Synthesis And Adsorption Properties Of Doped Mesoporous Carbon Materials

The adsorption method,which is efficient,simple and no secondary pollution,was widely used to solve the problem of dye wastewater.Carbon material was the most widely used adsorbent because of its stable chemical properties,large specific surface area and high adsorption efficiency.Althougn activated carbon was a kind of adsorbent widely used at present,the cost and regeneration of activated carbon limited its use.Therefore,it was especially important to seek adsorbent with higher adsorption capacity and regeneration capacity,Nowadays,mesoporous carbon materials had great potential in dye adsorption,because it could avoid the transmission limit of heavy molecular in microporous carbon material.In order to enhance the interaction between dye molecules and mesoporous carbon and increase the adsorption capacity of dyes,modification of mesoporous carbon was also needed.In this paper,two kinds of mesoporous carbon materials were prepared,characterized and tested to the dye adsorption and recycling performance,and the adsorption kinetics might exist in the dye adsorption process was researched.It mainly includes the following two parts:The first part: B and N co-doped mesoporous carbon was synthesized by carbonization of dried gel,which was fabricated through sol-gel method that EDTA was targeted as carbon source and nitrogen source,the block copolymer P123 as soft template,the ethyl silicate(TEOS)as the pore forming agent,and boric acid as doping agent,pore expanding agent and catalyst.Structural properties were characterized by means of XRD,XPS,N2 adsorption desorption,thermogravimetry.The experimental results showed that the surface area of B and N co-doped mesoporous carbon was obviously larger than that of nitrogen doped mesoporous materials.The adsorption capacity of dye onto B and N co-doped mesoporous carbon was higher than that of nitrogen doped mesoporous carbon.This was mainly due to the specific surface area playing a major role in it.The adsorption amount of basic dye rhodamine B and the acid dye methyl orange to B and N co-doped mesoporous carbon had little difference,it was mainly because of both acidic boron functional groups and basic nitrogen functional groups.Therefore,the results of cyclic experiment could be known adsorbent had good adsorption performance after five cycles,which was proving that the B and N co-doped mesoporous carbon material had good stability.By fitting the kinetic equation to the experimental data of dye adsorption,it was found that pseudo two order kinetics was more suitable to explain the kinetics of dye adsorption process,this was that chemical adsorption was the speed controlling step of the whole adsorption process.The second part: Nitrogen-doped magnetic mesoporous carbons N/Co-mC was obtained from carbonization of metal organic framework compound Co/Zn-ZIF fabricated at room temperature,using 2-methyl imidazole as carbon source and nitrogen source,six hydrated cobalt nitrate as magnetic source,six hydrated zinc nitrate as precursor,and methanol as solvent.The prepared mesoporous carbon was characterized by XRD,XPS,N2 adsorption desorption,magnetic strength of vibrating sample and thermogravimetry.The adsorption experiments of rhodamine B and methyl orange were carried out.The experimental results showed that the adsorbption capacity of nitrogen-doped magnetic mesoporous carbon synthesized for methyl orange was greater than the adsorption capacity of rhodamine B.This was mainly because of the presence of electrostatic attraction between the basic nitrogen functional groups with acidic dye methyl orange,which was preferred to adsorbption of methyl orange.In addition,the results of cyclic experiments showed that the mesoporous carbon adsorbent had good stability and could be separated from aqueous solution with good separation effect.By fitting the kinetic equation to the experimental data of dye adsorption,it was found that pseudo two order kinetics was more suitable to explain the kinetics of dye adsorption process,this was that chemical adsorption was the speed controlling step of the whole adsorption process.