Visible light-driven photocatalytic degradation of doxycycline using ZnO/g-C₃N₄/biochar composite in aqueous solution

Nguyen Van Hung,Bui Thi Minh Nguyet,Nguyen Huu Nghi,Nguyen Minh Luon,Nguyen Ngoc Bich,Le Van Thanh Son,Nguyen Trung Kien,Dao Ngoc Nhiem,Nguyen Thanh Tuoi,Dinh Quang Khieu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4

In the present work, ZnO/g-C₃N₄/biochar was prepared, and it was used for visible-light driven photocatalytic degradation of some colorants (methylene blue, rhodamine B, methyl orange) and some antibiotics (doxycycline, ciprofloxacin, amoxicilline). Biochar was prepared by pyrolysing Phragmites australis biomass. The ZnO/g-C₃N₄/biochar composite was synthesized with the alkaline hydrolysis method. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transition electron microscopy, energy dispersive X-ray/elemental mapping, ultraviolet-visible-diffuse reflectance spectroscopy, photoluminescence spectroscopy, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy. The results show that ZnO nanoparticles with a large surface area are highly dispersed on the g-C₃N₄ particle surface and biochar. The composite exhibits superior photocatalytic degradation ability toward doxycycline, a broad-spectrum antibiotic of the tetracycline compared with individual components (ZnO or g-C₃N₄) and satisfies stability after six treatment cycles. The kinetics and degradation mechanisms of doxycyline were also addressed. In addition, the present catalyst also exhibits the photocatalytic degradation of methylene blue, rhodamine B, methyl orange, ciprofloxacin and amoxicillin in visible-light regions.

Highly effective adsorption of organic dyes from aqueous solutions on longan seed-derived activated carbon

Nguyen Van Hung,Bui Thi Minh Nguyet,Nguyen Huu Nghi,Nguyen Mau Thanh,Nguyen Duc Vu Quyen,Vo Thang Nguyen,Dao Ngoc Nhiem,Dinh Quang Khieu 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.3

In this study, longan seeds - an agricultural by-product was used to fabricate activated carbon (LSAC) through two-step pyrolysis with pre-carbonization at low temperature in the first step and then activation by H3PO4. LSAC with large surface area and porous structure exhibits an excellent capacity of absorption towards both cationic dyes (methylene blue (MB), rhodamine-B (RhB)) and anionic dyes (methyl orange (MO), congo red (CR)). Experimental data can be described well by the pseudo-second kinetic model. The maximum adsorption capacity based on Langmuir isotherm model was found as 502.84; 397.77; 464.66 and 350.64 mg.g−1 for MB, RhB, MO and CR, respectively. The adsorption of MB, RhB and CR on LSAC is spontaneous and endothermic, while that for MO is spontaneous but exothermic. Furthermore, the adsorption mechanism of dyes on LSAC was also studied showing that it can occur by electrostatic interaction, hydrogen bonding, the filling of pores involving the interaction between dye ions with specific functional groups such as –OH, –COOH, –NH2 and –PO43− on the LSAC surface. These results suggest that LSAC material may be envisaged as a promising adsorbent for treatment of wastewater in textile industries.

The Information Distribution Role of Facebook in Universities

Thi Nguyet Dung NGUYEN,Thi Thu Huong NGUYEN,Thi Phuong Anh NGUYEN,Thi Thu Huong NGUYEN,Thi Phuong Thao VU 한국유통과학회 2022 유통과학연구 Vol.20 No.5

Purpose: The paper employs the theory of planned behaviour, social identity theory, social presence theory, and social exchange theory to propose a model for using the social media platform Facebook in distributing information in universities. Research design, data and methodology: Data were obtained from 618 students at Hanoi University of Industry (HaUI) in Vietnam. The study used structural equation modeling in SPSS and the statistical analysis software AMOS version 24 to explore the information distribution role of Facebook. Results: Findings reveal that subjective norms and social presence play a key role in driving students to use Facebook for studying. In addition, university administrators can boost student satisfaction and academic achievement through Facebook. Interestingly, students who strongly identify with the brand name of the university have a strong connection with the university are more likely to engage in behaviors supportive toward the university. Conclusions: These findings show that Facebook had played a key information distribution role in universities. Thus, the study provides the executive board of the university and teachers can gain new understanding of why students employ Facebook for studying as well as capitalize on the platform to improve several operational metrics such as brand identification, student satisfaction, and academic achievement.

The Role of Zn Doping on the Catalytic Activity of the Nanoparticle Perovskite La0.7Sr0.3MnO3

Tran Thi Minh Nguyet,Nguyen Quang Huan,Tran Que Chi,Do The Chan,Nguyen Doan Thai,Nguyen Cong Trang,Luu Tien Hung,Le Van Tiep,Nguyen Van Qui 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃ The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃

Facile one-step synthesis of Ir-Pd bimetallic alloy networks as efficient bifunctional catalysts for oxygen reduction and oxygen evolution reactions

Nguyen, Anh Thi Nguyet,Shim, Jun Ho Elsevier 2018 Journal of Electroanalytical Chemistry Vol.827 No.-

<P><B>Abstract</B></P> <P>This paper introduces a facile one-step process to synthesize highly interconnected nanoporous Ir-Pd alloys supported on carbon that exhibit excellent bifunctional electrocatalytic activities for both the oxygen reduction and oxygen evolution reactions with reasonable stability in alkaline electrolytes. Nanoporous Pd networks with crystalline {111} faces were shown experimentally to serve mainly as active sites for the oxygen reduction reaction, whereas the Ir nanoparticles incorporated in the Pd nanoframe networks, where the optimized Ir:Pd ratio was 0.23:0.77 (<I>n</I> = 10), were responsible for the oxygen evolution reaction. Such three-dimensional architectures provide a high density of active sites for the oxygen electrochemical reaction and facilitate electron transport. More importantly, the nanoporous Ir-Pd alloy nanocomposites exhibited similar stability for the oxygen reduction reaction but superior catalytic activity to the commercial Pd catalyst in alkaline solutions. In addition, the materials were also highly active for the oxygen evolution reaction, e.g., a small overpotential at 10 mA cm<SUP>−2</SUP> (1.628 V vs. reversible hydrogen electrode), making it a high-performance bifunctional catalyst for both the oxygen electrochemical reaction. Rotating ring-disk electrode measurements showed that the oxygen reduction and oxygen evolution reactions on the Ir-Pd catalysts proceeded predominantly through the desired 4-electron pathway.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Facile one-step synthesis of a nanoporous Ir-Pd bimetallic alloy network. </LI> <LI> The composites exhibited bifunctional ORR/OER performance compared to Pd/C and Ir/C. </LI> <LI> Ir<SUB>23</SUB>Pd<SUB>77</SUB>/C exhibited the highest activity with good durability and overpotential. </LI> <LI> The properties of Ir<SUB>23</SUB>Pd<SUB>77</SUB>/C were due to its high surface area and high porosity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A highly active bifunctional electrocatalyst for the oxygen reduction and evolution reactions was developed based on a highly interconnected nanoporous Ir-Pd bimetallic alloy network.</P> <P>[DISPLAY OMISSION]</P>

Commentary: South Korean Factory Managers’ Transnational Life in Ho Chi Minh City by Chae Suhong

( Nguyen Nu Nguyet Anh ) 서울대학교 사회과학대학 인류학과 2019 Korean Anthropology Review Vol.3 No.-

(In lieu of an abstract) The article, “South Korean Factory Managers’ Transnational Life in Ho Chi Minh City,” written by Chae Suhong, discusses the concept of transnationalism based on the lives of South Korean (hereafter, Korean) managers working in and around Ho Chi Minh City, Vietnam. In his well written and clearly structured article, Chae presents a complex analysis of (1) movements of Korean skilled and managerial migrant workers toVietnam; (2) their socio-economic status affected by political and economic conditions of both the country of origin and the host country; and (3) their transnational lives, specifically in their transnational work and living spaces.

Rural Communication in the Covid-19 Pandemic: an Empirical Analysis from Thua Thien Hue Province, Central Vietnam

Nguyen, Hien Thi Dieu,Nguyen, Chung Van,Pham, Chung,Nguyen, Phong Thanh,Le, Cuong Chi Hung,Pham, Nhung Thi,Tran, Nguyet Thi Anh World Association for Triple Helix and Future Stra 2022 Journal of Contemporary Eastern Asia Vol.21 No.1

The world has witnessed the outbreak of the Covid-19 epidemic. Mainstream and social media are playing an important role in Covid-19 pandemic prevention. This research explores awareness, communication channels and effectiveness of communication in the Covid-19 pandemic in rural areas of Thua Thien Hue province, Central Vietnam. Primary information was collected from 181 respondents, who are farmers, non-farmers and students. Secondary information was collected from reports and statistical data. Television, word of mouth and local loudspeakers are the main channels of mainstream media while social media mentions the role of Facebook and Zalo to transfer Covid-19 pandemic information. Mainstream media is still the main channel of farmers and old people while non-farmers and young people tend to access information through social media. Communication has significantly contributed to improving awareness and action of rural people in the Covid-19 epidemic prevention.

Personality, Behavior, and Performance of Platform Workers: Evidence from Vietnam

Nguyet Nguyen,Thi Hoang Ha Tran The International Academy of Global Business and T 2023 The International Academy of Global Business and T Vol.19 No.5

Purpose - Based on personality - job fit theory (Kristof-Brown, 2006) and social exchange theory (Blau, 2017) we explaine evidence of the relationship between proactive personality, proactive feedback seeking behavior, and the job performance of platform workers. We also examine the moderating role of perceived organizational support in relationship between proactive personality and feedback seeking behavior and job autonomy as a moderating role between the proactive feedback seeking behavior and job performance of platform workers. Design/Methodology/Approach - This study follows structural equation modeling following a partial least square method on a sample group of 171 platform workers selected by convenient random sampling techniques and analyzed by SmarlPLS 4.0 to test research hypotheses. Findings - Research findings show that proactive personality plays an important role in promoting proactive behavior seeking feedback and job performance, and affirms the positive moderating role of perceived platform support between feedback seeking behavior and proactive personality. The study also confirmed that proactive feedback seeking behavior has a direct and indirect impact on the performance of platform workers, and this relationship is further strengthened in conditions of highly autonomous work. Research Implications - Some implications of human resource management on digital labor platforms are also proposed to improve the efficiency of human resource management.

Factors Affecting Capital Structure of Listed Construction Companies on Hanoi Stock Exchange

Nguyet Minh NGUYEN,Kien Trung TRAN 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

The aim of this article is to determine the influence of factors on the capital structure of construction companies listed on the Hanoi Stock Exchange. The data of the article were collected and calculated from the financial statements of 54 construction companies listed on Hanoi Stock Exchange from 2012 to 2019. With the application of E-view software in quantitative analysis to build panel data regression model (panel data), the article has built a regression model to determine the relationship of intrinsic factors affecting the capital structure of construction companies listed on Hanoi Stock Exchange. In the study, dependent variable is capital structure, determined by the debt-toequity ratio. Profitability, coefficient of solvency, size, loan interest rate, structure of tangible assets, and growth are independent variables. The results showed that the two factors of growth and firm size positively affect the capital structure, the profitability factor has the opposite effect on capital structure. Factors of short-term debt solvency, average loan interest rate and tangible asset structure have no correlation with capital structure. The findings of this article are useful for business administrators, helping business managers make the right financial decisions to make capital structure decisions in their own conditions.

Facile synthesis of MoS2 nanosheets-carbon nanofibers composite as catalysts for hydrogen evolution reaction

Nguyen Thi Minh Nguyet,Le Van Thang,Nguyen Huu HuyPhuc,Vinh-Dat Vuong,Tran Van Khai,Mai Thanh Phong 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

MoS2 nanosheets (NS) were directly grown on carbon nanofiber (CF) and employed as electrocatalyst for hydrogen evolutionreaction (HER). The structural, surface morphology and chemical composition of the nanocomposites were characterized byfield emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energydispersiveX-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy. XRD and TEM-EDS measurementsshowed that the molybdenum oxide precursor was successfully transferred into MoS2 nanosheets. It was confirmed from FESEMand TEM images that NS was uniformly distribution on surface of the CF. The HR-TEM images disclosed that the NSwas formed perpendicular to surface of CF fibers via the MoS2 layers growth parallel to CF surface which act as interface. The HER current density was about 12 mA cm−2 at catalyst loading of only 60 μg cm−2 at -0.384 V (vs. RHE).