scholarly journals Measuring Inner Layer Capacitance with the Colloidal Probe Technique

2018 ◽  
Vol 2 (4) ◽  
pp. 65 ◽  
Author(s):  
Alexander Smith ◽  
Plinio Maroni ◽  
Michal Borkovec ◽  
Gregor Trefalt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Alkali Metals ◽  
Diffuse Layer ◽  
Effective Dielectric Constant ◽  
Ion Hydration ◽  
Layer Potential ◽  
Probe Technique ◽  
Charge Regulation ◽  
Colloidal Probe

The colloidal probe technique was used to measure the inner layer capacitance of an electrical double layer. In particular, the forces were measured between silica surfaces and sulfate latex surfaces in solutions of monovalent salts of different alkali metals. The force profiles were interpreted with Poisson-Boltzmann theory with charge regulation, whereby the diffuse layer potential and the regulation properties of the interface were obtained. While the diffuse layer potential was measured in this fashion in the past, we are able to extract the regulation properties of the inner layer, in particular, its capacitance. We find systematic trends with the type of alkali metal ion and the salt concentration. The observed trends could be caused by difference in ion hydration, variation of the binding capacitance, and changes of the effective dielectric constant within the Stern layer. Our results are in agreement with recent experiments involving the water-silica interface based on a completely independent method using X-ray photoelectron spectroscopy in a liquid microjet. This agreement confirms the validity of our approach, which further provides a means to probe other types of interfaces than silica.

Structural and Catalytic Properties of the Alkali Metal Ion-Exchanged Y-Zeolites by 29Si and 27Al Solid-State NMR and FT-IR Spectroscopy

2005 ◽  
Vol 277-279 ◽  
pp. 708-719
Author(s):  
Chang Seop Lee ◽  
Hee Jung Lee ◽  
Sung Woo Choi ◽  
Jahun Kwak ◽  
Charles H.F. Peden
Keyword(s):  
Solid State ◽  
Alkali Metal ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Nmr Spectra ◽  
Catalytic Properties ◽  
Nox Reduction ◽  
29Si Nmr ◽  
Y Zeolites ◽  
X Ray

A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.

Field emission properties of nitrogen-doped diamond-like carbon films deposited by direct metal ion beam deposition

2001 ◽  
Vol 697 ◽  
Author(s):  
Kie Moon Song ◽  
Namwoong Paik ◽  
Steven Kim ◽  
Daeil Kim ◽  
Seongjin Kim ◽  
...  
Keyword(s):  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Nitrogen Doping ◽  
Ion Beam ◽  
Diamond Like Carbon ◽  
Emission Data ◽  
Nitrogen Doped ◽  
Ion Beam Deposition ◽  
Beam Deposition

AbstractNitrogen-doped diamond-like carbon (DLC) films were deposited on a silicon substrate by direct metal ion beam deposition (DMIBD). Partial pressures of nitrogen gas were changed to get different compositions of nitrogen in the DLC films. The composition and surface morphology of the films were examined using X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Effect of nitrogen doping on field emission property was studied. The field emission data indicated that the nitrogen doping lowered the turn-on field and increase the current density. It was believed that doping of nitrogen into the DLC film plays an important role in enhancement of the field emission. This enhancement of field emission could be explained by the improvement of electron transport through nitrogen-dope DLC layer.

Removal of Pb(II) and Cu(II) from aqueous solution using multiwalled carbon nanotubes/iron oxide magnetic composites

2011 ◽  
Vol 63 (5) ◽  
pp. 917-923 ◽  
Author(s):  
Jun Hu ◽  
Donglin Zhao ◽  
Xiangke Wang
Keyword(s):  
Carbon Nanotubes ◽  
Iron Oxide ◽  
Multiwalled Carbon Nanotubes ◽  
Sorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Precipitation Method ◽  
Multiwalled Carbon ◽  
Magnetic Composites ◽  
X Ray

Multiwalled carbon nanotubes (MWCNTs)/iron oxide magnetic composites (named as MCs) were prepared by co-precipitation method, and were characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in detail. The prepared MCs were employed as an adsorbent for the removal of Pb(II) and Cu(II) ions from wastewater in heavy metal ion pollution cleanup. The results demonstrated that the sorption of Pb(II) and Cu(II) ions was strongly dependent on pH and temperature. The experimental data were well described by Langmuir model, and the monolayer sorption capacity of MCs was found to vary from 10.02 to 31.25 mg/g for Pb(II) and from 3.11 to 8.92 mg/g for Cu(II) at temperature increasing from 293.15 to 353.15 K at pH 5.50. The sorption capacity of Pb(II) on MCs was higher than that of Cu(II), which was attributed to their ionic radius, hydration energies and hydrolysis of their hydroxides. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) were calculated from temperature dependent sorption isotherms, and the results indicated that the sorption of Pb(II) and Cu(II) ions on MCs were spontaneous and endothermic processes.

scholarly journals Deciphering lead and cadmium stripping peaks for porous antimony deposited electrodes

2016 ◽  
Vol 34 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Aqeel Ahmad Taimoor
Keyword(s):  
Heavy Metal ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Porous Electrodes ◽  
Electrochemical Sensing ◽  
Ex Situ ◽  
Electrochemical Tests ◽  
Diffusion Limitations ◽  
Lead And Cadmium ◽  
Cadmium And Lead

AbstractCadmium and lead are generally taken as model heavy metal ions in water to scale the detection limit of various electrode sensors, using electrochemical sensing techniques. These ions interact with the electrochemically deposited antimony electrodes depending on the diffusion limitations. The phenomenon acts differently for the in-situ and ex-situ deposition as well as for porous and non-porous electrodes. A method has been adopted in this study to discourage the stripping and deposition of the working ions (antimony) to understand the principle of heavy metal ion detection. X-ray photoelectron spectroscopy (XPS) technique was used to establish the interaction between the working and dissolved ions. In addition to the distinct peaks for each analyte, researchers also observed a shoulder peak. A possible reason for the presence of this peak was provided. Different electrochemical tests were performed to ascertain the theory on the basis of the experimental observations.

scholarly journals Effect of Nitric Acid Modification on Characteristics and Adsorption Properties of Lignite

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 167 ◽  
Author(s):  
Bo Huang ◽  
Guowei Liu ◽  
Penghui Wang ◽  
Xiang Zhao ◽  
Hongxiang Xu
Keyword(s):  
Nitric Acid ◽  
Surface Chemistry ◽  
Pore Structure ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Adsorption Properties ◽  
Acid Modification ◽  
X Ray ◽  
Adsorption Performance

The objective of this research was to explore the changes of the pore structure and surface properties of nitric-modified lignite and base the adsorption performance on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, several lignite samples were treated with different concentrations of nitric acid in order to get different pore structure and surface chemistry adsorbent levels. A common heavy metal ion contaminant in water, Pb2+, served as an adsorbate probe to demonstrate the change of modified lignite adsorption properties. The pore structure and surface properties of lignite samples before and after modification were characterized by static nitrogen adsorption, X-ray diffraction, Scanning electron microscope, Fourier transform infrared spectroscopy, zeta potential, and X-ray photoelectron spectroscopy. The experimental results showed that nitric acid modification can increase the ability of lignite to adsorb Pb2+. The adsorption amount of Pb2+ increased from 14.45 mg·g−1 to 30.68 mg·g−1. Nitric acid reacted with inorganic mineral impurities such as iron dolomite in lignite and organic components in coal, which caused an increase in pore size and a decrease in specific surface areas. A hydrophilic adsorbent surface more effectively removed Pb2+ from aqueous solution. Nitric acid treatment increased the content of polar oxygen-containing functional groups such as hydroxyl, carbonyl, and carboxyl groups on the surface of lignite. Treatment introduced nitro groups, which enhanced the negative electrical properties, the polarity of the lignite surface, and its metal ion adsorption performance, a result that can be explained by enhanced water adsorption on hydrophilic surfaces.

scholarly journals Corrosion Resistance of DLC Film-Coated SUS316L Steel Prepared by Ion Beam Enhanced Deposition

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Bei B. Han ◽  
Dong Y. Ju ◽  
Mao R. Chai ◽  
Hui J. Zhao ◽  
Susumu Sato
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Ion Beam ◽  
Acid Corrosion ◽  
Electrochemical Techniques ◽  
Ion Concentration ◽  
Dlc Coatings ◽  
Dlc Film ◽  
Corrosion Behaviors

In order to improve the conductivity and anticorrosive resistance of bipolar plates in fuel cells, the characterizations and corrosion behaviors of the DLC-coated SUS316L steel deposited with different gas ratios CH4/H2 and deposition times were investigated and evaluated. The chemical bonding structure and composition of the DLC coatings were confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The micromorphology and surface roughness of the DLC were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The element compositions of cross section were determined by electron probe microanalysis (EPMA). The interfacial contact resistance (ICR) was measured. Furthermore, the DLC-coated SUS316L steel was corroded by potentiostatic polarizations in a 0.5 M H2SO4 solution at 0.8 V, 90°C for 168 h, and the corrosion behaviors were investigated in the solution using electrochemical techniques. In addition, the metal ions in sulfuric acid corrosion solution were detected by inductively coupled plasma-atomic emission spectroscopy. The results indicate that the DLC coatings deposited at a lower gas ratio CH4/H2 of 1 : 1 could result in a decreasing ID/IG ratio of 1.03, low Ra roughness of 3.77 nm, low ICR of 12.9 mΩ cm2, and low metal ion concentration of 16.60 ppm in the corrosion solution. The significant improvement in the anticorrosion resistance of the DLC film was mainly due to the increased sp3 element and formation of the passive film. As a result, the DLC coating deposited on the SUS316L steel at CH4/H2 = 1 : 1 has better anticorrosion properties. However, the DLC film-coated SUS316L steel still cannot meet the corrosive resistance of the bipolar plate.

scholarly journals A modified ionic liquid clay to remove heavy metals from water: investigating its catalytic activity

2019 ◽  
Vol 17 (4) ◽  
pp. 2043-2058
Author(s):  
S. Kakaei ◽  
E. S. Khameneh ◽  
M. H. Hosseini ◽  
M. M. Moharreri
Keyword(s):  
Heavy Metal ◽  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Kinetic Studies ◽  
Heavy Metal Ion ◽  
Ambient Conditions ◽  
X Ray ◽  
Metal Ion Adsorption ◽  
Map Analysis

Abstract The new clay modified with triazole and triazolium ligands was prepared in this research. These materials were applied as abundant and eco-friendly adsorbents for removal of heavy metal ions such as Pb(II), Co(II) and Zn(II) ions. The adsorption efficiency of these materials was calculated by relevant equations such as Langmuir and Freundlich as well as kinetic studies with pseudo-first-order and pseudo-second-order models. These adsorbents proved to be very active on heavy metal ion adsorption. The characterization of these new materials was carried out by various techniques such as X-ray diffraction, thermogravimetric analysis, scanning electron microscope (SEM), X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy as well as SEM-map analysis. Eventually, the catalytic activity of the adsorbents which treated with heavy metal ion solutions was studied in the reduction of nitroarenes to its corresponding amines. The prepared adsorbent–catalyst materials indicated efficient catalytic activity in the reduction of nitroarenes to amines in ambient conditions. Graphic abstract

Charge Reversal of Sulfate Latex Particles by Adsorbed Linear Poly(ethylene imine) Probed by Multiparticle Colloidal Probe Technique

2011 ◽  
Vol 115 (29) ◽  
pp. 9098-9105 ◽  
Author(s):  
Marco Finessi ◽  
Prashant Sinha ◽  
István Szilágyi ◽  
Ionel Popa ◽  
Plinio Maroni ◽  
...  
Keyword(s):  
Ethylene Imine ◽  
Charge Reversal ◽  
Latex Particles ◽  
Probe Technique ◽  
Colloidal Probe ◽  
Linear Poly ◽  
Poly Ethylene

Synthesis of Aerogel-Metal Cluster Composites by Gamma Radiolysis

2002 ◽  
Vol 740 ◽  
Author(s):  
Massimo F. Bertino ◽  
Jared F. Hund ◽  
Guohui Zhang ◽  
Chariklia Sotiriou-Leventis ◽  
Nicholas Leventis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Gamma Ray ◽  
Metal Clusters ◽  
Metal Cluster ◽  
Surface Oxidation ◽  
Colloidal Suspensions ◽  
X Ray ◽  
Au Clusters

ABSTRACTNoble metal clusters (Ag, Au) were formed in a silica aerogel matrix by gamma irradiation of hydrogel precursors loaded with aqueous solutions containing Ag+ or [AuCl4]- ions. Hydrogels exposed to gamma rays assumed the color expected for colloidal suspensions of Ag (respectively Au) clusters. The hydrogels were subsequently washed and supercritically dried, without any evident change in color, indicating that the metal clusters were not removed during drying. Typical gamma ray doses were between 3 and 3.5 kGy, and achieved complete reduction of hydrogels containing metal ion concentrations in the 10-4-10-3 M range. Metal clusters in the aerogel monoliths were characterized with optical absorption, transmission electron microscopy, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. These techniques have shown that the clusters have a crystalline fcc structure. Au clusters consist of pure Au, while surface oxidation of Ag clusters was observed with XPS.

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