Side-Chain Structural Effect of a Harmful-Heavy-Metal-Anion Adsorbing Gel

Heavy-Metal-Anion Adsorption and Desorption Properties of <i>N,N</i>-Dimethylaminoethylacrylamide/Acrylamide Gels

“…In the same way as the previous studies [6][7][8][9], an aqueous solution of chromium trioxide is adopted as a model fluid which contains heavy-metal anion because the hexavalent chromium oxoanions CrO In the experiments of examining the DMAEAAm/ AAm gel's hexavalent-chromium oxoanion capturing functionality, each the purified gel cube was immersed in a cell filled with 40 mℓ of aqueous 16.8 mM CrO 3 solution for 24 hrs, then, the gel cubes were carefully taken out from the cells. After these procedure, Cr(VI) concentration and volume of each the remainder solution in the cell was measured.…”

“…total-polymer-concentration dependences of recovered Cr(VI) weight at 1 g of the pre-gel solutions, respectively. In the similar manner to the previous studies [6][7][8][9], the authors adopted this description to express definitely the amount of the DMAEAAm and AAm in the respective gels because the DMAEAAm /AAm gels expands in a different degree with the DMAEAAm composition ratio to AAm in the rinsing procedure in pure water.…”

“…Since the authors found the high heavy-metaladsorption efficiencies of the some hydrogels (estimated ~20wt% of network polymer in the case of poly(acrylamide/ sodium acrylate) [PAAm/SA] gel [5]) over other adsorbents, they have been studying the heavy-metal capturing property [5][6][7][8][9]: in the early stages, mainly on the hydrogels which captures heavy-metal cations [5]. However, because there are also harmful heavy-metal anions which are notorious for causing the environment pollution, such as AsO 4 3-, Cr 2 O 7 -2 and SeO 4 2-, they have been also developing heavy-metal-anion capturing gels and investigating their capturing efficiency [6][7][8][9].…”

“…Then, the author explored another aspect of the side-chain substitution effect terminal-group by examining the heavy-metal-anion capturing features of the copolymer gels of AAm and N,N-dimethylaminopropylacrylamide (DMAPAA) [9]. The structure of DMAPAA is almost identical with DMAEAAm except for the number of alkylene groups (2 in DMAEAAm and 3 in DMAPAA) from the main chain to the terminal group.…”

“…The structure of DMAPAA is almost identical with DMAEAAm except for the number of alkylene groups (2 in DMAEAAm and 3 in DMAPAA) from the main chain to the terminal group. In the investigation, the largest Cr(VI) capturing amount was found in the DMAPAA/AAm gels among the heavy-metal capturing gels which the authors investigated [5][6][7][8][9]. Because the polarization intensity of the side-chain terminal group of the DMAPAA/AAm gel (tertiary amine group) is not higher than that of the DMAEA-MeCl gel (quaternary ammonium group), the number of alkylene groups are also thought to play an important role in the ion-capturing mechanism.…”