Kinetic, thermodynamic and physical-chemical study of the removal of copper from cachaça using coconut fibers

Abstract

The use of coconut fiber as a copper adsorbent in cachaça was optimised, and changes in the chemical quality of the beverage were observed by analytical techniques. The influence of the adsorbent mass and copper concentration parameters was investigated using the Central Composite Design, and the optimum condition was obtained through the use of Response Surface Methodology. The equilibrium of the adsorption reaction was obtained within 120 min. The kinetic data were better adjusted for the Elovich model (Elovich and Zhabrova 1939) and the isotherm data for the Sips model (Sips 1948). The maximum adsorption capacity was 1.38 mg g⁻¹. Slight changes in the physicochemical quality of the beverage were observed, including a decrease in volatile acidity and alcohol content. Copper levels in cachaça decreased from 8.57 mg L⁻¹ to 4.97 mg L⁻¹ after adsorption. Therefore, the use of biomass as a metal ion adsorbent in beverages can be successfully employed.

Keywords:

• Cachaça
• biomass
• adsorption
• copper

Acknowledgement

The authors thank the Central of Analysis and Chemical Prospecting of the Federal University of Lavras for supplying the equipment for chromatographic analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The present work was financially supported by the Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) projects [CAGAPQ 02424/16] and FAPEMIG [CAGAPQ02390/18], the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [309733/2017-0] and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance code 001 for the scholarships and financial support.