Chromate (CrO(4)(2-)) and copper (Cu2+) adsorption by dual-functional ion exchange resins made from agricultural by-products.
Chromate (CrO(4)(2-)) and copper (Cu2+) adsorption by dual-functional ion exchange resins made from agricultural by-products.
复制标题
DOI：
10.1016/j.watres.2006.04.030
复制
发表时间：
2006-07
期刊：
影响因子：
12.8
通讯作者：
W. E. Marshall;L. Wartelle
中科院分区：
文献类型：
--
作者：
W. E. Marshall;L. Wartelle
离子交换树脂通常具有单一的阳离子或阴离子官能团。同时具有阳离子和阴离子双重官能团的树脂并不常见。本研究的目的是以大豆壳、甘蔗渣和玉米秸秆为原料制备双功能离子交换树脂。采用两步法制备了双功能树脂。在前两步过程中，副产物与柠檬酸溶液反应，以增加负电荷，然后与交联剂二甲基二羟乙基脲(DMDHEU)和季胺(氯化胆碱)反应，向木质纤维材料添加正电荷。在第二个两步过程中，反应顺序颠倒，先加正电荷，再加负电荷。这些联合反应增加了副产物的阳离子和阴离子性质，与未经修饰的副产物相比，铜(Cu2+)阳离子和铬酸盐(CrO42−)阴离子的去除量增加了。反应的顺序似乎略微倾向于最后添加的功能。也就是说，如果最后加负电荷，得到的树脂比先加负电荷的可比树脂隔离更多的铜离子，反之亦然。在同时含有竞争阳离子和阴离子的溶液中，以Cu2+和CrO42−作为标记离子。与用于比较的商用阳离子或阴离子交换树脂相比，双功能树脂对标记离子的吸附与之相当或更多。没有一种商业树脂表现出与副产品树脂相同程度的双重功能特性。
Ion exchange resins commonly have a single functionality for either cations or anions. Resins that have a dual functionality for both cations and anions are uncommon. The objective of this study was to create dual-functional ion exchange resins derived from soybean hulls, sugarcane bagasse and corn stover. Dual-functional resins were prepared by two separate two-step processes. In the first two-step process, by-products were reacted with a solution of citric acid in order to impart additional negative charge, and then reacted with the cross-linking reagent dimethyloldihydroxyethylene urea (DMDHEU) and a quaternary amine (choline chloride) to add positive charge to the lignocellulosic material. In the second two-step process, the order of reaction was reversed, with positive charge added first, followed by the addition of negative charge. These combined reactions added both cationic and anionic character to the by-products as evidenced by the increased removal from solution of copper (Cu2+) cation and the chromate (CrO42−) anion compared to unmodified by-products. The order of reaction appeared to slightly favor the functionality that was added last. That is, if negative charge was added last, the resulting resin sequestered more copper ion than a comparable resin where the negative charge was added first and vice-versa. Cu2+and CrO42−were used as marker ions in a solution that contained both competing cations and anions. The dual-functional resins adsorbed as much as or more of the marker ions compared to commercial cation or anion exchange resins used for comparison. None of the commercial resins exhibited dual-functional properties to the same extent as the by-product-based resins.