LDH-Co-Fe-Acetate: A New Efficient Sorbent for Azoic Dye Removal and Elaboration by Hydrolysis in Polyol, Characterization, Adsorption, and Anionic Exchange of Direct Red 2 as a Model Anionic Dye

Abstract

A new, double hydroxide based on Co and Fe was elaborated on by forced hydrolysis in a polyol medium. Complementary characterization techniques show that this new phase belongs to the layered double hydroxide family (LDH) with Co2+ and Fe3+ ions located in the octahedral sites of the bucite‑like structure. The acetate anions occupy interlayer space with an interlamellar distance of 12.70 Å. This large distance likely facilitates the exchange reaction. Acetates were exchanged by carbonates. The as‑obtained compound Co‑Fe‑Ac/Ex shows an interlamellar distance of 7.67 Å. The adsorption of direct red 2 by Co‑Fe‑Ac‑LDH has been examined in order to measure the capability of this new LDH to eliminate highly toxic azoic anionic dyes from waste water and was compared with that of Co‑Fe‑Ac/Ex and Co‑Fe‑CO3/A (synthesized in an aqueous medium). The adsorption capacity was found to depend on contact time, pH, initial dye concentration, and heating temperature. Concerning CoFeAc‑LDH, the dye uptake reaches a high level (588 mg/g) due to the occurrence of both adsorption processes: physisorption on the external surface and chemical sorption due to the intercalation of dye by exchange with an acetate anion. The study enables us to quantify the uptake amount of each effect in which the intercalation has the most important amount (418 mg/g).

MIL-88A derived CoFe-layered double hydroxides with optimized composition for the enhanced electrocatalytic oxygen evolution reaction

“…The broad absorption band centered at ∼3430 cm −1 corresponds to the O–H stretching vibrations from the coordinated hydroxide ions or intercalated/adsorbed water molecules. 62–64…”

“…The broad absorption band centered at B3430 cm À1 corresponds to the O-H stretching vibrations from the coordinated hydroxide ions or intercalated/adsorbed water molecules. [62][63][64] ICP-AES was performed to find the actual content of Co and Fe in the as-prepared CoFe-LDHs. The results are summarized in Table 1.…”

Graphene and Other 2D Layered Nanomaterials and Hybrid Structures: Synthesis, Properties and Applications

“…Drici-Setti et al [ 21 ] prepared layered double hydroxides (LDHs) based on Co, Fe and acetate ions by forced hydrolysis in a polyol medium. The synthesized Co-Fe-acetate LDH exhibited anion exchange properties and the acetate interlayer species were successfully exchanged by carbonate anions with a topotactic reaction.…”