Příprava uhlíkatých materiálů mikrovlnou pyrolýzou odpadních živočišných kostí pro snižování koncentrace xylenu z odpadních plynů

Abstract

This thesis deals with the preparation of carbon-based materials (biochar) by microwave pyrolysis of waste animal bones (fresh beef and boiled beef, poultry, pork and chicken bones) which can be used as suitable precursors for sorbents used to remove volatile organic compounds from flue gases. The theoretical part of the thesis describes the current technology of processing waste animal bones, the principles of pyrolysis and also contains theoretical research of the issue. The practical part of the work is divided into several parts. In the first part, the raw materials of waste animal bones were characterized. The next part describes the preparation of biochar by microwave pyrolysis at a set microwave reactor power of 200, 400 and 600 W and the optimization of process conditions based on the evaluation of textural and structural properties of biochar. Based on the best textural properties, biochar from boiled beef bones was selected and their sorption capacity of xylene from air was measured and evaluated. The results show that the largest amount of biochar was obtained by pyrolysis of boiled beef bones at 200 W (62 wt.%). The best textural properties were shown by biochar prepared again from boiled beef bones, but at a power of 400 W (SBET: 153 m2.g-1 and Vnet: 331 mm3liq.g-1). The power of 200 W is insufficient, and the prepared biochar have a high content of volatile combustibles (4,5–7,7 wt.%) and also is inhomogeneous. IR spectra confirm the presence if hydroxyapatite and CO3-2 groups. Presence of -CH3 and -CH2 groups in VKV-C and KKV-C confirm imperfect pyrolysis, which correlates with the mass balance of pyrolysis and proximal analysis. The evaluated sorption capacity of xylene was in the range of 4,02–5,27 mlxylene.g-1 (17,72–23,05 mgxylene.g-1), when xylene bound to biochar was both physically and chemically.