Adosorption Of Heavy Metal Ions Of ?-cyclodextrin-Based Polyester Fabrics

Two functional polyester nonwoven fabrics,which can remove of heavy metal ions and/or dye in aqueous solution,are developed by using citric acid or sodium alginate along with ?-cyclodextrin.To begin with,the polyester nonwoven fabric is treated with a solution containing a mixture of citric acid and ?-cyclodextrin.The processing scheme is optimized on the basis of single factor analysis method.The effects of p H value,fabric dosage and other parameters on the adsorbing properties of as-prepared fabric are investigated on condition that the copper ion is used as the model.Also,the adsorption isotherm model and adsorption kinetic model are discussed,and the adsorption mechanism are further studied.Next,the polyester nonwoven fabric is modified with methacrylic acid and acrylamide,and then treated with the finishing liquid containing ?-cyclodextrin and sodium alginate.The adsorption properties of as-obtained polyester fabric for copper ion and methylene blue dye are studied.The effects of parameters such as p H value and fabric dosage on the adsorbing properties are also discussed,and the corresponding adsorption mechanisms are investigated.In addition,the surface morphology,chemical composition,structure,and thermal properties of as-finished polyester fabrics are characterized by means of scanning electron microscopy,X-ray energy dispersive spectroscopy,X-ray diffraction,infrared spectroscopy and thermogravimetric analysis methods.The experimental results indicate that:(1)The polyester nonwoven fabric is filled with a mixture that contains citric acid and ?-cyclodextrin by using sodium hypophosphite as catalytic agent.The optimal processing conditions are as follows: The finishing liquid is first prepared by using 4% citric acid,2% ?-cyclodextrin,and 1% sodium hypophosphite.The polyester fabric is etched by alkali solution for 120 min,and then treated with the above finishing liquid at 150 oC for 30 min.When 0.2 g of as-prepared fabric is added into 50 ml of 100 mg?l-1 copper ions solution at p H 5.0,the adsorption equilibration is obtained after 24 h.The removal rate of copper ions is over 80% and the corresponding adsorption capacity is about 20.25 mg?g-1.The adsorption isotherm model belongs to the Langmuir monolayer chemisorption.(2)The polyester nonwoven fabric is first modified with methacrylic acid and acrylamide monomer,and then filled with a mixture containing ?-cyclodextrin,sodium alginate and methylene bisacrylamide.When 0.5 g of as-prepared fabric is immersed into 50 ml of 100 mg?l-1 copper ions solution at p H 5.0,the adsorption equilibration time is about 12 h.The removal rate of copper ions is 56.03% and the corresponding adsorption capacity is 5.60 mg?g-1.As 0.4 g of as-prepared fabric is added into 50 ml of 200 mg?l-1 methylene blue dye solution at p H 10,the adsorption equilibration time is 6 h.The removal rate of dye molecules is 65.93% and the corresponding adsorption capacity is 16.48 mg?g-1.The adsorption behavior of copper ions follows the Langmuir monolayer chemisorption and pseudo-second-order kinetic model.The adsorption of methylene blue dye is conformed with the Langmuir and Freundlich isothermal adsorption models and pseudo-second-order kinetic model.