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Indium oxide nanofibers (NFs) were synthesized through a two‐step process involving electrospinning followed by calcination. The structural, microstructural, morphological, and elemental characteristics were thoroughly analyzed using techniques such as X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy‐dispersive spectrometry (EDS) mapping. The characterization of the In2O3NFs revealed their consistent thickness, structural integrity, and high purity. The nanofibers revealed a uniform diameter spanning from 20 to 50 nm. Upon subjecting the as‐spun nanofibers to heat treatment at 500 °C for 2 h, elongated In2O3nanofibers containing necked nanoparticles were successfully obtained. The first tests of ammonia sensing were done from 250 to 450 °C; the In2O3NFs sensor presented a good response of 2.05–100 ppm NH3at an operation temperature of 300 °C.

In this article, Vietnam ramie fiber from Moc Chau, Son La province was chosen as a reinforcement for polyamide 11 (PA11) to prepare full–biocomposites. To enhance the compatibility and adhesion with the matrix, the original ramie fiber (oRF) was treated with Ca(OH)2solution (tRF) and then modified by epoxy (mRF). Properties and structure of these fibers were characterized by tensile test, chemical composition, Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The obtained results showed the removal of hemicellulose and lignin after treatment improved the morphology and mechanical properties of the fiber. Rheology in melting state indicated the increase in the torque of PA11 matrix by adding tRF and mRF. The improvement in mechanical properties was observed for both PA11/tRF and PA11/mRF composites. After modification, epoxy on the fiber surface enhanced the adhesion and compatibility with the matrix. This led to a strong increase in Young's modulus, tensile strength and flexural strength of about 37%, 57%, and 33%, respectively. tRF and mRF also improved thermal stability of the composite as shown in TGA and DSC analysis. Finally, mRF showed a better compatibility with PA11 than tRF by observation of SEM images. Effect of different epoxy contents of modified ramie fiber (mRF) on the relative melt viscosity (torque) of biocomposite mixture.

Polypyrrole/SiO2nanocomposite doped with 3‐nitrosalicylic acid was synthesized in three concentrations of 3‐nitrosalicylic acid: 0.01 m, 0.005 m, and 0.0025 m. FTIR spectroscopy, thermogravimetric analysis (TGA), Raman scattering spectroscopy, and FESEM imaging further assisted in determining the shape and structure of the polypyrrole/nanocomposite product. The aluminum protection arrangement of the paint film comprising polypyrrole/SiO2nanocomposite doped with 3‐nitrosalicylic acid was proven by electrochemical methods. The salt spray test results also demonstrated the protective efficacy of the paint film comprising polypyrrole/SiO2nanocomposite doped with 3‐nitrosalicylic acid to suppress corrosion. The best corrosion prevention results were obtained with a polypyrrole/SiO2nanocomposite dispersion paint film doped with 0.01 m3‐nitrosalicylic acid at a concentration of 2%. Open circuit potential curves of aluminum coated with original paint film (Mo), paint film containing SiO2(T1), and paint film containing Ppy/SiO2(T2, T3, T4, and T5) according to immersing time in 3% NaCl solution.

In a one‐step procedure that did not require any surface preparation, polypyrrole (PPy) films doped with 3‐nitrosalicylic acid (3Nisa) became effectively electropolymerized on the aluminum substrate in aqueous solutions. Fourier transform infrared, scanning electron microscopy, and thermal gravimetric analysis were used to analyze the properties of PPy‐based films. Open circuit potential (OCP), electrochemical impedance spectroscopy, Tafel polarization, and salt spray tests were used to study the corrosion‐resistant efficiency of the coatings. The as‐prepared PPy films performed corrosion resistance on aluminum in the 3% NaCl solution. However, the PPy films prepared in the 0.01 msolution of 3Nisa showed the best protection ability on aluminum. The self‐healing characteristic of the PPy films was recorded by varying the potential in the OCP measurement. The findings indicate the potential of using 3‐nitrosalicylic acid‐doped PPy films for applications as anti‐corrosion coatings for aluminum. Tafel curves of samples Al, A1, A2, and A3 in 3% NaCl solution.

This paper introduces an innovative electrochemical sensor that detects enrofloxacin (ENR) utilizing a glassy carbon electrode (GCE) modified with reduced carbon nanotubes (rCNT). The fabrication process involved a simple drop‐coating technique using water‐soluble oxidized CNTs (oCNT), followed by electrochemical reduction to obtain the rCNT/GCE electrode. The electrochemical properties of the modified electrodes, including GCE, CNT/GCE, oCNT/GCE, and rCNT/GCE, were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrated significantly improved electrochemical surface area and faster electron transfer rate for the rCNT/GCE electrode compared to the other configurations. Consequently, the rCNT/GCE electrode exhibited the highest electrochemical signal for ENR detection. Under optimized conditions, the rCNT/GCE‐based sensor displayed excellent performance for ENR detection. It achieved a low detection limit of 0.002 µmand demonstrated linearity within the ranges of 0.005–0.05 µmand 0.05–1.5 µm. Furthermore, the proposed sensor exhibited good selectivity, as well as excellent repeatability and reproducibility. To assess the sensor's practical utility, a quantitative analysis of ENR in shrimp meat samples was conducted. The results demonstrated the high sensitivity and accuracy of the proposed sensor in quantifying ENR, highlighting its potential as a reliable tool for environmental monitoring of water resources.

Tungsten oxide (WO3) nanoplates were synthesized by a simple chemical precipitation technique. These nanoplates were decorated by Au nanoparticles via photoreduction route. The obtained samples were characterized by field emission scanning electron microscopy, X‐ray diffractometry and UV–vis diffuse reflectance spectroscopy to investigate their morphological, structural and optical properties. The SEM images show the plate morphology with the size in the range of 50–150 nm, their thickness ≈10 nm; spherical‐like Au nanoparticles ≈20 nm were attached to the surface of the WO3plates. These materials were applied for the simultaneous photocatalytic degradation of Rhodamine B (RhB) and Cr(VI) under visible light. Due to the efficient separation of photoinduced charge carriers and the enhanced visible light absorption ability, the photocatalytic performance of Au‐decorated WO3nanoplates was higher. The main active species responsible for the photodegradation reactions were identified by different scavengers and a photocatalytic mechanism was proposed. This work represents that WO3nanoplates are a promising candidate for the degradation of organic and inorganic pollutants from the industrial wastewater under sun light exposure.

In this article, a novel oil‐absorbent polymer was synthesized by graft polymerization of lauryl methacrylate (LMA) onto water hyacinth (WH) using 2,2′‐azobisisobutyronitrile (AIBN) as initiator and divinyl benzene (DVB) as a crosslinking agent. The effects of initiator content, LMA content, reaction temperature, reaction time, and crosslinker content on the superabsorbent polymer were investigated. The prepared graft copolymer WH‐g‐LMA was analyzed using FTIR, SEM, XRD, and TGA. In the presence of the better cross‐linker DVB (1.5%) and contact time of about 25 min, the maximal Q (oil sorption capacity) of co‐polymer towards crude and Soybean oils is 23.68 and 25.72 g g−1, respectively. The Q is reduced when sorbent dosage increased, but it increases with increasing the temperature and reaches a maximum of 40 °C. The reusability of co‐polymer is characteristic of 7 sorption/desorption cycles.

Stable and high‐mechanical‐strength gel polymer electrolytes have been investigated by doping lithium salts (LiBr, LiClO4, and Li2SO4) as additive factors into PVA‐CH3COONa systems and highly activated carbon electrodes for symmetrical solid‐state supercapacitors (SSCs). The investigation of the supercapacitors with the presence of lithium salts in the electrolyte not only enhances the mechanical property of gel polymer electrolytes (GPEs) but also improves the energy capability of supercapacitor devices. The electrode‐specific capacitance of supercapacitor‐doped LiClO4salt was at its maximum value at 100 F g−1(current density: 1.5 A g−1). These symmetrical SSCs are considered to have potential for developing eco‐friendly energy storage devices.

Here, the role of pores in the structure of inverse opal photonic crystals (IOPC) in binding proteins in comparison with their parent photonic crystal (PC) templates has been investigated. For this purpose, polyethyleneglycol diacrylate (PEGDA) coated with SiO2‐based PC (PEGDA/SiO2‐based PC) and PEGDA‐based IOPC were attached with fluorophore Alexa 488, which is a polyclonal secondary antibody, to investigate their fluorescence emission. Scanning electron microscopy (SEM) images showed face centered cubic (fcc) packing of the PEGDA/SiO2‐based PC. And it remained after the formation of PEGDA‐based IOPC. The presence of 3‐aminopropyl triethoxysilane (APTES) and Alexa 488 that immobilized the PEGDA‐based PC and PEGDA‐based IOPC was recognized by the appearance of bands at 850, 1175, and a dominant increase in the band at 1750 cm−1. Those were attributed to (N─H) wagging, (C─N) stretching, and (C═O) stretching vibrations, respectively. Reflectance spectra showed a blue shift of the Bragg photonic band gap of the PEGDA‐based IOPC in comparison with that of the PEGDA/SiO2‐based PC. The fluorescence images showed a significant increase in the fluorescence intensity of PEGDA‐based IOPC owing to the resonance effect. These obtained results indicated the role of pores in structure of PEGDA‐based IOPC in improvement of the attachment of Alexa 488 protein.

The effects of oxidation on physicochemical characteristics of thermoplastic canna starch were investigated. Thermoplastic starch (TPS) of native canna starch (CS) and oxidized canna starch (OCS) were prepared with different contents of sodium hypochlorite (1%, 3%, and 5% w/w) and 30 wt% of glycerol as plasticizer. Native starch‐based TPS (NTPS) and oxidized starch‐based TPS (OTPS) samples were tested for physicochemical, morphological, thermal, and mechanical properties. In OCS, the content of carboxyl and carbonyl groups increased with the increase in the content of oxidant, and this contributed to the improvement in CS plasticization efficiency. SEM images indicated that the morphology of OTPS samples was smoother than that of NTPS. The stronger interaction between OCS and plasticizer in OTPS was indicated by FTIR spectra. XRD confirmed that the crystallite type of starch was changed and their decrease in crystallinity is attributed to effects of both oxidation and plasticization. The carbonyl and carboxyl content had a large impact on Tgand ΔHgof OTPS. The higher content of these groups in OCS leads to the lower Tgand the lower ΔHg, which could make the plasticization easier. Due to the better plasticization in OTPS, their mechanical properties and thermal stability were enhanced.

Trimethoprim (TMP) is an effective antibiotic for treating many different infections, but it can lead to water pollution and pose a threat of generating antibiotic‐resistant bacteria through waste in the drug manufacturing process, use, and excretion of humans as well as animals. Due to its strong and non‐selective oxidizing ability, advanced oxidation processes (AOPs) utilizing UV/TiO2and H2O2are more efficient in removing them than conventional wastewater treatment. This work investigates TMP degradation in different water substrates by AOPs using UV/TiO2and H2O2. The results show that the apparent reaction rate constant to the TMP's degradation in the de‐ion water matrix is 0.0379; 0.1937; and 0.209 min−1for UV/TiO2, UV/H2O2, and UV/TiO2/H2O2processes. The rate of degradation of TMP in hospital wastewater is lower than that of lake water and de‐ion water. The major intermediate products obtained from the degradation of TMP in de‐ion water by UV/TiO2/H2O2process were recognized as C14H19O4N4(m/z: 307), C5H7ON4(m/z: 139), and C5H6O2N4(m/z: 155). Finally, the cost of TMP treatment in de‐ion water by several AOPs using photocatalyst and hydrogen peroxide was calculated, it is 0.88 $/m3for UV/H2O2; 33.01 $/m3for UV/TiO2process, and 18.77 $/m3for UV/TiO2/H2O2process.

Eight compounds, including 20(R)‐ginsenoside Rg3(1), Ginsenoside Rd (2), ginsenosides Rg2(3), ginsenosides Re (4), β‐sitosterol (5), daucosterol (6), stigmasterol (7), and stigmasterol‐3‐O‐β‐glucoside (8) were isolated from the Panax ginsengsprouts cultivated in Vietnam. Their structures were elucidated by 1H, 13C NMR, and MS spectroscopic techniques and compared with the previous publication. In addition, their inhibitory activity on NO production and cytotoxic effects against human embryonic kidney cells (HEK‐293A) and human hepatocellular carcinoma (HepG2) were evaluated. This is the first study of the phytochemical investigation of P. ginsengsprouts cultivated in Vietnam and ginseng sprouts also contained the same main active ginsenosides as in the 4–6‐year old roots.

In this study, a series of reactions were used to protect and deprotect hydroxyl and amine groups of D‐glucosamine which was obtained by the hydrolysis of chitin in concentrated HCl. Amidation of this protected monomer with aromatic and heteroaromatic acids was carried out in dichloromethane in the presence of DCC as a coupling reagent to produce new amides in good yields. Their structures were determined by NMR and MS spectra while their antifungal and antibacterial activities were screened.

From CHCl3‐soluble extract of the leaves of Taxus wallichiana(Taxaceae), collected in Lam Dong Province, five compounds were isolated and identified as sciadopitysin (1), ginkgetin (2), (S)‐(+)‐rhododenol (3), (+)‐erythro‐N‐benzoyl‐3‐phenylisoserine methyl ester (4), and (−)‐α‐conidendrin (5). Their chemical structures were determined by 1D and 2D NMR spectra and comparison with published data. Except for (−)‐α‐conidendrin, these remaining compounds were first reported of Taxus wallichiana. Among these compounds, ginkgetin (2), and (−)‐α‐conidendrin (5) showed significant α‐glucosidase inhibitory activity with the IC50values of 98.5, and 172.1 µm, respectively.

Streptomyces wuyuanensisA79 was isolated from the soil samples collected in Quynh Luong mangrove forest, Quynh Luu district, Nghe An province, Vietnam. This strain demonstrated antimycobacterial activity against Mycobacterium smegmatis. Compound 1(indole‐3‐carboxylic acid) was isolated from the culture extract of S. wuyuanensis(A79). This compound displayed the affection of ATPase activity of the recombinant ClpC1 protein, a regulatory protein of Mycobacterium tuberculosis. In addition, compound 1exhibited anti‐inflammatory activity through the inhibition of TNF‐α on LPS‐stimulated macrophage RAW264.7. This is the first time compound 1(indole‐3‐carboxylic acid) has been isolated from S. wuyuanensis. Indole‐3‐carboxylic acid was also reported for the first time its inhibition of M. tuberculosisClpC1 protein.

The influence of fabrication conditions on the corrosion properties of obtaining Zn‐SiO2plating was studied by electrochemical measurement methods and salt spray acceleration test. In which the current density is changed from 1.5 to 3.5 A/dm2and the solution pH is adjusted from 4.5 to 6.2. The obtained results show that the coating with the best corrosion resistance is obtained when applying the following manufacturing conditions: current density of 2 A/dm2, solution pH of 5.2‐5.4 at room temperature, stirring speed of 14 cycles/min.

In this study, achira (Canna edulis) starch was oxidized by sodium hypochlorite and the effects of different concentration of oxidation agent (1, 2, 3 and 5%) on the physicochemical properties, morphological properties and crystallinity of achira starch (AS) was investigated. The carbonyl and carboxyl content, starch colour parameters, swelling capacity, solubility, IR spectra, SEM and XRD of native and oxidized achira starch (OAS) were evaluated. IR spectra of oxidized starch samples showed a new absorption peak which was assigned to the characteristic peak of carbonyl C=O, proved that starch had been oxidized. At lower concentration of sodium hypochlorite, there was no clearly change on the morphology of OAS granules, however, at higher concentration of oxidant (5%), there were some indentations and cracks on the surface of OAS‐5 starch granules. Oxidation with sodium hypochlorite has no significant effect on the crystallinity of the starch. Both AS and OAS granules showed the typical B‐type X‐ray diffractogram, indicating that the oxidation occurred in the amorphous region. After treating with oxidized agent, content of carboxyl groups increased significantly, whereas content of carbonyl groups slightly increased. The total oxidation degree of OAS samples increased with the increase of the concentration of hypochlorite treatment. Oxidation with sodium hypochlorite clearly increased both the swelling capacity and solubility of achira starch. Whiteness of starch was also improved.

In this investigation, Al‐Mg alloy coating samples were deposited by the electric arc spray technique on SS400 steel substrate at various spraying parameters, namely, the spray current (150, 200 and 300 A), the air pressure (4, 4.5 and 5.5 bar) and the stand‐off distance (100, 162.8 and 200 mm). The structure morphology, phase composition, porosity, microhardness, adhesion and wear resistance of the coating were studied. The obtained results showed that the coating at the spray current of 300 A, the air pressure of 5.5 bar and the stand‐off distance of 162.8 mm has the lowest porosity and highest microhardness. In addition, this coating also has better adhesion to the steel substrate and wear resistance than other coatings. Moreover, X–ray phase analysis showed that the following phases are created on the surface of the Al‐Mg coatings: Al, Al2MgO4and Al3Mg2.

Mesoporous MFe2O4materials (M = Mn, Cu, and Co) as magnetic adsorbents for phosphate removal were synthesized by a simple coprecipitation method without annealing at high temperatures. Several techniques, including powder X‐ray diffraction, field emission electron scanning microscopy, nitrogen adsorption‐desorption and vibrating sample magnetometry were used to characterize the samples. The effects of M2+ions on their point of zero charge and their phosphate adsorption capacity were investigated. All three samples consist of nanosized particles with cubic spinel structure and ferromagnetic properties, which allows them to be easily separated from aqueous effluents using a magnet. According to the batch experiments, the adsorption isotherms and the adsorption kinetics for these mesoporous materials are well fitted with the nonlinear Langmuir model and the nonlinear pseudo‐second‐order model, respectively. Among them, CuFe2O4powder showed the best phosphate adsorption performance with the maximum P adsorption capacity of 27.49 mgP g‐1, which can be assigned to the highest surface area and the high pH value at its point of zero charge.

Essential oil obtained from hydrodistillation of the Vietnamese Syzygium boisanumleaves was analyzed by the GC/FID‐MS (gas chromatography/flame ionization detection‐mass spectrometry). Forty‐five compounds (90.08%) were namely identified, in which sesquiterpene hydrocarbons (73.07%) were the major chemical class. Among identified compounds, β‐caryophyllene (18.21%) and bicyclogermacrene (25.47%) were the principal compounds. This essential oil was comparable with the positive control streptomycin in an antimicrobial assay against three Gram‐positive bacteria Enterococcus faecalisATCC299212, Staphylococcus aureusATCC25923, and Bacillus cereusATCC14579. Docking study of two major sesquiterpene hydrocarbons β‐caryophyllene and bicyclogermacrene against bacterial DNA gyrase B showed that these two compounds mainly interacted with hydrophobic residues at the rim of the pocket, thereby they are possible inhibitors.

The first chemical investigation on Cardiospermum halicacabumL. growing in Vietnam led to the isolation and structural determination of nine flavonoid compounds, including quercetin 3‐O‐β‐D‐glucoside(1), quercetin 3‐O‐α‐L‐rhamnoside (2), quercetin (3), kaempferol 3‐O‐α‐L‐rhamnoside (4), kaempferol (5), apigenin 7‐O‐β‐D‐glucuronide butylester (6), apigenin 7‐O‐β‐D‐glucuronide methylester (7), apigenin (8), and luteolin (9). Their structures were established by using HR ESI MS, 1D and 2D NMR spectroscopic methods and comparison with those of the related published data. With exceptions to flavonoids 3and 8, the rest seven compounds (1‐2, 4‐7, and 9) were found for the first time from this plant. Notably, two rare flavonoids (6and 7) have not yet been reported from the Sapindaceae family before.

In this study, glycerol was used as plasticizer for the preparation of thermoplastic starch (TPS) from arrowroot starch (AS). Samples with different contents of glycerol (10, 20, 30 and 40 %wt) were prepared by extrusion technique. The properties of TPS were tested by analysis method. The FTIR, SEM and XRD data showed that the structure of arrowroot starch completely changed after extrusion process with the presence of glycerol at high temperatures. TPSs were plasticized and the relationship between plasticization degree and TPS properties was characterized and described by mechanical properties. The experimental results also showed that the tensile strength slightly decreased and the elongation at break significantly increased with the increase of the degree of plasticization.

This paper presents the modification of chitosan with polyphenols and application the modified chitosan in storage of tomatoes fruits. The ascorbic acid was used as a initiator for the modification reaction. The content of polyphenols was varied from 5 to 20 wt.% in comparison with chitosan weight. Some methods and techniques were used to characterize chitosan and modified chitosan including to infrared (IR) spectroscopy, DPPH assay and inhibition zone diameter by diffusion agar. The obtained results showed that chitosan was modified successfully with polyphenols. The modified chitosan samples have good antioxidant activity and against to E. coli, S. Aureus,and C. albicans. Based on the antioxidant activity and antimicrobial activity results, the most suitable content of polyphenols was found at 10 wt.%. The chitosan modified with 10 wt.% of polyphenols in a combination with nano Ag solution exhibits a significant efficiency on preventing the weight loss as well as remaining color, the firmness, and the soluble solids content (SSC) of tomato fruits during 20 days of testing. Moreover, the modified chitosan/nano Ag also has a great ability in inhibiting the growth of microbial on the skin of tomatoes during post‐harvesting storage.

In our present reports, an eco‐friendly approach of green‐synthesis of silver nanoparticles without using any toxic reducer or organic solvent was investigated. Pectin, a biopolymer, was used both as a reducing agent and a stabilizer. Response surface methodology (RSM) was carried out with four parameters: pectin concentration, AgNO3concentration, temperature, and time to obtain the minimum mean particle size of silver nanoparticles (response Y). The optimal conditions were pectin concentration of 1.64 mg/ml, silver nitrate of 3.26 mM, temperature of 36.6°C and time of 9.6 h. A silver particle size of 6.82 nm was obtained by Design Expert Software and silver particle size obtained experimentally was 6.62 nm. The physico‐chemical properties of the pectin‐silver nanocomposite were characterized by combined techniques including visible ultraviolet spectroscopy (UV‐Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), infrared spectra (IR), and X‐ray diffraction.

Eight compounds, including 11β,13‐dihydrovernolide (1), apigenin (2), kaempferol (3), quercetin 3‐O‐methyl ether (4), quercetin (5), syringaresinol‐β‐ᴅ‐glucoside (6), 3‐hydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐[4‐(3‐hydroxy‐1‐(E)‐propenyl)‐2,6‐dimethoxyphenoxy]propyl‐β‐ᴅ‐glucopyranoside (7), and 5‐(methoxymethyl)‐1H‐pyrrole‐2‐carbaldehyde (8) were isolated from the aerial part of Vernonia gratiosa. Their chemical structures were identified by NMR experiments along with the comparison of their spectroscopic data with those reported in the literature. In addition, all compounds were evaluated for their inhibitory effects on α‐glucosidase and xanthine oxidase. Among them, only compound 7showed the significant inhibition of α‐glucosidase with an IC50value of 47.08 ± 3.98 μg/mL and xanthine oxidase activity with an IC50value of 26.92 ± 1.04 μg/mL. Compounds 1‐5were firstly isolated from V. gratiosa, while compounds 6‐8were reported from the genus for the first time. This is the first study about this species growing in Vietnam.

UV‐curing of the coatings based on epoxy resin modified by black seed oil (EBSO); 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate ‐ a biscycloaliphatic diepoxide (BCDE) and photoinitiator triarylsulfonium hexafluoroantimonate salts (TAS) with various EBSO/BCDE weight ratios have been investigated. The variation of TAS and functional groups in the coatings like epoxy, hydroxyl, ether during the curing was followed by IR‐spectrometric analysis. The performance of the cured coatings has been determined. It was showed that increase of the EBSO/BCDE weight ratio from 20/80 to 80/20 led to changes both photocrosslinking and properties of investigated coatings: Consumption of total epoxy groups from 4.62 to 0.77 mole/kg, gel fraction from 76.9 % to 73.25 %, swelling degree from 235 % to 559 %, relative hardness from 0.84 to 0.16, flexibility from 10 to 1 mm, impact resistance from 5 to 60 kG.cm while gloss at 60oremained to be 100 % after 1.2s of UV‐ exposure.

In this study, nickel ferrite nanoparticles‐doped graphene oxide nanocomposite (NiFe2O4/GO or NG) was fabricated by impregnation method with five different mass ratios of NiFe2O4:GO, namely, 1:1, 3:7, 4:6, 7:3, and 6:4, corresponding to NG1, NG2, NG3, NG4, and NG5 samples. According to the catalytic efficiency of the Fenton reaction of methylene blue (MB), the NG3 sample was chosen as the most appropriate sample, which possessed the highest catalytic efficiency. The effects of volume of H2O2, reaction time, and MB concentration, on the catalytic efficiency of NG3, were also investigated. The results revealed that with the 0.5 mL H2O2, MB concentration of 150 mg/L, and 60 min, the NG3 sample exhibited the highest catalytic efficiency of more than 99 %. The characterization of NG3 was investigated by advanced analysis methods. The results indicated that NiFe2O4possessed a sphere shape with the size of 10‐30 nm, which was uniformly distributed on the GO sheets. Additionally, NG3 possessed a high specific surface area and magnetism. The above results confirmed that NiFe2O4/GO can be potentially applied in the treatment of organic dyes in water.

This research utilized Acacia crassicarpabark activated carbon and copper‐loaded activated carbon to generate a low‐price adsorbent material. The ACAC‐6 was created via going through multiple carbonization and chemical procedures. Cu‐ACAC‐6 was made by impregnating ACAC‐6 with copper ions. The produced substance was characterized analytically. The loading of cupric nitrate onto activated carbon was successful. Both ACAC‐6 and Cu‐ACAC‐6 were then investigated in a batch adsorption system under ideal experimental circumstances, such as initial concentration, temperature, and adsorbent mass. Adsorption follows a pseudo‐first‐order model with R2= 0.9802. The Langmuir isotherm model has been found to be the best correlation model in fitting with the data. The copper loaded activated carbon show a betterment in processing the two dyes. The Langmuir isotherm projected maximum adsorption capacities for Cu‐ACAC‐6 materials of 47.39 mg/g for MO and 60.96 mg/g for MB, which is greater than that of ACAC‐6.

Metal oxide composites integrating with carbon materials have attracted a great deal of attention as the potential photocatalysts for environmental treatment. The ZnO‐CuO composites intergrated with reduced graphene oxide (rGO) were successfully prepared via co‐precipitation method. The crystalline structure of the ZnO‐CuO/rGO ternary composites was examined by the X‐ray diffraction analysis. Field emission scanning electron microscopy analysis shows the distribution of metal oxides onto the plate‐like graphene. The calculated band gap values of the ZnO nanoparticles (3.16 eV) were decreased to 2.62 eV in the prepared (ZnO/CuO)/rGO ternary composites. In this work, the photocatalytic activity of the ZnO‐CuO/rGO with 15 % rGO photocatalyst was evaluated for the chemical oxygen demand (COD) of oily wastewater treatment process, which showed COD removal reaching 95 % after 6 h exposure to visible light irradiation. Moreover, the recycle and recovery test revealed the relatively good stability and repetitive use of ZnO‐CuO/rGO for high COD removal of oily wastewater.

This paper presents epoxidation using a Na2WO4/H2O2/H3PO4‐based complex catalyst, which is formed from in aqueous phase in situduring the process. The success of the epoxidation was demonstrated by the FTIR investigation results. A variety of factors such as reaction conditions, reactant and composition of catalyst system that influence the epoxidation reaction was examined through the oxirane content, yield, conversion, and catalyst selectivity. In which, the rate of addition of reactants as well as the catalytic complex is one of the influencing factors studied. The optimal ratio of the reactants as well as of the components of the catalyst system was found. The reaction was caried out at 60°C for one hour. The results show that 91 % of the double bonds were broken and 87.7 % of the double bonds were converted to epoxide groups, so the epoxidized oil has 6.7 % oxirane content and the catalytic selectivity reached 96.3 %.

The unique expansion properties of the interlayer space of montmorillonites allow for surface modification of bentonite. PEG is a nonionic polymer that can adsorb and intercalate into the interlayers of bentonite. The results of FTIR and TGA spectra allow confirming that PEG has not only covered bentonite but also inserted into the interlayers of bentonite. Therefore, the modified product can be applied not only as a dispersant in polymer composites, but also as an adsorbent. Moreover, a variety of technological factors affecting modification have been studied and the most suitable conditions have been proposed. In which, temperature, stirring speed, time and suspension concentration were selected at 25°C, 800 rpm, 8 h and 2 wt.%, respectively. The influence of the component ratio (Ben/PEG) on the modification process was also studied. The most suitable Ben/PEG ratio for each PEG type was also given. The results show that the interlayer spacing in modified bentonite depends not only on the technological conditions, the composition ratio but also on the molecular weight of PEG. Thus, the choice of PEG for bentonite modification will determine the d001basal spacing of modified product.

Valeriana jatamansiis hired as multiple remedies for treatment of insomnia and circulatory disorders, asthma, dry cough, jaundice, and skin diseases. A phytochemical investigation from the whole plant of V. jatamansi resulted in isolation and identification of five furofuran lignans including 8‐hydroxypinoresinol‐4‐O‐β‐D‐glucoside (1), 8‐hydroxypinoresinol‐4'‐O‐β‐D‐glucoside (2), prinsepiol‐4‐O‐β‐D‐glucopyranoside (3), (+)‐pinoresinol‐O‐β‐D‐glucopyranoside (4), and (+)‐syringaresinol (5) for the first time. Their structures were elucidated by analysis and comparison of their spectroscopic data with those reported in the literature. Furthermore, the biological properties of these isolates were evaluated in vitro for anti‐oxidant and anticancer activities.

A phytochemical study of the ethyl acetate extract (EtOAc) of Peltophorum pterocarpumstems, collecting from Ha Noi city, Vietnam, has resulted in the isolation and determination of six compounds, including bergenin (1), cinchonain Ia (2), lupeol (3), betulinic acid (4), gallic acid (5), and pyrogallic acid (6). The chemical structures of these compounds were characterized by NMR‐spectra, and MS data. Compounds 2and 6were found in the genus Peltophorumfor the first time.

An efficient procedure was proposed for the preparation of pregna‐4‐en‐17α,21‐diol‐3,20‐dioneby using nitrile method to result in high yield up to 56.0‐57.0 % from androst‐4‐en‐3,20‐dione, a key intermediate for producing corticoids.

Porous spherical LaFeO3(PS‐LFO) sample was prepared using a simple hydrothermal method and found to be a potential gas sensor for NH3detection. Structural characteristic of the sample was examined by several techniques, including X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD investigation confirmed the formation of porous spherical LaFeO3with a perovskite phase. TEM and SEM results revealed the porous structure of the material. The presence of functional groups was confirmed using Fourier transform infrared spectroscopy (FT‐IR). Orthorhombic porous spherical LaFeO3calcined at 700 oC was employed as a gas sensor for detection of ammonia gas. The results revealed that PS‐LFO‐based sensor showed p‐type gas sensing behavior with good sensitivity, rapid response, and sub‐ppm detection limit to ammonia gas at 325 oC.

Some low‐ppm concentrations of CuIIcomplex catalyst (15, 30 and 60 ppm) were used for synthesis of 4‐arm star PMMA (4sPMMA) via Atom Transfer Radical Polymerization using Activators Regenerated by Electron Transfer approach (ARGET ATRP). CuBr2/pentamethyldiethylene triamine and tin(II) 2‐ethylhexanoate were used as a complex catalyst and reducing agent, respectively. Characterization of 4sPMMA samples was performed by using conversion measurement, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC). The obtained results demonstrated that the concentration of CuIIof 30 ppm was suitable to prepare 4sPMMA with high monomer conversion up to 93.9 % at 80 °C for 24 hours (MnGPC= 29.7 kDa with target Mnof 30 kDa) for our case. Selected product of 4sPMMA in porous powder was next changed to rigid powder. Scanning electron microscopy measurement showed random‐shape morphology of the powder with bead size in the range of 5‐110 μm. Energy dispersive X‐ray analysis indicated that no traces of Cu and Sn metals were detected. The 4sPMMA beads can be prospectively used as a prepolymer component for acrylic bone cement.

In this study, lipid classes, fatty acid composition, and molecular species of betaine lipid of the green algae Halimeda incrassataLamx., collected from Truong Sa archipelago, have been identified. Five lipid classes including Pol, ST, FFA, TG, HW have detected on TLC chromatography. In the total lipid, 21 fatty acids have been indicated, in which, 4 fatty acids belonging to the PUFAs group with the valuable bioactivities and the high content are ALA, GLA, AA, EPA. From Halimeda incrassata, this is the first time 17 betaine lipid molecular species have been identified by HPLC‐HRMS technique. Interestingly, all of these molecular species belong to the diacylglyceryl‐N,N,N‐trimethylhomoserine group, which is the characteristic composition of the non‐flower plant.

Natural exposure and accelerated weather testing were carried out on high density polyethylene/organo‐modified calcium carbonate (HDPE/m‐CaCO3) composite. The natural exposure was conducted at Dong Hoi City, Quang Binh province (Viet Nam) for 36 months. The accelerated weather testing was carried out in a UV condensation weather device for 720 hours. The molecular weight of HDPE in HDPE/m‐CaCO3composites was decreased significantly with rising natural exposure time. The drop in mechanical properties of composite was also reduced. The change in tensile strength of HDPE/m‐CaCO3composite and average molecular weight of HDPE in the composite after testing was chosen to predict the service half‐life time of the composite. It was found that the tensile strength of composite tested in accelerated weather testing condition for 240.5 hours was as the same as the case tested for 337.5 days in natural exposure condition. The service half‐life time of the composite determined owing to the molecular weight and remained percentage of tensile strength was 11.2 months and 25.6 months, respectively.

In the present study, titania nanoparticles are highly dispersed on carbon nanotubes via hydrolysis process of tetra‐isopropyl‐orthotitanate Ti[OCH(CH3)2]4(TPOT). The obtained composite (TiO2/CNTs) is characterized by modern methods. The anatase‐TiO2phase is realized based on X‐ray diffraction spectrum at different pHs of hydrolysis solution. The band gap of TiO2/CNTs (Eg) is calculated by Tauc method using diffuse reflectance spectroscopy (DRS). The TiO2/CNTs composite plays as an active photocatalyst for methylene blue (MB) decomposition in aqueous solution. The effect of time to photocatalytic ability of TiO2/CNTs composite is described using Langmuir‐Hinshelwood kinetic model. The values of enthalpy variation (ΔH), entropy change (ΔS) and Gibbs free energy variation (ΔG) of the decomposition of MB are determined from thermodynamic study. In the range temperature from 283 K to 323 K, the positive values of ΔH and negative value of ΔG confirms endothermic and spontaneous nature of MB degradation. With the increase of temperature, the reaction occurs more easily, which is proved by more negative values of Gibbs free energy calculated from Van't Hoff equation.

Blends of polyphenylene oxide (PPO) and acrylonitrile butadiene styrene (ABS) were prepared by melt‐mixing method. Flammability of these blends was studied by using UL‐94 (plastics flammability standard)and LOI (limited oxygen index) tests. The results showed the role of PPO as flame retardant in the blends which can inhibit the burning process. All blends of PPO and ABS were graded as V‐1 and LOI values were higher than 21. As a physical mixture, tensile strength of PPO/ABS blends maintained values between the tensile of neat ABS and PPO. Melting rheology characterization of samples showed that the fabrication of PPO/ABS blend consumed less energy than that of PPO polymer.Differential scanning calorimetry analysis investigated that PPO and ABS were partially miscible in blend with two glass transition temperatures (Tg) which ranged between Tg of ABS and PPO.

In this study, we attempted to apply a four‐arm star poly(methyl methacrylate) (4sPMMA) as a prepolymer of acrylic bone cement. The 4sPMMA with viscosity average molecular weight of about 45 kDa was synthesized via Atom Transfer Radical Polymerization method using Activators Regenerated by Electron Transfer (ARGET ATRP). In practical use, the fine powder of precipitated 4sPMMA was changed to rigid beads followed by making sheet and pulverizing. Proton nuclear magnetic resonance (HNMR), Fourier transform infrared (FTIR) spectra of 4sPMMA beads indicated the star structure of 4sPMMA with bromide end groups (C‐Br). Scanning electron microscopy (SEM) image of 4sPMMA beads showed their random shapes with size in the range of 10‐100 μm, no traces of residual metal catalysts (Cu and Sn) were detected by Energy Dispersive X‐Ray (EDX) analysizer equipped with SEM instrument. Bone cement from 4sPMMA beads had been prepared manually and curing in rectangular and cylindrical molds. The setting characterization results showed that 4sPMMA bone cements exhibited lower maximum temperature (63.9 °C), lower setting temperature (45.6 °C), than those required in ISO 5833:2002. Other properties of 4sPMMA bone cement, such as bending strength, bending modulus and setting time met the requirements of above ISO standard.

The purpose of this research is to produce of esterified thermoplastic starch (ETPS) for reactive extrusion melt‐blending with polybutylene succinate (PBS) in film blowing application. Esterification TPS named M‐TPS and T‐TPS were prepared from cassava starch, glycerol (plasticizer), and maleic anhydride (MA), tartaric acid (TA) as reactive compatibilizers in a twin extruder, respectively. FTIR results showed that esterification reactions were successfully formed between both MA and TA with cassava starch. The esterified TPSs was then melt blended with PBS in the presence of four kinds of esterification catalysts. The effect of compatibilizer contents on the blend properties was studied in terms of tensile properties, melt flow index (MFI), and electron scanning microscopy (SEM). The results show that TA induced better compatibilization effect than MA did, as evidenced by the PBS/T‐TPS blend possessing higher strength than these of PBS/M‐TPS, although SEM images showed structural morphology of both blends is similar. The effect of the esterification catalyst type and contents on properties of the PBS/T‐TPS blend was also studied. The results from the Molau test confirmed the formation of graft‐copolymer (PBSgT‐TPS) at the interface of two phases of the blend when compatibilizers were added in the presence of an organotin compound catalyst.

In the present work, liquid deproteinized natural rubber (LDPNR) was prepared by oxidative depolymerization of deproteinized natural rubber using hydrogen peroxide (H2O2) and sodium nitrite (NaNO2) as oxidizing reagents. Structural characterization of LDPNRs was performed using FT‐IR, 1H‐NMR, 13C‐NMR, and Heteronuclear Multiple Quantum Coherence (HMQC) spectroscopy. After degradation, the intensity of vibration mode at 1660 cm‐1(νC=C) decreased, indicating the decrease in the number of C=C bonds in the NR chain. 1H‐NMR signals at 1.6 ppm and 13C‐NMR signals at 40.0 ppm appeared in the NMR spectra of LDPNR prepared in acidic condition suggesting the occurrence of isomerization from cis‐1,4‐isoprene units to trans‐1,4‐isoprene units. Epoxidation also occurred during degradation of DPNR as a side reaction. End groups of LDPNRs were found to depend on pH of reacted latex. LDPNR prepared in pH 5‐6 contains aldehyde end group, while LDPNR prepared at pH 8‐9 has a hydroxyl end group. The gel content of LDPNRs was found to reduce compared to that of DPNR, significantly. GPC was employed to determine molecular weight of LDPNRs. The results show that the degradation in acidic medium behaves more effectively in comparison to in alkaline medium.

Agricultural and forest residues could become potential sources of energy in various countries. However, incomplete understanding regarding physico‐chemical properties of these residues presents the main challenges for energy conversion processes. This study presented a complete and comprehensive database of characteristics and compositions of a wide range of agricultural and forest residues. Physical characteristics (moisture, bulk density, calorific value, volatile matter, fixed‐carbon content, and ash content), elemental compositions (C, H, N, O, and S), as well as lignocellulosic compositions (cellulose, hemicellulose, and lignin) of ten biomass residues were analyzed. The major impacts of the variability in biomass compositions to biochemical and thermochemical processes were also discussed.

This study was conducted to determine organophosphate ester compounds in indoor dust in Hanoi ‐ a populated city in Vietnam. In the study, the concentration and distribution of fifteen organophosphate esters (OPEs) were analyzed in indoor dust specimen. In general, the recorded total concentrations of OPEs in dust ranged from 2.7 to 14.1 μg/g and the average quantities varied from 0.2 to 1.0 μg/g. Particular, 100 % of survey samples were detected signals of OPEs, indeed, tris‐(2‐chloroisopropyl) phosphate (TCPP) and tris(2‐butoxyethyl)phosphate (TBEP) were two of the OPE substances, which their content accounted for the most in 15 analyzed compounds. OPE emission sources in indoor dust could be from locally used wide variety of consumer products and building materials in Hanoi houses. Moreover, tri‐m‐cresyl phosphate (TMCP) was practically observed in survey dust samples, and thus effects of traffic activities on OPEs contamination were not significant. Estimating human exposure to OPEs through directly absorbing foods was implemented and illustrated that this absorption route did not substantially affected adult and children health.

By investigating the chemical constituents of the roots of Launaea sarmentosa, collected at Can Gio beach, Can Gio district, Ho Chi Minh city, nine compounds were isolated including α‐amyrin acetate (1), β‐amyrin acetate (2), lupeol acetate (3), ψ‐taraksasterol acetate (4), luteolin (5), 4‐allyl‐2,6‐dimethoxyphenol glucopyranoside (6), scorzoside (7), ixerisoside D (8) and 9α‐hydroxypinoresinol (9). To the best of our knowledge, all compounds were reported in other species, but this is the first time they were known in L. sarmentosa. Four compounds (1‐4) from the n‐hexane extract were identified by 4‐dimethylaminopyridine‐catalyzed benzoylation. Their chemical structures were elucidated by means of 1D and 2D NMR, HR‐ESI‐MS data analysis and compared with those reported in the literature.

Pectin is a heterogeneous complex polysaccharide found in the primary cell wall of most cells. In this work, low‐methoxyl pectin was extracted from pumpkin (Cucurbita moschata). The obtained pectin was characterized by GPC FTIR and NMR spectra. The obtain results showed that structural feature of the pectin is a main chain of poly‐α(1→4)‐D‐galacturonic acid and occasionally interrupted by α(1→2)‐linked α‐L‐rhamnopyranose residues and branches Galp is linked to GalpA at C‐2 position.

There are major advances in the development of the nanostructured materials to enhance the reaction performance in catalytic field. Recent efforts have shown that high conversion efficiency and stability of efficient nanocatalysts can be achieved by combining the intrinsic properties of single components into heterostructures. The unprecedented combination affords the integrated nanocatalysts capable of overcoming the limitations of single components and addressing the issues of the assessment of the efficiency of the catalytic converters. The present review gives a concise overview of the heterostructured nanoarchitectures with a focus of the tailoring of their structural geometry, self‐construction and surface chemistry to effectively create integrated catalysts with multi‐functionalities. The novel integrated catalysts present in the critical review were emphasized these concepts by undergoing inherent synergistic effects in their heterojunction structures to emerge superior catalytic performance and high selectivity for promising applications. Various types of the integrated nanocatalysts including coupled particles, porous composites, organized hybrids, assembled films, and biomimetic replicas are presented in respect to the discussion of expressive statements for widespread emerging applications in artificial photosynthesis, graphene‐based catalysts, electrochemical gas sensing, water‐gas shift reaction, and methane fuel generation.

By replacing the 10 php (parts per hundred polyvinylchloride) DOP plasticizer with the epoxidized linseed oil (ELO) in polyvinylchloride (PVC) processing, a slight increase in tensile properties was observed. The water, 30 wt.% acetic acid, 10 wt.% KOH solution, sunflower oil and n‐hexane were used as media to evaluate the leaching characteristic. The sample weight increased slightly after soaking in water, 30 wt.% acetic solution and decreased slightly in 10 wt.% KOH solution, reduced sharply and strongly in sunflower oil and n‐hexane. The presence of ELO has shown an improvement in migration, volatilization characteristics and thermal property of PVC. The positive effect of ELO as a secondary plasticizer was most evident after 72 hours of soaking in n‐hexane because the shore A hardness of ELO plasticized PVC sample increased by 12 % while PVC sample without ELO was blistered and its shore A hardness could not be measured. The scanning electron microscopy was used to study the morphology of fractured surface the samples after immersing in n‐hexane.

The structure and bonding situation in platinum complexes containing slight tetrylene ligands [{PtCl‐C9H6NO}‐NHE] (Pt‐NHE)with E = C, Si, Ge were examined by DFT calculations with the levels are BP86/def2‐SVP and BP86/def2‐TZVPP. The predicted equilibrium structure of the ligands NHE in Pt‐NHEare bonded in distorted end‐on way to PtCl‐8‐hydroxyquinolines fragment with the bending angle, α, exhibits the biggest value in carbenes systems then slightly decrease from Pt‐NHCto Pt‐NHGe. Bond dissociation energies (BDEs), De(kcal.mol‐1), decrease from the carbene complex to the weaker bonded silylene and germylene manners. The BDE when considering dispersion correction at the BP86‐D3(BJ)/def2‐TZVPP level confirms that Pt‐E bond in Pt‐NHEbelongs to the effect of the bulky group in slight tetrylene NHEand Pt(II)‐group fragment which makes the intrinsic Pt‐E bond strength decreases from carbene to germylene complexes. The hybridization of atoms E and Pt have large pcharacters while the hybridization of atom Pt has greater dcharacter which lead to the Pt‐E bond possesses not only NHE→{PtCl‐C9H6NO} strong σ‐donation but also a significant contribution π‐donation NHE→{PtCl‐C9H6NO} and weak π‐backdonation metal‐ligand NHE←{PtCl‐C9H6NO} in complexes Pt‐NHE.