Quasi-isothermal (Q-TG), cryoporometric (DSC) and adsorption characterization of activated carbons

Abstract

In the presented paper, the structural and energetic heterogeneities of the activated carbons (ACs) surfaces were investigated. The ACs of well-developed microporosity were obtained from the spent coffee grounds as a result of pyrolysis (N2 or CO2) with the chemical activation of H3PO4 (I = 1, 1.5 or 2 w/w). The low-temperature N2 adsorption, the quasi-isothermal thermogravimetry as well as the low-temperature differential scanning calorimetry were employed. Moreover, the selected materials adsorption properties were studied in relation to methylene blue (MB). The micro/mesoporous structure of the carbons was proved. The different types of water clusters on the surface indicated the carbons surface heterogeneity. The activated carbons are characterized by the high sorption capacity (qe,exp = 200.3–237.67 mg g−1) as for MB. The adsorption process was described by means of the Radke–Prausnitz isotherm model. Graphical abstract: [Figure not available: see fulltext.]