Adsorption of leather dyes on activated carbon from leather shaving wastes: kinetics, equilibrium and thermodynamics studies

ABSTRACT

In this work, the adsorption of Acid Black 210 (AB210) and Acid Red 357 (AR357) onto activated carbon prepared from leather shaving wastes (ACLW) was investigated. The activated carbon presented a surface area of 800.4 m²/g with an average pore size of 1.27 nm. The kinetic study showed that the adsorption of both dyes followed the Elovich kinetic model while the AB210 and AR357 isotherm data were well described by the Langmuir and BET models, respectively. Furthermore, the Boyd plot revealed that the adsorption of the leather dyes on activated carbon was mainly governed by film diffusion. The pH had a strong influence on the adsorption, and the higher amounts of dye adsorbed were obtained at pH 2. The obtained activated carbon exhibited a high monolayer adsorption capacity of 573.9 and 204.4 mg/g for AB210 and AR357, respectively. Its high capacity is mainly attributed to its basicity (0.17 mmol/g) and high surface area. Desorption efficiency of the spent activated carbon was found to be 54.3% and 43.0% for AB210 and AR357, respectively. The spontaneity of the process was demonstrated by the negative values of the Gibbs free energy change.

KEYWORDS:

• Activated carbon
• leather dyes
• adsorption
• leather wastes and adsorption capacity

Acknowledgement

The authors would like to thank the Indústria de Peles Pampa for providing the leather wastes.

Disclosure statement

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

ORCID

Christian Manera http://orcid.org/0000-0002-3110-5636

Marcelo Godinho http://orcid.org/0000-0001-8630-1995

Additional information

Funding

The authors would like to thank the National Council for Scientific and Technological Development (CNPq) [438829/2016-6]; Higher Education Personnel Improvement Coordination (CAPES) [147439/2017] for financial support.