Electron beam initiated graft modification of cotton and preparation of high performance metal adsorbent

電子線誘起による綿のグラフト重合を利用した金属捕集材の開発

Parajuli, D.; 広田 耕一

Parajuli, D.; Hirota, Koichi

セルロースを主成分とする綿に電子線を照射してラジカルを生成させ、これにメタクリル酸グリシジル(GMA)をグラフト重合させた。グラフト率は、吸収線量(10-50kGy)にはほとんど依存せず220%程度であったが、GMA濃度(1-5%)が高いほど、また反応時間(30-120分)が長いほどグラフト率は上昇し最大で660%となった。また、DMSO以外の溶媒を用いて行った実験では、杉から抽出した精油によりGMAを分散させた系(20kGy, 3%GMA,反応時間2時間)で最も高いグラフト率300%が得られた。しかし、グラフト率240, 530, 660%の試料に対して、エチレンジアミンを修飾したところ、修飾率はグラフト率に関係なく32-35%であったことから、薬品量や吸着剤の製造コストの低減を考慮すると、グラフト率は250%程度で十分であることがわかった。

Cotton consisting of nearly 100% cellulose is one of the widely available natural polymers with versatile applications. In order to know the possibility of using cellulosic materials for the development of functional adsorbents by radiation induced vinyl graft modification method, cotton was studied as a representative biomass. In the present study, cotton was pre-irradiated with electron beam and glycidyl methacrylate (GMA) was grafted onto it. Various parameters like irradiation dose, monomer concentration, grafting temperature, time, etc were studied to achieve the optimum graft yield. Once GMA containing reactive epoxy group was grafted onto the cotton matrix, various functional groups possessing different selectivity behavior for different metals were introduced by simple chemical reaction. The newly developed functional-cotton derivatives were studied for their ion exchange performances and selectivity patterns mainly for the precious metals in HCl and HNO systems.