Preparation And Performance Research Of Functional Hydrogel Based On Cyclodextrin

With the development of society,organic dyes have become the main cause of water pollution.The adsorption method has the advantages of high cost-effectiveness and easy separation,and has become an effective strategy for the treatment of dye wastewater.How to design and prepare a highly efficient adsorption material with excellent mechanical properties,suitable three-dimensional pore-like structure and without causing secondary pollution has become a research problem.Hydrogels have the characteristics of high adsorption capacity,low cost and easy to handle,so they are ideal candidates for novel adsorbents.This paper aims to use molecular recognition design to prepare cyclodextrin-based hydrogel materials as adsorbents,and to explore their selective adsorption of dye molecules.Firstly,we synthesized cyclodextrin polymers(P-CD)as a host polymer and poly(acrylic acid)modified with adamantane(PAA-Ad)as a guest polymer.The formation of the hydrogel was due to the inclusion of ?-cyclodextrin(?-CD)and adamantane(Ad),which formed a three-dimensional cross-linked network structure.The mechanical properties and microstructures of the hydrogels could be adjusted by varying the concentrations of PAA-Ad.The results demonstrated that the hydrogels possessed higher adsorption capacity and different mechanisms in the adsorption of the four typical poisonous organic dye molecules used,including bisphenol A(BPA),4-aminoazobenzene(N-Azo),methylene blue(MB),and rhodamine B(RhB).Next,we designed a novel hydrogel using cyclodextrin polymer(P-CD)as a host polymer and poly(acrylic acid)modified with ferrocene(PAA-Fc)as a guest polymer.The prepared hydrogels had a three-dimensional porous network structure and large specific surface area.In addition,the gel-sol transition process would occur when the gel has redox stimulation.In particular,the maximum adsorption capacity of the hydrogel material reached 23.61mg/g for BPA and 24.64mg/g for MB.It was found that the adsorption process had high pH dependence.We further studied the host-guest recognition of cyclodextrin and azobenzene,and new hydrogel materials of poly(vinyl alcohol)/cyclodextrin-modified poly(acrylic acid)/azobenzene-modified poly(acrylic acid)(PVA/PAA-CD/PAA-Azo)were successfully prepared via host-guest interactions and hydrogen bonds.In addition,ultraviolet(UV)light irradiation and temperature change induce a gel-sol phase transition in the hydrogel materials.Due to the unique three-dimensional cross-linked network structure of the hydrogel material and the exposure of a large number of adsorption sites,the hydrogel materials have good stability and efficient adsorption capacity.