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.

Effect of plant growth regulator combination and culture period on in vitro regeneration of spinach (Spinacia oleracea L.)

Quyen Van Nguyen,선현진,부경환,이도성,이지현,임평옥,이효연,Key Zung Riu,이동선 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.1

The objective of this study was to develop an efficient system for the regeneration of spinach plants (Spinacia oleracea L.) by investigating the factors influencing callus and shoot induction. All plant growth regulator (PGR) combinations tested induced callus with high frequency (73–100 %), and the combination of 5 lM a-naphthaleneacetic acid (NAA), 10 lM 6-benzyladenine (BA) and 0.1 lM gibberellic acid (GA3) had the most significant effect on callus growth in term of weight (120.98 ± 22.56 mg). A high auxin-containing medium induced competent callus for shoot formation, while high cytokinin-containing media enhanced callus growth and made callus incompetent for shoot regeneration. Longer periods of callus induction in a high auxin-containing medium were required to form competent callus and led to a high regeneration capacity. The PGR combination shift from a high auxin to cytokinin ratio (ACR) to a low ACR resulted in highly efficient regeneration. Among the regeneration systems tested, the combination of 10 lM NAA and 0.3 lM GA3 for callus induction for 6 weeks followed by 2 lM NAA and 5 lM BA resulted in the highest plant regeneration frequency (83.33 ± 6.43 %) andthe highest number of plantlets per explant (7.93 ± 1.24). Somatic embryos at cotyledonary stage and plantlets were transferred to PGR-free medium to establish whole plants. Regenerated female plants grew well to maturity in the greenhouse (77.17 ± 9.80 %) and produced seeds (175.21 ± 28.01 firm seeds per plant).

Application of Total Quality Management in Developing Quality Assessment Model: The Case of Vietnamese Higher Education

Quyen Le Hoang Thuy To NGUYEN,Du Van NGUYEN,Ngoc Nguyen Mong CHU,Van Hong TRAN 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

The shift from elite education to mass education in Vietnam has met the demand for education for everybody as well as for quality human resource talent for an emerging nation. Under the resource constraint, understanding the quality dimensions of education and its priority level is important for effective and efficient policies. This study was carried out using both qualitative and quantitative methodologies to develop quality criteria and a ranking model. Two rounds of in-depth interviews were conducted with fifteen experts in the field, who were rectors, employers, and recruitment specialists to develop the quality framework applied in Vietnamese universities under total quality management (TQM), starting from the input of the senior secondary school leavers, through a teaching process to the output. The first round of interviews were unstructured questionnaires designed to explore the main factors in quality assessment model. The second round affirmed the experts’ agreement on the assessment model. Then, fuzzy logic was applied to rank eight criteria in the quality assessment model into priority order: cost, teaching and administrative staff, leadership, curriculum, student-related factors, internationalization, admissions, and campus. The results are critical for identifying the necessary actions to enhance the education quality and to further research on the optimal quality model.

<i>In situ</i> growth of flower-like V₂O₅ arrays on graphene@nickel foam as high-performance electrode for supercapacitors

Van Hoa, Nguyen,Quyen, Tran Thi Hoang,Nghia, Nguyen Huu,Van Hieu, Nguyen,Shim, Jae-Jin Elsevier 2017 Journal of alloys and compounds Vol.702 No.-

<P><B>Abstract</B></P> <P>Hierarchical flower-like V<SUB>2</SUB>O<SUB>5</SUB> growth on graphene and nickel foam electrodes was fabricated by using chemical vapor deposition and hydrothermal methods for electrochemical capacitors. Taking advantages of the high conductivity of graphene, high capacitance of well-defined V<SUB>2</SUB>O<SUB>5</SUB> flower-like structure and open framework of three-dimensional nickel foam, the resulting electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability. The specific capacitance was as high as 1235 F g<SUP>−1</SUP> at a current density of 2 A g<SUP>-1</SUP>, suggesting its potential as a high performance electrode for supercapacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchical flower-like V2O5/graphene/nickel foam electrodes was fabricated. </LI> <LI> The electrodes exhibited rapid electron and ion transport, large electroactive surface area. </LI> <LI> The specific capacitance was as high as 1235 A g−1 at a current density of 2 A g−1. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Preliminary study of doxycycline adsorption from aqueous solution on alkaline modified biochar derived from banana peel

Van-Truc Nguyen,Thanh-Binh Nguyen,Thi-Dieu-Hien Vo,Nguyen Duy Dat,Thi-Kim Quyen Vo,Xuan Cuong Nguyen,Viet-Cuong Dinh,Thi-Ngoc-Chau Le,Thi-Giang-Huong Duong,Manh-Ha Bui,Xuan-Thanh Bui 대한환경공학회 2023 Environmental Engineering Research Vol.29 No.3

This study explores the adsorption of doxycycline (DOX) from aqueous solutions onto biochar derived from banana peel, which was prepared using a potassium hydroxide activation method (KOH-BPB). The biochar properties were characterized based on morphology, surface area (SBET of 710.241 ㎡ g<SUP>−1</SUP>), functional groups, and surface charge (pHPZC = 7.7). Parameters, including initial pH, DOX concentration, and ionic strength, that influenced the DOX adsorption capacity of KOH-BPB were examined. Adsorption equilibrium of DOX on KOH-BPB was assessed through four isothermal models: the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. The obtained data were most compatible with the Langmuir model (R² = 0.9879). KOH-BPB has a maximum DOX absorption capacity of 121.95 mg g<SUP>-1</SUP> which exceeds that of many comparable absorbents. The maximum DOX removal was 96.7% at pH 6, a DOX concentration of 20 mg L<SUP>-1</SUP>, and a KOH-BPB dose of 1.0g L<SUP>-1</SUP>. These findings reveal that biochar from banana peel effectively removes antibiotic residues from water. This study provides a potential, low-cost, and environmentally friendly adsorbent.

Drynaria bonii spore culture: optimization of culture conditions and analysis of gametophyte and sporophyte development

Quyen Van Nguyen,Hang Thi Khuat,Yen‑Ngoc Thi Nguyen,Dung Thi Vu,Thu‑Ha Bui,부경환 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.5

Drynaria bonii H. Christ is a medicinal plant that has traditionally been used for the treatment of chronic diseases and tuberculosis. However, D. bonii has not yet been cultivated or propagated. In this study, we optimized the conditions for the spore culture of D. bonii to produce sporophytes. First, we evaluated the efects of various factors, such as temperature, light intensity, potting material, and pH, on spore germination and early gametophyte development. Under optimal culture conditions, 95–99% of the spores germinated within 2 weeks of culture. Next, based on these results, we established a culture system for gametophyte development and sporophyte production. Mature gametophytes frst appeared 5 months post-germination (mpg), and at 12 mpg, the rate of production of heart-shaped gametophytes reached 56.6%. Sporophytes at the early frst-leaf stage frst appeared at 6 mpg, and at 12 mpg, the rate of formation of sporophytes reached 15.4%. Interestingly, 6.3% of all gametophytes produced multiple sporophytes. Additionally, 42–62% of the gametophytes also produced multiple secondary gametophytes, indicating a high potential of D. bonii gametophytes to generate new gametophytes and, subsequently, sporophytes. When transferred to new trays or pots, sporophytes grew well and showed 100% survival. Overall, we conclude that this spore culture system can be successfully used for the propagation of D. bonii sporophytes.

Effect of plant growth regulator combination and culture period on in vitro regeneration of spinach (Spinacia oleracea L.)

Nguyen, Quyen Van,Sun, Hyeon Jin,Boo, Kyung Hwan,Lee, Doseung,Lee, Ji-Hyun,Lim, Pyung Ok,Lee, Hyo Yeon,Riu, Key-Zung,Lee, Dong-Sun 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.1

The objective of this study was to develop an efficient system for the regeneration of spinach plants (Spinacia oleracea L.) by investigating the factors influencing callus and shoot induction. All plant growth regulator (PGR) combinations tested induced callus with high frequency (73-100 %), and the combination of 5 ${\mu}M$ ${\alpha}$-naphthaleneacetic acid (NAA), 10 ${\mu}M$ 6-benzyladenine (BA) and 0.1 ${\mu}M$ gibberellic acid ($GA_3$) had the most significant effect on callus growth in term of weight ($120.98{\pm}22.56$ mg). A high auxin-containing medium induced competent callus for shoot formation, while high cytokinin-containing media enhanced callus growth and made callus incompetent for shoot regeneration. Longer periods of callus induction in a high auxin-containing medium were required to form competent callus and led to a high regeneration capacity. The PGR combination shift from a high auxin to cytokinin ratio (ACR) to a low ACR resulted in highly efficient regeneration. Among the regeneration systems tested, the combination of 10 ${\mu}M$ NAA and 0.3 ${\mu}M$ $GA_3$ for callus induction for 6 weeks followed by 2 ${\mu}M$ NAA and 5 ${\mu}M$ BA resulted in the highest plant regeneration frequency ($83.33{\pm}6.43%$) and the highest number of plantlets per explant ($7.93{\pm}1.24$). Somatic embryos at cotyledonary stage and plantlets were transferred to PGR-free medium to establish whole plants. Regenerated female plants grew well to maturity in the greenhouse ($77.17{\pm}9.80%$) and produced seeds ($175.21{\pm}28.01$ firm seeds per plant).

Ultrafine Copper Nanoparticles Exhibiting a Powerful Antifungal/Killing Activity Against Corticium Salmonicolor

Van Du Cao,Phuong phong Nguyen,Vo Quoc Khuong,Cuu Khoa Nguyen,Xuan Chuong Nguyen,Cap Ha Dang,Ngoc Quyen Tran 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

In this paper ultrafine copper nanoparticles (CuNPs) were prepared from copper salt via chemical reduction method with sodium citrate dispersant and polyvinylalcol (PVA) capping polymer. The colloidal CuNPs were characterized by using UV–Visible spectroscopy, Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD) techniques. Our obtained results indicated that the CuNPs were produced ranging from 2 to 4 nm in diameter. The colloidal solution at 7 ppm of CuNPs exhibited a powerful antifungal activity against Corticium salmonicolor (C. Salmonicolor). Fungal killing assays showed colloid solutions containing 10 ppm of CuNPs killed entirely the cultured fungus. A highly killing activity against the fungus was also performed when the CuNPs were sprayed on pink disease-infected rubber trees. These positive results may offer a great potential to produce CuNPs-based eco-fungicide for pink disease.

Ultrafine Copper Nanoparticles Exhibiting a Powerful Antifungal/Killing Activity Against Corticium Salmonicolor

Cao, Van Du,Nguyen, Phuong Phong,Khuong, Vo Quoc,Nguyen, Cuu Khoa,Nguyen, Xuan Chuong,Dang, Cap Ha,Tran, Ngoc Quyen Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

In this paper ultrafine copper nanoparticles (CuNPs) were prepared from copper salt via chemical reduction method with sodium citrate dispersant and polyvinylalcol (PVA) capping polymer. The colloidal CuNPs were characterized by using UV-Visible spectroscopy, Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD) techniques. Our obtained results indicated that the CuNPs were produced ranging from 2 to 4 nm in diameter. The colloidal solution at 7 ppm of CuNPs exhibited a powerful antifungal activity against Corticium salmonicolor (C. Salmonicolor). Fungal killing assays showed colloid solutions containing 10 ppm of CuNPs killed entirely the cultured fungus. A highly killing activity against the fungus was also performed when the CuNPs were sprayed on pink disease-infected rubber trees. These positive results may offer a great potential to produce CuNPs-based eco-fungicide for pink disease.

Applying Stochastic Fractal Search Algorithm (SFSA) in Ranking the Determinants of Undergraduates Employability: Evidence from Vietnam

DINH, Hien Thi Thu,CHU, Ngoc Nguyen Mong,TRAN, Van Hong,NGUYEN, Du Van,NGUYEN, Quyen Le Hoang Thuy To Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.12

Employability has recently become the first target of the national higher education. Its model has been updated to catch the new trend of Industry 4.0. This paper aims at analyzing and ranking the determinants of undergraduate employability, focusing on business and economics majors in Ho Chi Minh City, Vietnam. In-depth interviews with content analysis have been primarily conducted to reach an agreement on a key group of factors: human capital, social capital, and identity. The Stochastic Fractal Search Algorithm (SFSA) is then applied to rank the sub-factors. Human capital is composed of three major elements: attitude, skill, and knowledge. Social capital is approached at both structural and cognitive aspects with three typical types: bonding, bridging, and linking. The analysis has confirmed the change of priority in employability determinants. Human capital is still a driver but the priority of attitude has been confirmed in the contemporary context. Then, social capital with the important order of linking, bridging, and bonding is emphasized. Skill, knowledge, and identity share the least weight in the model. It is noted that identity is newly proposed in the model but a certain role has been found. The findings are crucial for education strategies to enhance university graduate employability.