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This study investigated the feasibility of using domestic and industrial wastewater as substrates for bioelectricity generation in a microbial fuel cell (MFC) system. Samples were collected from the Ulaanbaatar Central Wastewater Treatment Plant, and electrochemically active microorganisms were isolated and cultured. Of 79 pure cultures, three cultures showed high activity as measured by cyclic voltammetry, with domestic wastewater culture #29 having the highest current (~2700 μA), followed by domestic wastewater culture #1 (~2600 μA), and industrial wastewater culture #1 (~2200 μA). The electron acceptor effect at the cathode revealed significant differences in MFC performance: KMnO₄ exhibited the highest voltage (~680–720 mV), K₂Cr₂O₇ an intermediate level, and K₃Fe(CN)₆ the lowest. Next, the most efficient cultures from industrial wastewater-1 and KMnO₄ were selected and tested in a two-chamber MFC system, where the voltage reached ~765 mV and the power density was 66.11 mW/m³. The obtained results indicate that microbial cultures isolated from wastewater have high electrochemical activity and potential for generating bioelectricity using microbial fuel cell technology.
This study investigated the feasibility of using domestic and industrial wastewater as substrates for bioelectricity generation in a microbial fuel cell (MFC) system. Samples were collected from the Ulaanbaatar Central Wastewater Treatment Plant, and electrochemically active microorganisms were isolated and cultured. Of 79 pure cultures, three cultures showed high activity as measured by cyclic voltammetry, with domestic wastewater culture #29 having the highest current (~2700 μA), followed by domestic wastewater culture #1 (~2600 μA), and industrial wastewater culture #1 (~2200 μA). The electron acceptor effect at the cathode revealed significant differences in MFC performance: KMnO₄ exhibited the highest voltage (~680–720 mV), K₂Cr₂O₇ an intermediate level, and K₃Fe(CN)₆ the lowest. Next, the most efficient cultures from industrial wastewater-1 and KMnO₄ were selected and tested in a two-chamber MFC system, where the voltage reached ~765 mV and the power density was 66.11 mW/m³. The obtained results indicate that microbial cultures isolated from wastewater have high electrochemical activity and potential for generating bioelectricity using microbial fuel cell technology.
This study explored the biotechnological production of lactobionic acid through the oxidation of whey, a by-product generated during milk and dairy processing, using the bacterium Gluconobacter frateurii. The bacterial strain used in the experiments was isolated from rotten apples. Identification was carried out by PCR amplification of the 16S rRNA gene, followed by nucleotide sequencing. Comparison of the obtained sequence with those in the NCBI GenBank database confirmed, with 99% similarity, that the isolated microorganism was Gluconobacter frateurii. The identified strain was cultivated in liquid whey-based media to assess its capacity for lactobionic acid production. Based on bacterial growth and cell count analysis, whey derived from industrial acid-treated curd was determined to be the most suitable substrate. The bacterium Gluconobacter frateurii was grown in pretreated whey medium, and lactose concentrations were monitored at 24, 36, 48, 60, 72, 84, 98, 115, and 154 hours after the onset of fermentation. The lowest lactose concentration, 1.18 g/L, was observed after 115 hours, indicating that a fermentation period of approximately four days is sufficient under liquid culture conditions. Following the completion of fermentation, the formation of lactobionic acid was confirmed using thin-layer chromatography (TLC). The product was then isolated through recrystallization, achieving a lactose conversion yield of 74%. The purified lactobionic acid was further analyzed to determine its physicochemical properties and biological activity. This research demonstrates that whey, commonly regarded as a waste product of dairy manufacturing, can be effectively utilized through biotechnological methods to produce lactobionic acid, a high-value compound with important applications in the pharmaceutical and cosmetic industries.
Atmospheric oxidation of copper concentrates during storage and transport leads to mass gain and copper grade depletion, presenting significant operational and economic challenges for the mining industry. Using two sun-exposed samples, this study investigated the oxidation behavior of copper concentrates under typical Mongolian summer conditions over four months (May 14-September 18). The oxidation process was divided into three sequential stages based on pH variation and mineralogical phase transformations: (I) initial mild acidification, (II) intensified bio-oxidation facilitated by Fe(III) generation, and (III) final stabilization associated with advanced sulfide oxidation. Key analytical techniques included pH monitoring, atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), reflected-light microscopy and SEM-EDS. The XRD results revealed the progressive degradation of chalcopyrite and the emergence of oxidized copper phases, confirming mineralogical conversion under ambient oxidation. Additionally, an exponential-type predictive model was developed to estimate copper content decreasing as a function of temperature and humidity. These findings provide a scientific basis for understanding oxidation-induced degradation during storage and support proactive strategies for effectively handling, preserving, and transporting copper concentrates under real-world conditions
ABSTRACT Samples were taken from the PLS solution of the L-SX-EW copper cathode plants and the activities of iron and sulfur oxidizing bacteria were determined, cultured, separated, and identified in 9K medium. The bacteria isolated from the solution were used singly and in consortium in shaking flask tests on low-grade copper sulfide ore to determine the copper metal recovery. In order to determine the presence of bacterial activity, a leaching test without bacteria was conducted and the results of the test with bacteria were compared and concluded. The feed ore used in the shaking flask test had a copper content of 0.18% and oxidized copper was 7.01%, secondary 40.79%, and primary sulfide 46.53%. The solutions for the testwork were plant raffinate and synthetic solution. The bacteria isolated and cultured from the PLS solution were identified as Acidithiobacillus caldus, Leptospirillum ferriphilum, Acidiphilium cryptum, and Ferroplasma acidarmanus by the Magigene Microbiology Laboratory in China. Total 35 shaking flask experiments were conducted for 7 days under the conditions of 10, 20, and 35 °C, ore particle size P60/70/80=75μm, and solution 1.0, 1.5, 1.8 and 2.0. The copper recovery in the bioleaching experiment ranged from 8 to 35%. The experimental results showed that the best effect on copper recovery was at 35 °C, while the lowest copper recovery was at 10 °C. This indicates that temperature has a strong effect on bacterial activity. The results of the experiments on the effects of solution pH and ore particle size showed very little difference in results. This indicates that only bacterial activity has a strong influence on the copper recovery rate in this experimental study. The copper leaching rate increased from 25% to 35% in the bioleaching process using bacteria.
While numerous studies have explored the fabrication of 2D MoS₂, research utilizing natural rock sources remains largely unexplored. Highly pure MoS2 powder was attained from natural rock from Erdenetiin Ovoo deposit by petrographic method. Then two types of ultrasonication solvent-based exfoliation methods were applied. The physicochemical properties were explored using Ultraviolet-visible spectrometry, X-ray diffraction, Scanning electron microscopy, Raman spectrometry, and Cyclic voltammetry. Using salt during solvent-based exfoliation helped attaining more few-layer nanosheet with more bandgap energy. By the Pourbaix analysis, the electrochemical stability of 2D MoS2 samples were defined, which is crucial for their applications in electrochemistry.
The article studies the effect of feed additives "Sel-Plex" on increasing the viability and productivity of laying hens, improving the nutritional and biological value of chicken eggs. "Sel-Plex" as part of the main diet of laying hens increases the viability of the bird - increases egg production per initial layer by 86.75%, 87.51%, and 89.0%, the selenium content in the eggs of industrial hens fed with compound feed enriched with Sel-Plex (0.5 mg selenium/ kg) and Sel-Plex (0.3 mg selenium/ kg), after 1 month of the experiment was increased by 86.3% and 101.1%, respectively.
The contents of protein, fat, and carbohydrates in eggs can be adjusted according to their nutritional type. Based on the study of the characteristics of Ugtuul, Nash, and Tumen Shuvuut eggs, it can be observed that the moisture, pH, protein, ash, and fat content of the eggs are similar. Nash eggs are lower in weight and higher in carbohydrates, while Tumen Shuvuut eggs are rich in yolk protein.
Энэхүү судалгааны ажлаар байгалийн цеолит болон гулуронатын полимер ашиглан усан орчноос хүнд металыг шингээх чадвартай композит материал гарган авах тохиромжтой нөхцөлийг тогтоолоо. Цеолит нь сүвэрхэг бүтэцтэй, хөнгөнцагаант суурь болон катион, усны молекулуудыг агуулсан эрдэс бөгөөд шингээгч материалд өргөн хэрэглэгддэг нэгдэл юм. Тасралттай шингээлтийн процессын үед нунтаг цеолит нь шингээлтийг сайтар явуулах боловч, тасралтгүй баганан шингээлтийн үед нунтаг материал нь усыг нэвтрүүлэх чадваргүй байдаг. Иймээс мөхлөг хэлбэрийн (packed bed) баганан шингээлтэнд тохирох жижиг үрэл хэлбэрийн композит материалыг гарган авах, улмаар усан орчинд хичнээн удсан ч буцаж тэлэхгүй байх материалыг гарган авах нь бидний судалгааны ажлын гол зорилго болсон билээ. Тасралтгүй урсгалтай аргаар явагдах баганан процессын үед композит материалаар тэлэлтгүй ус нэвтрүүлэх хурд нь тогтмол байх нь шингээлтийн баганын чухал үзүүлэлт болно. Иймээс мөхлөг хэлбэрийн үрлэн шингээгч материалыг гарган авахдаа усан орчинд тэлэлт өгөхгүй байх тохиромжтой нөхцлийг тогтоон, амжилттай гарган авлаа. Цеолит агуулсан композит материалыг гарган авахад Na-альгинатын полимерын концентрацийг 1-2\% байхад тохиромжтой болох нь харагдлаа. Түүнчлэн $CaCl_2$-ын уусмалтай харьцуулахад $BaCl_2$-ийн уусмалаар бэлтгэсэн композит үрэл нь тэлэлтийн харьцаа багатай байгаа нь уусмал дотор хангалттай хэмжээний $Ba$ атом байхад тогтвортой композит үрэл үүсэж болохыг харуулж байна. $BaCl_2$ - ийн 10% - ийн үед гарган авсан материал нь тэлэлтийн харьцаа 1 орчим байлаа.
In this study the result of theoretical calculation and experiments, terminal groups with high efficiency of Organic Photovoltaics (OPVs) were chosen based on a linear correlation between the efficiency of OPVs and dipole moments of terminal groups of the Self Assembled Monolayers (SAM) molecules by modifying the anode electrode surface chemically. The obtained results are the evidence of formation of self-assembled monolayer, which is fundamental method of nanotechnology. The result gives us the opportunity of preliminary calculation of the main performance of the OPVs considering the dipole moments of the terminal groups of surface-active molecule. By inserting SubPc which has high HOMO level as an electron donor, the Voc was reached from 0.54 V to 0.71 V due to formation of non-Ohmic contact with increasing the difference of HOMO of donor and LUMO of acceptor from 0.55 eV to 1.1 eV. As these results, electron donor material which has high value of HOMO should be used when the Ohmic contact was formed in OPVs was proved.
Because the combustion of automobile fuel has a negative impact on the environment, many countries such as China, Japan, South Korea, and Germany produce dimethyl ether and use it as fuel and gasoline. In this research work, the dehydration reaction to extract dimethyl ether from methanol was modeled on DWSIM program and the three main parameters of the reactor (conversion, selectivity, reactor yield) were calculated. Three basic parameters of the reactor were varied in the calculations and the simulated results were compared with the experimental values. A kinetic model has been established for the dehydration of methanol to dimethyl ether over γ-Al2O3 acid function, the most widely used catalyst. The kinetic parameters are based on solving the mass conservation equation for each component, on the assumption of plug flow and isothermal operation. The methanol conversion was increased with increasing the feed temperature, in contrast lover methanol conversion was calculated with higher pressure. Increase of the reaction yield were observed in the condition where higher molar fraction of water in the feed. The dimethyl ether can be separated with 96% purity by means of gas-liquid separator and distillation column after the reaction. The comparing the degree of methanol conversion with the experimental value performed under the same conditions, it was in good agreement with the experimental value at a temperature lower than 361°C.
ABSTRACT The determination of the chemical composition of particulate matter is important to predict the sources, formation, and effects of pollutants in the atmosphere. In 2019, the Mongolian government banned the use of raw coal in Ulaanbaatar and promoted the use of an improved briquette fuel. As a result, atmospheric PM was reduced by approximately 50%, and ambient air quality was improved. On the other hand, the atmospheric sulfur dioxide concentration was increased more than two times. However, the chemical composition of the particulate matter (PM) has still not been evaluated since 2019, when they started the use of briquette fuel. This study focuses on the seasonal variations of the chemical composition of PM2.5 using ninety-five daily PM2.5 samples that were collected in Ulaanbaatar between 2017 and 2021. Ion chromatography and a carbon analyzer were used to examine the major nine inorganic ions and organic/elemental carbon. In warm seasons, magnesium, sodium, calcium, and potassium ions are higher than they are in cold seasons and are possibly dominated by natural origins, while sulfate was dominant during the cold season. The carbonaceous composition, sulfate, nitrate, and ammonium accounted for the majority of fine particles in winter. Except for summer, sulfate ions predominated, possibly due to fuel combustion. Chloride ion concentrations were increased in the last two winters, 2020 and 2021, when compared to 2017.
The determination of the chemical composition of particulate matter is important to predict the sources,formation, and effects of pollutants in the atmosphere. In 2019, the Mongolian government banned the use ofraw coal in Ulaanbaatar and promoted the use of an improved briquette fuel. As a result, atmospheric PM wasreduced by approximately 50%, and ambient air quality was improved. On the other hand, the atmospheric sulfurdioxide concentration was increased more than two times. However, the chemical composition of the particulatematter (PM) has still not been evaluated since 2019, when they started the use of briquette fuel. This studyfocuses on the seasonal variations of the chemical composition of PM2.5 using ninety-five daily PM2.5 samplesthat were collected in Ulaanbaatar between 2017 and 2021. Ion chromatography and a carbon analyzer were usedto examine the major nine inorganic ions and organic/elemental carbon. In warm seasons, magnesium, sodium,calcium, and potassium ions are higher than they are in cold seasons and are possibly dominated by naturalorigins, while sulfate was dominant during the cold season. The carbonaceous composition, sulfate, nitrate, andammonium accounted for the majority of fine particles in winter. Except for summer, sulfate ions predominated,possibly due to fuel combustion.
This study assesses the seasonal variations, potential sources, and health risks of fine particulate matter, PM2.5. Samples (n = 83) were collected at two urban sites of Ulaanbaatar. Inorganic ions, organic/elemental carbon, and metals were analyzed. Results exhibited a distinctive seasonality for all chemical compositions with sulfate being the dominant species of PM2.5 in winter. Comparably high concentrations of sulfate, nitrate, and ammonium were measured in winter, while concentrations of calcium and magnesium were higher in spring and summer rather than in other seasons. The results revealed that dominant sources of atmospheric PM2.5 are mainly due to emissions of coal combustion in the heating period, and soil dust resuspension is in the non-heating period.
In this study, increasing the work function of ITO (Indium Tin Oxide) electrode while reducing that of Al cathode was examined to successfully improve the Voc (Open Circuit Voltage) values of the of Organic PV (Photovoltaic) cells. For MIM (Metal Insulator Metal) type organic PV cells, the Vbi (Built in Potential) results from the Δφ (Work Function Difference) between the anode and cathode electrodes. Using high work function values for the ITOs used as an anode, an improvement in Vbi resulting from Δφ would be expected with organic PV cells. In the cells with Al cathode (named as bilayer cell), a slight increase in PCE from 0.13 % in the case as-cleaned ITO to 0.46 % in the case ITO modified with NO2– terminal group was observed. The FF value for the devices with variously configured ultra-thin layer such as BCP/Al, BCP/C6H5COOLi/Al, Alq3/Al, and Alq3/C6H5COOLi/Al is still larger (1.3 times increased) than those of the other devices with Al and C6H5COOLi/Al cathode electrodes. Introduction
The device performance of organic photovoltaics (OPVs) deposited on ITO electrodes were reported. For a typical device configuration of ITO/ZnPc/C60/Al with and without BCP as an exciton blocking layer, the device performances, including Jsc, Voc, FF, and p have been examined. In addition, the correlation between the change in the work function by the chemical modification of ITO and the device performances, including Jsc, Voc, FF, and ηp is examined and the PV characteristics before and after the chemical modification of ITO electrodes were compared.
Organic thin film photovoltaic (PV) cells have attracted attention because of their ease of fabrication and potential for low cost production. In this paper, we study the effects of chemical modification of indium-tin-oxide (ITO) on the performance of organic PV cells. The organic PV cells are fabricated, with the cell configuration of ITO/sub phthalocyanine (SubPc) (20 nm)/fullerene (C60) (40 nm)/Al with and without bathocuproine (BCP) (10 nm) between C60 and Al. By the use of para-substituted benzenesulfonyl chlorides with different terminal groups of H- and Cl-, the energy offset at the ITO/SubPc interface is tuned widely depending upon the interface dipoles and thus the correlation between the change in the ITO work function and the performance of the PV cells by chemical modification is examined.
Keywords. Organic Solar Cells, Efficiency, BCP, CuPc, Open Circuit Voltage, HOMO, LUMO Abstract. The performance and understanding of organic solar cells has progressed considerably over the last few years. An organic photovoltaic cell is fabricated, with the device configuration of indium-tin-oxide (ITO)/copper phthalocyanine (CuPc)/buckminsterfullerene (C60)/Al. The cell performance under illumination is examined with different organic layer and electrode structures. A cell incorporating 10-nm-thick organic layer of bathocuproine (BCP) as an exciton blocking layer shows a short circuit photocurrent density (Jsc) of ~3.5 mA/cm2, an open circuit photovoltage (Voc) of ~0.45 V, and a fill factor (FF) of ~0.5 with white Xe light illumination with an intensity of 100 mW cm-2.
Abstract. The performance and understanding of organic solar cells has progressed considerably over the last few years. An organic photovoltaic cell is fabricated, with the device configuration of indium-tin-oxide (ITO)/copper phthalocyanine (CuPc)/buckminsterfullerene (C60)/Al. C60 acts as an electron acceptor organic material while CuPc corresponds to a donor. The cell performance under illumination is examined with different organic layer and electrode structures. A cell incorporating 10-nm-thick organic layer of bathocuproine (BCP) as an exciton blocking layer shows a short circuit photocurrent density (Jsc) of ~3.5 mA/cm2, an open circuit photovoltage (Voc) of ~0.45 V, and a fill factor (FF) of ~0.5 with white Xe light illumination with an intensity of 100 mW cm-2.
UV-Visible absorption spectra of organic semiconductor materials such as zinc phthalocyanine (ZnPc) and buckminsterfullerene (C60) in thin film and solution are reported at room temperature under the ambient atmosphere. Two-layer ITO/ZnPc(20 nm)/C60(40 nm)/Al cell was fabricated by using a vapor deposition system. The absorption information for ZnPc and C60 as well as ZnPc/C60 layers would be useful for evaluating and fine tuning frontier energy levels of a donor/acceptor pair for optimum solar cell applications.
