Imidazolium-based Poly（Ionic Liquid）s PDVIm-Cl And PDVIm-Cl-FeCl₄:Preparation And Applications In Dye Adsorption And Degradation

Poly(ionic liquid)s(PILs)have great application potential in adsorption,catalysis and other fields with the advantages of ILs and polymers.In the treatment of dye wastewater,PILs,as the modified components of adsorbents,play a significant role in improving the performance,but are rarely directly used for dye adsorption.In addition,PILs have not been studied as Fe-based heterogeneous Fenton catalyst for dye degradation.In this study,crosslinked imidazolium-based mesoporous PILs:poly(N,N’methylene-bis(1-(3-vinylimidazolium))chloride)(PDVIm-Cl)and PDVIm-Cl-FeCl4,were synthesized for the adsorption and degradation of dye,respectively.The main research contents are as follows.A cationic imidazolium-based PIL:PDVIm-Cl,with low monomer molecular weight and large number of anions(Cl-)per unit mass was synthesized and applied in the adsorption of anionic dyes:methyl orange(MO),sunset yellow(SY),reactive blue 19(RB19),congo red(CR).Results indicated that PDVIm-Cl exhibited excellent adsorption ability towards anionic dyes,and the maximum adsorption capacity for RB19(2605 ± 254 mg·g-1)was almost twice the maximum amount of adsorption capacities reported.Moreover,the removal efficiencies of anionic dyes by the PIL were almost unaffected by pH(2-10)and other interfering ions(cationic dye,Cl-).In addition,it can be proved that the PIL has excellent reusability and practical application potential through the achievable continuous column adsorption-desorption process and the available desorption solution volume which is far less than the original untreated solution volume.At last,combined with the experimental characterization and quantum chemical calculation results,it is known that the adsorption of anionic dyes by PDVImCl was a joint process including ion exchange,electrostatic interaction,hydrogen bonding and π-π stacking.On the basis of synthesizing IL monomer of PDVIm-Cl,the PIL PDVIm-Cl-FeCl4 with the paired anions of Cl-and FeCl4-was obtained by free radical polymerization after adding FeCl3·6H2O.Compared with homogeneous Fenton catalyst,PDVIm-ClFeCl4 has the advantages of easy recovery and free from pH restriction with active Fe(Ⅲ)sites uniformly distributed in the PIL by binding with the polymer skeleton in the form of FeCl4-.The PIL can effectively catalyzed the degradation of cationic dye malachite green under mild conditions with great stability and reusability.The research results proved the feasibility and potential of PILs as Fe-based heterogeneous Fenton catalyst in dye degradation.