Study on the influence of inductive groups on the performance of carboxylate-based hydrogel polymer network
Study on the influence of inductive groups on the performance of carboxylate-based hydrogel polymer network
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诱导基团对羧酸基水凝胶聚合物网络性能影响的研究
DOI：
10.1016/j.polymertesting.2019.106117
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发表时间：
2019
期刊：
影响因子：
5.1
通讯作者：
Kazuhiro Hara
中科院分区：
文献类型：
--
作者：
Nguyen Sura;Hirotaka Okabe;Brian A. Omondi;Albert Mufundirwa;Yoshiki Hidaka;Kazuhiro Hara
研究了BR和CH3诱导基团对羧酸盐基水凝胶吸附剂负载量的影响。用FTIR、UV-Vis、~(13)C核磁共振和DSC等方法对合成的金属离子捕集用丙烯酸钠(NaAc)和2-溴丙烯酸(BRAC)共聚物水凝胶的结构和功能进行了表征。红外光谱和UV-Vis光谱均表明，BrCH3基团与羰基(C═O)形成了电荷转移络合物，固体核磁共振显示Br基团在水凝胶骨架上以附属物的形式出现。通过在水凝胶基质上引入BR基团，从而利用该基团的高电负性势和诱导效应化学，显著增加了H+离子的离解，从而提高了羧酸基的负载量。这有利于更高的离子交换能力，从而使从多元素金属离子竞争溶液中吸附时的吸附容量最多增加4倍。在单离子非竞争性溶液中，由于BR基团的作用，其对钒的吸附容量从119 mg/g增加到373 mg/g，提高了三倍。但CH3的加入反而降低了水凝胶的吸附容量(<119 mg/g)，同时也降低了官能化水凝胶的溶胀度。
We report study on the effect of Br and CH3inductive groups on the loading capacity of carboxylate-based hydrogel adsorbent. Synthesized sodium acrylate (NaAc) and 2-Bromoacrylic acid (BrAc) copolymer hydrogels for metal ion capture were characterized using FTIR, UV–Vis,13C NMR, and DSC methods for structural and functional properties. Both FTIR and UV–Vis spectra indicated formation of a charge transfer complex between Br, CH3groups and the carbonyl (C═O) group whereas solid-state NMR evidenced Br group appearance as an appendage on hydrogel backbone. By incorporating Br group on the hydrogel matrix and consequently exploiting the high electronegativity potential and inductive effect chemistry of this group, there was a significant increase in dissociation of H+ions and hence higher loading capacity of carboxylate group. This facilitated higher ion exchange ability, resulting in up to 4 times increase in adsorption capacity during adsorption from multi-element metal ion competitive solution. Separately, when applied on single ion non-competitive solution, its adsorption capacity on vanadium increased three-fold from 119 mg/g to 373 mg/g due to the effect of Br group. However, the CH3had a negating effect instead lowering the adsorption capacity (below 119 mg/g); while also caused lower swelling ratio of carboxylate-functionalized hydrogel adsorbents.