Preparation Of ?-cyclodextrin Composite Material And Study On Its Adsorption To Methylene Blue

The use of dyes has added a lot of colors to people's lives.A variety of dyes are used in various fields,especially in papermaking,cosmetics,and textile industries.These dyes not only bring visual enjoyment to people,but also endanger the health of the environment,animals,plants and humans because of the large amount of random emissions.These dyes can cause serious harm because most of them have a stable aromatic hydrocarbon structure.These dyes are not easy to be decomposed under natural conditions and oxidants,and can be very stable in the environment.Therefore,how to remove the dye in water has become a more concerned issue today.Among the various treatment methods,the adsorption method is widely used because it is easy to operate,low in cost,and convenient for mass production.In order to better use the adsorption method,it is very important to find a clean adsorbent with high adsorption efficiency.The typical adsorbent activated carbon(AC)has been widely used in the treatment of pharmaceutical,chemical and other sewage industries.The AC has a large specific surface area and an excellent pore structure,so it has high adsorption efficiency and large adsorption capacity for sewage dyes.Graphene oxide(GO)is also widely used in adsorption.GO is obtained by special treatment of expanded graphite,which also has rich porous structure and surface functional groups.?-Cyclodextrin(?-CD)is an oligomer that is easily available,safe,and easily degradable in cleaning.It can be combined with other substances,and the resulting polymer has excellent properties and is widely used.In this paper,?-CD and citric acid(CA)were used for cross-linking under potassium dihydrogen phosphate cross-linking agent,and AC and GO were added during the polymerization process to prepare a new material ?-cyclodextrin cross-linked citric acid doping Activated carbon(CA-?-CD/CA)and ?-cyclodextrin cross-linked citric acid doped graphene oxide(CA-?-CD/GO).The new materials CA-?-CD/AC and CA-?-CD/GO were characterized by scanning electron microscope(SEM),infrared spectroscopy(FTIR),and specific surface area analysis(BET).The prepared new materials CA-?-CD/AC and CA-?-CD/GO were used to adsorb methylene blue(MB)dye in water,and explored the influence of different influencing factors on the adsorption effect.Langmuir,Freundlich model,thermodynamics and kinetic analysis were performed on the data obtained from the experiment.According to the analysis results,it can be known that the adsorption of MB by the new composite material complies with the Langmuir model.Under this model,the maximum adsorption capacity of CA-?-CD/AC and CA-?-CD/GO at 303 K is 862.07 mg/g and 609.756 mg/g,respectively.Compared with,the existing adsorption materials citric acid cross-linked ?-cyclodextrin(295.20 mg/g),?-cyclodextrin citric acid activated carbon(166.67 mg/g),?-cyclodextrin function multi-walled carbon nanotubes(90.90 mg/g)the adsorption capacity increased significantly,making CA-?-CD/AC and CA-?-CD/GO composites provide a certain reference value in adsorption.The results of adsorption kinetics indicate that the process of CA-?-CD/AC and CA-?-CD/GO following MB adsorption follows the Pseudo-second-order model.Thermodynamic analysis of experimental data shows that the adsorption of MB by CA-?-CD/AC and CA-?-CD/GO is spontaneous and the whole process is exothermic.