Synthesis of arsenic graft adsorbents in pilot scale

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

The zirconium (Zr(IV))-type adsorbent for As(V) removal was synthesized by radiation-induced graft polymerization with phosphoric monomer and the subsequent chemical modification with Zr(IV) by loading on phosphoric units. The Zr(IV)-type adsorbent can rapidly remove As(V) to low concentration. In order to apply for a large amount of water treatment, it is necessary to construct of synthesis method in pilot scale. Synthesis method of graft adsorbent in pilot scale was investigated by setting up the equipment which was composed of reaction tanks, washing tank and pump. The equipment can produce the adsorbent which is maximum 0.3 20 m size in one batch graft reaction. To evaluate the optimum condition in this equipment, it was required the optimization of several condition such absorbed dose, monomer concentration, reaction temperature and reaction time. A nonwoven cotton fabric as a trunk polymer was irradiated, then it was placed into the reaction tank with the deaerated monomer solution. The components of the monomer was phosphoric acid mono- (50%) and di- (50%) ethyl methacrylate ester. As a result, the degree of grafting of 150% was obtained at absorbed dose of 20 kGy with 5% monomer solution mixed by deionized water for 2 hours at 40 C. Finally after loaded of Zr(IV) on grafted nonwoven fabric, As(V) adsorbent was achieved in pilot scale.