Sawdust pellets from coniferous species as adsorbents for NO2 removal

Carbonaceous adsorbents based on sawdust pellets from coniferous tree species were obtained by carbonisation at different temperatures and different periods of time. The effect of NO2 adsorption in dry and wet condition on the sorption ability of the chars obtained was tested. The results have shown that NO2 sorption properties of chars depend on the conditions of pyrolysis and the conditions of adsorption. The best NO2 sorption capacity of 18.3 and 43.1 mg/g in dry and wet conditions, respectively, was noted for the char sample pyrolysed at 800 °C for 60 min. The FTIR spectra of the exhausted samples reveal a great increase in the intensity of the band at ∼1380 cm−1 assigned to the vibrations of –NO2, –ONO2 or NO 3 - , while in the DTG curves a new peak appears in the range 200–400 °C assigned to the release of nitrogen compounds of low stability in high temperatures.