Preparation Of Thiol/Thioether-functionalized Porous Organic Polymers For Adsorption Of Pollutants

Porous organic polymers?POPs?is a kind of new functional materials.Due to their several advantages,including large specific surface area,good physical and chemical stability,unique pore structure and easy functionalization,POPs have received much attention and have been widely used in gas storage,separation,heterogeneous catalysis,and adsorption.In this dissertation,two new kinds of functionalized POPs have been prepared for the simultaneous adsorption of organic pollutants and mercury?II?ion.The detailed research contents are presented as follows:First,using 1,3,5-tri?4-bromine phenyl?benzene and1,3,5-triacetylene benzene reagents,a porous aromatic framework polymers?PAF?was obtained via the Sonogashira coupling reaction.Then,the thiol/thioether-functionalized PAFs?PAF-SH and PAF-SMe?were obtained through the chloromethylation?using paraformaldehyde and HCl as reagents?and thiol/thioether functionalization?using NaHS and NaSCH3 as reagents?.The PAF-SH and PAF-SMe were characterized by FT-IR,TGA,SEM,XRD,nitrogen adsorption-desorption isotherms,and elemental analysis.Moreover,the adsorption properties of these two adsorbents towards toluene,m-xylene and mercury?II?were studied.Results showed that two adsorbents all presented high adsorption ability and fast binding kinetics.The adsorption amounts of toluene?c0=640?g/mL?,m-xylene?c0=480?g/mL?and mercury?II??c0=800?g/mL?on PAF-SMe were 591,425 and 144 mg/g respectively,and those on PAF-SH were 586,408 and 183 mg/g respectively.The adsorption saturation times of toluene,m-xylene and mercury?II?on two adsorbents were 5,1 and 30 min,respectively.The Langmuir isothermal adsorption model was used to calculate the maximum adsorption Q_max of toluene,m-xylene and mercury?II?of PAF-SMe,which were 159.5 mg/g,370.4 mg/g and 145.3 mg/g,respectively.The maximum adsorption Q_max of toluene,m-xylene and mercury?II?of PAF-SH were 205.3 mg/g,294.1 mg/g and 191.2 mg/g,respectively.Furthermore,two adsorbents have been successfully applied to the simultaneous adsorption of three pollutants from the simulated sewage with all adsorption efficiencies higher than 90%.Second,a new monomer?1,3,5-tri?4-aminophenyl?benzene,TABPB?was synthesized first and characterized by FT-IR,¹H-NMR ¹³C-NMR and HRMS.Then,using TABPB and 2,5-divinylterephthalaldehyde as reagents,a covalent organic framework?COF?intermediate?COF-V?was obtained via Schiff base reaction.After that,using 1,2-ethanedithiol as reagent,a thiol-functionalized COF?COF-S-SH?was obtained through the thiol-ene reaction in the presence of 2,2-azobisisobutyronitrile.The COF-S-SH was characterized by FT-IR,TGA,SEM,XRD,nitrogen adsorption-desorption isotherms,solid ¹³C-NMR spectrum,EDX and elemental analysis.Moreover,the adsorption ability of COF-S-SH for toluene,m-xylene and mercury?II?on were studied.Results showed that COF-S-SH presented good binding ability to benzene?c₀=160?g/mL?,toluene?c₀=160?g/mL?,ethylbenzene?c₀=160?g/mL?,m-xylene?c₀=160?g/mL?and mercury?II??c₀=800?g/mL?with the adsorption efficiencies of 85,137,129,142and 502 mg/g respectively.The adsorption saturation times for pollutants were 5,5,4,3 and 60min.The Langmuir isothermal adsorption model was used to calculate the maximum adsorption Q_max of benzene,toluene,ethylbenzene,m-xylene and mercury?II?of COF-S-SH,which were179.9 mg/g,200.8 mg/g,147.5 mg/g,214.1 mg/g and 602.4 mg/g,respectively.Furthermore,COF-S-SH showed good simultaneous adsorption ability towards BTEX and mercury?II?in a simulated sewage with all highly removal efficiencies.