Teh-Hua Tsai

Extraction Equilibrium of Indium(III) from Nitric Acid Solutions by Di(2-ethylhexyl)phosphoric Acid Dissolved in Kerosene

The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR3 in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.

Solvent extraction of palladium(II) from acidic chloride solutions using tri-octyl/decyl ammonium chloride (Aliquat 336)

AbstractIn this study, the effect of different operating conditions including on the extraction of palladium (II) from HCl solution by using tri-n-octylmethylammonium chloride (Aliquat 336)/kerosene was evaluated at 25°C. Different stripping reagents such as AlCl3, KCl, NaCl, NH4Cl, HCl, and thiourea were evaluated. The results indicate that the mixture of chloride and thiourea would lead to the highest stripping conversion for palladium (II) (i.e. >99%).The extraction distribution ratios were found to increase with the increase in the extractant concentration and decrease with the concentration of chloride ion. In addition, the compositions of palladium complexes in organic phase and equilibrium constant of recovered extraction reaction were estimated. Furthermore, the recovery efficiency of palladium(II) in acidic chloride solution was performed and compared.

Recovery of palladium(II) from acidic chloride solution using kerosene containing tri-n-octyl/decyl amine (Alamine 336)

Abstract This study employed a tri-n-octyl/decyl amine (Alamine 336) as an extractant dissolved in kerosene to extract palladium(II) from HCI solution at 25°C. The experiments of different stripping reagents such as HCI, NaCl, KCl, BaCl2, AlCl3, and thiourea were compared, respectively; and the optimal status was determined. The results showed that the extraction distribution ratios are proportional to the extractant concentration and disproportional to chloride ion concentration. By graphical analysis, the compositions of palladium complexes in organic phase and equilibrium constant of recovered extraction reaction were examined. Finally, the recovery efficiency of palladium(II) in acidic chloride solution was determined.

Rapid Preparation of WO3 Nanorods Via Microwave-Assisted Solvothermal Synthesis

A simple and efficient method enables to synthesize nanorods WO3 with high quantity by microwave-solvothermal. It has been found that ethanol involves the features of inexpensive and environmentally friendly, which is more suitable to be considered as a solvent. Tungsten oxide is an important transition metal oxide material, which possesses some unique properties such as electrochromic, opochromic, and gaschromic properties. The authors used the microwave assisted solvothermal method, which has the advantages of both microwave and solvothermal methods, to synthesize 1-D tungsten oxide such as nanorods. The synthesis of tungsten oxide nanorods has been investigated under microwave-solvothermal conditions at 240°C, and uses WCl6 and poly(ethylene glycol) (PEG) 20000 as a precursor and dispersant in 20% ethanol. The average diameter of WO3 nanorods were 80–100 nm and 3 μm long. The crystallized products were characterized by X-ray diffraction, thermogravimetric analysis, dynamic light scattering, X-ray fluorescence, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and transmission electron microscopy.

More healthy teas innovatively treated utilizing gold nanoparticles

As observed from the literature, not much effort is made on increasing the content of healthy components of total polyphenols in teas by using post-treatment technologies based on nanoparticles (NPs). In this work, we report a new strategy on the green preparation of Au NPs from bulk Au sheets by employing a thermal reduction method in a solution containing chitosan (Ch) and trisodium citrate. The synthesized Au NPs are innovatively applicable for treating commercial teas at room and elevated temperatures for increasing the contents of their healthy components. Encouragingly, the content of the total polyphenols in the treated teas, including less oxidized oolong tea and fully oxidized black tea, can be significantly increased by ca. 100% and 30%, respectively, compared to corresponding untreated teas. In addition, the ability to scavenge free hydroxyl radicals for oolong tea can be enhanced by ca. 20% after the Au NPs-treatment. These results suggest that this alternative approach based on prepared Au NPs promises the availability of healthier teas.