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Synthesis of Nano Titanium Dioxide and Its Application in Photocatalysis
Truong Van Chuong,Le Quang Tien Dung,Dinh Quang Khieu 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
This paper presents a simple way to synthesize titaniumdioxide nanotubes by using a microwave- assisted reaction of TiO2 particles and NaOH solution. The main advantage of the introduction of microwave into the reaction system is the extremely rapid kinetics for synthesis. This method is simple and easy to reproduce. Structural and microstructural characterizations of titania nanotubes were accomplished using X-ray diffraction (XRD), scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM) techniques. The specific surface area was calculated using the Brunauer-Emmett-Teller model and was found to be 52 m2/g. A high photocatalysis of our TiO2 nanotubes was obtained. This paper presents a simple way to synthesize titaniumdioxide nanotubes by using a microwave- assisted reaction of TiO2 particles and NaOH solution. The main advantage of the introduction of microwave into the reaction system is the extremely rapid kinetics for synthesis. This method is simple and easy to reproduce. Structural and microstructural characterizations of titania nanotubes were accomplished using X-ray diffraction (XRD), scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM) techniques. The specific surface area was calculated using the Brunauer-Emmett-Teller model and was found to be 52 m2/g. A high photocatalysis of our TiO2 nanotubes was obtained.
Ho Van Minh Hai,Dinh Quang Khieu,The Ky Vo,Van Cuong Nguyen,김진수 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.3
Core-shell carbon sphere (CS)@α-Fe2O3@Ag was synthesized via a multistep hydrothermal method. First, the D-glucose hydrothermal process was employed to synthesize micron-size CSs on which α-Fe2O3 was grown to obtain the composite sphere of CS@α-Fe2O3. Thereafter, Ag+ was reduced on the surface of the CS@α-Fe2O3 sphere using NaBH4 agent to produce the core-shell CS@α-Fe2O3@Ag. Finally, microsphere composite CS@α-Fe2O3@Ag was coated on a glassy carbon electrode (GCE) to enhance its electrochemical performance in the simultaneous determination of uric acid (UA), xanthine (XN), and hypoxanthine (HP). Results indicated that the CS@α-Fe2O3@Ag-coated GCE exhibited improved voltammetric sensitivity toward UA, XN, and HP compared to bare GCE. The oxidation peak currents of the simultaneous detection of UA, XN, and HP increased linearly in the concentration range of 0.5–8.0 µmol L−1. The detection limits of the fabricated electrodes for UA, XN, and HP were −0.042, 0.089, and 0.048 µmol L−1, respectively, being more sensitive than many other modified GCEs. Moreover, the CS@α-Fe2O3@Ag-coated GCE exhibited good stability and repeatability. This study opens a new perspective for developing highly efficient electrodes for electrochemical analysis.
Highly efficient adsorption of arsenite from aqueous by zirconia modified activated carbon
Pham Ngoc Chuc,Nguyen Quang Bac,Dao Thi Phuong Thao,Nguyen Trung Kien,Nguyen Thi Ha Chi,Nguyen Van Noi,Vo Thang Nguyen,Nguyen Thi Hong Bich,Dao Ngoc Nhiem,Dinh Quang Khieu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.2
Nguyen Duc Cuong,Tran Thai Hoa,Dinh Quang Khieu,Nguyen Duc Hoa,Nguyen Van Hieu 한국물리학회 2012 Current Applied Physics Vol.12 No.5
The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity. The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity.
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.
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.