A Possibility of Hydro gels as Environment Purifying Materials

Clouding Properties of Maleic Acid/Acrylamide Gels

“…Gel is a kind of two-component system made up of solvent and network. Because of this structural characteristic, the interactions between the two constituents affect considerably properties of the gel [1,2], which are very interesting and seem also to be utilizable for the industrial applications as a smart material [3][4][5]. Besides, some gels also show curious structural features in the dehydrated state, such as micro-phase separation, of which the structure is quite sensitive to environmental conditions [6,7].…”

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

“…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].…”

“…As the first examinatiom of the heavy-metal-anion capturing property of hydrogels, copolymer gels of dimethylaminoethylmethacrylate quaternised with methylchloride (DMAEMA-MeCl) and acrylamide (AAm) was adopted as the adsorbent [6]. In the examinations, their high heavy-metal-anion capturing efficiency and a possibility as an environment purifying material were revealed [6]; the amounts of the captured heavy-metal anions by the DMAEMA-MeCl/AAm gels [6] are higher than PAAm/SA [5] and CMC-Na [5] gels, which capture heavy-metal cations, and needless to say, higher than other adsorbents such as zeolite, ion-exchange resins.…”

“…Then, the authors investigated Cr(VI)-capturing property of the copolymer gels of N,N-dimethylaminoethylacrylamide (DMAEAAm) and AAm in order to make clear the role of the terminal group [8]: the structure of DMAEAAm is almost identical with DMAEA-MeCl except for polarizing terminal group in the side chain. In the investigations, it was found that the DMAEAAm/AAm gels capture ~1/2 the amount of Cr(VI) that the DMAEA-MeCl/AAm gels adsorb, which indicates an important role of 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.…”