Synthesis Of ?-cyclodextrin-based Nanosponge And Its Applications For The Removal Of Alkaline Red 46 And Rhodamine B From Aqueous Solutions

A large number of dye wastewater is produced every year in China,and the dye wastewater is characterized by high concentration of organism,containing complicated components,its range of pH is very big,its range of quality and temperature of dyeing wastewater is of great quantity,poor biochemical purification ability and difficult to be degraded etc.And the dyes in wastewater have strong toxicity and potential mutagenicity,carcinogenicity.That wastewater without treatment discharged directly will result in serious environmental problem,affect the ecosystem balance and human being health.Cyclodextrin-based nanosponges(CDNS)are a novel kind of polymers and are safe,biodegradable materials with nappreciable toxicity in environment.However,as an adsorbent,there is little research on dye wastewater,and it has loads of demerits such as lower adsorption capability and its adsorption rate is relatively slow etc.Therefore,it is necessary to synthesize Cyclodextrin-based nanosponges and explore its application in dye wastewater treatment.In this work,CDNS were fabricated in one-step solvothermal method by the polymerization of?-Cyclodextrin and diphenyl carbonate.And CDNS were characterized by FTIR,XRD,TGA-DTG and SEM in order to investigate its characteristic and stability.As two of the familiar dyes,Basic red 46 and Rhodamine B are employed as the model contaminant,and the adsorption of Basic red 46 and Rhodamine B are systematically investigated by tuning a series of parameters such as amount of adsorbent,pH,the molar ratio of?-CD and DPC,time and initial concentration in order to explore its application in the treatment of dye wastewater.The experimental data indicates that the best adsorption capacities of Basic red 46 were reported at101.43 mg/g when at 10 mg,?-CD:DPC=1:6,pH=5,120 min and 180 mg/L,and the best adsorption capacities of Rhodamine B were reported at 52.33mg/g when at 10 mg,?-CD:DPC=1:4,pH=6,120 mg/L and 180 min.The adsorption capacities of Basic red 46 is higher than that of Rhodamine B could due to the structure differences between the two dye molecules so that the area of effective contact were different,which might help explain disparate effects.Meanwhile,the experimental data were fitted by kinetic models(pseudo-first-order and pseudo-second-order kinetic model)and isothermal adsorption models(Langmuir and Freundlich isotherms).The study showed the correlation coefficients(R~2)of pseudo-second-order kinetic model(Basic red 46 and Rhodamine B)were 0.9959 and 0.9943,respectively.The correlation coefficients(R~2)of Langmuir isotherms(Basic red 46 and Rhodamine B)were 0.9973 and 0.9953,respectively.What is more,according to Langmuir isotherm model,the best uptake capacities for two dyes were105.6 mg/g and 56.88 mg/g,which are closer to the best amount adsorbed of Basic red 46(101.43 mg/g)and Rhodamine B(52.33 mg/g),respectively.In conclusion,the uptake of two dyes followed pseudo-second-order kinetic model and Langmuir isotherms,which represented a clear chemical process by monolayer adsorption.