Preparation And CO₂ Adsorption Performance Of Amine-loaded Silica Aerogel

With the CO2 pressure increasing gradually for people’s breath in confined space such as submarines and the space station, the needless CO2 should be removed for the sake of their healthy. Along with the enhancing of submarine endurance and the advance of space station technology, comes the need for new adsorption material for low-pressure CO2.In this thesis, amine-loaded silica aerogel, a kind of material with great specific surface area and a great amount of amines, was prepared by sol-gel, aging and dring with TEOS and APTES.et.al, and its structures and performances were studied by physical adsorption instrument, dynamic adsorption instrument, Hot-disk thermal constant analyzer, SEM, XPS, TG-DSC, FT-IR.et.al. Results show that:(1) The preparing and adsorption mechanisms of amine-loaded silica aerogel were studied. With TEOS and APTES as raw material, amine groups may distribute well on the surface of silica aerogel through sol-gel process. The adsorption of amine-loaded silica aerogel on CO2 can be achieved through the reaction between amines and CO2 in low pressure(CO2 pressure<1KPa).(2) The influences of raw material ratio, gel, aging and drying on pore structure and nitrogen content of amine-loaded silica aerogel were studied. The structure uniformity is good, the specific surface area and the nitrogrn content is large, when EtOH/(TEOS+APTES) equals 10, APTES/TEOS equals 0.65, Wa-1/TEOS equals 1, gel temperature is-15℃, aging temperature is 60℃, aging time is longer than 3 days, and EtOH supercritical dring is used, as a result, the CO2 adsorption capacity is high.(3) The CO2 adsorption performance and thermophysical characteristics of amine-loaded silica aerogel were studied. The CO2 adsorption capacity is 1.85mmol/g at 25℃ when CO2 pressure is 0.5KPa and relative humidity is 60%, which is 1.28mmol/g when CO2 pressure is 1KPa but without H2 O. Desorption can be finished quickly in N2 atmosphere in less than 30 min when the temperature is 100℃. The CO2 adsorption capacity doesn’t decrease after 9 cycling. The adsorption heat of amine-loaded silica aerogel is 93.8KJ/mol, and its specific thermal capacity is 1.23±0.03J/g·K. With low energy consumption, good selectivity, high low-pressure CO2 adsorption capacity, fast adsorption/desorption speed, mild desorption condition and good cycling stability, amine-loaded silica aerogel is one of excellent adsorption materials for low-pressure CO2.