Arsenate removal from water by a weak-base anion exchange fibrous adsorbent

A weak-base anion exchange fiber named FVA with primary amino groups for selective and rapid removal of arsenate species was prepared by means of electron irradiation induced liquid phase graft polymerization of N-vinylformamide onto polyethylene coated polypropylene fibers and by the subsequent alkaline hydrolysis of amide group on the grafted polymer chains. Two types of FVA were prepared. One was a non-woven cloth type named FVA-c for the batch-mode study, which clarified that uptake of arsenate species decreases with an increase in pH, and chloride and sulfate do not strongly interfere with uptake of arsenate species different from conventional anion exchange resins based on crosslinked polystyrene matrices. The other was a filamentary type one named FVA-f used in the column-mode study, which clarified that arsenate species were successfully removed from neutral pH arsenate solutions containing 1.0–99 mg of As/L at feed flow rates of 100–1050 h−1 in space velocity (SV). The most important findings are that the 1% breakthrough point in uptake from the arsenate solution containing 1.0 mg of As/L at the high feed flow rate of 1050 h−1 in SV was as large as 4670 bed volumes, giving the 1% breakthrough capacity of 0.298 mmol/g of FVA-f. Adsorbed arsenate was able to be quantitatively eluted with 1 M hydrochloric acid and FVA-f was simultaneously regenerated. Then, the repeated use of FVA-f was possible.