preprints.org > chemistry > applied chemistry > doi: 10.20944/preprints201908.0076.v1

Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Version 1 : Received: 5 August 2019 / Approved: 6 August 2019 / Online: 6 August 2019 (12:23:23 CEST)

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy³⁺) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m²·g^-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N₂ is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m²·g^-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g^-1 and 33.52 mg·g^-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

dysprosium; activated carbon; spent coffee ground; adsorption

CHEMISTRY, Applied Chemistry