Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components

Currently, the main trend of the pulp and paper industry development is bio-refining. It is based on integrated and deep processing of wood raw materials to obtain products with higher value added and reduced amount of waste. One of the high priority tasks of bio-refining is improvement of technology of by-product (sulphate soap) extraction from spent liquor with an increase in the yield and quality of the resulting product and a decrease in the level of environmental pollution. The complexity and energy intensity of sulphate soap extraction from spent liquor depends on many factors, including the species used for wood cooking, composition of extractives, the method of wood preparation for delignification, etc. Sulphate soap is a multicomponent emulsion with a predominant content of resin and fatty acids, small amount of unsaponifiable substances and an admixture of lignin, which is mainly extracted from waste liquior by settling. The low degree of its extraction is associated with the absence of systematical data on the mutual influence of the sulphate soap components. In this work, the patterns of intermolecular interaction of the individual components of the by-product (sulphate soap) are found. For this purposes the critical concentration of micelle formation (CCM) and surface tension depression of surface-active sodium oleate and sodium abietate and their mixtures of varying compositions were determined by the methods of tensiometry and conductometry. A detailed analysis of its mixed micelles and adsorption layers was carried out using the Rubin–Rosen pseudophase model. The interaction mechanisms of components in mixtures are explained. The impact on the composition of micelles and adsorption layers of the more surface-active sodium oleate was detected in mixed solutions. A maximum synergistic effect of micelle formation was observed in mixtures with a predominant content of sodium abietate. Analysis of experimental data and the result of sulphate soap modeling allow substantiating the complexity of its extraction from waste liquor after wood cooking with the presence of hardwood over 30 %, which is explained by the reduced content of resin acids in black liquor. For citation: Yakubova O.S., Demiantseva E.Yu., Smit R.A., Dubovy V.K. Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 196–205. DOI: 10.37482/0536-1036-2021-6-196-205

Activation of the Hypoxia-Inducible Factor Pathway Inhibits Epithelial Sodium Channel-Mediated Sodium Transport in Collecting Duct Principal Cells

Background Active sodium reabsorption is the major factor influencing renal oxygen consumption and production of reactive oxygen species (ROS). Increased sodium reabsorption uses more oxygen, which may worsen medullary hypoxia and produce more ROS via enhanced mitochondrial ATP synthesis. Both mechanisms may activate the hypoxiainducible factor (HIF) pathway. Because the collecting duct is exposed to low oxygen pressure and variations of active sodium transport, we assessed whether the HIF pathway controls epithelial sodium channel (ENaC)-dependent sodium transport. Methods We investigated HIF's effect on ENaC expression in mpkCCDcl4 cells (a model of collecting duct principal cells) using real-time PCR and Western blot and ENaC activity by measuring amiloride-sensitive current. We also assessed the effect of hypoxia and sodium intake on abundance of kidney sodium transporters in wild-type and inducible kidney tubule-specific Hif1α knockout mice. Results In cultured cells, activation of the HIF pathway by dimethyloxalylglycine or hypoxia inhibited sodium transport and decreased expression of βENaC and γENaC, as well as of Na,K-ATPase. HIF1α silencing increased βENaC and γENaC expression and stimulated sodium transport. A constitutively active mutant of HIF1α produced the opposite effect. Aldosterone and inhibition of the mitochondrial respiratory chain slowly activated the HIF pathway, suggesting that ROS may also activate HIF. Decreased γENaC abundance induced by hypoxia in normal mice was abolished in Hif1α knockout mice. Similarly, Hif1α knockout led to increased γENaC abundance under high sodium intake. Conclusions This study reveals that γENaC expression and activity are physiologically controlled by the HIF pathway, which may represent a negative feedback mechanism to preserve oxygenation and/or prevent excessive ROS generation under increased sodium transport.

Natural lead-enriched biochar modifies TiO2 photocatalytic activation of sodium persulfate to degrade 2,4-dichlorophenol

Due to the rapid development of the modern chemical industry, a large amount of chlorophenol pollutants remain in the environment. It poses a serious threat to the ecological environment and human health. Advanced oxidation technologies (AOPs) have the characteristics of mild reaction conditions and strong oxidation capacity, and are currently recognized as safe and effective pollutant treatment technologies. In this study, natural lead-rich biochar materials were used to activate sodium persulfate to degrade 2,4-dichlorophenol, and natural lead-rich biochar modified TiO2 photocatalytically degraded 2,4-dichlorophenol. Then, using natural lead-rich metal biochar/TiO2 material, photocatalysis combined with active sodium persulfate to degrade 2,4-dichlorophenol. The experimental results show that the combination of photocatalysis and activated sodium persulfate reaction can completely degrade 100 mg/L 2,4-dichlorophenol under UV light for 3 h, and the degradation efficiency is much higher than the sum of the two separate reactions. Quenching experiments show that SO4- • radicals play the most important role in the three free radicals (SO4- •, •OH and •O2- ) in the advanced oxidation combination system. Finally, the reaction mechanism of the two advanced oxidation combined systems are speculated.

Electrochemically activated solutions in beekeeping

The article studies in detail the disease of the mixed form of infectious diseases of honey bee brood. The characteristics of pathogens, features of diagnostics and control of this disease of honey bees are indicated. When conducting epizootic monitoring of bee diseases encountered in surveyed apiaries, it was found that a large percentage of mycosis lesions is associated with the weakening of bee families resulting from adverse weather conditions and insufficient feed base (50-68.3 %). It was further complicated by the process of varrosy invasion, which occurred in all surveyed apiaries with an invasion intensity of more than 4%. In studying the effect of weather conditions on the epizootic process, a peculiarity of the course of infectious breeding diseases in the bee family was established. It was characterized by the onset of symptoms of ascospherosis (solid chalky pieces in the cell and at the bottom of the hive) during periods of adverse weather (cold, prolonged rain). Symptoms of ascospherosis appeared not only in healthy families but also in families undergoing treatment. During the laboratory examination of dead larvae, cultures of different pathogens were isolated. A study of the contamination of cellular honey, which was selected from sick and conditionally healthy bee families, indicated that Ascosphaera apis culture was more commonly isolated and 100% contaminated. We also calculated the epizootic index of infectious diseases of bees that were found on the apiaries surveyed. Ascospherosis was found to be the longest recorded in comparison with other infectious diseases and the epizootic index was accordingly higher. And the development of European foulbroods, other types of rot and aspergillosis occurred against the background of bee ascospherosis. In a study of intestinal toxic effects of active sodium hypochlorite at concentrations of 0.7%, 0.5% and 0.25% a.d., it was found that the drug did not cause bee death within 72 hours after feeding in any group of bees. Active sodium hypochlorite effectively decontaminates test objects at a concentration of 2.5 g / l for two hours. When using cells from sick families, the concentration of 5.0 g / l was effective.