A novel Fe3+ loaded polyacrylamidoxime modified waste wool adsorbent (Fe3+/W-g-PAO) was prepared to eliminate fluorinion (F-) in aqueous solutions.To be specific

polyacrylonitrile (PAN) was first grafted onto the waste wool by traditional free radical polymerization

in which thiol groups on waste wool were act as active sites for chain transfer.Subsequently

cyano-groups were converted to amidoxime groups.The prepared adsorbent (W-g-PAO) could successfully load Fe3+

due to the outstanding coordination ability of amidoxime groups with Fe3+.Fe3+/W-g-PAO possessed excellent adsorption capacity for F-

and the adsorption process was rapid and efficient.The adsorption process of F- on Fe3+/W-g-PAO could be fitted well by the quasi-two dynamics model and Langmuir model.However

by this adsorption style

the adsorption capacity of F- on W-g-PAO was only 14.26 mg/g.If the formation of coordination compounds of Fe3+ and F- was first prepared

the adsorption capacity of F- on W-g-PAO could be improved significantly to 49.2 mg/g.That's because Fe3+ could be reduced into Fe2+ during the loading process of Fe3+.The results indicated that the structure of Fe(III)[F-]3[-NH2]3 was formed when F- was adsorbed on Fe3+/W-g-PAO.In conclusion

the material prepared in this work

W-g-PAO

has the advantages of low-cost

recyclable and excellent adsorption capacity

which can be used as a promising material for the application in the treatment of waste water containing fluoride ions.