Layered Double Hydroxides for Remediation of Industrial Wastewater from a Galvanic Plant

Abstract

Owing to their structure, layered double hydroxides (LDHs) are nowadays considered as rising materials in different fields of application. In this work, the results obtained in the usage of two different LDHs to remove, by adsorption, some cationic and anionic pollutants from industrial wastewater are reported. The two compounds MgAl-CO3 and NiAl-NO3 have been prepared through a hydrothermal synthesis process and then characterized by means of PXRD, TGA, FESEM, and FTIR spectroscopy. The available wastewater, supplied by a galvanic treatment company, has been analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES), resulting as being polluted by Fe(III), Cu(II), and Cr(VI). The water treatment with the two LDHs showed that chromate is more efficiently removed by the NiAl LDH through an exchange with the interlayer nitrate. On the contrary, copper and iron cations are removed in higher amounts by the MgAl LDH, probably through a substitution with Mg, even if sorption on the OH− functional groups, surface complexation, and/or precipitation of small amounts of metal hydroxides on the surface of the MgAl LDH could not be completely excluded. Possible applications of the two combined LDHs are also proposed.

Thermal analysis of MgFe-Cl Layered doubled hydroxide (LDH) directly synthetized and produced “via memory effect”

“…The interlayer region is very flexible and able to host several types of compounds, both anions (strongly bonded), cations and organic molecules. This property explains the interest in these materials as catalysts, anionic sponge [7,8] and cations adsorber [7][8][9]. More recently, LDHs are attracting interest in the energy storage systems area, both as supercapacitors and batteries materials [10,11].…”

Functionalization of magnetic chitosan microparticles for high-performance removal of chromate from aqueous solutions and tannery effluent

“…The accumulation of hazardous metals in the food chain and their dramatic effects on human and animal beings clearly explain that their control in wastewater is progressively becoming more drastic. Chromate is frequently found in industrial wastewater issued from metal finishing [1], metallurgy and tanneries (among others) at very high levels. The treatment of these contaminated waters is thus critical for these industries, for minimizing their impact on the environment and water bodies, as well as maximizing the recycling of water resources [2].…”

Layered Double Hydroxides (LDHs)

“…The main areas of interest range from renewable energy production to water purification and remediation, including functionalized materials for piezoelectric nanogenerators and gas sensing. Great attention is paid to biomedical applications and to the synthesis of hybrid smart nanocomposites, which involve expanding sectors such as drug-delivery, food packaging and safety.Within this Special Issue, eight articles are collected, and are divided between synthesis techniques [1-3], applications [4][5][6], and review works [7,8].The first work, related to the synthesis of Mg-Al, Ca-Al, Zn-Al and Cu-Al LDHs, is the one carried out by Barnard and Labuschagne [1]. The authors, in order to propose a green synthesis technique, implement the wet mechanochemical method through the use of a Netzsch LME 1 horizontal bead mill, designed "ad hoc" for wet grinding applications.…”

“…Within this Special Issue, eight articles are collected, and are divided between synthesis techniques [1-3], applications [4][5][6], and review works [7,8].…”

“…The capability to exchange interlayer anions is another remarkable characteristic of LDHs, and can be exploited to either adsorb or release anionic species from or into the environment. In Reference [5], Cardinale et al explore the adsorption properties of MgAl-CO 3 and NiAl-NO 3 LHDs for the removal of some heavy metals from real wastewater, supplied by a galvanic treatment company. The authors found a certain degree of selectivity of these LDHs, in that Cr(VI) is more efficiently removed by the NiAl LDH through an exchange with the interlayer nitrate.…”