One of the main tasks of modern nanochemistry is the controlled synthesis of metal nanoparticles (MNPs) and in particular of silver (AgNPs). AgNPs have wide applicability in catalysis, electronics, sensors and biomedicine, which makes interest in this material. In the last decade, the "green" method of synthesizing nanoparticles of metals, which is includes minimizing of the use of toxic substances as reducing agents and based on the chemical reduction of Argentum ions and the stabilization of AgNPs by organic, non-toxic substances. Therefore, as an alternative, the electrochemical method of synthesis AgNPs is promising, where the value of the electrode potential or current density is an effective factor in influencing the geometry of nanoparticles and their size distribution.
The anode behavior of silver in solutions of surfactant is practically not investigated. Therefore, the proposed work is devoted to the study of the dependence of the rate of anodic dissolution of silver in solutions of bio-surfactant-rhamnolipid (RL) from parameters: concentration of RL, pH of medium and temperature, which will be the basis for controlled electrochemical synthesis.
Taking into account the properties of ramnolipid molecules, investigated processes can be represented by the following basic electrochemical and chemical stages: the formation of Ag+ads ions, adsorption by the stabilizer of formed ions [AgRL]+ads, the formation of the AgOHads complex with a predominant number of OHˉ ions, the formation of ramnolipid complex [AgRL]+solution. It was been established that the proposed processes primarily depend on the above parameters.
The results of the anodic dissolution process of silver in aqueous solution of rhamnolipid are presented. It is shown that for increasing the parameters: C = 0,5-2,0 g/l, pH = 7-11, t = 20-50 oC, - high densities of anode currents are provided, that is, the rate of anodic dissolution corresponds to the technological speed of synthesis Ramnolipid Complex to Argentina. The value of the activation energy, which indicates the diffusion components of the anode currents and the increase in the values of the temperature coefficient, indicates the presence of both diffusion and absorption factors of the anode currents.
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