Proton binding to humic nano particles: Electrostatic interaction and the condensation approximation

2021 ◽  
Author(s):  
Luuk K Koopal ◽  
Juan Xiong ◽  
Wenfeng Tan ◽  
Takumi Saito ◽  
Marcelo Avena
Keyword(s):  
Proton Affinity ◽  
Electrostatic Interaction ◽  
Nano Particles ◽  
Proton Binding ◽  
Electrostatic Contribution

Proton binding to “carboxylic” and “phenolic” sites of humic nano particles (HNPs) is determined by the total proton affinity that is due to a specific and an electrostatic contribution. These...

Role of electrostatic interactions in the adsorption kinetics of nanoparticles at fluid–fluid interfaces

2016 ◽  
Vol 18 (7) ◽  
pp. 5499-5508 ◽  
Author(s):  
Venkateshwar Rao Dugyala ◽  
Jyothi Sri Muthukuru ◽  
Ethayaraja Mani ◽  
Madivala G. Basavaraj
Keyword(s):  
Surface Tension ◽  
Adsorption Kinetics ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Dynamic Surface Tension ◽  
Nano Particles ◽  
Fluid Interfaces ◽  
Dynamic Surface ◽  
Kinetics Of

The dynamic surface tension measurements are used to elucidate the contribution of electrostatic interaction energy barriers for the adsorption of nano-particles to the interfaces.

scholarly journals Evaluation of the Electrostatic Contribution to the Retention of Modified Nucleosides and Nucleobases by Zwitterionic Hydrophilic Interaction Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Diego García-Gómez ◽  
Encarnación Rodríguez-Gonzalo ◽  
Rita Carabias-Martínez
Keyword(s):  
Electrostatic Interaction ◽  
Salt Concentration ◽  
Mobile Phase ◽  
Hydrophilic Interaction Chromatography ◽  
Modified Nucleosides ◽  
Hydrophilic Interaction ◽  
Low Salt ◽  
Electrostatic Contribution ◽  
Quantitative Basis ◽  
Clinical Interest

This work explores the benefits and limitations, on a quantitative basis, of using zwitterionic hydrophilic interaction chromatography (ZIC-HILIC) for the separation of several modified nucleosides and nucleobases of clinical interest. The target compounds were hydroxylated and methylated derivatives: 8-hydroxy-guanine, 8-hydroxy-guanosine, 8-hydroxy-2′-deoxyguanosine, 1-methyl-guanine, 7-methyl-guanine, and 9-methyl-guanine. A quantitative evaluation of the electrostatic interaction based on a systematic study of the nature and concentration of the salts in the mobile phase has been carried out. From the obtained results, it may be concluded that separation is based on a mechanism of partition and interaction through weak electrostatic forces: the contribution of the electrostatic interaction to the retention of the charged analytes reaching values between 25 and 52% at low salt concentration. However, the electrostatic contribution decreased progressively as the salt concentration rose.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

1993 ◽  
Vol 51 ◽  
pp. 1058-1059
Author(s):  
J. Liu ◽  
M. Pan ◽  
G. E. Spinnler
Keyword(s):  
Supported Catalysts ◽  
Imaging Techniques ◽  
Nano Particles ◽  
Metal Particles ◽  
Shape Structure ◽  
Dynamical Simulations ◽  
Small Metal Particles ◽  
Extract Information

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

Polycaprolactone based membranes for the degradation of diclofenac present in water samples using ZnO nanoparticles as the active agent

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3153-3161
Author(s):  
Marco Antonio Juárez Sánchez ◽  
Miguel Ángel Meléndez Lira ◽  
Celestino Odín Rodríguez Nava
Keyword(s):  
Zno Nanoparticles ◽  
Wastewater Treatment Plants ◽  
Active Agent ◽  
Heterogeneous Photocatalysis ◽  
Nano Particles ◽  
Electrical Characteristics ◽  
Unit Operation ◽  
Fields Of Study ◽  
Drug Contamination ◽  
Positive Results

AbstractDrug contamination in water is one of the current fields of study. Since 1990, the presence of drugs in drinking water has been a concern to scientists and public. In Mexico, these organic compounds are not efficiently removed in wastewater treatment plants; therefore, alternative methodologies have been studied that allow these compounds to have a high percentage of degradation or be completely degraded. One example of these techniques is heterogeneous photocatalysis which has obtained positive results in the degradation of drugs using ZnO nanoparticles. These are commonly selected for their electrical characteristics, even though they disperse in water and an additional unit operation is required to separate them from the liquid medium. To eliminate drugs with nano particles in a single stage, polycaprolactone-based membranes with adhered ZnO nanoparticles, by means of electrospinning, were prepared to degrade drugs such as diclofenac. The technique used has shown to efficiently break down diclofenac in 4 hours according to the capillary electrophoresis readings.

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