Eletro-oxidação de glicerol sobre eletrodos de platina modificados com hidróxido de cobalto

AUTOR(ES)

Edson Archela

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

05/04/2012

RESUMO

The increased production of biodiesel has resulted in the overproduction of glycerol that has generated fear of improper disposal, due to low market value of the product and consequent lack of interest. Glycerol, discovered in 1779 by Scheele, is used industrially in the production of over 1500 products such as toiletries, cosmetics, food, beverages and polymer synthesis. Recently, interest in the glycerol has aroused renewed attention due to its overproduction, as a byproduct of biodiesel production. In order to take advantage of the abundance of this product a stream of research focused on new applications for glycerol was created. In this context, the electrochemical behavior of the film cobalt hydroxide, electro co-precipitated on platinum electrode was studied as a new viewpoint as electrocatalyst and electroanalytical. After optimization of the electrodeposition of film cobalt hydroxide (which showed improved response to the film when electro co-precipitated by chronopotentiometry for 5 min and reading the samples using glycerol and KOH 0.3 mol.L-1 as the support electrolyte). The modified electrode was tested for oxidation glycerol 0.15 mol L-1 on FTIR and the tests at different speeds voltammetric scan for the understanding of reaction mechanisms involved and to determine the in situ oxidation products of glycerol on the modified electrode. The film showed a density of current equal to 0.68 mA.cm-2, and a power density of 0.5 mW.cm-2. Moreover, the formation of glyceric and tartronic acids allows the film to be used for obtaining products of higher value from the oxidation of glycerol. From the electroanalytical s point of view, the optimized film was tested for electro-oxidation of low concentrations of glycerol to construct a calibration curve, which showed under optimal conditions, linearity coefficient equal to 0.9968 and a sensitivity of 1.37 mA mol-1.L with a detection limit equal to 82.77 umol.L-1, comprising the range from 0 to 1.6 mmol.L-1. A good linearity as wide concentration range indicates that this electrode can be used to determine the content of glycerol in real samples. For this, a sample of blonde glycerin was subjected to electrochemical measurement analysis for glycerol content. Results presented very close to that obtained by gas chromatography (1.03 % error).

ASSUNTO(S)

glycerin análise eletroquímica glicerina cobalto - indústria eletrocatálise electrochemical analysis cobalt industry electrocatalysis

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