Study On Adsorption Function Of Amino-functionalized Mesoporous Silica And Simulation Of Adsorption Process

With the development of modern industry, the emission of carbon dioxide andwaste water containing heavy metal ions cause serious harm to the environment andhuman health. Carbon dioxide as a greenhouse gas has become a global environmentproblem and it emission lead to the global temperature increased and the sea-level rise.Removal o f h eavy m etal i ons f rom w aste w ater i s es sential due t o t heirbio-accumulation tendency, toxicity, persistency and non-biodegradability in nature.Adsorption w as c onsidered f or t he b est w ay t o de aling w ith recovery of c arbondioxide and low concentration of copper waste water, and it was used more widely.In this paper, a series of amine-functionalized mesoporous silica were preparedvia an anionic surfactant-mediated synthesis method and applied to CO₂adsorptionand deep removal of copper ions from aqueous solution. With isobutyric acid, lauricacid, p almitic a cid, N-Lauroyl-L-glutamic a cid and N-stearoyl-l-glutamic acid asstructure directing agent, γ-aminopropyltriethoxysilane as co-structure directing agentand tetraethyl orthosilicate as silica source. The force of forming the silicamicelle isthe direct electrostatic interaction between the positively charged amino groups inγ-aminopropyltriethoxysilane and the negatively charged head groups in the anionicsurfactant via t he S-N^+I-mechanism, and t he a lkoxysilane s ite ofγ-aminopropyltriethoxysilane is co-condensed w ith i norganic pr ecursors （tetrathtylorthosilicate） to form silica wall. The am ine-functionalized mesoporous silica wascharacterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogenphysisorption and thermogravimetric analysis. The adsorption capacity of samples forCO₂and N₂was measured using static method and dynamic method. The effects ofthe type of surfactant and the content of γ-aminopropyltriethoxysilane on the structureof mesoporous silica, adsorption capacity for CO₂and N₂, and adsorption separationfactor of CO₂/N₂were studied. The saturated adsorbents were regenerated by hightemperature or vacuum, and the regenerative capacity of the adsorbents was evaluated.The C₁₂GluA-APS-0.3sample was also used to remove of Cu²⁺ions from aqueoussolution, and adsorption capacity for Cu²⁺and adsorption rate was measured in thesolution with different concentrations. Copper adsorption process had been studiedfrom both kinetic （Pseudo-first-order kinetic and Pseudo-second-order kinetic） and equilibrium （Freundlich and Langmuir） points of view for C₁₂GluA-APS-0.3material.The adsorption isotherms of C₁₂GluA-APS-0.3material for CO₂and N₂weremeasured at323.15K, and the mixture of CO₂and N₂was separated by pressureswing adsorption （323.15K,0M Pa） us ing C₁₂GluA-APS-0.3as a dsorbent. Thesimulation of pressure swing adsorption was rarely reported because of a variety ofreasons, aspen adsim software was used to simulate the adsorption process in thispaper, a nd t he a ppropriate s imulation m odel was w ell de scribed t he a dsorptionprocess. In order to further the application of simulation model, the components inLigusticum chuanxiong was separated by adsorption in supercritical carbon dioxide（SC-CO₂,8.8M Pa and323.15K）, and then the process was simulated using aspenadsim. In order to further used simulation model and built simulation model for liquidphase a dsorption, Ligusticum chuanxiong i s a ssumed t o be a qua si-binary s ystemmade up of s lightly a dsorbed ps eudcomponents a nd s trongly a dsorbedpseudcomponents. The adsorbent was regenerated by adding a strippant in SC-CO₂,and t he s lightly adsorbed ps eudcomponents a nd s trongly ps eudcomponents （therecovery of85%） were successfully obtained in the adsorption and desorption step.The effects of the adsorption time and the flow rate of strippant on the concentrationsof t he c omponents i n t he e ffluent a nd t he r ecovery of t he p roducts were al soinvestigated. The w hole a dsorption s eparation process was s imulated with a spenadsim successfully and the amount of adsorbed components on t he adsorbents waspredicted graphically.