scholarly journals Structural properties and adsorption of uranyl ions on the nanocomposite hydroxyapatite/white clay

2021 ◽  
Author(s):  
E. Broda ◽  
A. Gładysz-Płaska ◽  
E. Skwarek ◽  
V. V. Payentko
Keyword(s):  
Zeta Potential ◽  
Surface Charge Density ◽  
Potential Surface ◽  
Nitrogen Adsorption ◽  
Uranyl Ions ◽  
Uranium Removal ◽  
Nanocrystalline Composites ◽  
Adsorption Desorption ◽  
Desorption Method ◽  
White Clay

AbstractUranium is more and more extensively applied as a source of energy and can be potentially used for nuclear weapon production. Owing to that fact, the problem of uranium expansion in the environment is the object of research and draw attention many scientists. One of the most effective methods of uranium removal from the wastewater (where uranium is present in a low concentration and occurs mainly in the form of uranyl ion, UO22+) is the adsorbent usage. It is important to discover an adsorbent which will be effective, widely available and cheap. The paper discusses properties and the ability of U (VI) adsorption on a clay and nanocomposite clay/Hap (hydroxyapatite) obtained by wet method. The adsorbents were characterized by the mentioned below tests: XRD, XRF, the porosity (nitrogen adsorption–desorption method), zeta potential, surface charge density and sorption of U (VI). It was shown that nanocrystalline composites Hap/white clay can be appropriate adsorbent for removal of uranyl ions. The adsorption depends on the temperature and pH of the solution.

Novel Route for Incorporation of Palladium Nanoparticles into Mesostructured Silicas Sba 15 and Sba-16

2013 ◽  
Vol 22 (3) ◽  
pp. 096369351302200
Author(s):  
N. Ivashchenko ◽  
V. Tertykh ◽  
J. Skubiszewska-Zięba ◽  
R. Leboda ◽  
S. Khainakov ◽  
...  
Keyword(s):  
Palladium Nanoparticles ◽  
Nitrogen Adsorption ◽  
Pd Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Desorption Method ◽  
Material Study

Palladium nanoparticles with controlled size were synthesized within the pores of the mesoporous SBA-15 and SBA-16 silicas with grafted silicon hydride groups. Nitrogen adsorption-desorption method, X-ray diffraction and transmission electron microscopy (TEM) were used for characterization of palladium-containing composites. Results of material study clearly revealed that Pd nanoparticles prepared by this method were located inside the porous channels and were quite uniform in size (mostly 5–6 nm). The influence of metal content on the particles size and porous structure of supports was investigated.

scholarly journals Effect of Carbon Deposits on the Structure of Hybrid C/TiO2/SiO2 Adsorbents

2001 ◽  
Vol 19 (5) ◽  
pp. 385-395 ◽  
Author(s):  
R. Leboda ◽  
V.M. Gun'ko ◽  
M. Marciniak ◽  
W. Grzegorczyk ◽  
J. Skubiszewska-Zięba
Keyword(s):  
Silica Gel ◽  
Fumed Silica ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Structural Features ◽  
Carbon Phase ◽  
Pore Size Distributions ◽  
Improved Technique ◽  
Adsorption Desorption ◽  
Desorption Method

The structural characteristics of pyrocarbon/X (X = fumed silica, mesoporous silica gel, fumed titania/silica, CVD-TiO2/fumed silica, CVD-TiO2/silica gel) prepared using several precursors [CH2Cl2, cyclohexene and TiO(AcAc)2, where Ac = acetylacetonate] were studied using the nitrogen adsorption/desorption method and an improved technique to allow the calculation of pore size distributions applying regularization procedures. Various pore models were used for the carbon phase. The pyrocarbon structure and distribution on the TiO2/SiO2 supports depends primarily on the structural features of the titania phase which exhibits catalytic activity in the pyrolysis of organic materials. The formation of relatively large concentrations of pyrocarbon typically reduces the porosity and specific surface area of the hybrid adsorbents produced.

scholarly journals Characterization of Commercial TiO2 P90 Modified with ZnO by the Impregnation Method

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tetiana А. Dontsova ◽  
Olena I. Yanushevska ◽  
Svitlana V. Nahirniak ◽  
Anastasiya S. Kutuzova ◽  
Grigory V. Krymets ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Composition ◽  
Electrical Properties ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Impregnation Method ◽  
Adsorption Desorption ◽  
Desorption Method ◽  
Commercial Tio2

This article is devoted to TiO2/ZnO nanocomposites’ creation by modifying with the commercial TiO2/P90 product using the impregnation method and identifying the effect of the ZnO modifier on its adsorption, structural, photocatalytic, and electrical properties. The synthesized TiO2/ZnO nanocomposites were characterized by XRD, XRF, XPS, and low-temperature nitrogen adsorption-desorption methods. As a result, nanostructured TiO2/ZnO composites with the ZnO content of 2, 5, 10, and 15% were obtained. It was shown that the phase composition of TiO2/P90 does not change during the nanocomposite synthesis. XPS studies of TiO2/ZnO nanocomposites indicated the presence of Ti4+, Zn2+, O2−, and OH states on their surface, which is associated with TiO2, ZnO, and hydroxide ions. The nitrogen adsorption-desorption method showed that the commercial TiO2/P90 sample is nonporous, and all TiO2/ZnO nanocomposites are characterized by almost the same homogeneous mesoporous structure. Experimentally established sorption and photocatalytic properties depend on the specific surface area and electrostatic interaction with dyes. The effect of the ZnO modifier on I-V characteristics of the TiO2/P90 sample was revealed. The obtained experimental data showed that the TiO2/P90 sample contains one type of current carriers, and TiO2/2ZnO and TiO2/5ZnO nanocomposites are characterized by two types of current carriers.

scholarly journals Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1519
Author(s):  
Jong Gyeong Kim ◽  
Sunghoon Han ◽  
Chanho Pak
Keyword(s):  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Electronic States ◽  
Nitrogen Adsorption ◽  
Reduction Reaction ◽  
Phosphorus Doping ◽  
X Ray ◽  
Precious Metal Catalysts ◽  
Adsorption Desorption

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

Surface charging parameters of charged particles in symmetrical electrolyte solutions

2020 ◽  
Vol 22 (35) ◽  
pp. 20123-20142
Author(s):  
Hadi Saboorian-Jooybari ◽  
Zhangxin Chen
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Electrolyte Solution ◽  
Surface Charge Density ◽  
Potential Surface ◽  
Research Work ◽  
Charged Particles ◽  
Electrolyte Solutions ◽  
Surface Charging ◽  
Curvature Dependence

This research work is directed at development of accurate physics-based formulas for quantification of curvature-dependence of surface potential, surface charge density, and total surface charge for cylindrical and spherical charged particles immersed in a symmetrical electrolyte solution.

scholarly journals Adsorption of malic acid at the hydroxyapatite/aqueous NaCl solution interface

2021 ◽  
Author(s):  
Władysław Janusz ◽  
Ewa Skwarek
Keyword(s):  
Zeta Potential ◽  
Malic Acid ◽  
Particle Sizes ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
Radioisotope Method ◽  
X Ray ◽  
Solution Interface ◽  
Adsorption Desorption ◽  
Kinetics Of

AbstractThe aim of the study was the basic incidence on the phenomenon of adsorption that occurs at the hydroxyapatite/malic acid interface, leading to a change in the surface properties of hydroxyapatite, Analytical methods used in the research: X-ray diffraction (XRD) as well as by the, adsorption–desorption of nitrogen (ASAP), potentiometric titration. The specific adsorption of malic acid ions at the hydroxyapatite interface was investigated by means of the radioisotope method. The zeta potential of hydroxyapatite dispersions was determined by electrophoresis with Zetasizer Nano ZS90 by Malvern. The particle sizes of hydroxyapatite samples were analyzed using Masteriszer 2000 Malvern. Studies on the kinetics of malic acid on hydroxyapatite from a solution with an initial concentration of 1 mmol/dm3 have shown that the adsorption process is initially fast, followed by a slow adsorption step. An increase in the pH of the solution causes a decrease in the malic acid adsorption as a result of competition with hydroxyl ions. The presence of adsorbed malic acid was confirmed by the FTIR measurements. The effect of malic acid adsorption on the zeta potential and particle size distribution of hydroxyapatite in the NaCl solution was investigated.

Effect of Carbon Pre-Treatment on Pd Dispersion in Synthesis of Pd/C Catalyst

2014 ◽  
Vol 804 ◽  
pp. 149-152 ◽  
Author(s):  
Ji Sun Kim ◽  
Jae Ho Baek ◽  
Myung Hwan Kim ◽  
Seong Soo Hong ◽  
Man Sig Lee
Keyword(s):  
Surface Area ◽  
Nitrogen Adsorption ◽  
Area Ratio ◽  
High Dispersion ◽  
Co Chemisorption ◽  
Pd Dispersion ◽  
Before And After ◽  
Pre Treatment ◽  
Treated Carbon ◽  
Adsorption Desorption

In this study, we confirmed effect of carbon pre-treatment on Pd dispersion in synthesis of Pd/C catalyst. Physical characteristics on the surface of before and after pre-treated carbon were analyzed by nitrogen adsorption-desorption analysis. The dispersion and size of Pd particles were analyzed by XRD, FE-TEM and CO-chemisorption. After pre-treatment, surface area of carbon were decreased. And mesopore area ratio were increased with decreasing micropore area ratio. In the case of pre-treated carbon, we confirmed high dispersion of Pd particles.

Preparation, Characterization and Photocatalytic Activity of F, Fe-Codoped Nano-TiO2

2013 ◽  
Vol 448-453 ◽  
pp. 169-173
Author(s):  
Chun Yan Yan ◽  
Wen Tao Yi
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Neutral Red ◽  
Reaction Model ◽  
X Ray Diffraction ◽  
Pseudo First Order Reaction ◽  
Adsorption Desorption ◽  
Desorption Method

Pure and F, Fe-codoped TiO2 were prepared by sol-hydrothermal process, in which titanium (IV) n-butoxide, Fe (NO3)2·6H2O and NH4F were used as precursors. And the samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and N2 adsorption-desorption method. The results showed that the F, Fe-codoped samples were principally single-phase anatase structures, and the particles possessed higher BET area than that of pure TiO2. The photocatalytic activity and reusability of the catalysts under UV light (365nm) was investigated with neutral red as the model compound. The results showed that F (2.0%), Fe (4.0%) codoped TiO2 had the highest photocatalytic activity among all as-prepared samples. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood (L-H) pseudo first order reaction model.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

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