Recent developments in the preparation and properties of nanometer-size spherical and platelet-shaped particles and composite particles

Adair, James H.; Li, T.; Kido, T.; Havey, K.; Moon, Jooho; Mecholsky, John J.; Morrone, A.; Talham, Daniel R.; Ludwig, Matthias; Wang, L.

doi:10.1016/s0927-796x(98)80001-6

Cited by 170 publications

(106 citation statements)

References 114 publications

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“…3 shows that the absorbance peak in the spectrum of sample S-33 changes with time from 466 nm after 5 min to 487 nm after 1 h and then remains the same. The observed red shift in the surface-plasmon resonance has been explained previously in greater detail (8,16). An increase in the chemisorption of the hydrolyzed silanolic groups onto the silver surface, leading to demetallization, has been suggested in order to explain the red shift.…”

Section: Figsupporting

confidence: 78%

Coating of Nanosize Silver Particles with Silica

Hardikar

Matijević

2000

Journal of Colloid and Interface Science

188

133

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Section: Figsupporting

confidence: 78%

Coating of Nanosize Silver Particles with Silica

Hardikar

Matijević

2000

Journal of Colloid and Interface Science

188

133

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“…Deionized water was used (specific conductivity = 0.4 × 10 -7 S/m) for all experiments. The procedure used to prepare CaCO 3 particles is similar to that applied to produce platelet-like CdS particles in the octylamine/water bilayer systems (Adair et al, 1998). The general procedure can be described as follows, 25 mL 0.05 M CaCl 2 and 0.05 M Na 2 CO 3 aqueous solutions were mixed with 31.97 mL octylamine and 1.33 mL amylamine to form two individual batches of self-assembled bilayers (amylamine is able to stabilize the octylamine/water bilayer and provide a well-defined bilayer structure) (Yener et al, 2002).…”

Section: Particle Synthesismentioning

confidence: 99%

“…Analogy to the monolayer-confined synthesis, octylamine/water bilayer systems was employed by Adair et al (1998) to grow a number of nanoscale platelets including CdS, (Adair and Suvaci, 2000;Adair et al, 1998) Ag (Yener et al, 2002) and SiO 2 (Wang et al, 2006) at ambient condition. When mixed with water under appropriate weight ratio, the amines will orient in such a way that allows organic layer and aqueous layer to alternate in the solution, mainly because of the amphiphilic nature of the organic molecules (Adair et al, 1998;Ralston et al, 1942). The thickness of each layer is directly related to the amine to water weight ratio, which provides an effective pathway to manipulate the template thereby the nanoparticle thickness during synthesis.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Wang

White

Adair

2014

KONA

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Calcium carbonate particles with various shapes and morphologies were prepared via precipitation in an octylamine/water self-assembly bilayer systems. Crystal structure and shape of the CaCO 3 particles were determined by the water to octylamine molar ratio R of the bilayer. At R = 16.0, phase pure calcite particles with a "hopper crystal" morphology were formed, the average particle size of the hopper crystal is 10 μm with welldefined edges on the hopper faces. Decrease the R ratio to 7.2 eventually leads to the formation of 3 μm tabular CaCO 3 particles which are predominated by vaterite structure. For an intermediate R of 10.8, spherical vaterite aggregates and rhombohedral calcite particles were produced. Thermal decomposition of the CaCO 3 particles was observed at around 710°C. The mechanism of particle evolution in the self-assembly bilayer, particularly the formation of "hopper crystal" calcite was discussed.

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“…It is generally known that a condensed phase could exhibit different physical and chemical properties than its bulk phase as its dimension is reduced to a nanometer scale (Adair et al, 1998;José-Yacamán and Mehl, 1998). For a given mesoporous material, two factors are expected to control the ion sorption capability of the material: the accessible pore surface area and the effect of nano-scale pore space confinement.…”

Section: Introductionmentioning

confidence: 99%

Potential applications of nanostructured materials in nuclear waste management.

Braterman

Phol²,

et al. 2003

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This report summarizes the results obtained from a Laboratory Directed Research & Development (LDRD) project entitled "Investigation of Potential Applications of SelfAssembled Nanostructured Materials in Nuclear Waste Management". The objectives of this project are to (1) provide a mechanistic understanding of the control of nanometerscale structures on the ion sorption capability of materials and (2) develop appropriate engineering approaches to improving material properties based on such an understanding. 4 The project has been focused on two types of nanostructured materials: self-assembled mesoporous materials and layered double hydroxides. The major results are summarized below:• Acid-base titration experiments were performed on both mesoporous alumina and alumina particles under various ionic strengths. Under the same chemical conditions, the surface charge per mass on mesoporous alumina was as much as 45 times higher than that on alumina particles. This difference cannot be fully explained by the surface area difference between the two materials. The titration data have demonstrated that the nano-scale confinement has a significant effect, most likely via the overlap of the electric double layer (EDL), on ion sorption onto mesopore surfaces. This effect cannot be adequately modeled by existing surface complexation models, which were developed mostly for an unconfined solid-water interface.• As the pore size is reduced to a few nanometers, the difference between surface acidity constants (∆pK = pK 2 -pK 1 ) decreases, giving rise to a higher surface charge density on a nanopore surface than that on an unconfined mineral-water interface. The change in surface acidity constants results in a shift of ion sorption edges and enhances ion sorption on nanopore surfaces. Also, the water activity in a nanopore is greatly reduced, thus increasing the tendency for inner sphere complexation and mineral precipitation. All these effects combine to preferentially enrich trace elements in nanopores. This enrichment mechanism has a significant implication to many fundamental geochemical issues such as the irreversibility of ion sorption/desorption and the bioavailability of subsurface contaminants. The discovery of this mechanism provides a scientific basis for engineering high-performance ion adsorbents for nuclear waste management.• Layered double hydroxides (LDH) have shown a great promise for removing anionic contaminants. The anion sorption coefficients (K d ) have been measured for both activated and non-activated Mg-Al LDH materials. The activated material has a much higher anion sorption coefficient than the non-activated one, indicating that calcination can significantly improve anion sorption capacity of LDH. Sorption isotherms for Re and Se on the activated LDH material roughly follow the Freundlich isotherm, indicating the existence of various sorption sites with different sorption capabilities. Anions tend to first sorb on the external surface sites. As the anion concentration or the ionic strength ...

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Recent developments in the preparation and properties of nanometer-size spherical and platelet-shaped particles and composite particles

Cited by 170 publications

References 114 publications

Coating of Nanosize Silver Particles with Silica

Coating of Nanosize Silver Particles with Silica

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Potential applications of nanostructured materials in nuclear waste management.

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