Preparation and Characterization of Physicochemical Properties of Spruce Cone Biochars Activated by CO(2)

In this study the pyrolysis of Norway spruce cones, a lignocellulosic biomass was made. The biochar product was obtained by means of the physical activation method. CO(2) was used as the activating gas. The surface properties of biochars were characterized by the nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM/EDS), X-ray fluorescence energy dispersion spectroscopy (ED-XRF), thermal analysis (TGA/DTA), infrared spectroscopy (ATR FT-IR), Raman spectroscopy and the Boehm’s titration method as well as the point of zero charge (pH(pzc)). The adsorption capacity and the possibility of ammonia desorption (TPD) were also examined. It has been shown that spruce cones can be successfully used as a cheap precursor of well-developed surface biochars, characterized by a large pore volume and good sorption properties. All obtained activated biochars exhibit a largely microporous structure and an acidic character surface. The investigated activated materials have the specific surface areas from 112 to 1181 m(2) g(−1). The maximum NH(3) adsorption capacity of the activated biochar was determined to be 5.18 mg g(−1) (88.22 mmol g(−1)) at 0 °C. These results indicate the applicability of spruce cones as a cheap precursor for the sustainable production of the cost-effective and environmentally friendly biochar adsorbent.