Portal de Periódicos da CAPES

Alkaline modified oil shale fly ash: Optimal synthesis conditions and preliminary tests on CO2 adsorption

2011; Elsevier BV; Volume: 196; Linguagem: Inglês

10.1016/j.jhazmat.2011.09.006

1873-3336

Janek Reinik, Ivo Heinmaa, Uuve Kirso, T Kallaste, Johannes Ritamäki, Dan Boström, Éva Pongrácz, Mika Huuhtanen, William Larsson, Riitta L. Keiski, Krisztián Kordás, Jyri‐Pekka Mikkola,

Concrete and Cement Materials Research

Environmentally friendly product, calcium–silica–aluminum hydrate, was synthesized from oil shale fly ash, which is rendered so far partly as an industrial waste. Reaction conditions were: temperature 130 and 160 °C, NaOH concentrations 1, 3, 5 and 8 M and synthesis time 24 h. Optimal conditions were found to be 5 M at 130 °C at given parameter range. Original and activated ash samples were characterized by XRD, XRF, SEM, EFTEM, 29Si MAS-NMR, BET and TGA. Semi-quantitative XRD and MAS-NMR showed that mainly tobermorites and katoite are formed during alkaline hydrothermal treatment. Physical adsorption of CO2 on the surface of the original and activated ash samples was measured with thermo-gravimetric analysis. TGA showed that the physical adsorption of CO2 on the oil shale fly ash sample increases from 0.06 to 3–4 mass% after alkaline hydrothermal activation with NaOH. The activated product has a potential to be used in industrial processes for physical adsorption of CO2 emissions.