Multi-component adsorption study by using bone char: modelling and removal mechanisms

ABSTRACT

Highly efficient simultaneous removal of paracetamol and Cu²⁺ ions from aqueous solutions was accomplished by using bovine bone char (BC). The adsorption behaviour was determined by kinetic and equilibrium studies of both single and binary system solutions. BC is a predominantly mesoporous material with a surface area of 103 m² g⁻¹. The influence of the initial pH on Cu²⁺ removal was tested, suggesting that the optimal pH was 3.0. The removal of paracetamol from single and binary systems was 9.45 and 12.7%, respectively. On the other hand, the Cu²⁺ removal was 36.2% for a single system, suggesting a higher affinity for BC. Moreover, in the case of binary mixtures, the presence of paracetamol led to an enhanced affinity of Cu²⁺ due to a synergistic/cooperative mechanism, which led to a copper removal of 97.3%. The cooperative model was successfully adjusted to the equilibrium data of the binary systems. The modelling results indicated the formation of a first adsorption layer where paracetamol and copper are retained, and a second layer with a great affinity for copper ions after the formation of a Cu-paracetamol complex, leading to higher removal of Cu²⁺.

GRAPHICAL ABSTRACT

KEYWORDS:

• Bone char
• paracetamol
• heavy metal
• competitive adsorption
• co-adsorption

Acknowledgements

This study was supported by the National Council for Scientific and Technological Development (CNPq) and the Coordination for the Improvement of Higher Level (CAPES) by the CAPES / Chemical Engineering Department / process 88881.135075 / 2016-01. The authors also acknowledge the LGCPA/UEM. This work was also supported by the Associate Laboratory for Green Chemistry-LAQV which is financed by Portuguese funds from FCT/MCTES (UID/QUI/50006/2019).

Disclosure statement

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

Additional information

Funding

Conselho Nacional de Desenvolvimento Científico e Tecnológico; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Fundação para a Ciência e Tecnologia.