Sinteza in karakterizacija biooglja pridobljenega iz različnih vrst odpadne biomase s subkritično vodo

magistrsko delo študijskega programa II. stopnje

Darja Predikaka (Avtor), Mojca Škerget (Mentor), Željko Knez (Komentor)

Povzetek

Namen magistrske naloge je sintetizirati in karakterizirati biooglje, ki smo ga dobili iz odpadne biomase s pomočjo subkritične vode. Sinteza biooglja je potekala v subkritični vodi z različnimi odpadnimi materiali in z dvema različnima plinoma za vzpostavitev atmosfere v reaktorju, N2 in CO2. Temperature sinteze pri tem nismo spreminjali in je vedno znašala 225 °C. Da bi ugotovili vpliv sušenja na lastnosti biooglja, smo uporabljali klasični termični postopek sušenja in metodo s superkritičnim CO2. Določili smo izkoristek sinteze biooglja različnih materialov in dobljenim vzorcem določili zeta potencial, z adsorpcijo dušika smo izmerili specifično površino, volumen in povprečni premer por. Vsem vzorcem smo posneli tudi FTIR spekter. Vse rezultate smo primerjali tudi z lastnostmi komercialno dosegljivega aktivnega oglja. Rezultati kažejo na najvišje izkoristke biooglja, ko smo za začetni material izbrali zmleto in z vodo predhodno ekstrahirano macesnovo skorjo. Pri teh pogojih smo dosegli 68,3 % izkoristek biooglja, ko smo uporabili dušik kot plin za vzpostavitev tlaka v sistemu, medtem ko smo pri vzorcu, ki je bil sintetiziran pri istih pogojih, a se je pri tem uporabil CO2, dobil produkt bolj enakomernejše oblike. Izkoristek biooglja pri uporabi CO2 kot plina za vzpostavitev tlaka v reaktorju je bil nekoliko nižji, in sicer 66,5 %. Rezultati merjenja zeta potenciala kažejo na to, da ima najnižji zeta potencial biooglje dobljeno iz mlete in v vodi predhodno ekstrahirane macesnove skorje, pri tlaku 215 bar, pri podaljšanem reakcijskem času tj. 6 h. Zeta potencial tega produkta znaša -34,33 mV. Največjo specifično površino vzorca smo dosegli pri biooglju macesnove skorje, ki je bil sušen s postopkom superkritičnega sušenja. Pri teh pogojih smo dobili specifično površino vzorca, ki je znašala 225,82 m2/g. Specifična površina aktivnega oglja je znašala 886,53 m2/g. FTIR spektri kažejo, da so si vzorci po sestavi med seboj zelo podobni in da je vpliv različnih plinov na površinske funkcionalne skupine majhen. Razlika se kaže le v prisotnosti O-H vezi, kar kaže na različno pripravo vzorcev.

Ključne besede

biooglje;subkritična voda;biomasa;hidrotermična karbonizacija;BET;zeta potencial;ATR-FTIR;magistrske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2016
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[D. Predikaka]
UDK:	661.183.2.091.3(043.2)
COBISS:	20303894
Št. ogledov:	1224
Št. prenosov:	135
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Synthesis and characterization of biochar produced from different types of waste biomass with subcritical water
Sekundarni povzetek:	The purpose of the master's thesis is to synthesize and characterize biochar, which was obtained from waste biomass using subcritical water. The synthesis of biochar was conducted insubcritical water with a variety of materials, using two different gases, namely N2 and CO2. The temperature of synthesis was not changed and was always set to 225 °C. In order to determine the influence of drying on the properties of biochar, the classical thermal air-drying method and the method with supercritical CO2 were used. The yield of biochar of different biowaste materials was determined and for the obtained products the zeta potential was measured. Furthermore, the specific surface area, average pore volume and diameter was determined using the nitrogen adsorption method. For all obtained biochar samples the FTIR spectra were measured. All obtained results were compared to the properties of commercially available activated carbon. Results show that the highest biochar yield was obtained for grinded and with water are extracted larch bark. At these conditions a maximal yield of 68.3% was obtained, when nitrogen was used as the gas for maintaining the pressure inside the reactor,. On the other side, the biochar that was synthesized at the same conditions but instead CO2 was used had more evenly distributed particle size. At these conditions, 66.5 % of the starting material could be converted into biochar. Results from the measurement of the zeta potential have shown that the lowest zeta potential was obtained for the larch bark biochar that was before the synthesis grinded and extracted, and afterwards treated in subcritical water at 215 bars and at a reaction time of 6 hours. The zeta potential of this product was -34.33 mV. The highest specific area of a sample was obtained for larch bark, which was dried using the supercritical drying method. At these conditions a specific area of 225.82 m2/g could be obtained. The specific area of activated carbon was 886.53 m2/g. The FTIR spectra have shown that the obtained samples are similar to each other. There are no significant differences in the surface funcional groups between the samples when different gases are used. The difference is only in of O-H bonds, which indicates the difference in preparation of the samples.
Sekundarne ključne besede:	biochar;subcritical water;biomass;hydrothermal carbonization;zeta potential;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Magistrsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	X, 70 str.
ID:	9149087