| With the rapid development of modern chemical industry,industrial wastewater including heavy metal ions and organic dyes was discharged into the environmental water.The wasterwater being affected by the food chain was indirectly absorbed by the human,so that there were many serious diseases,which become a major social problem to be solved.Therefore,achieving sewage discharge standards,and establishing the wastewater treatment technology are very significance.Traditional methods mainly include chemical treatment,resin and activated carbon adsorption,reverse osmosis and other methods.However,those methods exist high cost,difficult to meet the emission requirements or cause secondary pollution and other issues.Therefore,it is necessary to research and development of excellent adsorption materials.Electrospinning nanofibers have the advantages of small specific surface diameter,high adsorption speed,short regeneration time,easy elution,continuous preparation,etc..It shows a good application prospects in the industrial wastewater treatment which is the hotspot in recent years.In this paper,two kinds of cross-linked nanofibers were prepared by electrostatic spinning using the ?-cyclodextrin and polyethyleneimine.And the adsorption properties of metal ions and organic dyes were studied.As the low solubility of cyclodextrin in PVA / H2 O solution,it is difficult to obtain the crosslinked PVA / ?-CD nanofibers with high cyclodextrin content,The PVA / ?-CD nanofibers were treated with HFIP / H2 O as the solvent,and then treated with glutaraldehyde to prepare PVA / GA / ?-CD Nanofibers,which Cyclodextrin content is mentioned to 70%.Compared with before being cross-linked,those changes of composition and morphology for the nanofibers were studied by Infrared Spectroscopy and Scanning Electron Microscopy.The adsorptive properties of the PVA/GA/?-CD nanofibers to seven water-soluble dyes were investigated.The results show that the adsorptive effect of fiber on malachite green,methyl violet and congo red is better thanothers,and the maximum adsorptive capacity are 124.7 mg/g,121.14 mg/g and 127.39mg/g,respectively.After four cycles of adsorption-desorption,the dye removal rate is still 80%.It will have a good applicative prospect in wastewater treatment with dye.With polyacrylonitrile being the carrier,polyethyleneimine being the adsorbent and epichloro-hydrin being the cross-linking agent,the cross-linked PEI / EPI / PAN nanofibers which didn't dissolved in water were obtained by electrospinning and thermal cross-linking.The composition and morphology of nanofibers before and after being cross-linked were studied by infrared spectroscopy and scanning electron microscopy.The adsorption experiments which copper ions,lead ions,chromate ions and methyl orange in water were adsorpted by the nanofibers were investigated.The factors affecting the adsorption performance(such as solution p H,adsorbent,time and temperature,etc.)were studied.The results showed that the maximum adsorption capacity of crosslinked PEI / EPI / PAN nanofibers to copper ions and lead ions reached 349.65 mg/g and 289.85mg/g,respectively,the maximum adsorption capacity of methyl orange is 636.94 mg /g,the chromate of maximum adsorption capacity is 211.86 mg/g.After 4 or 5 cycles,the adsorption rate was still about 90%,75% and 60%,respectively.Based on the polyacrylonitrile / polyethyleneimine solution,the cross-linked PEI /PAN/ EPI nanofibers were obtained by PEI/PAN electrospinning fibers which were cross-linked with epichlorohydrin / acetone.The adsorption experiments of the nanofiber adsorbing methyl orange,chromate,Copper ions and lead ions were investigated.It was found that the maximum adsorption capacitys were 595.24 mg/g,194.55 mg/g,314.46mg/g and 277.77 mg/g,respectively. |
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