چكيده به لاتين
In this project, using used cigarette filters with hydrothermal carbonization method, hydrochar absorbent was investigated for the absorption and detection of CO2 gas. Investigating the performance of hydrochar can provide a valuable adsorbent for CO2 gas absorption from biomass and environmental waste. The synthesis of hydrochars for this research and the preliminary absorption tests of all hydrochars were done. Two adsorbents, H-208, which were synthesized at 200°C with water for 8 hours, and HA-204, which were synthesized at 200°C for 4 hours with 1 M HCl, are the two adsorbents that have the highest absorption at and had the same pressure than other absorbers, they were selected for further study. FTIR, XRD and CHNOS analyzes showed that the synthesis of hydrochars was done well. The BET analysis showed the surface area of the adsorbents to be 27.97 and 29.04 m2/g, respectively, and BJH also showed the pore size values of 1.85 and 1.64 nm for H-208 and HA-204, respectively. CHNOS analysis showed that the highest degree of carbonization belonged to H-208 sample and this sample has more polarity than HA-204 sample. The adsorption isotherm for both adsorbents followed the Freundlich model, which indicates a heterogeneous adsorbent surface and CO2 absorption is done in the form of several layers on the adsorbent surface. Kinetic results showed that the energy levels on the absorbent surface are not homogeneous and at high temperature the fractional model is the best model to describe the relationship between absorption capacity and reaction time. CO2 absorption in hydrochars is of physical-chemical absorption type and the values of ∆H° For H-208 and HA-204, it was -20.666 and -18.481 KJ/mol, respectively. The laboratory data in RSM for this research were fit with quadratic model. F-value and p-value of the model were equal to 184.95 and >0.0001, respectively. The highest impact in parameters on CO2 absorption was respectively for pressure, temperature, and the lowest impact was for HCl concentration. The highest values of CO2 absorption for H-208 and HA-204 adsorbents at 25°C and 9 bar pressure were 1028 and 1003 mg/g, respectively. The adsorption of CO2 gas by the synthesized hydrochars was attributed to a combination of physico-chemical adsorption mechanisms. The synthesized hydrochar adsorbents showed the ability to recognize CO2 gas. At a concentration of 10000 ppm of CO2 gas, the response percentage was 9.5%, which means an increase in the resistance of the absorbent against CO2 gas by 9.5% compared to its resistance in air, and at a concentration of 1000 ppm with a response percentage of 2.5%, CO2 gas was detected.
