Study On The Preparation And Adsorption For The Modified Activated Carbon Fiber By Mesorporous Silica

Volatile organic compounds(VOCs) were some organic compounds with a melting point below room temperature and boiling point between 50 and 260 degrees Celsius. As one type of VOCs, low concentration toluene was widespread in the indoor air and industrial areas, living in this environment for a long time would cause a serious threat to people’s health. The emission of radionuclide uranium was important to the environment, if not handled properly, it would cause not only the waste of resources, but also infinite harm to human health. There were many treatment of wastewater, then the combines of adsorption / desorption process was combined with the catalytic process method could effectively remove indoor low concentration of toluene, the individual method of adsorption could effectively remove the uranyl ion in the wastewater. The activated carbon fiber(ACF) modified by Silica could effectively improve the hydrophobic properties, therefore, which was expected to be widely used in the removal of indoor low concentration toluene. What is more, introducing amino functional groups onto the surface of porous materials could also greatly improve the uranyl ion adsorption capacity.Objective: By comparing the adsorption of different silica loading of ACF in the same condition, to make clear the effect of hydrophobicity on the adsorption performance, then screened out the best effective of the modified materials. By the use of amino functional groups related to the occurrence of chelating ion, these amino functional groups were introduced into the porous material to improve the removal efficiency of the uranium ions.Method: The ACF materials had large specific surface area, through slow hydrolysis of silica tetraethyl, ACF were coated by silica gel method for the synthesis of silica modified ACF material. The amino modified mesoporous materials were synthesized by the method of high temperature treatment and the amino groups were introduced into the channels by impregnation. Dynamic adsorption behavior of low concentration toluene on modified ACF was analyzed by using mass spectrometry with multiple channels. The surface structure of the modified ACF was observed by using scanning electron microscope. The modified ACF pore structural information was studied by nitrogen adsorption stripping experiment, the changes of surface functional groups of modified ACF were studied by FTIR analysis respectively.Result: 1. The morphology of silica-modified ACF which was prepared by sol-gel synthesis method was studied by scanning electron microscope, the ACF surface presented different thickness of the silica layer with the increase of the package of silica. The results of low concentration toluene adsorption data on the ACF and modified ACF showed that the thickness of the silica layer and the adsorption of hydrophobic material performance and was closely related to the adsorption of toluene. 2. By using ammonia with modified ACF surface containing oxygen groups in high temperature reaction, the amino groups introduced on the surface of ACF, through adsorption properties of milling uranyl ions. It was found that under appropriate conditions on the surface of ACF and introduction of amino could enhance the adsorption capacity of uranyl ions. 3. By the TEPA impregnated method, amino was introduced into the modified SBA-15 materials. The further study on the milling uranyl ion adsorption properties showed that SBA-15 loading on the mesoporous had strong adsorption capacity for uranyl ions. The uranium ion adsorption rate could be as high as 98% in the low concentration of uranyl ions.Conclusion: 1. The modified ACF adsorption of low concentration toluene study showed that the appropriate amount of silica package loading on the ACF could not only improve its thydrophobic properties to enhance its adsorption ability for hydrous toluene, but also could improve its thermostability to increase the ability of regeneration adsorption performance in the stripping process. 2. The ACF amino modified by amino functional groups could enhance its adsorption capacity of uranium ion by coordinating with uranyl ions, thereby enhancing the adsorption capacity of uranyl ion.3. Introducing the amino onto the mesoporous SBA-15 also could enhance its adsorption capacity of uranyl ion by the effect of amine ligand.