Biochar prepared from castor oil cake at different temperatures: A voltammetric study applied for Pb2+, Cd2+ and Cu2+ ions preconcentration

Published Date

15 November 2016, Vol.318:526–532, doi:10.1016/j.jhazmat.2016.07.041

Title 

Biochar prepared from castor oil cake at different temperatures: A voltammetric study applied for Pb²⁺, Cd²⁺ and Cu²⁺ ions preconcentration

• Author 

• Cristiane Kalinke ^a
• Antonio Sálvio Mangrich ^b,c
• Luiz H. Marcolino-Junior ^a
• Márcio F. Bergamini ^a,,,

• aLaboratório de Sensores Eletroquímicos (LabSensE), Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba, PR, Brazil
• bLaboratório de Química de Húmus e Fertilizantes, Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba, PR, Brazil
• cInstituto Nacional de Ciência e Tecnologia de Energia e Ambiente (INCT E&A/CNPq), Brazil

Received 18 May 2016. Revised 24 June 2016. Accepted 18 July 2016. Available online 19 July 2016.

Highlights

• •
  Effect of temperature of pyrolysis in the adsorption properties of biochar.
• •
  Electroanalytical application of biochar obtained from castor cake oil under different temperature pyrolysis.
• •
  Simple and feasible voltammetric procedure for evaluation of adsorption of Pb(II), Cd(II) and Cu(II) ions by biochar.
• •
  Carbon paste electrodes for evaluation of biochar ability in the preconcentration of electroactive cations.

Abstract

Biochar is a carbonaceous material similar produced by pyrolysis of biomass under oxygen-limited conditions. Pyrolysis temperature is an important parameter that can alters biochar characteristics (e.g. surface area, pore size distribution and surface functional groups) and affects it efficacy for adsorption of several probes. In this work, biochar samples have been prepared from castor oil cake using different temperatures of pyrolysis (200–600 °C). For the first time, a voltammetric procedure based on carbon paste modified electrode (CPME) was used to investigate the effect of temperature of pyrolysis on the adsorptive characteristics of biochar for Pb(II), Cd(II) and Cu(II) ions. Besides the electrochemical techniques, several characterizations have been performed to evaluate the physicochemical properties of biochar in function of the increase of the pyrolysis temperature. Results suggest that biochar pyrolized at 400 °C (BC400) showed a better potential for ions adsorption. The CPME modified with BC400 showed better relative current signal with adsorption affinity: Pb(II) > Cd(II) > Cu(II). Kinetic studies revealed that the pseudo-second order model describes more accurately the adsorption process suggesting that the surface reactions control the adsorption rate. Values found for amount adsorbed were 15.94 ± 0.09; 4.29 ± 0.13 and 2.38 ± 0.39 μg g⁻¹ for Pb(II), Cd(II) and Cu(II) ions, respectively.

Graphical abstract

Keywords

• Biochar
• Pyrolysis temperature
• Carbon paste electrode
• Voltammetric techniques

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• DOC (912K)

• ⁎ 
  Corresponding author.

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