Application of electrochemical impedance spectroscopy: A phase behavior study of babassu biodiesel-based microemulsions.
Microemulsions are thermodynamically stable systems of two immiscible liquids, one aqueous and the other of organic nature, with a surfactant and/or co-surfactant adsorbed in the interface between the two phases. Biodiesel-based microemulsions, consisting of alkyl esters of fatty acids, open a new means of analysis for the application of electroanalytical techniques, and is advantageous as it eliminates the required pre-treatment of a sample. In this work, the phase behaviours of biodiesel-based microemulsions were investigated through the electrochemical impedance spectroscopy (EIS) technique. We observed thatan increase in the amount of biodiesel in the microemulsion formulation increases the resistance to charge transfer at the interface. Also, the electrical conductivity measurements revealed that a decrease or increase in electrical properties depends on the amount of biodiesel. EIS studies of the biodiesel-based microemulsion samples showed the presence of two capacitive arcs: one high-frequency and the other low-frequency. Thus, the formulation of microemulsions plays an important role in estimating the electrical properties through the electrochemical impedance spectroscopy technique.
Laboratório de Pesquisa em Química Analítica, Universidade Federal do Maranhão, 65085-580 São Luís, Maranhão, Brazil.
Thulio C
TC
Pereira
Laboratório de Pesquisa em Química Analítica, Universidade Federal do Maranhão, 65085-580 São Luís, Maranhão, Brazil.
Carlos A F
CAF
Conceição
Departamento de Química e Biologia, Universidade Estadual do Maranhão, 65055-970 São Luís, Maranhão, Brazil.
Alamgir
A
Khan
Departamento de Química e Biologia, Universidade Estadual do Maranhão, 65055-970 São Luís, Maranhão, Brazil.
Raquel M T
RMT
Fernandes
Coordenação de Ciência e Tecnologia, Universidade Federal do Maranhão, 65085-580 São Luís, Maranhão, Brazil. Electronic address: maira.ferreira@ufma.br.
Maira S
MS
Ferreira
Laboratório de Pesquisa em Química Analítica, Universidade Federal do Maranhão, 65085-580 São Luís, Maranhão, Brazil.
Edmar P
EP
Marques
Laboratório de Pesquisa em Química Analítica, Universidade Federal do Maranhão, 65085-580 São Luís, Maranhão, Brazil.
Aldaléa L B
ALB
Marques
D028023:Arecaceae / Q000737:chemistry*; D056804:Biofuels / Q000032:analysis*; D058266:Dielectric Spectroscopy / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D004655:Emulsions / Q000032:analysis*; D004867:Equipment Design; D044367:Phase Transition
D056804:Biofuels; D004655:Emulsions
Biodiesel; Electroanalytical; Electrochemical impedance spectroscopy; Microemulsions; Nyquist diagram