Preparation and characterization of activated carbons obtained from the waste materials impregnated with phosphoric acid(V)

Abstract

In the paper spent coffee grounds were used as a precursor to obtain activated carbons. The raw material was impregnated with phosphoric acid(V) at the different impregnations ratios: 0.5, 1, 1.5, 2. Carbonization was carried out according to two procedures differing in activation atmosphere (N2 or CO2). The obtained activated carbons were characterized on the basis of low-temperature nitrogen adsorption/desorption, thermal analysis, potentiometric titration method, X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Carbons obtained according to procedure 2 (activation in CO2) were characterized by better developed porosity, e.g. surface (SBET to 720.9 m2/g) and pore volume (Vp to 0.334 cm3/g). All obtained carbons had surface acidic (mainly carboxyl) groups and exhibited the amorphous structure. The thermal analysis showed that the obtained materials were thermally stable up to the temperature ~ 420 °C.