Harmful-Heavy-Metal-Anion Adsorbing Property of Acrylamide/Dimethylaminoethylacrylatemethylchloride Gel

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

“…The structural difference between DMAEAMeCl/AAm gels and DMAEMA-MeCl/AAm gels are only on the side-chain group in the opposite side of the functional group across the main chain: hydrogen in the DMAEA-MeCl/AAm gels and methyl-base in the DMAEMA-MeCl/AAm gels. In the investigations, it was observed that the Cr(VI)-capturing behaviors with changing the functional-part ratio and total network concentration are similar to those of the DMAEMA-MeCl/AAm gels: The recovered Cr(VI) amount increases with DMAEA-MeCl molar ratio in the lower ratio range while the fashion becomes saturated in the higher DMAEA-MeCl molar ratio region, besides the similar trends can be also confirmed in the total network concentration dependences [7]. In addition to the above-mentioned features, it is noteworthy that that the Cr(VI)-adsorbing efficiency of the DMAEA-MeCl/AAm gels are clearly surpass those of the DMAEMA-MeCl/ AAm gels [7], which may come from the difference in the network configuration.…”

“…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.…”

“…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].…”

“…Next, in order to examine the hydrogels' structural effect on the heavy-metal-anion capturing property, the authors measured the heavy-metal-anion capturing amount of dimethylaminoethylacrylate-methylchloride (DMAEAMeCl) / acrylamide (AAm) gels [7]. The structural difference between DMAEAMeCl/AAm gels and DMAEMA-MeCl/AAm gels are only on the side-chain group in the opposite side of the functional group across the main chain: hydrogen in the DMAEA-MeCl/AAm gels and methyl-base in the DMAEMA-MeCl/AAm gels.…”

“…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.…”