Boehmite and Akaganeite 1D and 2D Mesostructures: Synthesis, Growth Mechanism, Ageing Characteristics and Surface Nanoscale Roughness Effect on Water Purification

Abstract

The role of surface nanoscale roughness on the charging behavior of nanostructured γ-AlOOH (Boehmite) and β-FeOOH (Akaganeite)/γ-AlOOH (Boehmite) mesostructures deposited onto siliceous substrates has been investigated. Two-dimensional (2D) quantum-sized and one-dimensional (1D) nanometer size γ-AlOOH (Boehmite) structures and 2D atomically-thin β-FeOOH (Akaganeite) nanobelts with a mean width of approximately 10 nm were deposited onto siliceous substrates in aqueous processes at moderate temperatures. Low cost and large scale manufacturing of siliceous substrates coated with 2D and 1D γ-AlOOH (Boehmite) crystallites of 2.7 ± 0.5 nm in diameter, with an average length of 2.9 ± 0.9 nm and 250 ± 50 nm, respectively, that were further functionalized with atomically thin 2D β-FeOOH (Akaganeite) nanobelts was demonstrated. Zeta potentials of surfaces have been characterized by direct measurement of streaming potentials in NaCl aqueous electrolyte. A model explaining the pH dependent behavior of the zeta potential was proposed. The isoelectric point values of rough nanostructured surfaces are three pH units higher as compare to the flat crystalline γ-AlOOH (Boehmite) and β-FeOOH (Akaganeite) surfaces, resulting in a high removal efficacy of submicron particles from aqueous suspension by the surfaces with combined microscale and nanoscale structures. This suggests the existence of a coupling electrokinetic effect of the local electrical double layer (EDL) fields with the local flow fields.

Enhancement of cytotoxic and antioxidant activities of Digenea simplex chloroform extract using the nanosuspension technique

“…As a consequence, Fig. 1d shows a reduced zeta potential (-5.5 mV) [62], which might be attributable to PVA's nonionic stabilizing characteristics creating a coat around ChlE nanoparticles. As a surfactant, tween 40 is also important for making nanosuspension because it lowers the free surface energy of ChlE-NS molecules, which keeps them from sticking together [63].…”

pH dependent reactivity of boehmite surfaces from first principles molecular dynamics

“…The PZC determined from the vertical energy gap method is 9.36, in agreement with the prior experimental work reported to be 9.5 AE 0.5 pK a units. 6 (100) Surface…”

“…This yields a PZC (or other property) that is highlydependent on the morphology of the nanoparticle; for instance platelets of the aluminum oxyhydroxide mineral boehmite, AlO(OH), that primarily expose the (010) surface have a reported PZC of 9.5 whereas nanorod particles that increased the surface area the (100) and (101) faces have a value of 11.4. 6 Yet advances to synthesis methodologies are now allowing for the selective production of nanoparticles with specific morphologies, as in the recent work of Zhang et al that has focused upon boehmite nanoparticle synthesis. 7 Boehmite is important to many scientific communities and serves as an excellent framework for understanding variations in surface properties as a function of nanoparticle morphology.…”

“…This yields a PZC (or other property) that is highly-dependent on the morphology of the nanoparticle; for instance platelets of the aluminum oxyhydroxide mineral boehmite, AlO(OH), that primarily expose the (010) surface have a reported PZC of 9.5 whereas nanorod particles that increased the surface area the (100) and (101) faces have a value of 11.4. 6…”

Smart Nanostructured Materials: From Molecular Self-Assembly to Advanced Applications

“…In the study by L. A. Kaledin et al [5], the aluminumwater reaction has successfully been used to produce 2D and 1D quantum (and nanometer) size of γ-AlOOH (Boehmite) and β-FeOOH (Akaganeite)/γ-AlOOH (Boehmite) mesostructures deposited onto siliceous substrates in a one-step process at moderate temperature. The investigation of the role of surface nanoscale roughness and charging behaviour evidenced that the isoelectric point values of rough nanostructured surfaces were three pH units higher compared to the flat crystalline γ-AlOOH (Boehmite) and β-FeOOH (Akaganeite) surfaces, resulting in a high removal efficacy of submicron particles from aqueous suspension by the surfaces with combined microscale and nanoscale structures.…”