Science and Technology Development Journal - Natural Sciences

Journal Information
ISSN / EISSN : 2588-106X / 2588-106X
Total articles ≅ 412
Filter:

Latest articles in this journal

An Nang Vu, Anh Mai Tran, Nghi Tuyet Nguyen, Duyen My Ngoc Lam, Phong Pham Nam Le, Nhan Thuc Chi Ha, Hieu Van Le
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.924

Abstract:
In this work, nanohybrid of zinc oxide/ cellulose nanocrystals (ZnO/CNC) was successfully prepared by using a low cost and green method for photocatalytic degradation of methylene blue (MB). CNC had been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The obtained CNC with carboxyl groups could act as a stabilizing and supporting agent to anchor ZnO nanoparticles. The chemical and crystal structures, morphology, thermal and photocatalytic properties of the ZnO/CNC nanohybrid were characterized by FESEM, FTIR, XRD, FESEM, BET, EDX, TGA, DRS and photocatalytic tests. Analyses of FTIR spectra, XRD, and FESEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. The TGA analysis demonstrated that the ZnO loading sample (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. ZnO/CNC cuold be absorpted ultraviolet light and have high value of specific surface area (SBET), based on the DRS spectra and the nitrogen adsorption – desorption isotherms analysis, respectively. ZnO/CNC displayed more photocatalytic activity than pure ZnO upon degradation of methylene blue due to strong interaction between the CNC and ZnO nanoparticles. The maximum degradation of MB was about 95% in 150 minutes for the ZnO/CNC.
Lien Hoa Dieu Nguyen, Hào Chí Lê, Thy Ngoc Diem Nguyen, Ly Thi Thao Nguyen, Le Thu Thi Nguyen, Thai Quoc Bui, Phuong Thu Tran
Science and Technology Development Journal - Natural Sciences, Volume 5, pp 1245-1255; doi:10.32508/stdjns.v5i3.1035

Abstract:
Aglaia is the largest genus of the Meliaceae family with about 120 species, which grow mainly in the tropical and subtropical regions. In Vietnam, the genus contains about 30 species. Many are used in folk medicine for the treatment of different diseases. Rocaglamides, bisamides, lignans, triterpenoids and steroids are the main classes of compounds found in the genus. Some of them exhibit diverse biological activities. This research work reports the isolation of four compounds from A. odorata and A. hoaensis. Extraction was carried out using Soxhlet extractors with organic solvents followed by concentration of the solvents to yield crude extracts. Isolation was performed using column chromatography on silica gel and gel permeation on Sephadex LH-20. Chemical structures were determined using 1D NMR (1H, 13C NMR, DEPT), 2D NMR (HSQC, HMBC, COSY, NOESY), IR and HRESIMS spectroscopic methods, and comparison of the spectral data with those in literature. Two triterpenoids, aglaiadoratol and 3b -friedelinol, were isolated from the whole tree of A. odorata. Two other compounds, (+)-syringaresinol lignan and threo-9,10-O-isopropylidene- 13-hydroxy-(11E)-octadecenoic acid, a derivative of fatty acid, were obtained from the bark of A. hoaensis. Among the four isolated compounds, this is the first time that aglaiadoratol has been reported in the world. In addition, (+)-syringares inol ligan and threo-9,10-O-isopropylidene-13- hydroxy-(11E)-octadecenoic acid are reported here for the first time in A. hoaensis.
Pham Duc Dung, Tai Huu Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 5, pp 1275-1283; doi:10.32508/stdjns.v5i3.1008

Abstract:
This research prepared new generation of ionic liquid (Deep eutectic solvent, DES) from L-proline and p-toluenesulfonic acid. The ionic liquid has an asymmetric center in its structure because the original amino acid has an asymmetric center. Subsequently, the ionic liquid was studied catalytic activity in reactions of quinoline[3,2-c]pyrano derivatives synthesis. Conditions affecting the reaction and rate of the two products were also investigated. The results of the reaction conditions showed that aprotic polar solvents gave better yields and the best reaction conditions were: temperature: 50oC, time: 2 h, catalytic amount: 35% mol . The ratios of two product isomers showed that the reaction always forms a mixture of two diastereomers and the trans products were synthesized with moderate enantiomeric excess (40% for four derivatives) compared with the cis products. In addition, the results on catalytic reuse also showed that the catalyst had good usability without significant decreasing activity. When benzaldehyde and aniline were changed with their derivates bearing donating electron group (-CH3), the reaction yields slightly decrease. However, benzaldehyde bearing withdrawing electron group (-F) gave moderate yield.
, Kha Minh Lê, Thịnh Gia Phùng, Hoàng Văn Nguyễn, Phụng Mỹ Loan Lê
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.1032

Abstract:
In this work, a single phase of P2-Na0:67Mn0:75Ni0:25O2 (NaMNO) material was successfully synthesized via a coprecipitation method with the size varying from 2 to 4 mm. According to the atomic absorption spectroscopy (AAS), all the metallic elements were uniformly distributed in the bulk material with the desired ratio Mn¸Ni = 3¸1. The electrochemical properties of P2-NaNMO were investigated in carbonate-based electrolytes using 1M NaClO4 or 1M NaPF6. Among these electrolytes, this cathode exhibited the best electrochemical performance with initial capacity up to 205.7 mAh/g and capacity retention reaches 63.2% during 60 cycles when using 1M NaClO4/PC + 2% (v/v) VC. Indeed, vinylene carbonate (VC) additive plays an important role in improving the performance of NaMNO cathode through the formation of a stable cathode electrolyte interphase layer (CEI). Electrochemical impedance spectroscopy (EIS) was performed to demonstrate CEI layer formation indicated by the elevation of the electrode surface film and double layer impedance in the initial cycle. During cycling, galvanostatic intermittent titration technique (GITT) helps to calculate the Na+ ion diffusion coefficient, which was increased clearly at the working voltages of Mn3+/Mn4+ and Ni3+/Ni4+ redox couples.
Van Hung Phan, Thu Uyen Tran Thi, Tien Khoa Le
Science and Technology Development Journal - Natural Sciences, Volume 5, pp 1316-1325; doi:10.32508/stdjns.v5i3.1037

Abstract:
In this work, we proposed to immobilize Fe2O3 nanoparticles on the surface of magnetic CuFe2O4 particles by a facile impregnation – annealing method at different annealing temperatures (200, 300, 400 and 500°C) in order to create new heterogeneous photo-Fenton catalysts with enhanced catalytic performance for the oxidation of organic dyes. The influences of annealing temperatures used in the synthesis procedure on the phase composition, the morphology, the particle size and the surface functional groups of our catalysts were investigated by XRD, FE-SEM and FTIR techniques, respectively. The photo-Fenton catalytic performance was evaluated by the degradation of methylene blue under both UVA and visible light illumination in the presence of H2C2O4 as radical-producing source. According to the experimental results, Fe2O3 nanoparticles were successfully coated on CuFe2O4 surface, which successfully formed the α-Fe2O3 phase in the phase composition and also increased the Fe3+ content on the surface. As a consequence, the rate constant of photo-Fenton catalytic degradation of methylene blue over these samples were clearly improved. More especially, owing to the good magnetic property of CuFe2O4 component, our CuFe2O4/Fe2O3 samples were easy to be separated from the solution by a magnet, making them more feasible in practical applications of environmental treatment. Among our catalytic samples, the CuFe2O4/Fe2O3 sample annealed at 300°C showed the best performance with the highest rate constants under both UVA light and visible light. Its catalytic activities was found to be 6.8 times higher than CuFe2O4 under UVA light and 2.1 times higher than CuFe2O4 under visible light. However, when the annealing temperature was up to 500°C, the catalytic activity was reduced, which can be explained by the growth of particles and the stabilization of surface Fe-O bonds.
, Hoang Ngo Phan, Tuan Minh Nguy, Huong Thanh Tran
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.1063

Abstract:
Tomato is one of the most popular foods in the world. However, drought stress has strongly decreased the growth and yield of tomatoes. Therefore, the study on drought-tolerant tomatoes is essential. In this paper, tomato cultivar TN704, which is popularly grown in Vietnam's Southeast and Vietnam's Mekong Delta was selected. The combination of auxin (IAA, indoleacetic acid) and cytokinin (zeatin) at different concentrations was investigated to determine the effective regeneration media. Then, the drought pretreatment was applied to obtain drought-tolerant shoots. The drought tolerance of regenerated shoots was checked by culture in the drought stress condition after two generations (F1 and F2). The physiological and biochemical changes of regenerated shoots in the drought stress condition were analyzed. The MS 1 2 medium supplemented with 0.2 mg/L IAA and 0.5 mg/L zeatin was the effective medium for in vitro shoot regeneration from tomato leaves. The drought pretreatment (MS 1 2 with 20 g/L mannitol) increased the number of regenerated shoots which can develop in the drought stress condition. The regenerated shoots in the F1 and F2 generations grew strongly under drought conditions. The content of chlorophyll, carotenoid and proline, the intensity of respiration and photosynthesis, and the activity of auxin and cytokinin in leaves of F1 and F2 plant were higher than the control.
Huu Tho Le, Truc Thanh Thi Duong, Phu Hoang Dang, Truong Nhat Van Do, Hai Xuan Nguyen, Mai Thanh Thi Nguyen, Nhan Trung Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.1031

Abstract:
Salacia chinensis L., known as “Chop mao” in Vietnam, is a climbing shrub that belongs to the Celastraceae family. The stem of S. chinensis L. is used as a traditional medicine for the treatment of diabetes, rheumatoid arthritis, back pain, … The dried powdered stem of S. chinensis L. was collected in Phu Yen province and was extracted with methanol to yield methanol extract. The methanol extract was suspended in H2O and partitioned successively with n-hexane, CHCl3, EtOAc to obtain n-hexane, CHCl3, EtOAc, and H2O fractions, respectively. The CHCl3 fraction was subjected to a series of chromatographic separation to afford four purified compounds including 3-oxolup-20(29)-en-30-al (1), betulin-3-caffeate (2), 2-(4-hydroxy-3,5-dimethoxylphenyl)ethanol (3), and acetosyringone (4). Their structures were elucidated on the basis of the spectroscopic analysis and comparison with literature data. The isolated compounds were tested for their α-glucosidase inhibitory activity. The result indicated that all compounds (1-4) possessed significant α-glucosidase at the testing concentration of 100 µM with the percent inhibition values of 9.5 ± 1.3, 70.89 ± 0.25, 44.2 ± 1.6, and 6.7 ± 1.7 %, respectively. In addition, betulin-3-caffeate (2) and 2-(4-hydroxy-3,5-dimethoxylphenyl)ethanol (3) show more potent α-glucosidase inhibitory activity, with IC50 values of 69.7 and 152.0 µM, respectively, than that of positive control acarbose (IC50 = 214.5 µM).
Thế Luân Nguyễn, Tiến Khoa Lê, Châu Ngọc Hoàng, Hữu Khánh Hưng Nguyễn, Thị Kiều Xuân Huỳnh
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i2.1042

Abstract:
The Cu doped ZnO photocatalysts were prepared on ZnO substrate modified with copper nitrate by thermal shock method with different ratio % molar Cu : Zn = 0.3, 0.5, 1.0, 2.0 and 5.0 in order to study the impacts of copper content on the photocatalytic activity of ZnO under both UV and Vis light irradiation. The crystal structure, morphology bulk and surface were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Their photocatalytic activities were studied via time-dependent degradation of methylene blue in aqueous solution. The results exhibit that crystal structure and morphology of Cu doped ZnO photocatalysts is not modified significally than ZnO original but surface charateristicschanged greatly. The photocatalyst was doped with copper content under 2% showed formation of Cu species. These samples perform photocatalytic activity higher than ZnO. The CuNZO-0.05-500 had the highest rate constants for methylene blue degradation (kUV = 6,901 h-1, kVIS = 0,224 h-1), which are about 2.2 times and 1.3 times higher than unmodified ZnO under UV light and Vis light, respectively. However, the CuNZO-5.0-500 which had the formation of CuO phase and unchangeable ZnO's surface has photocatalytic activity similar to pure ZnO.
Dung Thuy Nguyen, Thien Minh Ngo, Hoang Lam Huy Le
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.1013

Abstract:
The coastal area, from Tien Thanh to Ke Ga including Thuan Quy and Tan Thanh communes, is among the regions having a high economic growth rate of Ham Thuan Nam district, Binh Thuan province. The economic growth rate thanked to the development of coastal tourist sites and cultivating areas of dragon fruit, resulted in the increased water demand. Due to the limitation of the water supply system and surface water, the region's main supply comes from the groundwater. The massive and uncontrolled exploitation could lead to the exhaustion and pollution of water reservoirs in the coastal Quaternary aquifer. To serve the management and use of groundwater resources, we calculated the used reserves of the entire area by modeling the layer containing water in the area using the Modflow module of GMS software 10.4 (Groundwater Modeling System). The input data were collected through the suction pump experiment, water samples, survey on exploitation, and results of research reports of nearby areas. The normalized steady-state models showed that aquifers in the area were recharged by rainwater, and re-fed to rivers, partly forming the flows to the sea. If the amount of wasted water into the sea was considered as the total exploitable reserve, the used reserve of underground water in this area is 70,158 m3/day.
Thong Nguyen Hoang, Thuyen Le Xuan, Van Tran Thi
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i3.1054

Abstract:
Microalgae blooms are one of the most serious environmental problems that greatly affect the living environment of aquatic organisms. They deplete the oxygen source in the water, seriously depleting the respiratory oxygen source for organisms living in the water body. Some species of microalgae are also capable of producing toxins, typically blue-green algae, poisoning aquatic organisms and causing death, health effects on human life when ingested. This paper presents the results of research on mapping algae concentration distribution to support water quality assessment for Dau Tieng reservoir. Landsat satellite imagery was used for qualitative and quantitative assessment of algae presence in the lake area. Calculation results showed that algae concentration had a linear correlation with the band ratio of the 3-band algorithm (3BDA (2), and was a combination of spectral reflective bands in the green wavelength bands GREEN, RED and near infrared NIR. We simulated the spatial distribution of algae concentrations on the entire lake area on 3 points of time when satellite images had been collected. Result of this study showed that remote sensing technology can be used for monitoring the appearance and change of algae concentration in water, which is an essential measurement for timely providing warnings as well as assisting in monitoring and managing water environment quality to minimize damages to people and the ecosystem.
Back to Top Top