Selective Accumulation of Rare-Earth and Heavy Metal Ions by a Fucoidan-Inorganic Composite Material

The accumulation of rare-earth and heavy metal ions from wastewater is important for industrial technology. However, practical accumulators are expensive with respect procurement raw materials, synthesis, preparation. Therefore, it preferable to accumulate using sustainable resources, such as natural polymers. Fucoidan, a water-soluble polymer, sulfated polysaccharide the cell-wall brown algae. fucoidan behaves an acidic in aqueous solution. We prepared fucoidan-inorganic composite material by mixing silane coupling reagent, bis(3-(trimethoxysilyl)propyl)amine (SiNSi). This fucoidan-SiNSi (F-SiNSi) showed water-insoluble property. due encapsulation into three-dimensional network SiNSi siloxane bonding. When F-SiNSi immersed ion-containing solution, accumulated ions. binding affinity each ion was Ca(II), Mg(II) << Nd(III) < Cu(II), Zn(II), Ni(II), La(III) In(III) Y(III). Additionally, maximum-accumulated amounts Nd(III), La(III), In(III), Y(III) were 140, 200, 190, 230, 270 nmol per mg fucoidan, respectively. Furthermore, molar ratios groups (the sulfate carboxyl groups) ions, 0.081–0.156. selectivity mechanism related fucoidan.