Preparation And Properties Of Cyclodextrin Group Cationic Dye Adsorbent Modified By Acid Anhydride

In recent years,with the rapid rise of industry,human large-scale activities have caused a certain degree of damage to the ecosystem on which human lives.In particular,the discharge of dye wastewater has caused pollution to water resources and reduced the quality of human living environment.Therefore,how to solve this problem has become a research hotspot.Because adsorption method has the advantages of simple design and convenient operation,many researchers have adopted adsorption method to solve the problem of dye wastewater pollution.In this thesis,the environmentally friendly cyclodextrin was used as the research object.Multiple carboxyl groups were introduced into cyclodextrin through the ring-opening esterification of anhydride and cyclodextrin,and a variety of adsorbents were prepared.The high efficiency cationic dye adsorbent was obtained throughπ-πinteraction,electrostatic interaction and hydrogen bonding.Specific research contents are as follows:（1）Polyphthalic anhydrideβ-cyclodextrin（Ph AEs-β-CD）,a highly efficient adsorbent,was prepared by using Ph A modifiedβ-cyclodextrin and self-crosslinking method,and its adsorption properties for cationic dyes were studied.The results showed that Ph A,as a crosslinking agent,not only provides coordination sites for the binding of cationic dyes,but also has a large specific surface area（332.14 m²/g）due to the existence of rigid aromatic groups in its structure,which is conducive to the removal of dye molecules.The maximum adsorption capacities of Ph AEs-β-CD on basic green（MG）,crystal violet（CV）,cationic peach FG（FG）and methylene blue（MB）were 3288.80,2407.87,2264.40 and 1401.33 mg/g,respectively.And the adsorbent has good regeneration performance,after five adsorption-desorption cycles,the removal rate of dye can still reach 90%.These results indicate that Ph AEs-β-CD has potential application value in the treatment of dye wastewater.（2）In order to further improve the performance of the adsorbent,we use the self-assembly of cetyltrimethyl ammonium bromide（CTAB）,and then,on the self-assembly surface of CTAB,tetraethyl silicate and Ph A-β-CD were condensed to form a crosslinked polymer adsorbent,and studied its removal properties of cationic dyes.The introduction of inorganic material Si O₂ makes the adsorbent expose more adsorption sites,and the adsorption capacity of the adsorbent has been improved,the maximum adsorption capacities of Ph A-β-CD-Si O₂ for MG,CV,FG and MB were 3694.36,3136.44,2798.00 and 2014.67 mg/g,respectively.After five cycles of adsorption,the dye removal rate could reach 90%.The prepared Ph A-β-CD-Si O₂ provides a strategy for the treatment of dye wastewater.（3）In order to improve the adsorption rate of the adsorbent,firstly,double bonds were introduced by grafting maleic anhydride（MA）onto the surface of cyclodextrin.Then,templates（PMS）were formed with the help of styrene（St）and MA.Finally,divinylbenzene（DVB）was used as a crosslinking agent to form a crosslinked polymer adsorbent with hollow network structure on the surface of PMS through free radical polymerization.Its effect on the removal of cationic dyes was also studied.Effect.The results showed that DVB,as a crosslinking agent,increased the density of active adsorption sites and further improved the adsorption capacity of adsorbent due to the existence of rigid aromatic groups in its structure and the formation of three-dimensional cross-linking network structure.The maximum adsorption capacities of St-DVB-MA-β-CD for MG,CV,FG and MB were 3796.63,3471.28,3032.4 and 2299.67 mg/g,respectively.After five cycles of adsorption,the dye removal rate can reach 90%,the preparation of St-DVB-MA-β-CD provides a solution for the treatment of dye wastewater.