Removal of Excess Alkali from Sodium Naphthenate Solution by Electrodialysis Using Bilayer Membranes for Subsequent Conversion to Naphthenic Acids

The processing of solutions containing sodium salts of naphthenic acids (sodium naphthenate) is in high demand due to the high value of the latter. Such solutions usually include an excessive amount of alkali and a pH of around 13. Bipolar electrodialysis can convert sodium naphthenates into naphthenic acids; however, until pH 6.5, the naphthenic acids are not released from the solution. The primary process leading to a decrease in pH is the removal of excess alkali that implies that some part of electricity is wasted. In this work, we propose a technique for the surface modification of anion-exchange membranes with sulfonated polyetheretherketone, with the formation of bilayer membranes that are resistant to poisoning by the naphthenate anions. We investigated the electrochemical properties of the obtained membranes and their efficiency in a laboratory electrodialyzer. Modified membranes have better electrical conductivity, a high current efficiency for hydroxyl ions, and a low tendency to poisoning than the commercial membrane MA-41. We propose that the primary current carrier is the hydroxyl ion in both electromembrane systems with the MA-41 and MA-41M membranes. At the same time, for the modified MA-41M membrane, the concentration of hydroxyl ions in the anion-exchanger phase is higher than in the MA-41 membrane, which leads to almost five-fold higher values of the specific permeability coefficient. The MA-41M membranes are resistant to poisoning by naphthenic acids anions during at least six cycles of processing of the sodium naphthenate solution.

PHYSIC-CHEMICAL PROPERTIES OF TYPICAL CHERNOZEMS OF PRYDNISTERSK PODILLYA

This article analyzes the physic-chemical properties of typical chernozems. According to the methods, a laboratory study was performed. Physic-chemical parameters that are typodiagnostic for subfacial classification division of typical chernozems of the Prydnistersk Podillya are determined. Typical chernozems of the Prydnistersk Podillya are low-humus (2.78–3.98%). With depth, the humus content decreases by an average of 0.2% for every 10 cm, which indicates a uniformly accumulative type of distribution of organic matter in the profile of chernozems. In the same direction, humus reserves are declining. There is a spatial correlation between the humus content and the amount of physical clay in the fine soil. Humic acids predominate in the humus to a depth of 90–100 cm (Sgk: Sfk is 1.12–1.78). The general tendency of relative “fulvatization” of the arable layer as a result of its agrotechnical depletion is noticed. In relation to SGC to total organic C, chernozems of the study area are characterized by a high and very high degree of humification of organic matter. It is highest (62–70%) in the soils of the key section “Humentsi”, decreasing to 52–62% and 43–63% in the western direction. The humic acids of typical chernozems are dominated by calcium humates (GK-2). The largest number of them (29–35%) is concentrated on the contact boundary of humus and carbonate profiles. The convex nature of the distribution curves of the fraction of 2 humic acids and a sharp decrease in its content deeper than 100 cm, indicates their high migration capacity and the possibility of significant deposition of only a significant excess of calcium carbonates. The intensity of migration processes of the GK-2 fraction decreases in the direction of increasing the stiffness of hydrothermal conditions, due to the pulling of carboxylic acid salts closer to the soil surface, supersaturation of the solution with calcium bicarbonate, and as a consequence, increasing the total alkalinity in the humus horizon. The capacity of cation exchange (ECO) of typical chernozems is quite high (29–32 mmol-eq / 100 g of soil) with the dominance of calcium and magnesium cations in the composition of the soil-absorbing complex (GVC). There is a general tendency to increase these indicators in chernozems with low values ​​of SCC of the territory. The pH of the aqueous extract of typical chernozems of the Prydnistersk Podillya increases with depth from weakly acidic in the arable horizon to weakly and medium-alkaline within the carbonate profile. The reasons for such changes in the increase with the depth of the concentration of Ca2 + bicarbonates, which in their dissociation leads to an increase in the amount of hydroxyl ion and increase the alkalinity of the soil. The carbonate profile of typical chernozems is dominated by migratory forms of carbonate neoplasms - mold, carbonate plaque, veins. The vertical curve of carbonate content has an eluvial-illuvial type of profile structure. The content and reserves of carbonates in the 1.5-meter layer of typical chernozems increase from the west (434–714 t / ha) to the east (979–1847 t / ha). Key words: physic-chemical properties, typical chernozems, humic horizon, humic acids, carbonate profile.

Enhanced electrocatalysts fabricated via quenched ultrafast sintering: physicochemical properties and water oxidation applications

The synthesis of transition metal oxides is typically time- and energy-consuming. Recently, fast sintering methods have demonstrated great potential to reduce ceramic sintering time and energy use, improving the commercial prospects of these materials. In this article, a quenched ultrafast high-temperature sintering (qUHS) technique is developed to sinter metastable brownmillerite SrCoO2.5 (SCO) in less than a minute. Surprisingly, SCO fabricated by qUHS shows higher activity for the oxygen evolution reaction (OER) compared to solid-state-reaction-synthesized SCO. Comparing samples produced by these two techniques, the increased OER performance of SCO qUHS is likely due to the synergistic combination of surface Co chemical state, higher mesoporosity and enhanced hydroxyl ion (OH-) adsorption. This work demonstrates the potential of qUHS for producing high-performance electrocatalysts and provides detailed insights into the impact of ultrafast sintering on the materials' physical properties and electrocatalytic activity.

Aesthetic Outcomes of Early Occlusal Loaded SLA Dental Implants with Hydroxyl Ion Modified Surface—A 12 Months Prospective Study

Background: Many efforts have been made recently to arrange a newer, more hydrophilic and more osteoconductive implant surface. One of the possible options in this matter is modification with hydroxyl ion. Materials and Methods: Forty implants with the diameters 3.5 and 4.0 mm were inserted as a single missing tooth restoration protocol in the frontal aspect of the maxilla. All implants were loaded early in a 4 week period. Prior to and during the surgery, the following indices were considered: height of keratinized tissue, the thickness of soft tissue, and the initial level of bone tissue. After 12 months, the implant and the tissues in its direct vicinity were evaluated once more with the following indices: marginal bone loss (MBL), height of keratinized tissue (HKT), probing pocket depth (PPD), pink and white aesthetics scores (PES, WES), as well as pain sensations combined with the procedure (VAS). All results were related to the diameter of the implant and thickness of periodontal biotype. Results: High aesthetic outcomes were reported regardless of soft tissue thickness and implant diameter. The VAS score was higher for the 4.0 implant group, and the thickness of soft tissue had no influence on VAS. In case of implantation in thin or soft tissue, higher MBL levels were reported (0.26 mm), while in case of a thick phenotype, MBL was 0.06 mm. Conclusions: Hydrophilic surface implants can be used for a protocol of early functional occlusal loading. The initial thickness of soft tissue does not influence aesthetic outcomes and does not raise pain perception, although it may elevate crestal bone resorption.

Polyphenol Rich Ajuga bracteosa Transgenic Regenerants Display Better Pharmacological Potential

Ajuga bracteosa Wall. ex Benth. is an endangered medicinal herb traditionally used against different ailments. The present study aimed to create new insight into the fundamental mechanisms of genetic transformation and the biological activities of this plant. We transformed the A. bracteosa plant with rol genes of Agrobacterium rhizogenes and raised the regenerants from the hairy roots. These transgenic regenerants were screened for in vitro antioxidant activities, a range of in vivo assays, elemental analysis, polyphenol content, and different phytochemicals found through HPLC. Among 18 polyphenolic standards, kaempferol was most abundant in all transgenic lines. Furthermore, transgenic line 3 (ABRL3) showed maximum phenolics and flavonoids content among all tested plant extracts. ABRL3 also demonstrated the highest total antioxidant capacity (8.16 ± 1 μg AAE/mg), total reducing power, (6.60 ± 1.17 μg AAE/mg), DPPH activity (IC50 = 59.5 ± 0.8 μg/mL), hydroxyl ion scavenging (IC50 = 122.5 ± 0.90 μg/mL), and iron-chelating power (IC50 = 154.8 ± 2 μg/mL). Moreover, transformed plant extracts produced significant analgesic, anti-inflammatory, anticoagulant, and antidepressant activities in BALB/c mice models. In conclusion, transgenic regenerants of A. bracteosa pose better antioxidant and pharmacological properties under the effect of rol genes as compared to wild-type plants.

Ajuga Bracteosa Transgenic Regenerants Display Better Pharmacological Potential

Ajuga bracteosa Wall. ex Benth is an endangered medicinal herb used against different ailments in folklore medicines. Here, we aimed to create a new insight to the fundamental mechanisms of genetic transformation in the ethnomedicinal usage of this plant. We transformed the plant with rol genes of Agrobacterium rhizogenes and raised the regenerants from the hairy roots. The transgenic regenerants were screened for in vitro antioxidant activities, a range of in vivo assays, and linked the activities with elemental analysis, polyphenol content and different phytochemicals found through HPLC. Among 18 polyphenolic standards, kaempferol was found most abundant in all transgenic lines (up to 101.26 ± 6 µg/mg). Furthermore, among all tested plant extracts, transgenic line 3 (ABRL3) showed maximum phenolics (13.39 ± 2µg GAE/mg) and flavonoids content (4.75 ± 0.16 µg QE/mg). ABRL3 also demonstrated potent total antioxidant capacity (8.16 ± 1 µg AAE/mg), total reducing power, (6.60 ± 1.17 µg AAE/mg), DPPH activity (IC50 = 59.5 ± 0.8µg/mL), hydroxyl ion scavenging (IC50 = 122.5 ± 0.90 µg/mL), and iron chelating power (IC50 = 154.8 ± 2 µg/mL) among all plants. Transformed plant extracts also produced significant analgesic, anti-inflammatory, anticoagulant, and antidepressant properties in in vivo mice model as compared to control untransformed plant material. Additionally, no abnormal behavior or lethality was observed in any animal tested. In conclusion, transgenic regenerants of A. bracteosa pose better pharmacological properties under the effect of rol genes as compared to wild type plants.

Іnvestigation of complex formation of cobalt (ІІ) ions with polyacrylic acid

The process of formation of cobalt (II) ion complexes with polyacrylic acid, their influence on the size of the tangle of polyacrylic acid macromolecules and the concentration of monomer units in it have been studied. It is shown that the reaction at a temperature of 20–300 ºC forms a complex in which the cobalt ion binds two carboxyl groups of polyacrylic acid. Binding of the third carboxyl group to the complex is prevented by a sufficiently flexible polyacrylic acid chain. Increasing the temperature significantly increases the flexibility of the polyacrylic acid chain. The formation of complexes at elevated temperature proceeds in the first order by cobalt (II) ion and hydroxyl ion and by zero order – by polyacrylic acid. The change in the concentration of monomer units in the tangle of polyacrylic acid macromolecules during the formation of a complex with a cobalt (II) ion proceeds in the first order.

Antioxidant and Cytotoxic Activities of Beach Morning Glory (Ipomoea pes-caprae)

The present study aimed to evaluate the in-vitro and in-vivo antitumor potential of Ipomoea pes-caprae (I. pes-caprae). Petroleum ether (60-80oC), methanol, aqueous, and swaras extracts prepared from the whole plant of I. pes-caprae. Antioxidant activity of I. pes-caprae was evaluated by using 2, 2-diphenyl-1-picrylhydrazylhydrate (DPPH), reducing power, and hydroxyl ion scavenging assay methods. The cytotoxic effect of I. pes-caprae was evaluated by using Trypan blue and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against animal melanoma cancer (B16F10), human stomach cancer (Kato-III), and human colorectal cancer (HT-29) cell lines. The ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR), and Mass spectra were recorded for the structure elucidation of isolated compounds. These isolated compounds of I. pes-caprae were evaluated biologically at two doses of 25 and 12.5 mg/kg body weight on male C57BL mice to explore the antitumor activity against melanoma cancer. The scavenging range (IC50) of the extracts of I. pes-caprae was found to be 63.40±2.26 to 74.77±2.28 μg/ml, and the cytotoxic range (CTC50) for MTT assay was found to be 62.54±3.27 to 73.70±1.32 μg/ml. Based on IR, NMR, and mass spectroscopic analysis and by chemical transformation, structures of three compounds A, B, and C were elucidated as 3’-methoxy-3,4’,5,7-tetrahydroxy flavone, 3,7-dimethoxy-8-methyl-4’,5-dihydroxy flavone, and 3’-methoxy-4’,5,7-trihydroxy flavone-3-glucoside, respectively. All isolated compounds were shown antitumor potential against melanoma cancer.