Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2019-09, Vol.9 (10), p.1372
• Main Authors: Alcaraz, Lorena, Escudero, María Esther, Alguacil, Francisco José, Llorente, Irene, Urbieta, Ana, Fernández, Paloma, López, Félix Antonio
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorption; Aqueous solutions; Coffee; Dysprosium; Electric vehicles; Experiments; Pore size; Pores; Potassium hydroxide; Potassium hydroxides; Raw materials; Scanning electron microscopy; spent coffee ground; Surface chemistry; Water vapor
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano9101372

This paper describes the physicochemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. Potassium hydroxide (KOH)-activated carbon is a microporous material with a specific Brunauer–Emmett–Teller (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, but it does not significantly depend 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 a fit to the Langmuir model and pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous, and favorable process.