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Investigation of radiation resistance of adsorbents using the 90Sr – source 利用 90Sr - 源研究吸附剂的抗辐射能力
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.094
O. Sych, Yu. M. Kilivnik, M. M. Pop, H. V. Vasylyeva, V. Lazur, O. H. Okunev
Purifying aqueous solutions from radioactive contamination is an extremely relevant scientific topic today. Many organic and inorganic adsorbents can be recommended for the adsorption of heavy metal ions and radionuclides from aqueous solutions, or as carriers for storage and disposal of radioactive waste. Since radionuclides are sources of ionizing radiation, the radiation resistance of the adsorbent is an important characteristic. These studies aim to investigate the titanium silicate behavior and its adsorption properties' changes or their invariability in the field of intense β-radiation. Experimental techniques describe the synthesis of titanium silicate adsorbent by sol-gel method and the study of its adsorption capacity toward Ba2+ cations. The adsorption of Ba2+ cations was investigated under batch conditions with neutral pH of the solution. Initial and residual concentrations of Ba2+ cations were controlled by direct complexometric titration with Na-EDTA with Eriochrom Black T as an indicator. The study of the radiation resistance of the adsorbent to high-energy β-radiation was performed using a 90Sr-90Y β- - source “Sirius” installed in the Microtron Laboratory of the Uzhhorod National University. The distance from the source to the adsorbent samples was 20 cm. The flux of electrons at this distance was 108 el/cm2‧per second. The maximum energy of beta particles was 0.456 MeV for 90Sr and 2.28 MeV for 90Y. The maximum duration of exposure was 21 days, which corresponds to 1310 Gy. Raman spectroscopy of irradiated and nonirradiated samples of TiSi was performed using a Raman spectrometer XploRA PLUS installed in the Center for Collective Use of Scientific Equipment “Laboratory of Experimental and Applied Physics” of Uzhhorod National University. Results consist of kinetic of Ba2+ adsorption by titanium silicate and irradiated titanium silicate; isotherm of Ba2+ adsorption and Raman spectrum of nonirradiated, irradiated titanium silicate (TiSi) and TiSi after Ba2+ adsorption. Results showed that the value of the maximal adsorption was 140.5±9.2 mg/g (6.55 %) under a confidence level of 95 %. The adsorption values of barium ions by irradiated and non-irradiated titanium silicate coincide. This indicates that the adsorption properties of this adsorbent do not change under the influence of such a radiation dose. The Raman spectra of irradiated and non-irradiated titanium silicate coincide, while they do not identify free radicals, or ionic formations, which would indicate a change in the properties of the adsorbent under the influence of beta radiation. It can be argued that this adsorbent is radiation-resistant to beta-radioactivity, with a radiation dose of 1310 Gy. The main conclusion of the present work is that the studied sample of titanium silicate is radiation-resistant. It can withstand a radiation dose of 1310 Gy without changing its adsorption properties. Titanium silicate can be used for the adsorption of strontium radionuclides,
净化水溶液使其免受放射性污染是当今一个极为重要的科学课题。许多有机和无机吸附剂都可用于吸附水溶液中的重金属离子和放射性核素,或用作储存和处理放射性废物的载体。由于放射性核素是电离辐射源,因此吸附剂的抗辐射性是其重要特征。这些研究旨在探讨硅酸钛在强β辐射环境下的行为及其吸附特性的变化或不变性。实验技术描述了溶胶-凝胶法合成硅酸钛吸附剂及其对 Ba2+ 阳离子吸附能力的研究。在溶液 pH 值为中性的批处理条件下研究了 Ba2+ 阳离子的吸附情况。用 Na-EDTA 直接络合滴定法控制 Ba2+ 阳离子的初始浓度和残余浓度,并用 Eriochrom Black T 作为指示剂。利用安装在国立乌日霍罗德大学微电子实验室的 90Sr-90Y β - 源 "天狼星",对吸附剂的高能 β - 辐射抗性进行了研究。光源到吸附剂样品的距离为 20 厘米。在这个距离上的电子通量为每秒 108 艾耳/平方厘米。90Sr 和 90Y β 粒子的最大能量分别为 0.456 兆电子伏特和 2.28 兆电子伏特。辐照时间最长为 21 天,相当于 1310 Gy。使用安装在乌日霍罗德国立大学科学设备集体使用中心 "实验和应用物理实验室 "的拉曼光谱仪 XploRA PLUS 对辐照和未辐照的钛硅样品进行了拉曼光谱分析。研究结果包括硅酸钛和辐照硅酸钛吸附 Ba2+ 的动力学、Ba2+ 吸附等温线以及未辐照、辐照硅酸钛(TiSi)和吸附 Ba2+ 后硅酸钛的拉曼光谱。结果表明,在置信度为 95% 的条件下,最大吸附值为 140.5±9.2 mg/g(6.55%)。辐照硅酸钛和非辐照硅酸钛对钡离子的吸附值相吻合。这表明这种吸附剂的吸附特性在这种辐射剂量的影响下没有发生变化。辐照硅酸钛和未辐照硅酸钛的拉曼光谱相吻合,但没有发现自由基或离子形态,这表明吸附剂的性质在贝塔辐射影响下发生了变化。可以说,这种吸附剂对辐射剂量为 1310 Gy 的 β 辐射具有抗辐射性。本研究的主要结论是,所研究的硅酸钛样品具有抗辐射性。它可以承受 1310 Gy 的辐射剂量而不改变其吸附特性。硅酸钛可用于吸附锶放射性核素,也可作为处理放射性废物的载体。
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引用次数: 0
Mechanical, thermooxidative and biodegradable properties of composites from epoxyurethanes and chemically modified hemp woody core 环氧聚氨酯与化学改性麻木芯复合材料的机械、热氧化和生物降解特性
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.067
T. Samoilenko, L. Yashchenko, N. Yarova, O. O. Leta, O. O. Brovko
Natural fibre reinforced polymer composites nowadays are considered to be attractive cheap, safe and eco-friendly materials. The main problem of such composites related to the hydrophilicity of plant fibres may be successfully solved by chemical modification of their surface. However, some characteristics of the materials may be suppressed after this procedure. Therefore, the aim of the research is to find out the impact of chemical modification of filler on thermooxidative stability, tensile and flexural strength, as well as on biodegradability of polymer composites. The novelty of this work is in the examining new materials on the basis of Si-containing epoxyurethanes and chemically treated hemp woody core (HWC). Woody core that is the side product of hemp industry requiring its apropriate utilization was exposed to mercerization with sodium hydroxide solution and to further functionalization with epoxidized soybean oil (ESO) or 3-aminopropyltriethoxysilane (APS). Raw and surface treated HWC was used as reinforcement for two types of organic-inorganic epoxyurethane matrices made from sodium silicate, polyurethane prepolymer based on polyisocyanate and castor oil, and either diglycidyl ether of bisphenol-A (DGEBA) or ESO as epoxy component. Functionalization of HWC led to better mechanical properties of composites. Compared to the corresponding materials including untreated filler, maximum increase in flexural strength (26 %) was observed for the samples with ESO-containing epoxyurethane and silanized HWC, while maximum increase in tensile strength (53 %) was revealed for the ones with DGEBA-containing epoxyurethane and oil treated HWC. Thermooxidative stability was also higher for composites reinforced with functionalized HWC. The specimens with APS-treated HWC performed the best at thermal decomposition. The values of their T50% were up to 68 °C more than those for composites with unmodified filler. At the same time, the samples based on APS- or ESO-treated HWC were the most resistant to biodegradation, which may be concluded from their smallest weight loss during soil burial test.
如今,天然纤维增强聚合物复合材料被认为是具有吸引力的廉价、安全和环保材料。此类复合材料的主要问题与植物纤维的亲水性有关,可以通过对其表面进行化学改性来成功解决。不过,经过这种处理后,材料的某些特性可能会受到抑制。因此,研究的目的是找出填料的化学改性对聚合物复合材料的热氧化稳定性、拉伸和弯曲强度以及生物降解性的影响。这项工作的新颖之处在于以含硅(Si)环氧聚氨酯和经化学处理的麻木芯(HWC)为基础研究新材料。麻木芯是麻类工业的副产品,需要适当加以利用。麻木芯经过氢氧化钠溶液丝光处理,再经过环氧化大豆油(ESO)或 3-氨基丙基三乙氧基硅烷(APS)进一步功能化。将未加工和表面处理过的 HWC 用作两种有机-无机环氧聚氨酯基材的增强材料,这两种基材分别由硅酸钠、基于多异氰酸酯和蓖麻油的聚氨酯预聚物以及双酚-A 二缩水甘油醚 (DGEBA) 或环氧乙烷作为环氧成分制成。对 HWC 进行官能化处理可提高复合材料的机械性能。与含有未处理填料的相应材料相比,含有 ESO 环氧聚氨酯和硅烷化 HWC 的样品的抗弯强度提高幅度最大(26%),而含有 DGEBA 环氧聚氨酯和油处理 HWC 的样品的拉伸强度提高幅度最大(53%)。使用功能化 HWC 增强的复合材料的热氧化稳定性也更高。经 APS 处理的 HWC 试样在热分解方面表现最佳。与未改性填料的复合材料相比,它们的 T50% 值高达 68 °C。同时,经 APS 或 ESO 处理的 HWC 样品最耐生物降解,这可以从它们在土壤掩埋测试中最小的重量损失中得出结论。
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引用次数: 0
Structure and stability of MnOx-Na2WO4/SiO2 catalyst for oxidative condensation of methane 用于甲烷氧化缩合的 MnOx-Na2WO4/SiO2 催化剂的结构和稳定性
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.130
Sevinj Osmanova, G. Azimova, S. Zulfugarova, E. Ismailov, Dilgam Taghiyev, J. Thybaut
Samples of MnOx-Na2WO4/SiO2 based on a mesoporous silica matrix were synthesized using manganese acetate, sodium tungstate, tetraethoxysilane (TEOS) as precursors and cetyltrimethylammonium bromide (CTAB), citric acid and triethanolamine as pore generating agent and characterized by scanning electron microscopy with energy dispersive elemental analysis (SEM/EDS), X-ray diffractometry (XRD), electron magnetic resonance (EMR), N2 adsorption-desorption measurements and tested as a catalyst for the reaction of oxidative condensation of methane (OCM). It is shown that the MnNaW/SiO2 catalyst consists of Mn2O3, MnO2, Na2WO4 and SiO2 phases. The EMR and SEM/EDS data indicate a noticeable effect of the reaction conditions on the surface structure and the distribution of catalytically active components in the catalyst structure. Significant changes in the values of the specific surface area and pore volume of the samples with increasing temperature and duration of the reaction were found (the values of the specific surface area and pore volume, respectively, 116.8 m2/g and 0.590 cm3/g - up to and 46.1 m2/g and 0.232 cm3/g after 15 hours of catalyst operation in the OCM reaction at 800 °C). It has been shown that under the conditions of the OCM reaction, the elemental composition of the surface of the MnOx-Na2WO4/SiO2 catalyst changes, and the degree of change depends on the duration of the OCM reaction. Under the influence of the reaction mixture CH4/O2, the content of Mn and W decreases in the first two hours, and the trend towards a decrease in their amount on the catalyst surface with an increase in the duration of the OCM reaction is generally preserved. A detailed X-ray phase analysis also indicates a change in the phase composition of this catalyst under the influence of the CH4/O2 reaction mixture. It is assumed that under the reaction conditions (700–800 °C) the MnOx-Na2WO4/SiO2 catalyst is silicon dioxide particles basely with the cristabolite structure, the surface of which is coated with molten sodium tungstate containing nanosized particles of MnOx structures activated by sodium ions and WOx.
以醋酸锰、钨酸钠、四乙氧基硅烷(TEOS)为前驱体,十六烷基三甲基溴化铵(CTAB)为成孔剂,合成了基于介孔二氧化硅基质的 MnOx-Na2WO4/SiO2 样品、通过扫描电子显微镜与能量色散元素分析 (SEM/EDS)、X 射线衍射仪 (XRD)、电子磁共振 (EMR)、N2 吸附-解吸测量对其进行了表征,并将其作为甲烷氧化缩合反应 (OCM) 的催化剂进行了测试。结果表明,MnNaW/SiO2 催化剂由 Mn2O3、MnO2、Na2WO4 和 SiO2 相组成。EMR 和 SEM/EDS 数据表明,反应条件对催化剂结构中的表面结构和催化活性成分的分布有明显影响。随着温度的升高和反应时间的延长,样品的比表面积和孔体积值都发生了显著变化(在 800 °C 的 OCM 反应中,催化剂工作 15 小时后,比表面积和孔体积值分别为 116.8 m2/g 和 0.590 cm3/g;在 800 °C 的 OCM 反应中,催化剂工作 15 小时后,比表面积和孔体积值分别为 46.1 m2/g 和 0.232 cm3/g)。研究表明,在 OCM 反应条件下,MnOx-Na2WO4/SiO2 催化剂表面的元素组成会发生变化,变化程度取决于 OCM 反应的持续时间。在反应混合物 CH4/O2 的影响下,Mn 和 W 的含量在最初两小时内下降,随着 OCM 反应时间的延长,催化剂表面上 Mn 和 W 含量下降的趋势基本保持不变。详细的 X 射线相分析还表明,在 CH4/O2 反应混合物的影响下,该催化剂的相组成发生了变化。据推测,在反应条件(700-800 °C)下,MnOx-Na2WO4/SiO2 催化剂是基本具有嵴烷结构的二氧化硅颗粒,其表面涂有熔融钨酸钠,其中含有被钠离子和 WOx 活化的纳米级 MnOx 结构颗粒。
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引用次数: 0
Effect of zeolites modification on their adsorption properties 沸石改性对其吸附特性的影响
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.077
L. Eprikashvili, T. Kordzakhia, M. Zautashvili, N. Pirtskhalava, M. Dzagania, G. Tsintskaladze, T. Sharashenidze
Atmospheric air pollution is determined by the functioning of both technogenic and natural sources of pollution. The main anthropogenic sources of pollution are: transport, industrial enterprises, energy facilities and agriculture. In order to select a rational and effective method of atmospheric emissions purification from harmful components, systematic study was carried out to identify the potential of natural zeolites of Georgia. In particular, four samples of zeolite-containing rocks were investigated: analcime, clinoptilolite, phillipsite, mordenite and their modified forms. By means of the chromatographic method of researching the adsorption properties of natural zeolites, the best adsorption capability of mordenite and its modified hydrogen form obtained by two methods towards nitrogen oxides has been revealed. The perspective and profitability of using the hydrogen form of mordenite treated with ammonium in the processes of purification of nitrous gases from exhaust gases is shown, as well as the possibility of using the recovered products (aqueous solutions of ammonium salts) obtained from its regeneration as a nitrogen fertilizer in agriculture. The experimental adsorption purification of the sample (H-mordenite) was carried out in the process of research. The sample was taken from the outlet pipe of the contact apparatus in the ammonia oxidation shop of the nitric acid production enterprise of LLC “Rustavi Azoti”. It has been found that the modified mordenites can be proposed as an environmentally friendly, highly efficient sorbent in the processes of air purification from toxic impurities. Of the two forms of H-mordenite investigated, the adsorption data obtained for NH4+-ion-modified mordenite is approximately 20 % better than the acid-modified form. It should be noted that the use of granulated zeolites (mordenite) in adsorbers with dense packing is very effective. It is also important from the economic point of view that it is possible to reuse spent high-silica sorbents after their regeneration by oxidation method, since such zeolites are resistant to oxidants, such as hydroxyl radicals, ozone, etc., and it is possible to regenerate them without removing them from adsorber.
大气空气污染取决于技术污染源和自然污染源的作用。主要的人为污染源有:交通、工业企业、能源设施和农业。为了选择合理有效的方法来净化大气排放物中的有害成分,我们进行了系统研究,以确定格鲁吉亚天然沸石的潜力。特别是对四种含沸石的岩石样本进行了调查:安石、clinoptilolite、phillipsite、mordenite 及其改良形式。通过色谱法研究天然沸石的吸附特性,揭示了通过两种方法获得的莫代石及其改良氢形式对氮氧化物的最佳吸附能力。在净化废气中的氮气过程中使用经铵处理的氢型莫来石的前景和盈利能力,以及将其再生后的回收产品(铵盐水溶液)用作农业氮肥的可能性都得到了证实。在研究过程中,对样品(H-莫来石)进行了吸附净化实验。样品取自 "Rustavi Azoti "有限责任公司硝酸生产企业氨氧化车间接触装置的出口管道。研究发现,在净化空气中有毒杂质的过程中,改性莫丹土可以作为一种环保、高效的吸附剂。在所研究的两种 H 型莫来石中,NH4+ 离子改性莫来石的吸附数据比酸改性莫来石高出约 20%。值得注意的是,在具有致密填料的吸附器中使用粒状沸石(莫迪尼特)非常有效。从经济角度来看,同样重要的是,用过的高硅吸附剂在通过氧化法再生后可以重新使用,因为这种沸石对羟基自由基、臭氧等氧化剂有抵抗力,而且可以在不从吸附器中移除的情况下进行再生。
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引用次数: 0
Removal of cesium and strontium ions from aqueous solutions using metakaolin based geopolymers 使用偏高岭土基土工聚合物去除水溶液中的铯和锶离子
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.102
D. V. Tarnovsky, O. S. Fedoryshyn, O. A. Vyshnevskyi, I. V. Romanova
The aim of presented work was to synthesize geopolymers based on the metakaolin and to determine their adsorption capability in the process of cesium and strontium ions removal from the aqueous solutions. New approaches were proposed for obtaining the two samples of geopolymers in techologically suitable forms. Morphology of materials was investigated by means of X-ray fluorescence analysis (XRF), low-temperature nitrogen adsorption/desorption and scanning electron microscopic studies (SEM). As it follow from the data of XRF analysis, SiO2 and Al2O3 oxides found to be the major components in all samples investigated (~ 54–84 wt. %). As was determined by SEM studies, geopolymers consisted from nanosized particles, amorphous geopolymers binder and unreacted kaolin. It has been found that all samples involve the mesopores with approx. 1–40 nm radii. The greatest specific surface area calculated by the Brunauer-Emmet-Teller (BET) method had the sample obtained in the forms of spherical rods (SBET = 88 m2/g) that about 10 times greater than for initial kaolin taken for synthesis. The ion exchange capacities of materials in the process of Cu2+, Cs+ and Sr2+ removal from water solution were determined and it was found that these properties depends on the method of materials obtaining. Data showed that the geopolymers were more effective for removal the desired ions than initial kaolin. The greatest adsorption capacity towards cesium ions was received on the samples obtained in forms of pyramids and was reached 1.75 mmol/g. Experimental data were fitted into the Langmuir models and the main Langmuir constants were calculated. When analysing the data of investigation with comparing the literature data it was noted that geopolymers obtained can be used in adsorption technology for purification of water from radionuclides as technologically suitable sorbents.
这项工作的目的是合成基于偏高岭土的土工聚合物,并确定它们在从水溶液中去除铯和锶离子过程中的吸附能力。研究人员提出了新的方法,以获得技术上合适的两种土工聚合物样品。通过 X 射线荧光分析(XRF)、低温氮吸附/解吸和扫描电子显微镜研究(SEM)对材料的形态进行了研究。从 X 射线荧光分析数据中可以看出,二氧化硅和氧化铝是所有研究样品的主要成分(约 54-84 重量百分比)。扫描电镜研究表明,土工聚合物由纳米颗粒、无定形土工聚合物粘合剂和未反应的高岭土组成。研究发现,所有样品都含有半径约为 1-40 纳米的中孔。用布鲁诺-艾美特-泰勒(BET)法计算出的最大比表面积是球形棒状样品(SBET = 88 m2/g),比合成时使用的初始高岭土大 10 倍左右。在从水溶液中去除 Cu2+、Cs+ 和 Sr2+ 的过程中,对材料的离子交换能力进行了测定。数据显示,土工聚合物比初始高岭土更有效地去除所需的离子。以金字塔形式获得的样品对铯离子的吸附能力最大,达到 1.75 mmol/g。实验数据与 Langmuir 模型相匹配,并计算出主要的 Langmuir 常数。在分析研究数据并与文献数据进行比较后发现,所获得的土工聚合物作为技术上合适的吸附剂,可用于吸附技术,以净化水中的放射性核素。
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引用次数: 0
Photocatalytic discoloration of organic dyes in water dispersion medium by anatase-based binary nanocomposites 锐钛酸二元纳米复合材料对水分散介质中有机染料的光催化褪色作用
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.119
O. Lavrynenko, M. Zahornyi, O. Pavlenko, E. Paineau
Currently, textile and food industries produce a significant volume of sewages containing azo dyes and other organic pollutants. These effluents are serious environmental threats, so new methods for their treatment and the degradation of azo dyes are attracting much attention. Composite materials based on TiO2 modified by noble metals and nanoceria show high activity in the photodegradation of organic contaminates and are proposed for hydrogen synthesis as well. To optimize the treatment of contaminants, different processes can combine including the strategies of adsorption, photoluminescence, photocatalysis, etc. The synthesized TiO2-based nanomaterials (sols, powders) will be exploited for bioremediation due to their small size and surface plasmon resonance from noble metals. Binary nanocomposites based on TiO2 were obtained by the chemical co-precipitation method from solutions of titanium tetraisopropoxide (TTIP) and inorganic salts of cerium, silver, and palladium. It has been stated that TiO2 is represented by anatase with primary particle size (CSR) from 8.5 to 16.8 nm, depending on the nature and concentration of the dopant. It is shown that Ag is reduced on the surface of anatase particles and blocks their growth, while Pd and Ce penetrate the titanium dioxide matrix in the form of small clusters with the deformation of the anatase crystal lattice. Nanocomposite particles formed loose and fragile aggregates, which spontaneously dispersed in solutions of dyes with the formation of colloid-stable sols, required the use of a centrifugal field for their sedimentation. Nanoparticles of TiO2&Pd were electronegative and others were electropositive according to the values 4.1÷9.6 of ZPC (zero point of charge). It was shown that the particles of all composites sorbed Methylene Blue (MB) without photocatalytic activity under the visible light to any dye. Moreover, anionic dyes such as Orange-G (Or-G) and Methyl Orange (MO) were excellently discolorated in the presence of TiO2&Pd system; cationic dyes of MB and Rhodamine B (RhB) discolorated too with the TiO2, TiO2&CeO2, and TiO2&Ag systems under UV light action. As such, photocatalysis tests showed that Orange-G’s and MO’s discoloration was higher for TiO2&Pd (2 wt. %) and TiO2 systems with the correlation coefficient R2 0.999.
目前,纺织和食品工业产生了大量含有偶氮染料和其他有机污染物的污水。这些污水对环境构成严重威胁,因此处理这些污水和降解偶氮染料的新方法备受关注。以贵金属和纳米陶瓷修饰的二氧化钛为基础的复合材料在光降解有机污染物方面表现出很高的活性,并被建议用于氢气合成。为了优化污染物的处理,可以结合不同的工艺,包括吸附、光致发光、光催化等策略。合成的二氧化钛基纳米材料(溶胶、粉末)因其尺寸小和与贵金属的表面等离子体共振,将被用于生物修复。通过化学共沉淀法,从四异丙醇钛(TTIP)和铈、银、钯等无机盐的溶液中获得了基于二氧化钛的二元纳米复合材料。根据掺杂剂的性质和浓度,二氧化钛的主要粒度(CSR)为 8.5 至 16.8 纳米。研究表明,Ag 在锐钛矿颗粒表面被还原,阻碍了其生长,而 Pd 和 Ce 则随着锐钛矿晶格的变形以小团簇的形式渗透到二氧化钛基体中。纳米复合粒子形成了松散而脆弱的聚集体,它们自发地分散在染料溶液中,形成胶体稳定的溶胶,需要使用离心力场才能沉降。根据 ZPC(电荷零点)值 4.1 至 9.6,TiO2&Pd 纳米粒子呈负电性,其他粒子呈正电性。研究表明,所有复合材料的颗粒都能吸附亚甲基蓝(MB),在可见光下对任何染料都没有光催化活性。此外,阴离子染料如橘红-G(Or-G)和甲基橘红(MO)在 TiO2&Pd 系统的存在下被很好地褪色;阳离子染料 MB 和罗丹明 B(RhB)在 TiO2、TiO2&CeO2 和 TiO2&Ag 系统的紫外光作用下也会褪色。因此,光催化测试表明,TiO2&Pd(2 wt.%)和 TiO2 系统对 Orange-G 和 MO 的褪色率更高,相关系数 R2 为 0.999。
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引用次数: 0
Resonance properties of the solution of quercetin stabilized silver nanoparticles in a nutrient medium 营养介质中槲皮素稳定银纳米粒子溶液的共振特性
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.086
V. Z. Lozovski, A. Vasiljev, T. A. Vasyliev, I. S. Petrik, A. M. Eremenko, N. P. Rybalchenko
Changes in the light absorption spectrum when mixing colloids of Ag nanoparticles with a diameter of 7 nm in a quercetin shell with a nutrient medium were studied in the present article. Colloids of silver nanoparticles were prepared by chemical reduction of AgNO3 silver salt with sodium tetrahydroborate (NaBH4) in an aqueous solution. Quercetin is a flavonoid of plant origin. It was chosen to stabilize nanoparticles due to its capability to form complexes with metals. The quercetin shell is capable to preserve the bactericidal effect of silver NPs on bacteria and weaken their toxic effect on healthy cells of the human body. The absorption spectra of solutions from which nanoparticle colloids were synthesized were used to control the synthesis result. The Luria-Bertani nutrient medium was studied in the work. Absorption spectra of the nutrient medium and nanoparticle colloids were again obtained immediately before mixing. Then, the nutrient medium and the nanoparticle colloid were mixed in volume proportion 1:1, and the absorption spectrum of the mixture was mesured. The absorption spectrum of the mixture did not reproduce a simple overlay of the nanoparticle colloid spectrum on the absorption spectrum of the nutrient medium. To describe the experimental spectra, a colloid of stabilized silver nanoparticles, a nutrient medium, and a mixture of a colloid and a nutrient medium were considered by nanocomposites of various organic and inorganic nanoparticles in a liquid. As a result, experimental absorption spectra were theoretically approximated by related to these nanoparticles elementary oscillators. The error of the discrepancy between experimental and simulated spectra did not exceed 3%. Analysis of the complex spectra of the mixture of the nanoparticle colloid and the nutrient medium has shown that the frequency of the localized plasmon resonance in the nanoparticles most likely does not change. It means that for studying the effect of nanoparticles on biological objects (microbes or viruses), the wavelength of external irradiation must be chosen equal to the wavelength of LPR in the colloid.
本文研究了将直径为 7 纳米的银纳米粒子胶体装在槲皮素外壳中与营养介质混合时,光吸收光谱的变化。纳米银粒子胶体是通过在水溶液中用四氢硼酸钠(NaBH4)化学还原 AgNO3 银盐制备的。槲皮素是一种植物黄酮类化合物。由于槲皮素能与金属形成络合物,因此被选为稳定纳米粒子的原料。槲皮素外壳能够保持银纳米粒子对细菌的杀菌作用,并削弱其对人体健康细胞的毒性作用。利用合成纳米粒子胶体的溶液的吸收光谱来控制合成结果。工作中研究了 Luria-Bertani 营养培养基。在混合前立即再次获得营养介质和纳米粒子胶体的吸收光谱。然后,将营养培养基和纳米颗粒胶体按体积比 1:1 混合,并测定混合物的吸收光谱。混合物的吸收光谱并不是纳米颗粒胶体光谱与营养介质吸收光谱的简单叠加。为了描述实验光谱,我们将稳定银纳米粒子胶体、营养介质以及胶体和营养介质的混合物视为液体中各种有机和无机纳米粒子的纳米复合体。因此,实验吸收光谱可通过与这些纳米粒子基本振荡器相关的理论近似得到。实验光谱与模拟光谱之间的误差不超过 3%。对纳米粒子胶体和营养介质混合物的复合光谱分析表明,纳米粒子中局部等离子体共振频率很可能不会发生变化。这意味着,要研究纳米粒子对生物物体(微生物或病毒)的影响,必须选择与胶体中局部等离子共振频率相同的外部照射波长。
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引用次数: 0
Electrocatalytic reduction of water clusters on binary alloys of molybdenum with iron subgroup metals in an alkaline medium 钼与铁亚族金属二元合金在碱性介质中的电催化还原水簇
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.035
V. N. Nikitenko, E. A. Babenkov, O. L. Bersirova, V. Kublanovsky
The total reorganization energy of the system and its components, the solvent reorganization energy and the transformation energy of reactants (water clusters [(H2O)nOH]-), during electrocatalytic hydrogen evolution on binary alloys of molybdenum with iron subgroup metals (Fe, Co, Ni) in an alkaline medium (30 wt. % NaOH solution) have been calculated. The calculated values of the solvent reorganization energy and the reorganization energy of water clusters are in agreement with the Marcus – Dogonadze – Kuznetsov theory. The dependence of the total reorganization energy of the system, the solvent reorganization energy, and the reorganization energy of discharging species (water clusters) on the electrolyte temperature has been calculated. It was shown that the total reorganization energy of the system and the activation energy of the electron-transfer reaction of electrocatalytic hydrogen evolution (HER) on binary alloys of molybdenum with iron subgroup metals in an alcaline vedium (30 wt. % NaOH solution) decrease linearly with increasing electrolyte temperature in the following order: Fe-54 at. % Mo > Ni-54 at. % Mo > Co-52 at. % Mo. The temperature dependences of the water cluster discharge reorganization energy and the activation energy on binary molybdenum alloys are linear and intersect in the boiling point region of 30 wt. % NaOH solution 384.7 K. At this temperature, the electrode process is limited by the diffusion of regenerating water clusters to the electrode surface. The calculated diffusion activation energy Ad is 9.9 kJ·mol–1. The value of the system reorganization energy lt is 39.8 kJ·mol–1, which is consistent with the theory of Markus – Dogonadze – Kuznetsov. Electrocatalytic activity of binary alloys of molybdenum with iron subgroup m
在碱性介质(30 wt. % NaOH 溶液)中,钼与铁亚族金属(Fe、Co、Ni)的二元合金在电催化氢进化过程中,计算了系统及其组分的总重组能、溶剂重组能和反应物(水簇 [(H2O)nOH]-)的转化能。溶剂重组能和水簇重组能的计算值与 Marcus - Dogonadze - Kuznetsov 理论一致。计算了体系总重组能、溶剂重组能和放电物种(水簇)重组能与电解质温度的关系。结果表明,钼与铁亚族金属的二元合金在碱性溶液(30 wt:Fe-54 at.Mo > Ni-54 at.Mo > Co-52 at.Mo > Co-52 at.二元钼合金上的水簇放电重组能和活化能的温度依赖性呈线性关系,并在 30 wt.计算得出的扩散活化能 Ad 为 9.9 kJ-mol-1。系统重组能 lt 的值为 39.8 kJ-mol-1,与 Markus - Dogonadze - Kuznetsov 的理论一致。钼与铁亚基 m 的二元合金的电催化活性
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引用次数: 0
Physico-chemical characteristics of microcrystalline cellulose from switchgrass (Panicum virgatum L.) obtained in the presence of a solid catalyst 在固体催化剂存在下从开关草(Panicum virgatum L.)中获得的微晶纤维素的物理化学特性
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.057
T. V. Tkachenko, O. O. Haidai, D. Kamenskyh, Y. Sheludko, O. V. Pavliuk, V. Yevdokymenko
The main idea of this work is the investigation of structural and morphological characteristics of microcrystalline cellulose with switchgrass (Panicum virgatum L.) by the method of organo-solvent cooking with the addition of various brands of ion-exchange resins instead of sulfuric acid. A sulfonated copolymer of styrene and divinyl benzene with two functional groups per ring - Purolite CT-275 and a sulfonated copolymer based on tetrafluoroethylene - Nafion NR-50 were chosen as initial ion exchange resins. Air-dry switchgrass (Panicum virgatum L.), a technical culture, was used for the research. Microcrystalline cellulose (MCC) was obtained from it by the method of organo-solvent cooking with the addition of a solid catalyst. Using the methods of XRD, FTIR-ATR, AFM, TGA and DSC, the structure and morphology of MCC were studied. It is found that the use of ion-exchange resins in the organo-solvent method of obtaining MCC in a batch reactor requires the use of protective covers for the catalyst to avoid its mechanical damage. It has been found that only sulfonated copolymers based on tetrafluoroethylene are stable in the cooking solution, in contrast to sulfonated copolymers of styrene and divinylbenzene, and allow obtaining MCC from millet with a yield of 53 % versus 40 % for the classical method and a degree of polymerization of 440 versus 578, respectively. Due to the destruction of amorphous binders in the MCC’s from switchgrass (Panicum virgatum L.), regardless of the conditions of its production, we observe further ordering of the structure of the obtained MCC which is expressed in narrower and more intense peaks in the range 2θ = 22–23°. The FTIR-ATR method showed that the obtained MCC has functional groups similar to commercial M-1021. The AFM method showed that MCC has a globular and wavy relief. Surface roughness with globular relief is 12.6 nm.
这项工作的主要思路是通过有机溶剂蒸煮法,加入不同品牌的离子交换树脂代替硫酸,研究开关草(Panicum virgatum L.)微晶纤维素的结构和形态特征。初始离子交换树脂选用了苯乙烯和二乙烯基苯的磺化共聚物(每个环有两个官能团)--Purolite CT-275 和基于四氟乙烯的磺化共聚物--Nafion NR-50。研究使用的是技术培养的风干开关草(Panicum virgatum L.)。通过添加固体催化剂的有机溶剂蒸煮法从中获得微晶纤维素(MCC)。利用 XRD、FTIR-ATR、AFM、TGA 和 DSC 等方法研究了微晶纤维素的结构和形态。研究发现,在有机溶剂法中使用离子交换树脂在间歇反应器中获得 MCC 时,需要为催化剂使用保护罩,以避免其受到机械损伤。研究发现,与苯乙烯和二乙烯基苯的磺化共聚物相比,只有基于四氟乙烯的磺化共聚物才能在蒸煮溶液中保持稳定,因此从小米中获得 MCC 的产率为 53%(传统方法为 40%),聚合度为 440(传统方法为 578)。由于开关草(Panicum virgatum L.)中的无定形粘合剂被破坏,无论其生产条件如何,我们观察到所获得的 MCC 结构进一步有序化,表现为在 2θ = 22-23° 范围内出现更窄、更强的峰。傅立叶变换红外-ATR 法显示,所获得的 MCC 具有与商用 M-1021 相似的官能团。原子力显微镜方法表明,MCC 具有球状和波浪状浮雕。球状浮雕的表面粗糙度为 12.6 nm。
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引用次数: 0
Colligative properties of various liquid blends vs. Temperature under confined space effects in pores of different adsorbents 在不同吸附剂孔隙的密闭空间效应下,各种液体混合物的胶粘性能与温度的关系
Pub Date : 2024-03-30 DOI: 10.15407/hftp15.01.003
V. Gun'ko, V. Turov
The temperature and interfacial behaviors of individual and mixed liquids are of importance from a practical point of view because changes in the phase state of compounds with decreasing temperature could lead to negative effects (e.g., frost damage of porous materials). However, the use of certain mixtures may prevent these negative effects due to the colligative properties of the solutions (cryscopic effects, CE) that lead to several effects including relative lowering of vapor pressure, boiling point elevation, and freezing point depression (FPD). Confined space effects (CSE) also leading to the freezing point depression can affect the colligative properties of liquid mixtures with respect to FPD. One could assume that for some systems with certain FPD due to CE for bulk solutions, there is no additivity (synergetic effect) of CSE and CE, but for others, the opposite results could be. To elucidate these interfacial phenomena, a set of liquid mixtures bound to different adsorbents could be studied using low-temperature NMR spectroscopy. The solutions included acids, bases, and salts as solutes, some liquids (e.g., dimethylsulfoxide, acetonitrile, n-decane) as co-sorbates and others (e.g., CDCl3, CCl4) as dispersion media. The adsorbents included various porous and highly disperse silicas, fumed alumina, carbons (activated carbons, graphene oxides), and porous polymers. So wide ranges of the systems studied could allow one a deeper insight into competitive or additive CSE and CE influencing the interfacial and temperature behaviors of bound liquids. The results of this analysis are of interest from both practical and theoretical points of view.
从实用角度来看,单独液体和混合液体的温度和界面行为非常重要,因为随着温度的降低,化合物相态的变化可能会导致负面影响(如多孔材料的冻害)。然而,使用某些混合物可以避免这些负面影响,这是因为溶液具有碰撞特性(晶体效应,CE),可产生多种效应,包括蒸汽压相对降低、沸点升高和冰点降低(FPD)。同样导致冰点降低的密闭空间效应(CSE)也会影响液体混合物在 FPD 方面的碰撞特性。我们可以假定,对于某些由于块状溶液的 CE 而具有一定 FPD 的体系,CSE 和 CE 不存在相加性(协同效应),但对于其他体系,结果可能恰恰相反。为了阐明这些界面现象,我们使用低温核磁共振光谱法研究了一组与不同吸附剂结合的液体混合物。溶液包括作为溶质的酸、碱和盐,一些液体(如二甲基亚砜、乙腈、正癸烷)作为助吸附剂,其他液体(如 CDCl3、CCl4)作为分散介质。吸附剂包括各种多孔和高分散硅、气相氧化铝、碳(活性碳、石墨烯氧化物)和多孔聚合物。所研究的系统范围如此之广,可以让我们更深入地了解竞争性或添加性 CSE 和 CE 对结合液体的界面和温度行为的影响。无论从实践角度还是理论角度来看,这一分析结果都具有重要意义。
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引用次数: 0
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Himia, Fizika ta Tehnologia Poverhni
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