Abstract

We prepared ethylenediaminetetraacetic acid (EDTA)-intercalated MgAl-layered double hydroxide (LDH-EDTA), then grafted acrylamide (AM) to the LDH-EDTA by a cross-linking method to yield a LDH-EDTA-AM composite; we then evaluated its adsorptive ability for Congo red (CR) and hexavalent chromium (Cr(VI)) in single and binary adsorption systems. The adsorption process on LDH-EDTA-AM for CR and Cr(VI) achieved equilibrium quickly, and the removal efficiencies were minimally affected by initial pH. The maximum uptake quantities of CR and Cr(VI) on LDH-EDTA-AM were 632.9 and 48.47 mg/g, respectively. In mixed systems, chromate removal was stimulated by the presence of CR, while the adsorption efficiency of CR was almost not influenced by coexisting Cr (VI). The mechanisms involved electrostatic attraction, surface complexation, and anion exchange for the adsorption of both hazardous pollutants. In the Cr(VI) adsorption process, reduction also took place. The removal efficiencies in real contaminated water were all higher than those in the laboratory solutions.

中文翻译：

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丙烯酰胺与EDTA夹层双氢氧化物的交联可提高Cr（VI）和刚果红的回收率：吸附和机理研究

摘要

我们制备了乙二胺四乙酸（EDTA）插层的MgAl层状双氢氧化物（LDH-EDTA），然后通过交联方法将丙烯酰胺（AM）接枝到LDH-EDTA，得到LDH-EDTA-AM复合材料。然后，我们评估了它在单和双吸附系统中对刚果红（CR）和六价铬（Cr（VI））的吸附能力。LDH-EDTA-AM对CR和Cr（VI）的吸附过程很快达到平衡，初始pH值对去除效率的影响最小。LDH-EDTA-AM上CR和Cr（VI）的最大吸收量分别为632.9和48.47 mg / g。在混合系统中，CR的存在促进了铬酸盐的去除，而CR（VI）的共存几乎不影响CR的吸附效率。其机理涉及静电吸引，表面络合，阴离子交换吸附两种有害污染物。在Cr（VI）吸附过程中，还发生了还原。实际污染水中的去除效率均高于实验室解决方案中的去除效率。