In situ synthesis of layered double hydroxides on γ-Al2O3 and its application in chromium(VI) removal

Abstract

Mg-Al layered double hydroxides (LDHs) adsorbent was synthesized in situ on γ-AlO for the removal of Cr(VI) from aqueous solution. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electronic microscopy and thermogravimetry and differential thermal analysis. Compared to the LDHs powder, the calcined LDHs sorbent prepared in situ on γ-AlO had higher specific surface area and was easy to recover and reuse. The adsorptive capacity for removing Cr(VI) from aqueous solution was resulting from the memory effect of LDHs based on the XRD results. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. Furthermore, the adsorbent exhibits excellent sorption-regeneration performances.

Oxyanion-Binding in a Bioinspired Nanoparticle-Assembled Hybrid Microsphere Structure: Effective Removal of Arsenate/Chromate From Water

“…A similar phenomenon was also seen for phosphate anions (Figure a) under the similar conditions. It has been reported that the interaction of phosphate with amine containing polypeptides present in the Diatom structure can generate supramolecular aggregates, and this phenomenon is therefore thought to be a key step in the biosilicification process …”

“…Both of arsenic and chromium exist in water mainly in their tetrahedral oxyanionic form. , Therefore, the removal of these oxyanions from drinking water either through natural biogeochemical processes or engineered approaches is imperative to mitigate its potential environmental and health risk. Conventionally, it is done by absorbing the ions on porous materials, ion-exchange resin, alumina, zeolite, activated carbon, iron compounds, clays, and so forth. − However, besides their main limitations in the removal capacity and selectivity, there are other factors, such as, the complicated methods or harsh conditions used in the preparation of the adsorbent materials; the stability and reusability of the materials over a wider pH range as required in the remediation process, and so forth, which have been detrimental to the practical applicability of these materials . Alternatively, the biogenic materials having the potential to remove the toxic anions via direct binding with the carboxyl and hydroxyl moieties present on these systems, have also been explored .…”

Novel synthesis of a clay supported amorphous aluminum nanocomposite and its application in removal of hexavalent chromium from aqueous solutions

“…have been used for the remediation of Cr(VI) in the environment but only physical sorption resulted in almost complete desorption in just 3 hours. 28,29 Here, for the rst time, we have synthesized amorphous aluminium by NaBH 4 reduction method and supported them on bentonite clay to prevent further aggregation of smaller particles and hence to have very high reactivity. Novel clay supported amorphous aluminium was characterized by XRD, TEM-EDS, FT-IR, XRF etc.…”

Silica based inorganic–organic hybrid materials for the adsorptive removal of chromium

“…A large number of natural and synthetic materials have been used for the adsorption-based removal of heavy metals from wastewater. [6][7][8][9] These materials include zeolites, clays, biosorbents, resins, activated carbon magnetic particles and silica. Simple and low cost adsorbents have been synthesized by several researchers for an effective removal of heavy metals including Cr(VI) even at low concentration.…”

“…Simple and low cost adsorbents have been synthesized by several researchers for an effective removal of heavy metals including Cr(VI) even at low concentration. [10][11][12][13][14][15][16][17] Li et al, demonstrated the preparation of chitosan nanobers with an average diameter of 75 nm and cross linked with glutaraldehyde for the removal of Cr(VI). 18 Aboutorabi et al, employed TMU-30 based metal-organic framework (MOF) containing isonicotinate N-oxide as adsorptive sites for the adsorption of Cr(VI) from aqueous solution.…”