Content Of Organic Components Research Articles

Production of recycled paper using harmless municipal sludge as a new biomass filler

Abstract Due to a shortage of resources, exploring new biomass fillers has become critical for paper making. In this study, we reported an eco-friendly strategy for fabricating low-cost and efficient recycled paper with high mechanical properties using corrugated cardboard waste paper and harmless municipal sludge (HMS). First, the characteristics of HMS, including the particle size, pH, specific surface area, organic functional groups and organic component content, were analyzed. Then, the influence of the amount of HMS on the properties of the recycled paper was studied. Finally, the strengthening mechanism of biomass filling recycled paper was discussed. The results showed that HMS, a biomass filler for recycled paper preparation, exhibited excellent physical and chemical properties, with a median particle size of 6.395 μm, a surface area of 39.974 m2 g−1 and organic functional groups. The tensile index of the recycled paper with 30 % HMS was 13.10 Nm/g, which was 16.4 % greater than that of the unfilled paper and showed better thermal stability. This excellent performance could be attributed to the uniform distribution of HMS on the fiber surface, which improved the accessibility of hydrogen bond formation between fibers. Thus, this study proved that HMS was an excellent biomass filler for producing recycled paper.

BIOCHEMICAL MARKERS OF BLOOD SERUM AND ARTICULAR CARTILAGE IN DIFFERENT FORMS OF IDIOPATHIC COXARTHROSIS PROGRESSION

Deformation due to arthrosis of the hip joint affects 40 % of the total number of patients with osteoarthritis, which is from 7 to 25 % of the adult population. For the activity of the pathological process evaluation we studied biochemical changes in the metabolism of collagen, namely: glycosaminoglycans (GAG), hydroxyproline (HP) fractions, collagenase, hyaluronidase activity, etc. Objective. To determine the biochemical changes in blood serum and articular cartilage depending on the form of progression of idiopathic coxarthrosis. Methods. 23 patients were examined (8 (34.8 %) men, 15 (65.2 %) women, age 45‒75 years and more) with idiopathic arthrosis of the hip joint IV stage (Kellgren–Lawrence). Progression forms of idiopathic coxarthrosis were distinguished: group I — rapid (the period from the initial to the final stage of the disease was 5 years and less), II — moderate (5‒10 years), III — slow (over 10 years). Collagenase activity, HP fractions, total GAG content were determined in patients’ blood serum, and collagen content was determined in the cartilage tissue of the femoral head. Results. Compared with the age reference norm in the blood serum of patients of group I activity collagenase increased to 114 %, in II and III — 122 and 135 %, respectively; the content of the free fraction of GP — up to 111, 169, 128 %, respectively; GAG concentrations — up to 110, 122, and 135 %, respectively; protein-bound HP was reduced to 60% in group II, up to 84 % — in group III. In cartilage tissue, the GAG content decreased in group III to 63 %, II — 55 %, I — 47 %; collagen — 32, 25, 24 % in accordance. Conclusions. The course of idiopathic coxarthrosis is determined by metabolic changes in the components of the organic basis of connective and cartilaginous tissues in blood serum. The most profound changes were found in the synthetic phase of HP metabolism, especially in the group with a rapid course disease. A decrease in the content of organic components of connective tissue (GAG and collagen) was determined

Isolation and determination of phenolic acids in rowanberry fruits (Sorbus L.) by gas chromatography

Species of the genus Sorbus L. (rowan) are woody plants growing in the Northern Hemisphere; they are of interest as decorative, food and medicinal plants. Rowan fruits contain a unique complex of macro- and microelements, as well as biologically active substances, including phenolic compounds. Complexity of the composition of plant samples requires the development of highly selective and sensitive methods for determining the content of organic components of different classes. A method for determining phenolic acids in rowan fruits is proposed. The method is based on two-stage chemical modification of the acids, and involves preparing methyl esters under acidic methanolysis conditions, liquid extraction with toluene, intermediate re-extraction into an aqueous alkaline solution, subsequent silylation with N, O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) and gas chromatographic determination of the obtained derivatives using a flame ionization or mass spectrometric detector. Conditions for extraction of phenolic acids from rowan fruits were studied according to the following parameters: type of extractant, sample to the extractant mass ratio, and duration of extraction (mechanical stirring). The stage of gas chromatographic determination of obtained phenolic acid derivatives was optimized, and their chromatographic characteristics established. The possibility of achieving practically complete separation of aliphatic acids and other accompanying components of a non-acidic nature from phenolic compounds in the course of sample preparation was demonstrated; which significantly increased both the selectivity and sensitivity of the determination of analytes. The range of determined content of phenolic acids (4-hydroxybenzoic acid, 2-hydroxybenzoic acid, 4-hydroxy-3-methoxy-benzoic acid, 4-hydroxycinnamic acid, 4-hydroxy-3-methoxy-cinnamic acid) in rowan fruits was 0.005–0.5 mg/g, the limit of detection was 0.001–0.002 mg/g, the relative error was 10–15%, the sample weight was 0.5 g, the total duration of the analysis was 4 hours.

Revisiting the dependence of retention factor on the content of organic component in the mobile phase in reversed-phase HPLC.

In high-performance liquid chromatography, the dependence of retention factor k on volumetric fraction ϕ of organic phase is expressed by log k=F(ϕ) with F(ϕ) obtained by measuring log k at different ϕ values. From F(ϕ), a value kw is calculated by taking ϕ=0. The equation log k=F(ϕ) is applied for predicting k, and kw is a descriptor of hydrophobic character of solutes and stationary phases. Calculated kw should not depend on the nature of organic component of mobile phase but extrapolation procedure leads to different kw for different organic components. The present study shows that the expression of F(ϕ) changes depending on the range of ϕ and the same function F(ϕ) cannot be used for the full range of ϕ from 0 to 1. Consequently, kw obtained by extrapolation of ϕ to zero is not correct because the expression of F(ϕ) was generated by fitting the data using ϕ with higher values. The present study shows the proper way to obtain the value of kw .

Effect of UV Exposure on the Mechanical Properties of Polyurethane-Coated Fabrics

Polyurethane materials can be used industrially in different ways, some of which can be used as textile materials or as auxiliary materials applied to textile materials. Polyurethane stands out as a widely used polymer for coating textile products used in outdoor applications, because of high stability at low temperature, flexibility, no or very little volatile organic component content, high water resistance, pH stability, excellent solvent resistance, weather resistance, and many other chemical and mechanical properties. In the study, cotton, polyester, and viscose fabrics were coated with polyurethane and aged under UV light to investigate the causes and behaviors of the mechanical degradation effects of UV on the coating material and fiber. The results indicate that the PU coating process improves the mechanical properties of textile materials while being exposed to UV rays deteriorates the fabric structure. The deterioration in the structure of raw and coated fabrics with the effect of UV increased the air permeability. According to the results of DSC analysis, the increase in the time of UV exposure did not create significant differences in terms of thermal degradation temperatures in both cotton and viscose fabrics. The glass transition temperatures (Tg) increase with more exposure to UV rays, and the UV exposure time had a negative effect on the melting temperature (Tm) and enthalpy (ΔH) of coated polyester fabrics.

Analysis of Organic Components in Various Butyl Rubber Closures and their Compatibility Study with Cefamandole Nafate by HPLC/GC-MS

Background: To control the quality of various butyl rubber closures and assess their applicability to cefamandole nafate, HPLC/ GC-MS methods were developed to qualitatively and quantitatively analyze the organic components in various types of butyl rubber closures and drug powder of cefamandole nafate for injection, and migration of these components from rubber closures to drug also were studied. Materials and Methods: The chemical components in the rubber closures and corresponding drug were identified by GC-MS in full scan mode and NIST mass library. A GC-MS method in SIM mode was established to quantitatively analyze siloxane compounds, aromatic hydrocarbons and saturated chain-hydrocarbons in rubber closures and drugs. An HPLC method was established to quantitatively analyze antioxidants and sulfides from rubber closures and drugs. The turbidity values of powder for injection were measured by a turbidimeter. Further, the correlation between the content of organic components in the drug and the clarity of the solution was analyzed. Results: It was found that the chemical components were released from butyl rubber closures and migrated to the drug, which influenced solution clarity of cefamandole nafate for injection and was the main factor to cause solution turbidity of powder for injection. The gradual migration of components occurred over time with the use of common butyl rubber closures, but the coated butyl rubber closures (rubber plated with membrane) were coated with a polytetrafluoroethylene film to block the contact between rubber closures and the drug, and could effectively prevent the migration of the components from rubber closures to drugs. The organic components in the butyl rubber closures were mainly identified as siloxanes, saturated chain-hydrocarbons, and antioxidants. An unknown ingredient was identified as 1-piperidinecarboxaldehyde, and trace amounts of toxic toluene were also detected within limits. Conclusion: It is suggested that rubber plated with membrane or rubber closures of high quality were applicable to cefamandole nafate for injection and should be used in its production. HPLC/ GC-MS methods can be used as an effective method for quality control of butyl rubber closures and compatibility research with drugs to ensure drug safety for the public.

Treatment of human waste in small-scale facilities: a prospective review

A sustainable approach to the small-scale treatment of portable toilet and septic tank waste is in need to minimise the associated public health and environmental risks. Treatment of human wastes is highly regulated by legislation in many countries given the high content of organic components and pathogens. In conventional wastewater treatment plants, sewage undergoes a series of treatment stages (primary, secondary and tertiary) before effluent discharge. Delivering this approach on a small scale, to meet demands of temporary events, public gatherings or remote locations provides benefits in reducing transport and bulk handling. For a small-scale treatment process to effectively work, the process steps need to be simplified and minimised. The potential of a new treatment scheme is reviewed where the first step is the solid–liquid fraction separation, followed by anaerobic digestion (AD) of the solid fraction, including energy recovery in a combined heat and power unit. The liquid fraction undergoes a series of filtration and disinfection steps to comply with effluent regulations. Digestate from AD is burned on site to provide local domestic/office heating. This has a great potential for application in different locations where inputs may be sporadic, such as outdoor festivals, disaster response scenarios and construction sites.

Development of hybrid mechanistic-artificial intelligence computational technique for separation of organic molecules from water in polymeric membranes

We have investigated the application of machine learning model for description of a physical process in separation of liquids. The considered process is a membrane system for removal of an organic component. Multiple machine learning models were taken into account, while the inputs are the results of a simulation conducted by computational fluid dynamics (CFD). Indeed, the coordinates (r and z) were used as the inputs to the models, and the models predicted the single output which was the content of organic component in the feed section of membrane (C). In the generated dataset, there are more than 8K rows of data included. Each row has two inputs (r and z) and one output (C). Among the models selected for this study are the Decision Tree, the Poisson regression, and the K-nearest neighbor. The hyperparameters were tuned using the grid-search method, and the final models were obtained. By R2-score criteria, Decision Tree, Poisson regression, and K-nearest neighbors had scored 0.9969, 0.9797, and 0.9841, respectively. According to this and other visual and numerical comparisons, Decision Tree is the most accurate model of this study. The maximum error by this model is 5.5 × 102 and its RMSE error rate is 4.829 × 101.

Investigation of the combustion process of the developed composite granules

The urgent task of each country is to achieve energy independence through the transition from traditional energy sources to alternative ones. Sewage treatment plants can be considered a potential source of additional raw materials. In Ukraine, one of the problems is the disposal of sludge that are more than 30 years old and to which activated sludge has not been added. This sludge has a low content of organic components, which are not suitable for combustion in pure form and fertilizers. Since the old sludge have a small content of organic components, for their better utilization it is proposed to create composite granules, their subsequent drying and combustion, during which the resulting ash will be used for the production of building materials. The aim of the work is to study the combustion of composite granules based on sludge, peat and biomass. The determined specific heat of combustion of composite granules exceeds this index of peat by 1.2 times. The study of the combustion process of composite granules showed that the obtained results can be used in fuel combustion in different ways. The combustion rate of granules is much lower than the combustion rate of the original biomass, but the combustion rate of a separate part of sludge prevails. The combustion rate of granules is much lower than the combustion rate of the original biomass, but the combustion rate of a separate part of sludge prevails. The conducted experiments showed the possibility of decontamination of sludge and its disposal as an alternative fuel.

ОЦІНКА ЯКОСТІ ПИТНИХ ВОД З РІЗНИХ ДЖЕРЕЛ ВОДОПОСТАЧАННЯ

Purpose. Monitor different sources of water supply in a particular region of Ukraine. Methodogy. To monitor the drinking water of the selected settlement of Cherkasy region, water from the water supply network (10 samples), water from the pump room (1 sample) and water from wells (26 samples) were selected and analyzed for 20 main chemical indicators in accordance with the requirements of DSanPiN 2.2.4-171-10 and DSTU 7525: 2014. Findings. It was found that tap water has a slight excess of iron and turbidity in 5 samples. The water does not contain aluminum, ammonium ions, nitrates, nitrites, residual amounts of free and bound chlorine and chlorination by-products. The sample of water from the pump room has a slight excess of silicon and salts of general hardness – calcium and magnesium ions. Water from the pump room in chemical composition (pH, dry matter, alkalinity, chlorides, sulfates, sodium) and the content of microcomponents is very similar to tap water, it has a slightly higher "color" and "turbidity", but the content of petroleum products and iron does not exceed drinking standards. water – 0.1 mg / dm3 and 0.2 mg / dm3, respectively. In this case, well water is the most unsuitable for drinking purposes. It was found that the largest excess of normalized values in these waters was observed when determining the dry residue (up to 4 standards), hardness (up to 5 standards), nitrate concentration (up to 9 standards).Originality. Monitoring of drinking water in the selected settlement of Cherkasy region and the analysis of the suitability of tap water, pump room water and well water for drinking needs.Practical value. The peculiarities of the chemical composition of drinking water supply facilities of this settlement have been established, in particular, much attention is paid to the determination of microelements and persistent organic toxicants at the level of their maximum permissible concentrations. The analysis of the obtained results testifies that the quality of tap water and pump room meets the current hygienic standards in terms of organoleptic parameters, general mineralization, hardness, alkalinity, content of organic components, and water in almost all wells does not meet.

Compositional components and methane production potential of typical vegetable wastes.

With the development of agriculture, a huge amount of vegetable waste (VW) is produced every year, posing a large considerable environmental problem that cannot be ignored. Anaerobic digestion (AD), as an eco-friendly, efficient, and sustainable biomass conversion technology, may be used to address the pollution caused by VW. The compositional components of various VWs are different, which will affect their biomethane potential and directly determine whether they are suitable substrates for AD. Thus, this study involved a systematic analysis of the composition and biomethane potential of 20 typical VWs. The results showed that the methane yields of the VWs were different (207.5-346.3 mL/g VS) owing to the differences in composition. More importantly, a correlation between the contents of organic components and methane production was established, and then used to predict methane production by VW rapidly. In addition, first-order model, modified Gompertz, and Cone models were used to describe the biochemical methanogenesis mechanism of these VWs. The results of this study can provide a reference for fundamental research on the AD of VW as well as serve a convenient and precise method to predict methane production by different VWs through analyzing compositional components, which will be beneficial for pollution prevention and the comprehensive utilization of VW in the future.

Polyurethaneacrylate/montmorillonite nanocomposites

In order to create polymer nanocomposites with high performance on the basis of polyurethaneacrylates (PUA) with montmorillonite (MMT), three methods of chemical modification of the layered silicate surface have been developed. The first modification method is based on using of two different functional modifiers (organophilic and reactive), the second method is based on modification with synthesized by us compound which contains urethane groups, and the third one in based on using synthesized by us modifier containing urethane and other reactive groups. Exchange capacity of the MMT surface was determined by adsorption of indicator “methylene blue”. Intercalation of modifier into the interlayer space of MMT was confirmed by X-ray analysis; the content of organic component in the modified MMT (MMT/M) was determined by thermogravimetric analysis. The resulting organoclay is purposed for the formation of nanostructured composites based on cross-linked polyurethane acrylates with improved physical and mechanical properties. The obtained polyurethaneacrylate nanocomposites with different type MMT/M exhibit the increased in 1,6–2,6 times tensile strength as compared to original polymer matrix. WAXS method has proved an intercalation of modifier into MMT interlayer space (increased distance between layers after modification), as well as the total exfoliation of MMT in PUA matrix, characterized by the disappearance of the absorption peak which is responsible for layered structure.

Measurement, correlation of solubility and thermodynamic properties analysis of 2,4,6-trinitroresorcinol hydrate in pure and binary solvents

The solubility of 2,4,6-trinitroresorcinol hydrate (TNR∙2/3H2O) in the pure solvents (methanol, ethanol, isopropanol and water) and the binary mixed solvents (methanol-water, ethanol-water and isopropanol-water) was measured by the laser dynamic method from 298.15 K to 323.15 K under the atmospheric pressure. The TNR∙2/3H2O do not change before and after the solubility measurement in the selected solvents. The solubility increases with the increase of the temperature, and methanol is more suitable for the cooling crystallization of TNR∙2/3H2O. In the pure solvents, the solubility order at the same temperature is: methanol > ethanol > isopropanol > water, which may be affected by the properties (such as hydrogen bond, polarity, dielectric constant, cohesive energy density etc.) of the alcohol solvents, self-association of water molecules, the hydrophobic wing of the TNR∙2/3H2O and so on. In the mixed solvents, the solubility has different sensitivity to the content of organic components (x2) in the solvent. The possible reason is that: the interaction between solvent and solvent plays an important role (the formation of azeotropic mixtures of alcohols and water, the interaction between water and alcohol solvents, the properties of the solvents etc.). The solubility data of TNR∙2/3H2O were compared with that of 2,4,6-trinitrophenol (TNP) that have been reported. It can be found that the solubility of TNP is always greater than that of TNR∙2/3H2O with the same solvent and temperature, and x2 = 0.63–0.69 (ethanol-water) and x2 ≈ 0.73 (isopropanol-water) are more suitable as the solvents for solution crystallization to separate TNR∙2/3H2O from the mixture of TNP and TNR∙2/3H2O. The experimental mole fraction solubility data (xexp) of TNR∙2/3H2O were correlated by the modified Apelblat, Van't Hoff, CNIBS R-K, and Jouyban-Acree-modified Apelblat model. All of these models give satisfactory results, and the Van't Hoff model has better correlation and helps to expand the solubility data of TNR∙2/3H2O. The thermodynamic properties during the dissolution process were analyzed based on the Van't Hoff. And the dissolution of TNR∙2/3H2O in the solvents used is considered to be an “endothermic, non-spontaneous and entropy-driven” process and the enthalpy is the main contributor to the Gibbs free energy in the process of dissolution.

Seasonal dynamics of organic components in fresh foliar litters at different gap positions in an alpine forest on the eastern Tibetan Plateau

The organic components in fresh litters are important chemical traits for evaluating the initial quality that controls decomposition of plant litter. This study aimed to assess the seasonal dynamics and drivers of organic components in four dominant fresh litters and their variations at different gap positions in an alpine forest on the eastern Tibetan Plateau. We measured the water- (WSE), organic- (OSE), acid-soluble extractables (ASE) and acid-unhydrolyzable residues (AUR) in fresh litters of fir (Abies faxoniana), cypress (Sabina saltuaria), azalea (Rhododendron lapponicum), and cherry (Cerasus duclouxii) at the gap center, gap edge, and under the closed canopy over 1 year in an alpine forest. The contents of organic components significantly varied among litter species and collecting time, and the ASE content also showed significant variations among gap positions. Manganese (Mn) was negatively related to the OSE content, and dissolved organic carbon (DOC) was the most significant factor affecting WSE and AUR contents. Magnesium (Mg) was the factor of great magnitude that significantly influenced the ASE content, and the correlation coefficient between Mg and ASE in the gap center was higher than that in other gap positions. The contents of organic components were markedly controlled by litter species over time, and ASE content varied significantly after gap formation. The seasonal dynamics of these organic components were strongly mediated by litter nutrients, such as Mg, Mn, calcium (Ca), and nitrogen (N), while DOC was a significant factor controlling WSE and AUR contents in fresh litters in this alpine forest.

Development of High-Efficient, Resource-Saving Technical Solutions for Wastewater Treatment in Galvanochemical Sector

This article presents the results of the analysis of samples of a machine-shop for the content of organic components and heavy metal ions. The proposed modernized technological scheme uses modern technological solutions for a machine-shop. Based on the analysis of sites and sewage treatment plants of galvanic production, as well as analysis of the presence of polluting components, technical solutions, which are going to increase the intensification and efficiency of water treatment and water treatment through the use of modern physical and chemical methods, technological methods and wastewater treatment devices have been developed. The introduction of additional sorption modules with activated carbon will reduce the ingress of toxic organic components (DBP, aniline, solvents: acetone, gasoline, ethyl acetate, polymer epoxy compounds, including: epoxy adhesives, polymer filler, epoxy-phenolic, phenolic-rubber and rubber adhesives, release adhesives) into wastewater. A modernized scheme using modern solutions will comply with Mosvodokanal standards.
 Keywords: wastewater, water treatment, toxic organic components, heavy metal ions

ИССЛЕДОВАНИЕ СОСТАВОВ ТЯЖЕЛЫХ МЕТАЛЛОВ И ФОСФАТОВ В ПОЛИМЕРНЫХ ВЕЩЕСТВАХ БИОМАССЫ АКТИВНЫХ ИЛОВ

Introduction. Heavy metals discharged with wastewater can lead to a toxic effect on the microbiocenosis of activated sludge and significantly decrease the degree of wastewater treatment, which dictates the need for a more detailed study and search for ways to detoxify activated sludge at the recycling stage and, at the same time, solve the problems of the neutralization of sewage sludge for safe soil disposal. To ensure the adequacy of the approach to the choice of the methodology for the neutralization of sludge, including sewage sludge, it is necessary to perform compositional analysis of their organic fractions and heavy metal compositions. Methods. To determine the quantitative content of organic components in activated sludge, a sample of sludge was dried to an air-dry state and then subjected to separation into fractions using a method based on the different solubility of compounds with the use of different solvents. Then, extractants were added step by step to the weighted samples of sewage sludge weighing about 2 g each (in a volume 20 times greater than the weight of the weighted sample (40 ml)). Results. The results of the study show that polysaccharides are the dominant form of the organic fraction (polymers) in sewage sludge. Most heavy metals were identified in acidic polysaccharides, humic-like acids and lipids. Significant concentrations of phosphates were observed for the same components of polymer substances in the biomass of activated sludges. Conclusion. The products of extraction of polymer substances of the activated sludge biomass and the content of heavy metals in them may indicate the biosorption of heavy metals by zoogleal accumulations (having a polysaccharide structure) of activated sludges in aeration tanks during biological treatment. Therefore, extracellular biopolymers can be a “target” in the development of targeted technologies for the neutralization of activated sludges.

Wpływ różnych metod modyfikacji powierzchni zębiny zębów mlecznych na adhezję materiałów światłoutwardzalnych – na podstawie piśmiennictwa

Bonding dental materials to dentinal surface, demineralised in particular, still poses a challenge for contemporary dentistry. Adhesion of filling materials to primary tooth tissue poses a greater difficulty compared to permanent teeth due to poorer enamel and intertubular dentin mineralisation and wider dentinal tubules. The bonding strength of dental materials to tooth surfaces depends on, among other things, surface development, the depth of cavity, as well as the associated degree of tissue mineralisation, the content of organic components and water, as well as the number and width of dentinal tubules. The quality of bonding of dental materials to dental tissues is also determined by the mode of substrate preparation, e.g. conventional drilling or air abrasion, and the type of adhesive system used - etch and rinse or self-etch approach. The choice of material that will ensure optimal bonding to the tooth surface under given conditions, i.e. microretention or chemical adhesion, is also important. The aim of the paper was to assess the effects of different methods for primary tooth dentinal surface modification on the adhesion of light-cured materials in experimental studies, based on literature data. The subject of adhesion of light-curing materials to the dentinal surfaces in primary teeth is current and worth further exploration. Self-etching systems are a good solution for filling carious cavities in primary teeth due to less aggressive demineralising effects on dentin compared to phosphoric acid. Demineralised surface is a difficult substrate for adhesive materials, especially in primary teeth; therefore, there is a need for procedures that will improve the retention of light-cured materials in these teeth. The use of air abrasion – mechanical development of the surface combined with chemical modification using self-etching systems may be one of solutions.

Дифференцирующее действие растворителя при необменной сорбции аминокислот ионообменниками

При необменной сорбции ионообменниками веществ одной природы действующие силы являются одинаковыми, что осложняет разделение многокомпонентных смесей. Регулирование доминирующих взаимодействий в сорбционных системах с помощью изменения условий проведения процесса, позволит более эффективно разделять вещества без применения дополнительных электролитов. Известно, что растворитель играет важную роль во многих физико-химических процессах, особенно на границе раздела фаз, поэтому целью работы являлось выявление закономерностей необменной сорбции глицина и триптофана из водно-спиртовых растворов с различным соотношением компонентов в растворителе анионообменником АВ-17-2П (Сl). В работе использована простейшая аминокислота, не имеющая бокового радикала (глицин) и самая гидрофобная аминокислота (триптофан), а также высокоосновный анионообменник АВ-17-2П в Сl-форме, имеющий в качестве функциональных групп четвертичный азот. Исследованы свойства водно-спиртовых растворов аминокислот, анионообменника и равновесие необменной сорбции при различном содержании этилового спирта в составе растворителя (0, 25, 40, 50, 60, 75, 100 % по объему). Установлено, что свойства водноспиртовых растворов аминокислот (триптофана и глицина) и ионообменника АВ-17-2П (Сl) определяются соотношением воды и этилового спирта в составе растворителя, а также наличием полярных и гидрофобных частей в структуре объектов исследования. Изменение свойств сорбента и исследуемых сорбатов в зависимости от содержания органического компонента в растворе носит немонотонный характер: набухание анионообменника минимально при 75% alc, а растворимость триптофана имеет максимум при 40% alc, чего, однако, не наблюдается для глицина. Выявлено, что необменная сорбция аминокислот анионообменником АВ-17-2П из водно-спиртовых растворов также носит немонотонный характер в зависимости от содержания органического компонента в составе растворителя – наблюдается минимум сорбции триптофана и максимум сорбции глицина при сопоставимом содержании воды и спирта в составе растворителя. Различие в закономерностях сорбции исследуемых аминокислот определяется различием в их свойствах – полярностью глицина и гидрофобностью триптофана. Изменение состава растворителя позволяет регулировать сорбционные характеристики в системах анионообменник-аминокислота и более эффективно разделять смеси цвиттерлитов за счет дифференцирующего действия растворителя.

Influence of CaO and HZSM-5 on oxygen migration in Chlorella vulgaris polysaccharide pyrolysis

With polysaccharides of Chlorella pyrenoidosa as the raw material, the effects of CaO and HZSM-5 on the yield of bio-oil and the oxygen content in each phase in the pyrolysis of Chlorella vulgaris polysaccharides (CVP), which occurred in a tube furnace at 600 °C, were comprehensively investigated. The reaction path of deoxidation was also analyzed by TG, GC and GC–MS. The GC–MS analysis of liquids showed that liquids from the pyrolysis of chlorella polysaccharides included a range of light oxygenated compounds (e.g., furans, ketones and phenols), and the oxygen content of furan compounds decreased significantly with CaO and HZSM-5. Compared with the direct pyrolysis of polysaccharides (CVP), the catalytic pyrolysis contributed to the decrease in the oxygen content of organic components by 7.32% and 5.76%. The GC analysis showed that there was a remarkable downtrend in the release of oxygen-containing gas (CO and CO2), and the emission of CO2 decreased from 53.11% to 32.92%. The results of the thermogravimetric analysis indicated that the reaction paths of deoxidation in the pyrolysis process of polysaccharides (CVP) with CaO and HZSM-5 varied from those of the direct pyrolysis process: the catalytic pyrolysis with HZSM-5 promoted the conversion of carbohydrate from furans to aromatics over strong acid sites, which was consistent with previous studies; CaO not only acted as a catalyst but also participated in the reaction to change the reaction paths. All results and findings can help to further understand the thermochemical utilization of CPP for bio-oil.

Molecular insights into hypomineralized enamel.

Hypomineralized enamel may be found in connection with the condition molar incisor hypomineralization (MIH), which has a prevalence of around 15% in most parts of the world. Molar incisor hypomineralization is associated with extensive objective and subjective problems, such as hypersensitivity of the affected teeth, enamel breakdown, and problems with retention of restorations. The etiology behind MIH has not yet been elucidated, but a number of possible factors, which affect the same or different functions of ameloblasts during their different stages of maturation, have been suggested. The aim of this study was to utilize multi-nuclear, solid-state nuclear magnetic resonance (ss-NMR) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) to elucidate any differences, at a molecular level, between enamel powder prepared from normal, healthy teeth and enamel powder prepared from teeth diagnosed with MIH. 31 P and 23 Na ss-NMR confirmed the presence of and two different Na+ sites in hypomineralized enamel, suggesting a heterogeneous chemical composition. The content of organic components was higher in hypomineralized enamel, as shown by both 13 C ss-NMR and ToF-SIMS, indicating the presence of higher numbers of proteins and phospholipids. The interplay between both is necessary for the formation and mineralization of enamel, which might be disturbed or halted in hypomineralized enamel.