Carbon molecular sieve-like activated carbon production and applications using carbon dioxide from different biomass

The aim of this study is to synthesize activated carbon having carbon molecular sieve from the three different biomass by physical activation method, and to investigate the adsorption properties of these activated carbons. The biomasses used in this study were walnut shell, pistachio shell and peach seed shell and were used without any pretreatment. Biomasses were first carbonized at a temperature range of 300-1000 oC (in 100oC increments) with a nitrogen gas flow rate of 100, 300 and 500 ml / min and a heating rate of 10oC / min. The sample was kept at maximum temperature for 1 h in all experiments. In solid (char), liquid and gas yields were calculated the carbonization process, As the temperature increases, the solid yield decreases while the liquid and especially the gas yield increases in the evaluation. Carbonized samples were taken directly (without processing, grinding, etc.) at a temperature of 800 and 900 °C using carbon dioxide (100 ml / min) physical activation process. The heating rate in the activation was fixed at 10 °C / min and activated at maximum temperature for 1 hour. In both the carbonization and activation process, the samples removed from the furnace were used in the experiments by cooling to room temperature. Consistent surface area values could not be obtained due to the lack of usable pore during the carbonization process. In carbonization, small units in the structure are separated from the structure as a gas and / or liquid product and partial structure is regulated. The purpose of carbonization is the use of liquid and gas products obtained as a result of the process, primarily as fuel and for industrial purposes. As a result of physical activation, the highest surface area was obtained from pistachio shell. This surface area was carried out at 600 oC, 100 ml / min N2 carbonization and 100 ml / min CO2 activation at 800 °C of pistachio shell. The surface area of this activated carbon was measured as 857.13 m2 / g. The highest area of the peach seed shell was determined at 500 °C 100 ml / min N2 carbonization, 800 ° C 100 ml / min CO2. The surface area of this activated carbon was found to be 686.74 m2 / g. The highest surface area of the walnut shell was at 800 °C, 100 ml / min N2 carbonization and 900 °C 100 ml / min CO2 activation. The surface area of this activated carbon is 720.41 m2 / g. Adsorption capacities of synthesized activated carbons were calculated using methylene blue. In addition, kinetic studies were performed at 3 different temperatures for samples with AFK8 and CK11 samples and their adsorption kinetics were examined. As a result of these kinetic studies, it was observed that the adsorption was consistent with the pseudo 2nd order kinetic equation and calculations were made. In addition, particle diffusion graphs of these samples were drawn and boundary layer thickness was calculated. The microstructure and morphologies of the synthesized samples were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR). The surface areas of the activated carbons were calculated by Bruneur - Emmet - Teller (BET) method. Density functional theory Plus (DFT Plus) pore distributions were observed.