New Porous Materials For Worm CO₂ Capture And Controlled-release Of Menthol

It is a challenge to fabricate the optimal composite for social requirement,not only the low cost and environment-benign process,but also the high efficiency of the product itself,and this is the aim of lots of scientists to pursuit unremittingly.The micelles inside the as-synthesized mesoporous silica are usually removed by either calcinations or extraction,which not only consumes energy or solvents,but also increases pollution therefore it is necessary to utilize these template micelles orientated inside the channel.One noteworthy example is the special solid base to control CO₂ in flue gas that causes 30-40%of CO₂ emission in the world.A large amount of CO₂ can cause a series of environmental problems,of course it is a serious threat to the ecological environment we live.Graphene added to magnesium salt could in situ separate MgO particles,and we fabricate the carbon-doped FeO-ZnO,have been successfully fabricated enabling the surface defects of MgO crystals well exposed which results in an efficient CO₂ sorbent.We adsorbe CO₂ with two different manners,combining IA of CO₂ and TPD resulted in a new method,IA-TPD,to examine the behaviour of different basic sites of MgO sorbent in warm CO₂ capturing.This thesis consists of the following parts:1.The tunable flexibility of template micelles in as-synthesized mesoporous silica is crucial for the thermal release of menthol this kind of volatile organic molecules.We use headspace vial to adsorbe menthol,the released menthol was forced into the sample loop and detected with the GC-MS technique.The micelles in as-synthesized mesoporous materials such as MCM-41 exhibited a temperature on-off effect,namely,they presented flexibility at the high temperature like 373 K,allowing menthol molecule to burst through them and enter into the channel.Once the temperature was lowered to ambient,the micelles exhibited inflexibility and became tetanic to block the channel.When the temperature was increased to 353 K,the micelle became soft again hence the menthol could escape from the channel to achieve thermal release.2.Increasing the efficiency of MgO-based sorbent includes but not limits to increasing the BET surface area of MgO,especially for warm CO₂ capture because adsorption of CO₂ at>423 K relies on the strong basic sites of MgO rather than the BET surface area.These strong basic sites are well known to depend on special surface' defects of MgO crystals where the Mg T cation is absent due to some reasons.Graphene added to magnesium salt could in situ separate the newly-formed small MgO particles in the decomposition of salt,enabling the surface defects of MgO crystals well exposed which results in an efficient CO₂ sorbent.We adsorbe CO₂ with two different manners,traditional CO₂ flow purging method and pulses method,combining IA of CO₂ and TPD resulted in a new method,IA-TPD,to examine the behaviour of different basic sites of MgO sorbent in warm CO₂ capturing.It is possible to monitor the absolute amount of CO₂ to be introduced and adsorbed as well as desorption in the TPD procedure,which helps to roughly explore the amount and distribution of basic sites.This strategy can also be used for preparation of CaO sorbent to prepare more environmental friendly and cheap adsorbent.3.The temperature of flue gas is usually at 423?673 K,it would cost lots energy-input to cool down the gas below 373 K.When the temperature is over 423 K,physical adsorption is no longer the leading role,so the development of new high-efficiency CO₂ adsorbent within medium temperature is crucial.In this thesis,we use magnesium acetate this kind of cheap precursor to doped ferrous acetate in situ prepared 3%FM sample,its mass fraction is only 3%,meeting the requirements of green environmental protection of the adsorbent,and the CO₂ adsorption amount is up to 35 mg g^-1 at 473 K.This approach improve the strong basic sites ratio hugely,and large proportion of strong basic sites is highly beneficial for the adsorbtion of CO₂ capture at 473 K,which provides a new way of thinking for design of efficient environmental protection solid adsorbent.