Arsenic removal from streaming water with graft adsorbent

Seko, Noriaki; Hoshina, Hiroyuki; Kasai, Noboru; Takahashi, Makikatsu*; Yoshii, Akihiro*; Tsunoda, Yasuhiko*; Shibata, Takuya*  ; Aketagawa, Yasushi*

Purification of waste water is important task from the viewpoint of economy and environmental preservation. In general, synthetic polymers such as polyethylene and polypropylene have been used as trunk polymer fibers due to their reactivity in the grafting process and high mechanical strength. Synthetic trunk polymers are, however, derived from petroleum resources. If a natural polymer such as cellulose is used as the trunk polymer for graft polymerization, the dependence on petroleum resources would decrease. In this study, a fibrous adsorbent for the removal of arsenic ion was synthesized by radiation-induced emulsion graft polymerization of 2-hydroxyethyl methacrylate phosphoric acid monomer (PA) onto nonwoven cotton fabric, and subsequent chemical modification by zirconium salts. The optimal pre-irradiation dose for initiation of graft polymerization of PA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 20 kGy. The synthesized fibrous adsorbents were applied for the removal of arsenic from streaming water. The purification system for 10 tons streaming water was assembled by stack of graft adsorbents in preliminal experiment. These adsorbents were decomposed by microorganisms and roughly 60 % in fabrics was finally changed to CO in 3 months.