Construction Of Novel Structural DNA Hybrid Hydrogels And Removal Of Pollutants In Water Environment

The water environment contaminated by low-concentration Polycyclic Aromatic Hydrocarbons(PAH)and metal ions is an area now of increasing concern at present.Due to the own characteristics,DNA hydrogels could be an effective adsorbent for pollutants in water,is of great importance to purify the polluted water.DNA hydrogels are highly hydrophilic three-dimensional gel materials with excellent swelling property.Owing to the rich functional groups,the materials display a high adsorption capacity for many substances.Because of the environmentally compatible property,DNA hydrogels have attracted the attention of many researchers.Recently,the DNA hybrid hydrogels which doped with different types of materials have been developed,which display richer functions and greater application potential in the field of environmental pollution treatment in comparison with pure DNA hydrogels.In the current study,the structure of the DNA hydrogels was elegantly tuned to improve the mass transfer rate as well as their adsorption property.Through the Pickering microemulsion template method and shear stress,porous structured DNA/carbon nanotubes(CNT)hybrid hydrogels and spherical DNA/Bovine albumin(BSA)hybrid micro-hydrogels were synthesized respectively,and their potential for applications in environmental field were further explored.The Pickering microemulsion template method is one of the most common methods to synthesize porous materials,but the stability is poor.In this paper,a novel pathway has been described to prepare porous structured DNA hybrid hydrogel using transiently existed Pickering emulsion that continuously generated during the reaction.Carbon nanotube was employed in this study for the Pickering emulsion template formation owing to its amphiphobic property.The porous DNA/CNT hybrid hydrogels(?27.1?m)were synthesized successfully.The prepared DNA/CNT hybrid hydrogels exhibited an adjustable porous structure depending on the amount of used CNT.Moreover,the as-prepared hybrid gel showed good thermal stability,fast swelling rate and high adsorption capacity.The experimental results demonstrated that the binding capacity of porous DNA/CNT hybrid hydrogels to trace PAH pollutants was improved compared with non-porous hybrid gel.The adsorption capacity could reach 307.2 g/g,probably because the porous structure could provide more binding sites.The fitting of the experimental data to the kinetic model further indicated that the adsorption reaction during the Liquid/DNA gel interface was the key adsorption process.In this study,the proposed synthetic method overcomes the poor stability of Pickering microemulsion used for preparing the porous DNA gel,which could be used to construct other functional porous gel with excellent structure and performance.Subsequently,the spherical DNA/BSA hybrid micro-hydrogel were synthesized with addition of BSA in the gel preparation process.Compared with the bulk gel,spherical hydrogel owned the advantages of high specific surface area and ease of manipulation.After the gelling process of DNA/BSA hybrid hydrogel,a spherical microgel was obtained by shear stress that originated from vortex.The prepared DNA/BSA hybrid micro-hydrogels had good stability.The experimental results showed that the micro-hydrogels had excellent adsorption capacity for trace PAH pollutants and metal ions(Cd²⁺,Co²⁺,Cr³⁺,Cu²⁺,Zn²⁺),demonstrating the potential of the material to be used in the enrichment step of micro-polluted water samples analysis.