Preparation Of β-cyclodextrin Composite Aerogel And Study On Its Adsorption To Methylene Blue

With the accelerating industrialization process in China,various organic dyes have been widely used in textile,paper-marking and cosmetics industries.These dyes typically have complex aromatic structures that are stable and non-degradable in the presence of light and heat or in presence of oxidizing agents.Without effective treatment,a large amount of wastewater containing dyes will cause serious environmental pollution,even endanger human health.At present,there are many methods for treating dye wastewater,in which the adsorption method is known for its simple operation,low cost and high efficiency.Therefore,the preparation of new adsorbent materials with low cost,high adsorption efficiency and no secondary pollution has become an urgent problem to be solved.As a typical porous adsorbent material,activated carbon(AC)has been widely used in various fields such as pharmaceutical industry,chemical industry and environmental protection because of its large specific surface area,pore structure,high adsorption capacity and removal efficiency.Graphene oxide(GO),as a derivative of graphene,has broad application prospects in the field of dye wastewater treatment because of its large specific surface area and abundant oxygen-containing functional groups.β-cyclodextrin(β-CD)is a low cost,nontoxic and biodegradable cyclic oligomer of glucopyranose units with seven repeating monomers.This structure gives rise to a remarkable capacity to form inclusion complexes in solution with organic molecules through host-guest interactions.Generally,β-CD polymer is usually prepared by crosslinking β-CD molecules with epichlorohydrin to adsorb organic dyes.In this paper,β-CD was used as the matrix and epichlorohydrin was used as the crosslinking agent.AC and GO prepared by the modified Hummers method were added separately during the polymerization.The novel polymeric β-cyclodextrin/activated carbon aerogel(β-CD/AC)and β-cyclodextrin/graphene oxide aerogel(β-CD/GO)were prepared by freeze-drying method.The physicochemical properties of β-CD/AC and β-CD/GO were characterized by SEM,FTIR,BET and TGA,respectively.The prepared β-CD/AC and β-CD/GO were applied to the removal of methylene blue(MB)in an aqueous solution,and their adsorption properties for MB under different conditions were investigated.The experimental results were analyzed by Langmuir and Freundlich models,thermodynamics and kinetic models.The results of the fitting showed that the adsorption of MB by the two composites followed the Langmuir model.The maximum adsorption capacities at 323 K calculated by this model were 208.33 mg/g and 181.82 mg/g,respectively.It can be seen from the adsorption kinetics model that the adsorption process of MB by β-CD/AC and β-CD/GO follows the Pseudo-second-order model.Thermodynamic parameters indicate that their adsorption processes are both spontaneous and exothermic.