Preparation Of Schiff Base Modified SBA-15 And Its Adsorption And Fluorescence Detection Of Heavy Metal Ions

Heavy metals are a class of elements that are harmful to human beings.Their accumulation in the human body to a certain extent will cause nerve damage and abnormal metabolism and other injuries to the human body.SBA-15 mesoporous silica is a good adsorbent carrier because of its large specific surface area,good stability and easily functionalized surface.Schiff base compounds are widely used in metal ion coordination,detection,adsorption,etc.In this thesis,several kinds of mesoporous silica SBA-15 modified with Schiff base groups were prepared by the postmodification method,and were studied from the aspects of structure characterization,adsorption and fluorescence detection.In the first part,two Schiff base condensation reactions of amino-functionalized SBA-15,terephthalaldehyde and 2-aminophenol were introduced,and the Bis-Schiff base adsorbents MSAP were finally prepared.It was found that the adsorption behavior conformed to the pseudosecond-order adsorption kinetic model and the Langmuir isotherm adsorption model.Under the optimal conditions,it was found that its maximum adsorption capacity for Pb(ⅠⅠ)could reach 151.5mg/g.Thermodynamic experiments confirmed the spontaneous and endothermic properties of Pb(Ⅱ)adsorption.Compared with amino functionalized SBA-15 in binary mixed ion solution,MSAP showed good selectivity to Pb(ⅠⅠ)in the presence of interfering ions such as Cu(ⅠⅠ),Cd(ⅠⅠ),Mn(ⅠⅠ),Mg(ⅠⅠ),Co(ⅠⅠ)and Ni(ⅠⅠ).In addition,the above-mentioned seven metal ion mixed liquids at three concentrations were set up,and MS-AP still showed the selective adsorption capacity for Pb(II).In the second part of the work,the tertiary amino group-modified SBA-15 was introduced into 5-chloromethyl salicylaldehyde by quaternization reaction to obtain MS-CSA,and then a Schiff base condensation reaction with the synthesized amino salicylaldehyde Schiff base occurred to form Nanoprobe material MS-NSP containing quaternary ammonium bonds and Bis-Schiff base groups.Subsequently,the detection sensitivity and fluorescence selectivity of metal ions were tested using this material,and it was found that it has good specific recognition ability for the detection of Cu(Ⅱ),and the detection concentration range of Cu(Ⅱ)was 0-4 mg/L,the detection limit was 0.19 μM.In the third part of the work,the coordinated Cu(II)organosilicon functional monomer 5-CAS@Cu(II)was prepared by adding template ions,and then the functional monomer was modified on the surface of magnetic mesoporous silica MSBA-15.Finally,the Cu(II)surfaceimprinted magnetic mesoporous silica adsorbent MSBA-15-IIP containing quaternary ammonium bonds and Schiff base groups was prepared by eluting Cu(ⅠⅠ)with acid.Then,the adsorption experiment of Cu(ⅠⅠ)was carried out on it,and it was found that the adsorption behavior conformed to the pseudo-second-order adsorption kinetic model and the Langmuir isotherm adsorption model,and the maximum adsorption capacity reached 32.7 mg/g.The thermodynamic experiment confirmed the spontaneity of Cu(ⅠⅠ)adsorption.In addition,in the binary ion interference test,it was found that MSBA-15-IIP has a higher selective adsorption capacity for Cu(II).This paper has 58 pictures,15 tables and 145 references.