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.

Non-equilibrium ThO(X) that was vibrationally hot but rotationally cold was produced by pulsed laser vaporization followed by supersonic expansion. This source was ideal for spectroscopic investigations of vibrationally excited levels of both the ground and electronically excited states. Laser induced fluorescence spectroscopy has been used to characterize vibrationally excited levels of the X, C, D, E, F and I states. Data for the ground state have been used to determine the potential energy curve for the energy range 0-13000 cm(1). In addition, transitions to newly identified states O'(0(+)) and L'(1) are tentatively assigned. The results are found to be in reasonable agreement with the predictions of ligand field theory models. (C) 2019 Elsevier Inc. All rights reserved.

Ligand field theory calculations of energy levels were performed for the neutral neodymium monoxide by treating the molecular electronic states as Nd2+ free-ion levels perturbed by the ligand field of O-2(-). Thirty six experimentally characterized NdO v = 0 energy levels were fitted using a single-atomic-configuration approximation LFT models that included Nd2+ molecular energy levels with the lowest (maximum S-c, maximum L-c) 4f-core atomic multiplet states of 4f(3)(I-4)6s, 4f(3)(I-4)5d, 4f(3)(I-4)6p, 4f(4)(I-5), and 4f(2)(H-3)6s(2), configurations. Predictions from these calculations were used to provide tentative assignments for 50 NdO bands reported in the literature. Term energies for eight new electronic states of NdO have been determined based on these assignments. The dipole moment for NdO [16.7]3 state and magnetic g(e) factor determined in Linton et al. (2008) were used to assign this state to the 4f(3)(I-4)6p electronic configuration. The integer valence, atomic-in-molecule, ionic bonding idea reveals atomic energy level patterns that are multiply replicated in the molecular energy level patterns of five Nd2+O2- atomic ion configurations. This underlying atomic ion structure gives rise to the complex and seemingly erratic unassigned bands reported in the literature. A comparison with ab initio calculations is given. The state symmetries and energy values of 54 levels of NdO 4f(3)(I-4)6s configuration from ab initio calculation reported in Allouche et al. (2006) coincide within accuracy of 8 cm (1 )(1 sigma) with a LFT model when the LFT parameters were allowed to vary. (C) 2019 The Author. Published by Elsevier Inc.

Two-dimensional (2D) and one-dimensional (1D) quantum-sized γ-AlOOH structures were deposited onto siliceous and cellulosic substrates in a one-step, aqueous, and moderate temperature process. Low cost, large scale manufacturing of siliceous and cellulosic substrates coated with 2D and 1D arrays of γ-AlOOH crystallites of 2.7 ± 0.5 nm in diameter, with an average height of 3 ± 2 nm and 250 ± 50 nm, respectively was demonstrated. Direct measurement of streaming potentials in NaCl aqueous electrolyte was accomplished in order to characterize the zeta potentials of the as mentioned surfaces. It was shown that the isoelectric point value of rough nanostructured surface is three pH units higher as compare to the flat crystalline γ-AlOOH surface, resulting in a high removal efficacy of submicron particles from aqueous suspension by the surfaces with combined microscale and nanoscale structures. Furthermore, ageing characteristics of the 2D and 1D γ-AlOOH crystallites were presented, which showed great removal efficiencies after seven to fourteen years of manufacturing.

Configuration interaction ligand field theory (CI LFT) calculations of the electronic energy levels of ThO were performed by treating the molecular electronic states as Th 2+ free‐ion levels perturbed by the ligand field of O2−. Twenty nine experimentally characterized ThO v = 0 energy levels, together with the energy difference between the v = 0 levels of the Y and W states were fitted using a CI LFT model that included Th 2+ 7s 2 , 6d7s, 6d2, 7s7p, 6d7p, 5f7s, and 7p2 configurations. Predictions from these calculations were used to provide tentative assignments for 171 out of 250 ThO band heads listed by Gatterer et al. [“Molecular Spectra of Metallic Oxides”, Specola Vaticana (1957)]. Term energies for 30 electronic states have been determined based on these assignments. Subsequently, the CI LFT model was refined by fitting to a set of 59 electronic term energies. The inclusion of CI effects together with integer valence, atomic‐in‐molecule, ionic bonding ideas reveals atomic energy level patterns that are multiply replicated in the molecular energy level patterns of six Th 2+ O2− atomic ion configurations (6d7s, 6d2, 7s7p, 6d7p, 5f7s, and 7p2) revealing the underlying atomic ion structure that gives rise to the complex and seemingly erratic unassigned bands reported in the Vatican Atlas. © 2018 Wiley Periodicals, Inc.

The vast majority of analytical and numerical models developed to explain pressure-driven electrokinetic phenomena assume that the local electrical double layer field over heterogenious surfaces is independent of the flow field and described by the Poison-Boltzman equation. However, for pressure-driven flow over a surface with heterogeneous patches with combined microscale and nanoscale structures the local electrical double layer fields are different above the patch and in the region between the patches. The nonuniform surface charge produces distortions in the equilibrium electrostatic field. The characteristic symptom of field distortion is the generation of flow velocities in all three coordinate directions, including a circulation pattern perpendicular to the main flow axis therefore severely distorting the Poisson-Boltzmann double layer. The result is an exceptionally high microbes and ions removal efficiencies from aqueous suspension by the alumina’s surfaces with combined microscale and nanoscale structures that strongly suggests existence of a coupling effect of the local electrical double layer (EDL) field with the local flow field.

The pristine point of zero charge (p.p.z.c) and zeta potential as a function of pH of boehmite oxide/hydroxide (α-Al2O3·H2O) have been determined for three filter media. The active component in the first two filter media is boehmite nanofibers, only 2 nm in diameter and about 300 nm long. Boehmite nanofibers create high zeta potential (ζtrue≥46 mV) in aqueous solutions in the pH range of 3–8. The p.p.z.c. values were determined to be 11.60 ± 0.15 for nanofibers grafted onto microglass fibers and 11.40 ± 0.15 for agglomerated nanofibers. In the third filter media, a boehmite nanolayer in the form of monocrystalline oxide/hydroxide with a thickness of approximately 1.2 nm is electroadhesively deposited onto siliceous support material with large surface area of about 50 m2/g, therefore forming a highly electropositive composite of boehmite nanolayer on the second highly electronegative solid. Boehmite’s oxide-hydroxide nanolayer surface creates high zeta potential (ζtrue≥50 mV) in aqueous solutions in the pH range of 3–8. The p.p.z.c. value was determined to be 11.38 ± 0.15. The reported values are within accuracy, but they are much higher than the values reported in the literature. X-ray powder diffraction data were supplemented by microscopy, infrared spectroscopy in order to characterize fully synthetic boehmite surfaces.

Aluminum oxide-hydroxide nanolayer with a thickness of approximately 1.2 nm is electroadhesively deposited onto silicious support material with large surface area of about 50 m2/g, forming a highly electropositive composite of boehmite nanolayer in the form of monocrystalline oxide/hydroxide (α-Al2O3·H2O) on the second electronegative solid. The composite can be viewed as a sphere with a rough surface and charge density of approximately 0.08 C/m2. This creates a significant electric field with negligible screening (ka ≪ 1) in the region close to the surface of the nanocomposite. This field attracts nano- and micron-sized particles from as far as 200 μm in a few seconds, many orders of magnitude greater than conventional Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, which predicts only nanometer-scale effects arising from the presence of the surface. The strong electric field on the surface is then able to retain small particles such as viruses, atomically thin sheets of graphene oxide, RNA, DNA, proteins, dyes as well as heavy metals such as cobalt, arsenic, and lead. Alumina’s nanolayer surface can be further functionalized by adding other sub-micron or nano-sized particles to target a specific contaminant. An example is shown where alumina nanolayer is coated with nano-sized iron monohydrate to yield an arsenic sorbent that shows high sorption capacity.

Aluminum oxide-hydroxide nanofibers, 2 nm in diameter and approximately 250 nm long, are electroadhesively grafted onto glass microfibers, therefore forming a macroscopic assembly of alumina nanofibers on the second solid in highly organized matter. The assembly can be viewed as a straight cylinder with rough surface and charge density of approximately 0.08 C/m2. This creates a significant electric field with negligible screening (ka ≪ 1) in the region close to the surface of the assemblies. This field attracts nano- and micron-size particles from as far as 0.3 mm in less than a few seconds, many orders of magnitude greater than the conventional Derjaguin–Landau–Verwey–Overbeek theory that predicts only nanometer-scale effects arising from the presence of the surface. The strong electric field on the surface is then able to retain particles such as micron-size powdered activated carbon as well as much smaller particles such as fumed silica nanoparticles of 10–15 nm in diameter, viruses, atomically thick sheets of graphene oxide, latex spheres, RNA, DNA, proteins, and dyes.

We have recently reported a nanoprobe technique based on time-of-flight secondary ion mass spectrometry (ToF-SIMS) capable of obtaining molecular information from individual nanoobjects. The technique is based on event-by-event bombardment/detection, where information from individual objects is obtained via coincidental secondary ion emission from single projectile impacts. Here, we demonstrate that the event-by-event mode is sensitive to the chemical and/or physical separation of molecular species. As a test case, two nanoobject samples with the same chemical composition were prepared with different morphologies. Both consisted of polystyrene spheres deposited onto nanoalumina whiskers, but their structures differed. One sample contained 30 nm spheres intact, and the other produced nanoflake structures. Bombardment with Au-400(4+) at 136 keV total impact energy demonstrates that conventional mass spectra do not reflect differences between the morphologies, whereas the coincidental mass spectra show significant differences in coemission of aluminum-based and carbon-based secondary ions. Copyright (C) 2010 John Wiley & Sons, Ltd.

This paper demonstrates how the strong inherent electropositive charge properties of nano alumina (AlOOH) fiber that is 2 nm in diameter is incorporated into media and can be used or modified with absorbents for purification of water containing many metal ions, endocrine disruptors and PCB’s. The nanoalumina (“NC”) media has a high dynamic response for adsorption, allowing purification within a very shallow bed with media depths less than 1 mm (e.g., by a single layer pleated cartridge) and doing so at flow rates an order of magnitude or greater than can be achieved with an ultraporous membrane. This study also correlates change in zeta potential with adsorption of Cu ions as a function of pH of the solution. A version of the NC media embodies powdered activated carbon (“PAC”) that is retained in the structure by electrostatic forces. The PAC version is capable of high efficiency in both particle adsorption and physical absorption. This media was challenged by organic pollutants representative of endocrine disruptors including trace pharmaceuticals and phenolic monomers. Dynamic absorption data are presented for Penicillin G, Bisphenol A and Flumequine, showing that a single layer of PAC is an effective absorber of such organics while in the ppm to low ppb billion range. Both NC and PAC filters were challenged by a mixture containing 209 PCB’s (a known carcinogen) and tested in accordance with EPA Method 1668A (detection limit 0.25-0.75 ng/L). At a challenge of 20,797 ng/L, the filter retained eight of the ten cogener PCB groups to less than detectable, with a total retention of 3.21 ng/L for all groups combined. (Beta coefficient ~ 6400). The NC filter, intended as a control, surprisingly retained PCB’s at least as good if not better than the PAC. The nanoalumina filters ability to retain PAC particles was tested. The nanoalumina structure shed ten to fifty times less particles than a control containing no nanoalumina. The theoretical basis for the retention is discussed. Purification of contaminants by PAC media therefore embodies three different mechanisms: electroadsorption and chemisorption by the nanoalumina, plus physical adsorption by the small PAC particles held within the media.

Nano alumina fibers, 2nm in diameter and approximately 0.25m long are electroadhesively grafted to a microglass fiber. A non-woven media is formed by conventional wet-laid paper making technology. The media has a high affinity for virus, DNA/RNA, proteins, endotoxins, and antigens. A model was developed using data from adsorption of 30nm latex spheres and was verified with MS2 coliphage. The media is capable of separating equal size 3 and MS2 viruses. The process may be used for concentration and separation of biological particles, at high rates of flow and at pressures less than1 bar over ambient.

An electrostatic filter containing powdered activated carbon (PAC) can retain high levels of microbes while the PAC within the structure has a high dynamic response as a chemical absorber. In water, a 2.5 '' diameter, 10 '' long pleated cartridge (without PAC) retained greater than 6 LRV (log retention value) of bacteria and >3 LRV of MS2 virus at flowrate of 1 gallon per minute (GPM). This study provides background data on the precursor filter, which uses a highly electropositive 2 rim alumina monohydrate fiber in a 2 mu m pore size media. Sub-micron particles are retained primarily by electrostatic forces. Data compare the PAC version to the precursor. The PAC filter has a higher retention of virus, and at least an equivalent retention of bacteria and fine (similar to 9 mu m) test dust. Data are shown for adsorption of dissolved iodine and chlorine by the PAC media under short (similar to 0.3 second) residence times, as compared to commercialized thin layer media containing granular activated carbon (GAC). The new PAC media has a dynamic adsorption rate at least two orders of magnitude greater than GAC media. The PAC media shows high promise as a chem-bio filter for purifying water. Preliminary data on air filter media are also presented.

Secondary ion mass spectrometry (SIMS) run in the event-by-event bombardment/detection mode provides a unique ability to obtain molecular information from single nano-objects, since assays are based on secondary ion coemission from single impacts. The characterization of individual nano-objects is demonstrated with negatively charged polymer spheres that are attracted to and retained by nanoalumina whiskers. The whiskers, 2 nm in diameter and approximately 250 nm in length, are grafted to a microglass fiber with an average diameter of approximately 0.6 microm and several millimeters long. The spheres are monodisperse polystyrene nanoparticles (30 nm diameter). Massive Au projectiles, specifically 136 keV Au(400)(4+), were utilized to bombard analyte surfaces due to its high efficiency for producing multi-ion emission identified by time-of-flight mass spectrometry. Our results show that this mode of mass spectrometry can provide information on the nature, size, relative location, and abundance of nano-objects in the field of view. The key to characterizing nanodomains is to monitor the coincidental secondary ion emission from the nanovolume perturbed by single projectile impacts.

We present secondary ion mass spectrometry (SIMS) data obtained from the bombardment of a novel nanomaterial with a suite of projectiles: Au1+, Au3+, Au9+, and Au400(4+). These are the first experiments where free-standing nano-objects were bombarded with kiloelectronvolt projectiles of atomic to nanoparticle size (Au400(4+)). The objects are aluminum monohydrate nanowhiskers, identified as crystalline boehmite (AlOOH) using X-ray diffraction. The nanoalumina is bonded to a microglass fiber that serves as a scaffold. The largest projectile, Au400(4+), has a diameter of approximately 2 nm, comparable to the nominal diameter of the nanowhiskers. There are notable differences in secondary ion (SI) response from sample volumes too small for full projectile energy deposition. The whisker spectra are dominated by small clusters--the most abundant species being AlO- and AlO2-. Bulk samples have larger yields for AlO2- than AlO-, whereas this trend is reversed in the whisker samples. Bulk samples give similar abundances of large SI cluster families [(Al2O3)(n)AlO2]- and [(Al2O3)(n)OH]-, whereas the whisker samples give an order of magnitude lower yield of these SIs. Given the nature of our experiments, i.e., the event-by-event bombardment/detection mode, we are uniquely able to obtain information from SIs emitted from single-projectile impacts. As such, effective yields were calculated in order to determine quantitative differences between the nano-objects and bulk samples.

We report quantum calculations of vibrational states of trans N-methyl acetamide (H3C-HNCO-CH3) in full dimensionality using the code MULTIMODE. In this code, the full potential is represented as a hierarchical sum of n-mode potentials in the normal coordinates. All 30 one- and 435 two-mode potentials are included in the sum, as well as a restricted set of 10 three-mode potentials corresponding to the experimentally probed amide band. The electronic energies on the various n-mode grids are obtained using ab initio Moller-Plesset perturbation theory with a triple-zeta quality, correlation-consistent basis set. Convergence tests of the low-lying vibrational eigenvalues of the amide band show that this limited three-mode representation of the full potential yields well converged results that are in excellent agreement with experiment. The infrared spectrum in the region of the amide bands is calculated and also agrees well with experiment.