present study was designed to examine the chemical composition of the essential oil, in vitro antioxidant activity and total phenolic and flavonoid content of extracts from plant parts (leaf, flower and stem) of Teucrium alyssifolium. The principle components of the essential oil were trans-β-caryophyllene (16.87%), ar-curcumene (11.43%) and bisabolene (11.06%), representing 39.36% of the oil. The total phenolic contents ranged between 13.99 and 41.54 mg of GAE/g of extract. The concentrations of flavonoids varied from 16.82 to 49.52 mg of Ru/g of extract. Antioxidant activity was determined in vitro using DPPH reagent and expressed as concentration of each extract required to inhibit radical by 50% (IC₅₀) values that ranged from 13.52 to 132.55 μg/ml. Our results have indicated that water extract of T. alyssifolium (part leaf) with a total content of polyphenols (41.54 mg of GAE/g) and an IC₅₀ of 13.52 μg/ml is more antioxidant.     

Thermochemical conversion of cellulose in polar solvent (sulfolane) into levoglucosan and other low molecular-weight substances

Pyrolysis of cellulose in sulfolane, an aprotic polar solvent, was conducted at the temperature between 200 and 330 °C. Sulfolane was used as a good solvent for levoglucosan, the major anhydromonosaccharide formed from cellulose pyrolysis, for prevention of the polymerization reaction. Cellulose was observed completely decomposed into soluble products in sulfolane within 3, 10, 60 and 480 min at 330, 280, 240 and 200 °C, respectively. The soluble products had molecular weights less than 500 after acetylation (GPC analysis) and similar product composition to that from cellulose pyrolysis under nitrogen (levoglucosan, levoglucosenone, furfural and 5-hydroxymethylfurfural by HPLC analysis). Pyrolysis of cellulose in polar solvent, which can solubilize anhydromonosaccharides, is proposed as a method for selective formation of levoglucosan and other low molecular-weight (MW) substances. As well, the cellulose pyrolysis in sulfolane did not suffer from carbonization reactions (microscopic and IR spectroscopic analysis) as did cellulose pyrolysis under nitrogen or in dioctyl phthalate (a poor solvent for levoglucosan) which gave brown/black solids. The residues obtained from the pyrolysis in sulfolane were colorless and gave similar IR spectra to that of the original cellulose. Based on these results, a ‘surface-peeling mechanism’ is proposed, and the role of the solvent in the mechanism is discussed.     

Interaction of tin (IV) chloride with sulfolane and between tin (IV) chloride and lithium chloride in sulfolane solution

Tin (IV) chloride reacts with sulfolane (S) to form a cis-octahedral adduct SnCl₄·S₂. Solutions of lithium chloride and tin (IV) chloride in sulfolane contain the complex ions SnCl ₅ ^– and SnCl ₆ ^2– at 11 and 21 mole ratios of constituents, respectively. The complexes are characterized by conductimetry and by Mössbauer, IR, and Raman spectroscopy.     

Determination of heavy metal concentrations in plants exposed to different degrees of pollution using ICP-AES

Plant samples (Plantago lanceolata - narrow leaf plantain and Cichorium endiviae - endive) were collected in the surroundings of heavy metal emission sources and in other less contaminated areas. After digestion in a closed microwave system using HNO(3), the concentrations of Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn were determined using ICP-AES. Detection limits for all the elements of interest are given. Differences in heavy metal uptake rate between both plant species were observed. The uptake is more intensive for endive than for narrow leaf plantain. High concentrations of some heavy metals were determined in the unwashed plant samples as a result of exposure to aerosols. Tukey's statistical test was used to confirm the discrepancy of Cr concentration in plant samples from various areas. Washing the leaves with water was found to remove a large amount of water-soluble aerosols.     

Human urine certified reference material CZ 6010: creatinine and toluene metabolites (hippuric acid and o-cresol) and a benzene metabolite (phenol)

A reference material for the biological monitoring of occupational exposure to toluene, benzene and phenol was prepared. O-cresol and hippuric acid (metabolites of toluene) are used for the biological monitoring of occupational exposure to toluene. Phenol, a metabolite of benzene, is used for the biological monitoring of exposure to benzene, but phenol can of course also be used as an indicator of exposure to phenol as well. The reference material (RM) used for the determination of these metabolites was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to toluene and those taking part in an inhalation experiment. Tests for homogeneity and stability were performed by determining urine concentrations of o-cresol, hippuric acid, creatinine and phenol. To investigate the stability of the RM, the urinary concentrations of o-cresol and phenol were monitored for eighteen months using GC and HPLC, while those of hippuric acid and creatinine were followed for five and six years, respectively, using HPLC. Analysis of variance showed that the concentrations did not change. The certified concentration values (and their uncertainties) of the substances in this reference material (phenol concentration c=6.46±0.58 mg l⁻¹; o-cresol concentration c=1.17±0.15 mg l⁻¹; hippuric acid concentration c=1328±30 mg l⁻¹; creatinine concentration c=0.82±0.10 g l⁻¹) were evaluated via the interactive statistical programme IPECA.     

Phytoremediation of arsenic by two hyperaccumulators in a hydroponic environment

Phytofiltration involves the use of plants to remove toxic compounds from water. Arsenic is an element of considerable environmental and toxicological interest because of its potential deleterious effects upon human health. In this research, a laboratory-constructed hydroponic system was employed to characterize phytofiltration for the uptake of arsenic and macronutrients by two arsenic hyperaccumulators, Pteris cretica cv Mayii (Moonlight fern) and Pteris vittata (Chinese brake fern). Arsenic was shown to preferentially accumulate in the leaves and stems of P. cretica cv Mayii compared to roots. The amounts of the macronutrients calcium and phosphorous absorbed were compared for control plants (growth solution) and plants exposed to arsenic(III) (growth solution and arsenic(III)). Significant differences in the concentration levels of the macronutrients were observed in roots, stems, and leaves between the control and arsenic-exposed plants. The arsenic contents of entire P. vittata plants exposed to hydroponic solutions containing arsenic(III) and arsenic(V) were compared, and no significant difference was observed.     

Synthesis and properties of poly(aryl ether ether ketone) copolymers with pendant methyl groups

Polyether ether ketone and polyether ether ketone copolymers were prepared by the nucleophilic substitution reaction of 4,4′-difluorobenzophenone with hydroquinone and with varying mole proportions of hydroquinone and methyl hydroquinone using sulfolane solvent in the presence of anhydrous K₂CO₃. The polymers were characterised by different physico-chemical techniques. The crystallinity of the polymers was found to decrease with increase in concentration of the methyl hydroquinone units in the polymer. Thermogravimetric studies showed that all the polymers were stable upto 430 °C with a char yield above 49% at 900 °C in N₂ atmosphere. The glass transition temperature was found to increase and the crystalline melting temperature and activation energy were found to decrease with increase in concentration of the methyl hydroquinone units in the polymer.