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In this study, we considered changes in the surface chemistry after introducing fluorine into the surface layer of nanoporous activated carbon (BAU) produced from the birch wood. Here, we examined the BAU treated with 1,1,1,2-tetrafluoroethane at the selected temperature in the range of 400–800 °C. Diverse methods, including chemical analysis, nitrogen adsorption–desorption, SEM–EDS, XPS, and 19F solid-state NMR, were used for the characterization of the prepared materials. It was found that one can introduce from 0.17 to 0.42 mmol of F per gram of BAU using fluoroalkylation at 400–500 °C. Increasing the temperature to 600 °C increases the fluorination efficiency, and the relatively high fluorine content of 1.86 mmol of F per gram of BAU can be reached. At least three group types, namely, C–F, CF2, and CF3 groups, were found by XPS and 19F solid-state NMR after such treatment. The content of “semi-ionic” fluorine drastically increases in the surface layer after high-temperature fluoroalkylation at 700 °C and 800 °C. This “semi-ionic” fluorine, in the form of C–F and CF2 groups, is directly conjugated with the π-electron system of the carbon matrix.

In the present work, we report, for the first time, the production of stable nanocolloids of highly monodisperse silver and gold nanoparticles (AgNPs and AuNPs) using phytosynthesis approach. With the aim to eliminate misinterpretations associated with the use of usually applied crude plant extracts, the presented study was focused on the use of polyphenolic fraction isolated from elderberry fruits (Sambucus nigra L.) for the synthesis. Obtained AgNPs and AuNP were characterized by UV–Vis and FTIR spectroscopy, DLS and TEM. We observed unexpectedly high capability of the natural polyphenols not only to form monodisperse nanoparticles but also to stabilise the concentrated nanocolloids (539 mg/L AgNPs and 739 mg/L AuNPs) for at least two years. Moreover, AgNPs showed strong antibacterial properties against pathogenic bacterial strains Staphylococcus aureus and Escherichia coli (inhibited after 15 min and totally stopped growth after 3 and 5 h at 3.125 mg/L concentration).

The cetylpyridinium (CP) dipicrylamide (DPA) ion pair has been synthesized and characterized by the FT-IR and NMR (1H and 13C) spectroscopy, theoretically studied and tested as ion-exchanger for cetylpyridinium selective electrodes. The molecular dynamics and further DFT optimization indicate face-to-face π-π stacking interaction between pyridinium and 2,4,6-trinitrophenyl rings. The presence of weak interactions between hydrogens of cetyl chain and oxygens of nitro groups of DPA anion was confirmed by RDG function analysis. Numeric reactivity descriptors computed at the B3LYP/6-31+G(d,p) level of theory show that CP-DPA has electrophilic character and can readily react with bases. Two fabricated electrodes with the CP-DPA ion-exchanger showed near-Nernstian responses towards CP chloride in the concentration range from 1 × 10−2 to 1 × 10−5 mol/L. In the case where dibutyl phthalate was used as plasticizer, the slope equals 57.2 ± 1.3 mV/decade, whereas for the case of dioctyl phthalate the slope is 61.6 ± 1.2 mV/decade.

Here, we have examined the nanoporous activated carbon fibers (ACFs) sulfonated using the direct sulfonation and the staged method that included bromination, followed by sulfidation and oxidation. TEM confirmed the nanoporous structure of the prepared sulfonated ACFs. Nitrogen porometry and 2D nonlocal DFT simulations showed the nanoporosity reduction and variations of the pore size distribution because of the functionalization. Comparison of parameters of the SO3H groups confined in nanopores, e.g., the thermal stability and catalytic potential, showed that the most efficient acid sites, in the catalytic 2-propanol dehydration to propylene, are the SO3H groups grafted by the staged Houben–Weil methods. From the productivity of reactions used at the preparation stage, and in contrast to the one-staged aromatic substitution, the bromine addition to π sites of the edges of carbon matrix supplies enough active sites and is a reason for further high yields of the grafted thermostable SO3H groups. Hydrolysis of the grafted bromine and the surface oxidation of nanopores walls are parallel reactions that lowered the SO3H-related acidity, increasing the total acidity to 1.5 mmol g−1. The reported nanoporous sulfonated ACFs are effective to be used in the dehydration reactions catalyzed by solid acids.

The production of propylene by dehydration of 2-propanol at solid-vapor interfaces, as an example of the acidcatalyzed surface reaction, was explored by using sulfonated polyacrylonitrile-derived activated carbon fibers (PAN-ACFs). To prepare these catalysts, the PAN-ACFs obtained by onestep carbonation-activation were modified with a surface coverage of high acidity. The surface of PAN-ACFs was sulfurated with sulfur vapors at high temperatures followed by oxidation, to yield the corresponding sulfonates. The chemical analysis showed that the carbon surface layer contains from 1.28 to 6.10 mmol$\mathrm{g}^{-1}$ of sulfur, including the contribution of sulfonic $(\mathrm{S}\mathrm{O}{}_{3}\mathrm{H})$ groups. In addition to sulfonic groups, the obtained catalysts contain carboxyl, lactone, and phenolic groups, which are formed as a result of oxidation treatment. In order to understand the changes in surface chemistry and the results of sulfuration and oxidation, the sulfonated PAN-ACFs were characterized by a variety of techniques including TPD MS, TGA, SEM, and FTIR ATR. During a typical temperature mode screening at catalyst testing, it was found that the sulfonated PAN-ACFs prepared by treatment with sulfur vapor at low temperature, at $400\circ \mathrm{c}$ and $500\circ \mathrm{c}$, are very efficient at dehydrating 2-propanol. A weighed mass of 100 mg of each of these catalysts was operated at 165-175°C in 12 hours, and the catalysts were characterized by high conversion of 2-propanol and high selectivity to propylene, with a propylene yield of about 100%. Furthermore, the solid acid catalysts have high stability and strong acidity and can be reused with no significant loss in the activity after the third cycle in the subsequent 20 cycles. The preparation of solid acid catalysts from PAN-ACFs affords a novel strategy for producing propylene through alternative green and sustainable technologies.

Oxidation of activated carbon (AC) with nitric acid was carried out, and the resulting AC/HNO 3 showed high capacity when used as supercapacitor electrode material operated in the KOH electrolyte. Oxidation caused different structural changes in the AC, reducing the specific surface area and the total pore volume. After oxidation, the content of all types of oxygen-containing groups and, especially, carboxyl groups showed a significant increase. Despite the significant reduction of the specific surface area, the specific capacitance of the oxidized AC in symmetric supercapacitor electrodes is 1.4 times larger than that for the pristine AC.

Adsorption is currently the most promising capture technology to shorten atmospheric emissions of carbon dioxide (CO2). In this article, we report on the adsorption of CO2 onto pristine, oxidized, and aminated activated carbon (AC) sorbents. From our findings, some functionalized AC sorbents have shown very promising results in the CO2 capture process. Their maximum adsorption capacity measured by the thermogravimetric method at 20 °C varies between 2.2 and 3.9 mmol CO2/g depending on the content of diethylamino and oxygen-containing groups. The functionalization of the carbon surface with diethylamino groups improves the adsorption capacity by 30–40%. The CO2 adsorption little depends on the texture parameters of the pristine AC sorbents. In the range from 20 to 100 °C, the CO2 thermodesorption showed the effective regeneration of the sorbents. The aminated carbon surface demonstrates the best CO2 adsorption but binds the adsorbed molecules stronger than the oxidized surface, which limits the sorbent regeneration.

Here we report on the preparation of effective aminated sorbents based on activated carbon (AC), which was produced from natural raw material (Apricot pits) for the removal of heavy metal ions from wastewaters. For effective functionalization, bromination and following amination were carried out. At the amination stage, the grafted bromine groups were substituted by amino groups. Amination by ethylenediamine and monoethanolamine alcohol solutions can replace 0.52 mmol of bromine groups by 0.51–0.57 mmol of amino groups per gram of sorbent. We showed that the aminated ACs could remove 90% of Cu(II) ions from aqueous solutions containing from 4×10−5 to 1×10−3 mol/L of Cu2+. The regeneration of used sorbents and the recovery of copper were also studied to evaluate the reusability of the sorbents.

estimation of toxicity of two new classes of heterocyclic condensed cationic surfactants was performed. The general synthetic approaches for obtaining the target heterocyclic systems of 1,2,4-triazole and thieno[2,3-d]pyrimidine classes were discussed and the main routes to increasing of the chemical libraries through the efficient introduction of long-chain substituents were pointed out. The estimation of toxicity was done through: (a) the prediction of the LD 50 values of acute rat oral toxicity with using GUSAR free online service; (b) the prediction of the LC 50 values of fathead minnow with 96 hours exposure, which were predicted with using T.E.S.T. software. Computed LD 50 and LC 50 values testify that proposed heterocyclic surfactants have the toxicity rates close to the widely used surfactants like cetylpyridinium chloride, cetyltrimethylammonium bromide, and benzalkonium chloride. Consequently, target cationic surfactants of 1,2,4-triazole and thieno[2,3-d]pyrimidine series can be considered as non-toxic detergents and will be synthesized for the next biological testing as disinfectants.

The fluoroquinolones are one of the most widely used classes of antibiotics. Enrofloxacin belongs to the class of fluoroquinolone antibiotics that have been intensively used for the treatment of bacterial infections in veterinary medicine. When antibiotic residues enter the soil, the main processes determining their persistence are sorption to organic particles and degradation. The article presents the results of studies on the sorption of enrofloxacin by different crops, provided that it’s various concentrations in the soil (1000mg·kg−1, 100mg·kg−1, 10mg·kg−1). Experimental studies have shown that the activity of absorbed antibiotics depends on its concentration in the soil and species of an agricultural plant. It was found that the most active antibiotic absorbs Lactuca sativa var. Crispa and Calendula officinalis. The lowest content of enrofloxacin among the five plants was in Mentha piperita. Adding to the soil of enrofloxacin at a concentration of 1000 mg·kg−1 leads to the formation of a high level of soil toxicity. In model ecosystems with Thymus serpillum and Mentha piperita, soil toxicity was more than 70%. The toxicity of enrofloxacin in the soil within In vivo experiments was on average 10% lower than in laboratory tests. The highest phytotoxic effect was observed in the soil of model ecosystems, where the concentration of enrofloxacin was 1000 mg·kg−1. It should be noted that in the soil where Lactuca sativa was grown, the phytotoxic effect was 56.17 % (In vitro) and 49.22% (In vivo). This is due to the active absorption of antibiotic by plants, which minimized the toxicity of the soil. The different terrestrial toxicological effects of enrofloxacin were studied using a series of bioassays and including sorption of fluoroquinolone antibiotic by five crop plants. Enrofloxacin is highly resistant, its biodegradation process is longer than other antibiotics, it is actively absorbed by the plants, and therefore it is necessary to control it content in phytoproduction.

In this article, we report on the dehydration of bioethanol over solid acid catalysts―0.1 mmol g−1 of phosphotungstic acid loaded on activated carbon carriers obtained from waste biomass. An ethanol vapor showed a selective transformation, catalyzed by the phosphotungstic acid, into diethyl ether at between 120 and 150 °C. At the temperature range of 180–205 °C, the ethanol conversion reaches almost 99.7% with 100% selectivity towards ethylene. The adsorption and catalytic studies have shown that the oxygen-containing functional groups on carbon solids act as sites of the immobilization of phosphotungstic acid and of the ethanol adsorption contributing to alcohol dehydration.

A new cetylpyridinium picrate ionic liquid has been synthesized and characterized by differential thermal analysis, XRD, FT-IR, and NMR (1H and 13C) spectroscopy. Differential thermal analysis indicates the congruent melting of cetylpyridinium picrate and a temperature range of liquid state is 47–267 °C. A solid form of the sample characterized with a polymorphic transformation at 37 °C, which was confirmed via the XRD analysis. The interionic charge-transfer interactions, namely the charge transfer from the picrate anion to the cetylpyridinium cation, were detected by comparison of NMR spectra of DMSO solutions of the ionic liquid and cetylpyridinium chloride. The H–NMR chemical shifts’ differences of about 0.2 ppm and 0.1 ppm were observed in the case of the o-protons and the α-methylene group protons, respectively. Additionally, the charge-transfering between the attracted ions was confirmed by DFT calculations. Based on the solid state NMR technique, the higher ions mobility was suggested for the solid sample of the ionic liquid in comparison to the solid cetylpyridinium chloride monohydrate. Moreover, the association constants KA at 22, 30, 40, and 50 °C, obtained from the electrical conductivity measurements, clearly testifies much lower dissociation in the case of picrate. The KA values of cetylpyridinium picrate and chloride in DMSO medium at 22 °C equal 748.7 L/mol and 525.0 L/mol, respectively. The performed DFT computations of the reduced density gradient function in four proposed structures of the new ionic liquid cation-anion pair identifies the presence of weak non-covalent C H•••O N interactions between cetyl chain hydrogen atoms and nitro groups of picrate was explored through DFT calculations and analysis of the RDG function.

We propose a facile route for the surface functionalization of activated carbons (ACs), which are used as a solid matrix with good mechanical properties, but have the deficiency of the active surface sites to form the AC-based solid acids (ACSA) by the direct chemical method. The route includes three stages that provide active and stable strong acidic surface layer. The surface chemistry changes at the functionalization stages were controlled with thermogravimetric (TG) and thermoprogrammed desorption (TPD) methods. N2 adsorption-desorption studies demonstrate the conservation of the AC meso- and macroporosity. According to XPS, DRIFT, TG-TPD-IR, and potential titrimetry data, the ACSA obtained by sulfonation of the styrene functionalized AC are contained up to 1.1 mmol g−1 of the strong acidic SO3H groups. The surface functionalization, as reported route, gives no prominent structural changes, from XRD data, the large macropores and transport channels maintain, from SEM data, and MicroRaman spectra show no defecting of the initial carbon matrix. The obtained ACSA are effective catalysts for the dehydration of 2-propanol and combine the high efficiency of work with the increased thermal stability of the surface layer. The thermoresistance of the ACSA significantly exceeds that of the Amberlyst-15 WET catalyst.

In this study, natural microporous activated carbon (AC) was barothermal treated with hydrogen peroxide vapors at 553 and 623 K. Nitrogen adsorption proves the formation of micro-mesoporous ACs with S ext of 350 m2 g−1 at S BET = 1250 m2 g−1. The texture of ACs drastically depends on the oxidant concentration and temperature at the treatment. Thermal behavior of the initial and obtained ACs was examined in an argon dynamic atmosphere with thermogravimetric (TG) analysis. Thermoprogrammed desorption coupled with infrared spectroscopy (TPD-IR) and MS spectroscopy monitoring of evolved gases were used to disclose the regularities of the surface groups thermodestruction. TG-TPD-IR shows that the barothermal oxidation suppresses the rich surface chemistry of the initial AC, of 1 mmol g−1 of oxygen-containing functional groups. The oxidation causes selective functionalization of the AC surface with 2.6–4.3 mmol g−1 of non-acidic quinolic (Qu) groups. The CO/CO2 release from the barothermal treated ACs has reached the Boudouard equilibrium at temperatures above 930 K. Thermal stability of two different surface centers, single spaced and vicinal Qu groups, is assigned as a factor responsible for issues related to the thermodesorption of CO/CO2 and the passage of the reversed reaction of Boudouard–Bell.

BACKGROUND Anthocyanins, compounds that represent the major group of flavonoids in berries, are one of the most powerful natural antioxidants. The aim of this study was to evaluate biological activities and comparison of anthocyanin-rich extracts prepared from chokeberry (Aronia melanocarpa), elderberry (Sambucus nigra), bilberry (Vaccinium myrtillus) and blueberry (V. corymbosum) on the porcine intestinal epithelial IPEC-1 cell line. RESULTS The IC50 values calculated in the antioxidant cell-based dichlorofluorescein assay (DCF assay) were 1.129 mg L−1 for chokeberry, 1.081 mg L−1 for elderberry, 2.561 mg L−1 for bilberry and 2.965 mg L−1 for blueberry, respectively. We found a significant negative correlation (P < 0.001) between cyanidin glycosides content and IC50 values. Moreover, extracts rich in cyanidin glycosides stimulated proliferation of IPEC-1 cells and did not have cytotoxic effect on cells at an equivalent in vivo concentration. CONCLUSIONS We found that the chokeberry and elderberry extracts rich in cyanidin glycosides possess better antioxidant and anticytotoxic activities in comparison to blueberry or bilberry extracts with complex anthocyanin profiles. © 2015 Society of Chemical Industry