13 research outputs found
Kinetic studies of the removal of Pt(IV) chloride complex ions from acidic aqueous solutions using activated carbon
The Influence of Steric Stabilization on Process of Au, Pt Nanoparticles Formation
Nanoparticles are very fascinating area of science not only due to their unique properties but also possibility of producing new
more complex materials, which may find an application in modern chemistry, engineering and medicine. In process of nanoparticles
formation very important aspect is a rate of individual stage i.e. reduction, nucleation and autocatalytic growth, because this
knowledge allows for proper materials design, morphology manipulation, stability. The last one aspect can be realized using proper
electrostatic, steric and electrosteric stabilization. However until now nobody reports and measures kinetic rates of all stages during
process of particles formation in the presence of steric stabilizers. Thus, the main contribution of this paper is determination of
individual rate constants for nanoparticles formation in the presence of steric stabilizers and their comparison to the system without
stabilizer. For this purpose, an aqueous solution of Au(III) and Pt(IV) ions were mixed with steric stabilizers like PVA and PVP,
and reduced using L-ascorbic acid as a mild and sodium borohydride as a strong reductant. As a results stable nanoparticles were
formed and process of their formation was registered spectrophotometrically. From obtained kinetic curves the values of observed
rate constants for reduction metal ions, slow nucleation and fast autocatalytic growth were determined using Watzky-Finke model.
It was found that the addition of polymer affects the rate of the individual stages. The addition of steric stabilizers to gold ions
reduced with L-ascorbic acid causes that the process of nucleation and autocatalytic growth slows down and the value of observed
rate constants for nucleation changes from 3.79路10-3 (without polymer) to 7.15路10-5 s-1 (with PVA) and for growth changes from
1.15路103 (without polymer) to 0.48路102 s-1 M-1 (with PVA). However, the rate of the reduction reaction of Au(III) ions is practically
unchanged. In case of using strong reductant the addition of polymer effects on the shape of kinetic curve for reduction of Au(III)
and it suggests that mechanism is changed. In case of Pt(IV) ions reduction with L-ascorbic acid, the process speeds up a little
when PVA was added. Determined values of observed rate constants for nucleation and growth platinum nanoparticles decrease
twice comparing to the system without polymer. The reduction of Pt(IV) ions with sodium borohydride accelerates when PVP was
added and slows down when PVA was used. Moreover, the size of obtained colloidal gold and platinum was also analysed using
DLS method. Obtained results (rate constants) may be useful in the process of nanomaterials synthesis, in particular in microflow
The Synthesis of Stable Platinum Nanoparticles in the Microreactor
W pracy, przedstawiono syntez臋 sferycznych klastr贸w zawieraj膮cych 3-4 nm nanocz膮stki platyny zamkni臋te w polimerowej otoczce. Proces formowania nanocz膮stek platyny zosta艂 zintensyfikowany poprzez u偶ycie mikroreaktora. U偶ycie mikroreaktora skr贸ci艂o czas reakcji redukcji oraz etapu zarodkowania do 6 s w temperaturze 105掳C w por贸wnaniu do procesu przeprowadzonego w reaktorze okresowym w temperaturze 40掳C. U偶ycie witaminy C jako bioreduktora chlorkowych kompleks贸w platyny(lV) oraz biokompatybilnego polimeru pozwala na uzyskanie nietoksycznych oraz stabilnych przez co najmniej 9 miesi臋cy produkt贸w. Przedstawiona metoda syntezy nanocz膮stek mo偶e stanowi膰 alternatywny spos贸b odzysku platyny z roztwor贸w zawieraj膮cych jej chlorkowy kompleks
Synteza stabilnych nanocz膮stek platyny w mikrokreatorze
In this work, the synthesis of the spherical clusters containing 3-4 nm platinum nanoparticles enclosed in a polymer capsule is described. The process of nanoparticles formation was intensified by using a microreactor. The application of microreactor enabled us to shorten the time of redox reaction and nucleation stage up to 6 seconds at 105掳C in comparison with the process carried out in a batch reactor at 40掳C. Using Vitamin C as a bio-reducer of platinum(IV) complexes and biocompatible polymers, the products non-toxic and environmentally friendly, stable for at least 9 months, were obtained. Presented procedure for nanoparticles synthesis seems to be an alternative method for platinum recovery from solutions containing platinum(IV) chloride complexions.W pracy, przedstawiono syntez臋 sferycznych klastr贸w zawieraj膮cych 3-4 nm nanocz膮stki platyny zamkni臋te w polimerowej otoczce. Proces formowania nanocz膮stek platyny zosta艂 zintensyfikowany poprzez u偶ycie mikroreaktora. U偶ycie mikroreaktora skr贸ci艂o czas reakcji redukcji oraz etapu zarodkowania do 6 s w temperaturze 105掳C w por贸wnaniu do procesu przeprowadzonego w reaktorze okresowym w temperaturze 40掳C. U偶ycie witaminy C jako bioreduktora chlorkowych kompleks贸w platyny(lV) oraz biokompatybilnego polimeru pozwala na uzyskanie nietoksycznych oraz stabilnych przez co najmniej 9 miesi臋cy produkt贸w. Przedstawiona metoda syntezy nanocz膮stek mo偶e stanowi膰 alternatywny spos贸b odzysku platyny z roztwor贸w zawieraj膮cych jej chlorkowy kompleks
2H and 4H silver colloidal suspension synthesis, as a new potential drug carrier
In this paper diffusion impact on the silver nanoparticles synthesis and their crystal structure is shown. For this purpose, comparative studies between continuous flow two-phase microdroplets systems vs. two-phase batch reactor were performed. Such two-phase configuration of the investigated system makes it possible to study the impact of mass transfer phenomenon on the nanoparticles formation process. In the case of two-phase microdroplets system, diffusion is replaced by convection, accelerated by interphase friction between water droplets and a continuous organic phase. It was concluded that under diffusion control it was possible to obtain silver nanoparticles with a hexagonal crystal structure. Moreover, for the first time using a chemical method, and diffusion rate-limiting step, the hexagonal structure 4H and 2H of Ag nanoparticles were synthesized. We suggest, that such hexagonal crystals can be applied as a smart drug delivery system, where the drug releases can be controlled by short light impulse. In effects, thermodynamically unstable 4H and 2H crystals transform to more dense-packed FCC structure.Marek Wojnicki, Tomasz Tokarski, Volker Hessel, Krzysztof Fitzner, Magdalena Luty-B艂och
Novel and effective synthesis protocol of AgNPs functionalized using L-cysteine as a potential drug carrier
Study of Gold, Copper and Nickel Adsorption, from their Acidic Chloride Solutions, Onto Activated Carbon
In this paper, a simple and effective method for gold recovery is described. The paper describes a way to recover gold onto
activated carbon from a synthetic solution of gold(III) chloride. The method can also be used on nickel(II) as well as copper(II)
chloride of where the metal ion ratios are comparable to the metal ratios found in some electronic waste.
With the use of activated carbon in the process of electrolyte purification it is possible to selectively remove gold in metallic
form from the solution. XPS studies have confirmed that metallic gold is present on the carbon surface. A spectrophotometric method was used to determine the concentration of Au(III) in the solution. Different concentration of nickel(II) as well as copper(II) were investigated. In all cases, adsorption and reduction of Au(III) to the metallic form was observed