Separation of Pd(II) and Pt(IV) from hydrochloric acid solutions by solvent extraction with Cyanex 301 and LIX 63

Truong, Hoai Thanh,Lee, Man Seung Elsevier 2018 Minerals engineering Vol.115 No.-

<P><B>Abstract</B></P> <P>In conventional solvent extraction processes, Pt(IV) and Pd(II) are separated by selective stripping from the loaded amines. Solvent extraction experiments were done to find extraction conditions to selectively extract Pd(II) over Pt(IV) from HCl solutions in the concentration range from 0.5 to 9 M. For this purpose, cationic, neutral and amines were employed to investigate the extraction behavior of the two metals from the single solution. LIX 63 and Cyanex 301 showed a selectivity for Pd(II) over Pt(IV) in the HCl concentration ranges tested in this work. The extraction percentage of Pd(II) by LIX 63 was greatly reduced as HCl concentration was higher than 7 M, while Pd(II) was completely extracted by Cyanex 301 even from 9 M HCl solution. FT-IR spectra of fresh and loaded Cyanex 301 showed that strong interaction occurred between Pd(II) complex and the PS bond in Cyanex 301. Therefore, it was very difficult to strip Pd(II) from the loaded Cyanex 301. The separation behavior of Pd(II) and Pt(IV) was compared between Cyanex 301 and LIX 63. Although the separation factor by Cyanex 301 was a little higher than that by LIX 63, LIX 63 was recommended as a suitable extractant for the selective extraction of Pd(II) over Pt(IV) owing to the ease of stripping of Pd(II) from the loaded LIX 63.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pd(II) was completely extracted by Cyanex 301 in the HCl concentration range of 0.5–9 M. </LI> <LI> FT-IR spectra indicated strong interaction between Pd(II) and the PS bond in Cyanex 301. </LI> <LI> The separation of Pd(II) from Pt(IV) was compared between Cyanex 301 and LIX 63. </LI> <LI> LIX 63 was recommended for the separation of the two metals on the basis of the stripping. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The Pd(II) was completely extracted by Cyanex 301 in the HCl concentration range of 0.5–9 M, while that of Pt(IV) was negligible at the same condition.</P> <P>[DISPLAY OMISSION]</P>

Separation of rhenium(VII), molybdenum(VI), and vanadium(V) from hydrochloric acid solution by solvent extraction with TBP

Hoai Thanh Truong,이만승 한국자원공학회 2017 Geosystem engineering Vol.20 No.4

To investigate the separation of Re(VII), Mo(VI), and V(V) from hydrochloric acid solution, solvent extraction with TBP was investigated. When HCl concentration was lower than 3 M, TBP could selectively extract both Re(VII) and Mo(VI), leaving V(V) in the raffinate. The extraction percentage of Re(VII) was much higher than that of Mo(VI) in 1 M HCl, while that of the two metals was similar at 2 M HCl solution. Since there was not much difference in the stripping percentage of Re(VII) and Mo(VI) from the loaded TBP using HCl, NaOH, and NH4OH solutions, it was difficult to separate the two metals by stripping. Our results indicated that it is possible to separate the three metals by solvent extraction with TBP from 1 M HCl solution.

Solvent Extraction of Tungsten(VI) from Moderate Hydrochloric Acid Solutions with LIX 63

Hoai Thanh Truong,김용환,이만승 대한금속·재료학회 2017 대한금속·재료학회지 Vol.55 No.6

The solvent extraction of tungsten(VI) from hydrochloric acid solutions using 5,8-diethyl- 7-hydroxydodecan-6-one oxime (LIX 63) was analyzed in solutions having an initial pH range from 2 to 5, by varying the concentration of metal and extractant. In our experimental range, the cationic exchange reaction as well as the solvation reaction occurred simultaneously. The cation exchange reaction was identified by applying a slope analysis method to the extraction data. The existence of cationic tungsten(VI) species was confirmed by ion exchange experiments with Diphonix resin at pH 3. Further study is needed to identify the nature of this tungsten cationic species.

EDTA Linker for S-scheme CdS/Spinel Oxides Heterojunction Photocatalyst for Visible-Light-Driven Hydrogen Production

VUONG HOAI THANH,MAHVELATISHAMSABADI TAHEREH,DANG THANH TRUONG,허승현,정진석 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.1

Herein, the fabrication of S-scheme CdS/ZMO photocatalysts through EDTA bridges for hydrogen production was reported. In this system, the role of EDTA molecules as a linker for binding CdS and ZMO (ZnMn 2 O 4 /Mn 3 O 4 spinel oxides composite) was investigated in detail. The optimized sample showed superior photocatalytic hydrogen evolution rate of 26.34 mmol. g −1 .h −1 , nearly two times higher than the system without EDTA. The outstanding photocatalytic activity could be due to the effi cient charge transfers caused by the interaction between EDTA molecules and two semiconductors. This study provides a clear insight into the critical role of inexpensive organic electron mediators in enhancing the photocatalytic performance of heterojunction photocatalysts.

Photocatalytic Degradation and Adsorptive Removal of Tetracycline on Amine-Functionalized Graphene Oxide/ZnO Nanocomposites

정진석,Thanh Truong Dang,Hoai-Thanh Vuong,강성구 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.4

Due to the rapid development of the livestock industry, particularly due to residual pharmaceutical antibiotics, environmental populations have been negatively affected. Herein, we report a ZnO/melamine-functionalized carboxylic-rich graphene oxide (ZFG) photocatalyst for visible light-driven photocatalytic degradation of tetracycline hydrochloride in aqueous solutions. The properties of the photocatalysts were evaluated by XRD, FTIR, XPS, Fe-SEM, HR-TEM, TGA, Raman spectroscopy, UV-Vis spectroscopy, zeta potential, and electrochemical measurements. The photocatalytic activity was measured using high-performance liquid chromatography. The photocatalytic properties of the ZFG photocatalyst evaluated against the tetracycline hydrochloride (TCH) antibiotic under visible light irradiation showed superior photodegradation of 96.27% within 60 min at an initial pH of 11. The enhancement of photocatalytic degradation was due to the introduction of functionalized graphene, which increases the light-harvesting capability and molecular adsorption capability in addition to minimizing the recombination rate of photogenerated charge carriers due to its role as an electron acceptor and mediator.

Determinants of Operational Self-Sustainability of Microfinance Institutions in Vietnam

LE, Thanh Tam,DAO, Lan Phuong,DO, Ngoc Mai,TRUONG, Thi Hoai Linh,NGUYEN, Thi Thuy Duong,TRAN, Chung Thuy Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

The purpose of this paper is to investigate the determinants of the Operational Self-Sustainability (OSS) of Vietnamese microfinance institutions (MFIs). This research uses both qualitative and quantitative research methods: (i) qualitative research was via in-depth interviews with ten microfinance practitioners, policymakers and researchers; (ii) quantitative research was conducted by using panel data of 34 MFIs in the period 2011-2015 with binary logistics and OLS regressions. Results are as follows: (i) MFIs' OSS in Vietnam are mainly determined by five key factors: portfolio at risk (PAR>30), capital structure, gross loan portfolio, scope of activities and legal form; (ii) OSS are most affected by legal status (social organizations have better OSS than formal MFIs or programs/projects), location (MFIs focus in one province have higher OSS than working nationwide or just in one district), capital structure (MFIs with more equity proportion have higher OSS); (iii) surprisingly, average loan size per borrower and age of MFIs do not have statistically significant correlation with OSS. The key recommendations are: (i) MFIs should focus on its professionality and increase its equity; (ii) related stakeholders such as State Bank of Vietnam should promote the enabling ecosystem for microfinance development to enhance poverty reduction and economic development.

Separation of Rhenium (VII) and Vanadium (V) from Hydrochloric Acid Solutions by Solvent Extraction

Thi Hong Nguyen,Hoai Thanh Truong,Man Seung Lee 대한금속ㆍ재료학회 2017 대한금속·재료학회지 Vol.55 No.10

The separation of Re(VII) and V(V) by solvent extraction with TBP was investigated by varying the HCl, metal and chloride ion concentrations. Re(VII) was selectively extracted over V(V) from the HCl solution. The highest separation between Re(VII) and V(V) occurred at a concentration of 2.0 M HCl. The extraction reaction of Re(VII) by TBP was verified using the slope analysis method. Changing the concentration ratio of the two metals and the chloride ion concentration had little effect on the extraction of V(V). Re(VII) could be completely stripped from the loaded TBP when the pH of the stripping solution was higher than 3.0. The obtained results can be utilized to develop a process for separating Re(VII) and V(V) from HCl solutions. (Received February 1, 2017; Accepted July 2, 2017)

One-Pot Preparation of Antibacterial Electrospun Polycaprolactone Membrane Embedded with Gamma Irradiation-Induced Silver Nanoparticles

Chien Minh Tran,Ngoc Thi‑Thanh Nguyen,Minh Hieu Ho,Vinh Khanh Doan,Khanh Loan Ly,Nhi Ngoc‑Thao Dang,Nam Minh‑Phuong Tran,Hoai Thi‑Thu Nguyen,Long Phuoc Truong,Thai Minh Do,Quyen Ngoc Tran,Hien Quoc Ng 한국섬유공학회 2023 Fibers and polymers Vol.24 No.1

In this study, we proposed a straightforward electrospun polycaprolactone (PCL) loaded with silver nanoparticles (SNPs)membrane fabrication process, in which SNPs were directly synthesized from silver nitrate (AgNO3) in PCL–acetone mixtureby gamma irradiation. The insolubility of AgNO3in PCL solution was solved using an auxiliary dimethyl sulfoxide solvent. As a physical approach, gamma rays readily converted silver ions into SNPs without the addition of harmful reductionagents, which reduced the cytotoxicity of the synthesized material. By avoiding some processes such as purification, solventremoval, or redispersion of SNPs, this method was more time-saving compared to other related studies. SNPs formation wasconfirmed by both UV–Visible spectrum (UV–Vis) and X-ray diffraction analysis. Scanning electron microscopy (SEM)revealed that the addition of SNPs significantly reduced the fiber diameter of PCL–Ag membranes compared to that of rawPCL. Uniform spherical-shaped SNPs incorporated in PCL fibers were observed under transmission electron microscopy(TEM). The tensile test showed that the electrospun PCL–Ag membranes exhibited good mechanical characteristics. Moistureeasily penetrated the porous microstructure of PCL–Ag, facilitating wound humidity regulation. Inductively coupledplasma-mass spectroscopy (ICP-MS) was employed to study the release profiles of SNPs at different time intervals. Overall,the PCL–Ag 500 ppm sample exerted excellent antibacterial activity against Pseudomonas aeruginosa and Staphylococcusaureus strains and low in vitro cytotoxicity.

Modeling and Energy Management Strategy in Energetic Macroscopic Representation for a Fuel Cell Hybrid Electric Vehicle

TOXUAN DINH,Le Khac Thuy,Nguyen Thanh Tien,Tri Dung Dang,Cong Minh Ho,Hoai Vu Anh Truong,Hoang Vu Dao,Tri Cuong Do,안경관 사단법인 유공압건설기계학회 2019 드라이브·컨트롤 Vol.16 No.2

Fuel cell hybrid electric vehicle is an attractive solution to reduce pollutants, such as noise and carbon dioxide emission. This study presents an approach for energy management and control algorithm based on energetic macroscopic representation for a fuel cell hybrid electric vehicle that is powered by proton exchange membrane fuel cell, battery and supercapacitor. First, the detailed model of the fuel cell hybrid electric vehicle, including fuel cell, battery, supercapacitor, DC-DC converters and powertrain system, are built on the energetic macroscopic representation. Next, the power management strategy was applied to manage the energy among the three power sources. Moreover, the control scheme that was based on back-stepping sliding mode control and inversed-model control techniques were deduced. Simulation tests that used a worldwide harmonized light vehicle test procedure standard driving cycle showed the effectiveness of the proposed control method.

Determinants Influencing Tax Compliance: The Case of Vietnam

NGUYEN, Thi Thuy Du'o'ng,PHAM, Thi My Linh,LE, Thanh Tam,TRUONG, Thi Hoai Linh,TRAN, Manh Dung Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.2

The purpose of this paper is to ascertain the key factors affecting tax compliance among Vietnamese firms in Vietnam. We employ both qualitative and quantitative research methods. Qualitative research has been carried out through focus group discussions with ten chief accountants and tax officers. Quantitative research has been conducted through interviews with 200 firms (chief accountants or financial directors) in Vietnam. Analysis of the model includes the following stages: (i) Cronbach's test for reliability of the scale, (ii) exploratory factor analysis (EFA), (iii) confirmatory factor analysis (CFA), and (iv) structural equation model (SEM). The results of the research show that voluntary tax compliance is directly affected by the three factors of audit probability, corporate reputation and business ownership. The probability of audit and severity of sanctions have the strongest impact on tax compliance. Therefore, the tax authorities need to strengthen the inspection of tax declarations, tax payments and tax refunds of firms. The paper confirms that enforced tax compliance is directly affected by the three factors of audit probability, sanction severity and social norms. Voluntary compliance and compulsory compliance have an effect on tax compliance, though voluntary compliance has a more powerful impact.