Fast Synthesis and Size Control of Gibbsite Nanoplatelets, Their Pseudomorphic Dehydroxylation, and Efficient Dye Adsorption

Abstract

In this paper, a simple and fast (4 days) procedure to synthesize colloidal gibbsite nanoplatelets (NPTs) from a single aluminum alkoxide (aluminum sec-butoxide) as precursor is presented. The introduction of a preheating step accelerated the precursor's hydrolysis/peptization and considerably shortened the overall reaction time while the acid concentration affected the uniformity of the platelets shape. This procedure was successfully exploited to rapidly produce gibbsite platelets of controllable sizes by combination with the seeded growth method. The use of a single alkoxide precursor induced high growth rates and allowed a fast control of the platelets size over a wide range (nano- to microscale after only three growth steps). No signs for size limitation were observed. The dehydroxylation sequence of the as-synthesized NPTs was systematically investigated. Thermally stable chi-alumina NPTs, pseudomorphs of the parent gibbsite platelets, with a micro/mesoporous structure and high specific surface area, were obtained. The synthesized gibbsite NPTs can efficiently adsorb Methyl Orange dye in wastewater treatment with removal efficiency up to 94.8%.

Atomistic Structure of Mineral Nano-aggregates from Simulated Compaction and Dewatering

“…Note that the SA reported in Fig. 3B is larger than that observed for gibbsite (i.e., 418 m 2 /g) 43 and typical clays (i.e., ~30 m 2 /g) 10 because of the small particle size in our simulations. The results suggest that decreasing the dewatering rate and water content reduces the porosity of nanoparticle aggregates.…”

“…5C ). This particle is much smaller than those synthesized in the laboratory or found in the nature 43 , 47 – 49 . However, this work focuses on the micro-porosity of nanoparticle aggregates, and in consideration of computational resources and simulation time, our particle size selection is a reasonable choice.…”

“…Each gibbsite layer consists of a sheet of octahedral Al atoms coordinated by 3 hydroxyl O atoms each above and below the Al sheet. Gibbsite grows well along the lateral (‘ a ’ and ‘ b ’) directions that include the octahedral sheets, resulting in thin hexagonal nanoparticles 43 , 47 – 49 . In our approach, a hexagonal gibbsite particle was cleaved from a slab of 3 layers of gibbsite along the (1 0 0) and (1 1 0) directions as shown in Fig.…”

Theoretical Study of Aluminum Hydroxide as a Hydrogen-Bonded Layered Material

“…On the other hand, there is another well-known interaction for weak interlayer binding, namely, the hydrogen bonding. Al(OH) with interlayer hydrogen bonds is an example which has been studied both experimentally and theoretically before [ 18 , 19 , 20 , 21 , 22 ]. However, their properties as a quasi 2D layered material have not been sufficiently appreciated compared to the vdW-interaction-mediated materials.…”

Combined microfluidics–confocal Raman microscopy platform for studying enhanced oil recovery mechanisms

“…Gibbsite nanoplatelets were synthesized using the so‐called hydrothermal method, which was reported before . Briefly, 0.05‐M HCl was dissolved in a 0.16‐M aluminum sec ‐butoxide (Sigma) aqueous solution.…”