Hochiminh City University of Natural Resources and Environment

Ho Chi Minh City, Vietnam

Hochiminh City University of Natural Resources and Environment

Ho Chi Minh City, Vietnam
SEARCH FILTERS
Time filter
Source Type

Van Thuan T.,Nguyen Tat Thanh University | Quynh B.T.P.,Nguyen Tat Thanh University | Nguyen T.D.,Nguyen Tat Thanh University | Ho V.T.T.,Hochiminh City University of Natural Resources and Environment | Bach L.G.,Nguyen Tat Thanh University
Surfaces and Interfaces | Year: 2017

This study aims at optimizing the adsorption of heavy metal ions onto banana peel derived activated carbon (AC) using response surface methodology (RSM) involving central composite design (CCD). The cheap, non-toxic and locally available banana peel was subjected to carbonization and subsequently KOH-activation to produce the porous AC, which was then characterized by SEM and FTIR analyses. In RSM study, the individual and interactive effects of three critical variables including heavy metal ion concentration, pH of solution and AC dosage on the adsorption capacity were optimized. The maximum adsorption capacity appeared to follow the order: Cu2+ (14.3 mg/g) < Ni2+ (27.4 mg/g) < Pb2+ (34.5 mg/g) that agreed well with the verification experiments, revealing the reliability and suitability of the optimization approach. In addition, the results of isotherm study show that the Langmuir model can be used to best describe the adsorption behavior of Cu2+ and Ni2+ onto the banana peel derived activated carbon. © 2016 Elsevier B.V.


Bach L.G.,Pukyong National University | Thanh Ho V.T.,Hochiminh City University of Natural Resources and Environment | Quynh B.T.P.,Nguyen Tat Thanh University | Lim K.T.,Pukyong National University | Anh T.C.,Korea Institute of Science and Technology
Journal of Nanoscience and Nanotechnology | Year: 2017

The structurally well-defined diblock copolymer, poly(methyl methacrylate)-b-poly(N-isopropylacrylamide) (PMMA-b-PNIPAM) amphiphilic diblock copolymer was successfully grafted onto the surface of Halloysite nanotubes (HNTs) via reversible addition-fragmentation chain transfer (RAFT) polymerization. In this approach, S-benzyl S'-trimethoxysilylpropyltrithiocarbonate was first immobilized onto the HNTs as the RAFT agent. The polymerization of MMA and NIPAM was then initiated and propagated on the HNTs surface by RAFT polymerization. The chemical structure and morphology of diblock copolymer grafted onto the HNTs surface were ascertained by FT-IR, and FE-SEM analyses. A moderate degree of functionalization of HNTs by polymer chains was obtained according to TGA results. This study has suggested a facile approach to prepare surface functionalized HNTs via RAFT polymerization, which is promising to open up a wider prospect for the fabrication and novel application of hybrid polymeric materials with diverse functionalities. Copyright © 2017 American Scientific Publishers.


Tran T.V.,Nguyen Tat Thanh University | Bui Q.T.P.,Nguyen Tat Thanh University | Nguyen T.D.,Nguyen Tat Thanh University | Thanh Ho V.T.,Hochiminh City University of Natural Resources and Environment | Bach L.G.,Nguyen Tat Thanh University
Water Science and Technology | Year: 2017

The present study focused on the application of response surface methodology to optimize the fabrication of activated carbon (AC) from sugarcane bagasse for adsorption of Cu2+ ion. The AC was synthesized via chemical activation with ZnCl2 as the activating agent. The central composite design based experiments were performed to assess the individual and interactive effect of influential parameters, including activation temperature, ZnCl2 impregnation ratio and activation time on the AC yield and removal of Cu2+ ion from the aqueous environment. The statistically significant, well-fitting quadratic regression models were successfully developed as confirmed by high F- and low P-values (<0.0001), high correlation coefficients and lack-of-fit tests. Accordingly, the optimum AC yield and removal efficiency of Cu2+ were predicted, respectively, as 48.8% and 92.7% which were approximate to the actual values. By applying the predicted optimal parameters, the AC shows a surprisingly high surface area of around 1,500 m2/g accompanied by large pore volume and narrow micropore size at low fabrication temperature. © IWA Publishing 2017.


Bach L.G.,Nguyen Tat Thanh University | Cao X.T.,Pukyong National University | Quynh B.T.P.,Nguyen Tat Thanh University | Ho V.T.T.,Hochiminh City University of Natural Resources and Environment | Lim K.T.,Pukyong National University
Molecular Crystals and Liquid Crystals | Year: 2017

In this study, a facile method for synthesis of conducting polymer/inorganic oxide hybrid nanocomposites, the poly(N-vinylcarbazole)/Titanium Dioxide (PVK-g-TiO2), was successfully developed via direct facile esterification reaction under extremely mild conditions. The TiO2 nanoparticles (TiO2 NPs) were first modified by 3-glycidoxypropyl trimethoxysilane in order to prepare the epoxy groups functionalized TiO2 NPs, followed by refluxing with ethanol solution of hydrochloric acid to convert the epoxy groups into alkyl-hydroxyl units. A sufficient amount of PVK was then grafted onto the as-modified TiO2 NPs via esterification reaction between the alkyl-hydroxyl units at the nanoparticle surface and the carboxyl-terminated PVK chains. Fourier transform infrared spectroscopy, Energy dispersive X-Ray, X-ray diffraction and thermogravimetric analysis were used to study the chemical and physical properties in surface functionalities. © 2017 Taylor & Francis Group, LLC.


Bach L.G.,Nguyen Tat Thanh University | Quynh B.T.P.,Nguyen Tat Thanh University | Thuong N.T.,Nguyen Tat Thanh University | Ho V.T.T.,Hochiminh City University of Natural Resources and Environment
Molecular Crystals and Liquid Crystals | Year: 2017

A novel fluorescent nanohybrid complex comprising of SiO2 nanoparticles, poly(2-hydroxyethyl methacrylate) (PHEMA), and photoluminescent (Eu3+) was synthesized by a combination of controlled surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization and coordination chemistry. Initially, PHEMA was grafted from the surface of SiO2 NPs by SI-RAFT and then reacted with succinic anhydride to provide carboxyl acid groups on the external layers of SiO2-PHEMA nanohybrids. The subsequent coordination of the nanohybrids with Eu3+ ions successfully afforded the photoluminescent Eu3+ tagged SiO2-PHEMA nanohybrid complex (SiO2-PHEMA-Eu3+). The structure and fluorescence properties of the Eu3+ coordinated nanohybrid complex were investigated using the respective physical and spectral studies. © 2017 Taylor & Francis Group, LLC.


Ho V.T.T.,Hochiminh City University of Natural Resources and Environment | Giang B.L.,Nguyen Tat Thanh University | Hong L.-S.,National Taiwan University of Science and Technology | Nguyen N.G.,National Taiwan University of Science and Technology
Molecular Crystals and Liquid Crystals | Year: 2017

Black silicon (b-Si) has been a subject of great interest in various fields including photovoltaics for its ability to reduce significantly the surface reflectance so that b-Si can absorb more than 98% of light signing on them. We have fabricated the b-Si anti-reflection via metal-assisted etching process using gold (Au) layer assisted nano-porous etching in this study. The b-Si layers were produced through a simple and effective method consist of a thin Au coating (d < 10 nm) that played as a catalyst layer onto Si (100) wafers prior immersion in a HF-H2O2-H2O solution at room temperature, resulting catalyze formation of a network of [100]-oriented nanopores. The SEM observation suggested that the vertically columnar structure with a ∼300 nm deep nanopores layers can be formed in the limited synthesis conditions as well as achieved the extremely low reflectance about 2% at wavelength from 400–1000 nm. © 2017 Taylor & Francis Group, LLC.


Bach L.G.,Nguyen Tat Thanh University | Bui Q.T.P.,Nguyen Tat Thanh University | Cao X.T.,Pukyong National University | Ho V.T.T.,Hochiminh City University of Natural Resources and Environment | Lim K.T.,Pukyong National University
Polymer Bulletin | Year: 2016

A facile strategy for growing the poly(2-hydroxyethyl methacrylate) encapsulated on the surface of SiO2 nanoparticles (SiO2/PHEMA) as a molecular host matrix for the luminescent Tb3+ via a combination of surface-initiated reversible addition fragmentation chain transfer polymerization and coordination chemistry was successfully developed. The structure, morphology and fluorescence properties of the materials were investigated using relevant physical and spectral techniques. The core–shell structure and uniform dispersion of SiO2/PHEMA and SiO2/PHEMA:Tb3+ complexes were found according to SEM and TEM analyses while their surface bonding characteristics were determined via FT-IR analysis. In photoluminescence measurement, the SiO2/PHEMA:Tb3+ nanoparticles showed characteristic emissions of Tb3+ with the strongest (5D4 → 7F5) green emission without detectable emissions of ligands, demonstrating that SiO2 framework covalently bonded with PHEMA segments acting as an efficient matrix for sensitization of fluorescent Tb3+ ions. © 2016 Springer-Verlag Berlin Heidelberg


Dinh N.T.,Hochiminh City University of Natural Resources and Environment | Hatta K.,Tokyo Institute of Technology | Kwon S.H.,Tokyo Institute of Technology | Rollon A.P.,University of the Philippines at Diliman | Nakasaki K.,Tokyo Institute of Technology
Biomass and Bioenergy | Year: 2014

Granular sludge from a full-scale methane reactor treating brewery wastewater was used as a seed for the treatment of glycerol in a laboratory-scale repeated-batch methane reactor, and the change in the microbial community during the acclimation stages was examined. Two types of substrate solutions, a glucose, sodium acetate, and lactic acid mixture, as well as glycerol, were prepared and fed by mixing the two solutions to increase the ratio, in a stepwise manner, of glycerol from 0% to 100%, while keeping a loading of COD at 2.5kgm-3d-1 throughout the fermentation process. Vigorous methane gas production, approximately 580dm3m-3d-1, was observed during the acclimation stages. Microbial analysis revealed that both bacterial and archaeal communities changed significantly; bacteria (genus Trichococcus and family Syntrophomonadaceae) became dominant rapidly after the start of acclimation, and archaea belonging to the hydrogenotrophic methanogens (genera Methanobacterium and Methanospirillum), increased gradually with the progress of acclimation. © 2014 Elsevier Ltd.


Hoang T.T.T.,Hochiminh City University of Natural Resources and Environment | Tu L.T.C.,Hochiminh City University of Natural Resources and Environment | Le N.P.,Hochiminh City University of Natural science | Dao Q.P.,Institute for Environment and Resources | Trinh P.H.,Institute for Environment and Resources
Wetlands Ecology and Management | Year: 2012

Vietnamese coastal wetlands have traditionally been used for shrimp farming, but with the expansion of commercial shrimp farming and the associated clearance of mangroves, these valuable ecosystems have been rapidly degraded. The application of veterinary antibiotics in shrimp culture is one of the major threats to Vietnamese mangroves. These antibiotics are released into the environment through wastewater streams from shrimp ponds and cause environmental problems as well as the occurrence of antibiotic resistant bacteria. However, there is only a limited amount of information available on the occurrence and fate of antibiotics in Vietnamese mangroves. Ciprofloxacin and norfloxacin are two of most commonly fluoroquinolones used in shrimp culture. Laboratory experiments were therefore carried out using saline shrimp pond water to investigate the fate of both antibiotics in a coastal wetland ecosystem. Furthermore, two wetland plant species (Ceratophyllum demersum and Chrysopogon zizanioides), were used for studying phytoremediation of both antibiotics through a hydroponic experiment. Both ciprofloxacin and norfloxacin were photodegradable but at a slow rate, whereas the biodegradation seemed to be insignificant. If given at an initial concentration of 5 or 10 mg/L, a higher removal of antibiotics was achieved using C. demersum: 40 % for norfloxacin and 44-39 % for ciprofloxacin, respectively. With C. zizanioides, ciprofloxacin and norfloxacin were reduced by 40-38 and 36-34 %, respectively. These results indicated that phytoremediation could be effective in the removal of both antibiotics. © 2012 Springer Science+Business Media B.V.


Thuy H.T.T.,Hochiminh City University of Natural Resources and Environment | Loan T.T.C.,Hochiminh City University of Natural Resources and Environment
Water, Air, and Soil Pollution | Year: 2014

Ciprofloxacin, griseofulvin, and rifampicin are three human antibiotics that are also widely used in the shrimp culture of Cangio coastal wetland (Vietnam, 10° 24′ 38″ N, 106° 57′ 17″ E). They have been detected in shrimp larvae pond and receiving water bodies. However, the environmental fate of these antibiotics in coastal wetland milieu is currently unknown. The aim of this study was to determine the degradation potential of these antibiotics in water and sediments from Cangio coastal wetlands. The effects of light, microbial activities, and presence of sediments on the degradation of all three antibiotics were investigated in "water-only" and "water-sediment" experiments. Results indicate that the environmental fate of those antibiotics was quite complex. Photodegradation seemed to play a major role in "water-only" system, since shorter t1/2 was observed for ciprofloxacin, griseofulvin, and rifampicin, with light than in the dark, for both sterile and non-sterile conditions. Biodegradation played a minor role in the disappearance of the antibiotics and was overlaid by photodegradation. In addition, sorption to sediment was of major importance for antibiotics, especially for ciprofloxacin and rifampicin. The t1/2 of these antibiotics in aqueous phase of "water-sediment"system was higher than for "water-only" experiments, indicating that a part of antibiotics were adsorbed by sediment. The biodegradation did not play a major role on sediment sorption of CIP and RIF, since no statistically significant differences between non-sterile and sterile conditions were observed. Only for GRI, the impact of the biodegradation to the sediment sorption could be found and led to the weak affinity to sediment sorption of this antibiotic. All three antibiotics were more sensitive to photodegradation than to biodegradation; however, the degradation rate was low. In addition, the sorption by sediment occurred also with a slow rate, so these antibiotics could recalcitrant persist in the coastal wetland environment. © Springer International Publishing 2014.

Loading Hochiminh City University of Natural Resources and Environment collaborators
Loading Hochiminh City University of Natural Resources and Environment collaborators