Известия Томского политехнического университета: Инжиниринг георесурсов (Jun 2020)
VOLTAMMETRIC DETERMINATION OF HYDROGEN PEROXIDE USING SENSORS BASED ON SILVER NANOPARTICLES IN OBJECTS OF TECHNOGENIC AND GEOLOGICAL ORIGIN
Abstract
The research deals with determination of low levels of hydrogen peroxide in objects of technogenic and geological origins. The aim of the work was to develop a sensitive sensor based on silver nanoparticles to detect hydrogen peroxide in water objects. Objects: artesian and rainwater collected in the city and suburbs. Methods: voltammetry, transmission microscopy. Results. The shape, size and amount of silver nanoparticles depend on the nature of the reducing agent. When using two reducing agents of borohydride and sodium citrate, the smallest spherical particles – from 0,5 to 17,5 nm, are obtained. When using sodium citrate, larger silver nanoparticles – from 10 to 55 nm, in various shapes are obtained. They are as follows: rod-shaped, prismatic, triangular with a particle size from 10 to 55 nm. AgNPs-Bg have a rod-like and prismatic shapes 5–65 nm in size, connected in chains, i. e. agglomerated. The mechanism of electrochemical processes of silver nanophase transition on the surface of graphite electrode to 0,1 M NaOH in the presence of various reducing agents is proposed. This mechanism does not depend on the nature of the reducing agent. A feature of electroreduction of silver nanophase obtained in the presence of citrate potassium is the reduction of silver ions from the complex ions [Ag(OH)2]–. The authors have proposed the mechanism of electrochemical transition processes of silver nanophase in the presence of various reducing agents. It was found that the cathode maxima at Ес=0,08 V corresponds to hydrogen peroxide reduction. Using a sensor based on the silver nanoparticles obtained in the presence of sodium citrate the dependence of the current of the maximum on hydrogen peroxide concentration was linear – in the range from 0,1–1 nM, and the detection limit was 0,087 nM. The content of hydrogen peroxide in rain and artesian water was determined. The proposed sesor modified by silver nanoparticles obtained in presence of sodium citrate is simple, rapid, and sensitive. This sensor has a wide range of concentrations for determination of hydrogen peroxide.
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