scholarly journals Obtaining a composite material based on cobalt (II) ferrite for purification of aqueous solutions

2019 ◽  
Vol 140 ◽  
pp. 02002
Author(s):  
Nina Shabelskaya ◽  
Marina Egorova ◽  
Galina Chernysheva ◽  
Vladimir Semchenko
Keyword(s):  
Composite Material ◽  
Aqueous Solutions ◽  
Crystallite Size ◽  
Surface Area ◽  
High Surface ◽  
Average Crystallite Size ◽  
Oxide Systems ◽  
Industrial Enterprises ◽  
Developed Surface ◽  
Bet Method

In modern society, the detrimental effect of industrial production on the environment is intensifying. Contaminated wastewaters of industrial enterprises deteriorate the environmental situation and violate the ecosystem stability. One of efficient methods of dealing with harmful impurities in wastewater is to remove them using adsorption active materials. Oxide systems of ferrites of transition elements are one example of materials with multifunctional properties. The possibility of synthesizing nanoscale cobalt (II) ferrite and a composite material based on it with the CoFe2O4/C composition was studied. The obtained materials were studied using X-ray phase analysis, electron microscopy (SEM), and the BET method of low-temperature nitrogen adsorption. It was established that cobalt (II) ferrite has a developed surface (the surface area measured by the BET method is 16 m2/g, the average crystallite size obtained by the Debye-Scherrer method is 4.0 nm). The mechanism of CoFe2O4 structure formation is considered. The composite material CoFe2O4/C is characterized by a high surface area (222 m2/g, average crystallite size of 1.1 nm) and exhibits increased adsorption ability with respect to copper (II) cations from aqueous solutions. The obtained results are of interest as materials for purification of aqueous solutions.

scholarly journals Investigation on adsorption capacity of TiO2-P25 nanoparticles in the removal of a mono-azo dye from aqueous solution: A comprehensive isotherm analysis

2014 ◽  
Vol 20 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Mohammad Behnajady ◽  
Shahrzad Yavari ◽  
Nasser Modirshahla
Keyword(s):  
Aqueous Solution ◽  
Crystallite Size ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Correlation Coefficients ◽  
Average Crystallite Size ◽  
Isotherm Models ◽  
Equilibrium Data ◽  
Pseudo Second Order

In this work TiO2-P25 nanoparticles with high surface area have been used as adsorbent for the removal of C.I Acid Red 27 (AR27), as an organic contaminant from aqueous solution. Characteristics of phases and crystallite size of TiO2-P25 nanoparticles were achieved from XRD and the surface area and pore size distribution were obtained from BET and BJH techniques. TiO2-P25 nanoparticles with almost 80% anatase and 20% rutile phases, the average crystallite size of 18 nm, have specific surface area of 56.82 m2 g-1. The effect of various parameters like initial AR27 concentration, pH, contact time and adsorbent dosage has been carried out in order to find desired adsorption conditions. The desired pH for adsorption of AR27 onto TiO2-P25 nanoparticles was 3. The equilibrium data were analyzed with various 2-, 3- and 4-parameter isotherm models. Equilibrium data fitted very well by the 4-parameter Fritz-Schluender model. Results of adsorption kinetics study indicated that the pseudo-second order kinetics provided the best fit with correlation coefficients close to unity.

scholarly journals Synthesis and properties of composite material CoFe2O4/C

2020 ◽  
Vol 81 (4) ◽  
pp. 184-189
Author(s):  
N. P. Shabelskaya ◽  
M. A. Egorova ◽  
G. M. Chernysheva ◽  
A. N. Saliev ◽  
A. N. Yatsenko ◽  
...  
Keyword(s):  
Composite Material ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Crystallite Size ◽  
Nitrogen Adsorption ◽  
Lattice Parameter ◽  
Transition Elements ◽  
Developed Surface

Scientific interest in the processes of forming the structure of magnetic spinels and composites based on them is due to the possibility of synthesis of materials with multifunctional properties. The process of formation of cobalt (II) nanocrystalline ferrite and CoFe2O4/C composite material is studied. The mechanism of formation of structure of materials including a stage of formation of hydroxides of transition elements, precursors on the basis of complex connections of cations of iron and cobalt with citric acid and their subsequent destruction at heating is offered. The synthesized materials were characterized by x-ray phase analysis, electron microscopy, low-temperature nitrogen adsorption, Debye-Scherrer methods. It is shown that cobalt (II) ferrite has a developed surface, the value of the surface area according to the BET method is 16 m2/g, the average size of the crystallites determined by the Debye-Scherrer equation is 4.0 nm. Activated carbon with a specific surface area of 685 m2/g was used to prepare the composite material. The resulting composite material has a surface area of 222 m2/g, the average crystallite size of 1.1 nm. Cobalt (II) ferrite, included in the composition of the composite material CoFe2O4/C, has a slightly higher value of the lattice parameter, compared with pure cobalt (II) ferrite, which is associated with a decrease in the degree of spinel inversion. The synthesized composite material was tested in the process of adsorption of copper (II) cations from an aqueous solution. It is shown that CoFe2O4/C exhibits an increased adsorption capacity for copper (II) cations in comparison with pure activated carbon, despite a decrease in the specific surface area. The result is explained by the involvement of cobalt (II) ferrite in the adsorption process. The obtained materials may be of interest as catalysts, adsorbents.

Nanoscale Topography of GC/Pt-C and GC/Pt-Ru-C Electrodes Studied by Means of STM, AFM and XRD Methods

2006 ◽  
Vol 518 ◽  
pp. 271-276 ◽  
Author(s):  
A. Kowal ◽  
P. Olszewski ◽  
D.V. Tripković ◽  
R. Stevanović
Keyword(s):  
Crystallite Size ◽  
Surface Area ◽  
Rietveld Method ◽  
High Surface ◽  
High Surface Area ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Crystallite Sizes ◽  
Nanoscale Topography ◽  
Two Phases

Electrodes, assigned as GC/Pt-C and GC/Pt-Ru-C, were formed by deposition of Ptbased catalysts (47.5 wt % Pt + high surface area carbon) and (54 wt. % Pt-Ru alloy + high surface area carbon) on glassy carbon (GC) discs. X-ray diffraction measurements were used for the determination of the average crystallite size and phase composition of both catalysts. Crystallite size for Pt-C catalyst was 2.9 nm for Pt-fcc. In the diffraction pattern of the Pt-Ru-C catalyst two phases, e.g. Pt-Ru-fcc and Ru-hcp were refined using the Rietveld method. Crystallite sizes were 3.9 nm for Pt-Ru-fcc and 2.8 nm for Ru-hcp. STM observations of the surface of GC/Pt-C and GC/Pt-Ru-C electrodes revealed the presence of metal particles of the size in the range 2-6 nm and Pt-C or Pt- Ru-C agglomerates in the range of several tenth of nm. The thickness of the Nafion covering layer determined by AFM is ca. 100 nm. A simplified scheme of the investigated electrodes was created.

Adsorption of tetrasulfide-functional silane on high surface area silica treated with aqueous and non-aqueous solutions

1998 ◽  
Vol 6 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Suwabun Chirachanchai ◽  
Rachanee Chungchamroenkit ◽  
Hatsuo Ishida
Keyword(s):  
Aqueous Solutions ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area

Ce–Zr materials with a high surface area as catalyst supports for hydrogenation of CO2

2020 ◽  
Vol 13 (04) ◽  
pp. 2040004
Author(s):  
Nikolay D. Evdokimenko ◽  
Alexander L. Kustov ◽  
Konstantin O. Kim ◽  
Igor V. Mishin ◽  
Vera D. Nissenbaum ◽  
...  
Keyword(s):  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Oxygen Storage Capacity ◽  
Hydrogenation Reaction ◽  
Oxygen Storage ◽  
Hexadecyltrimethylammonium Bromide ◽  
Developed Surface ◽  
Direct Hydrogenation

The most promising way of CO2 utilization is its catalytic conversion into valuable products, in particular, the direct hydrogenation of CO2 on heterogeneous catalysts to obtain such products as synthesis gas, hydrocarbons, alcohols, esters, carboxylic acids, and some other organic molecules. Heterogeneous iron-based catalysts possess a special position among the promising candidates for the synthesis of CO2-based hydrocarbons. However, individual iron oxide catalysts have a fairly low surface area, which requires their deposition on the support or modification. CeO2 is rather attractive in catalysis because of its high oxygen storage capacity. The most effective thermal stabilizer of CeO2 is ZrO2. In this work, cerium–zirconium systems with various Ce to Zr ratios were synthesized by the method of coprecipitation in the absence and presence of the hexadecyltrimethylammonium bromide template. These systems were characterized by adsorption of N2, XRD, and DTA-TG-DTG and used as supports for 5% Fe catalysts. The activity of synthesized Fe-containing catalysts was investigated in the reaction of CO2 hydrogenation. The developed surface and the presence of cerium in the supports are the possible reasons for the high activity of Fe-containing catalysts in the hydrogenation reaction of CO2.

Preparation and Characterization of Rice Husk Ash for Adsorption of Phenol from Aqueous Solutions

2014 ◽  
Vol 625 ◽  
pp. 498-502
Author(s):  
Samah B. Daffalla ◽  
Hilmi Mukhtar ◽  
Maizatul S. Shaharun
Keyword(s):  
Aqueous Solutions ◽  
Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Physiochemical Properties ◽  
Pseudo Second Order

In this research, the development of three (3) low-cost adsorbent materials from abundant waste rice husk was achieved via thermal treatment. The physiochemical properties of the developed adsorbents were evaluated. Their adsorption behaviours in batch system were evaluated for the removal of phenol from aqueous solutions by varying the pH (2 to 10). It was found that, the rice husk ash burned a 400oC for 1hr ‘RHA400,1’ has the highest surface area (201.36 m2.g-1) followed by RHA300,4(87.08 m2.g-1) and RHA600,1(43.22 m2.g-1), respectively. RHA400,1had shown the highest removal efficiency followed by RHA300,4and RHA600,1, towards phenol due to high surface area and porosity. The maximum uptake of phenol was found at pH 4. The adsorption kinetics was well described by both pseudo-second order and the Elovich models.

scholarly journals Facile Synthesis of Spherical Flake-shaped CuO Nanostructure and Its Characterization towards Solar Cell Application

2021 ◽  
Vol 18 (18) ◽  
Author(s):  
Jemibha PAULDURAI ◽  
Ahila Mudisoodum PERUMAL ◽  
Dhanalakshmi JEYARAJA ◽  
Panimaya Valan Rakkini AMAL
Keyword(s):  
Solar Cell ◽  
Crystallite Size ◽  
Surface Area ◽  
Average Crystallite Size ◽  
Lattice Parameter ◽  
Peak Position ◽  
Cuo Nanoparticles ◽  
Precipitation Method ◽  
Solar Cell Application ◽  
Morphological Studies

The aim of this work is to synthesis CuO nanoparticles and investigates their eminent properties to identify their diverse application capability in the field of solar cells.  In this work, CuO nanoparticles were synthesized by precipitation method using Copper (II) nitrate and Copper (II) chloride. Surface effects due to defects, structural properties related through lattice parameter, and crystallite sizes of nanoparticles have been identified from XRD. The crystal plane and reflection peak position was calculated using Bragg’s law. It showed that CuO nanoparticles have a monoclinic structure, and that the average crystallite size of CuO nanoparticles was 28.82 nm. n-type semiconductor behavior had a direct band of Eg = 1.465(2) eV, analyzed from optical studies by DRS. The band gap of the sample was determined from the reflectance spectra using Kubelka-Munk (K-M) function. Elements present were found through absorption peak of FTIR. The blue shifts observed in FTIR spectra in CuO nanoparticles were compared with that of bulk CuO, and absorption band agreed with XRD results.  Morphological studies revealed the formation of spherical flake-shaped formation of CuO. It had a higher surface area and was well-suited to solar cell applications. HIGHLIGHTS The CuO nanoparticles were synthesized by precipitation method The average crystallite size of CuO nanoparticles obtained in the range of 28.82 nm Spherical flake-shaped nanostruture with higher surface area formed in this method Optical property of CuO (Eg = 1.465 eV) and good electron mobility make it a suitable solar cell absorber material GRAPHICAL ABSTRACT

scholarly journals Morphology dependent photocatalytic efficacy of zinc ferrite probed for methyl orange degradation

2018 ◽  
Vol 83 (11) ◽  
pp. 1261-1271
Author(s):  
Huan-Yan Xu ◽  
Bo Li ◽  
Ping Li
Keyword(s):  
Methyl Orange ◽  
Crystallite Size ◽  
Surface Area ◽  
Zinc Ferrite ◽  
Average Crystallite Size ◽  
Photocatalytic Efficiency ◽  
X Ray Diffraction ◽  
Methyl Orange Degradation ◽  
Xrd Patterns ◽  
Calculated Average

Zinc ferrite (ZnFe2O4) photocatalysts with different morphologies (sizes and shapes) were synthesized to explore the effect of morphology on their photocatalytic efficiency. The results obtained using field emission scanning electron microscopy (FESEM) revealed that the obtained samples had the needle-, cube-, granule- and plate-like morphology, labeled as NZFO, CZFO, GZFO and PZFO, respectively. X-ray diffraction (XRD) patterns showed that all the samples had the spinel structure of ZnFe2O4 without any other impurities. The calculated average crystallite size followed the order NZFO<GZFO<CZFO< <PZFO. The surface area was inversely proportional to the average crystallite size and followed the order NZFO>GZFO>CZFO>PZFO. The photocatalytic efficiency for the degradation of methyl orange also followed the order NZFO> >GZFO>CZFO>PZFO. The morphology-dependent photocatalytic efficiency of ZnFe2O4 was closely related with its crystallite size and surface area. The smaller the crystallite size was, the larger the surface area was, and the higher the photocatalytic efficiency was.

scholarly journals INFLUENCE OF SYNTHESIS TECHNO-CHEMICAL PARAMETERS ON PHYSICOCHEMICAL CHARACTERISTICS OF BIOMIMETIC CALCIUM-PHOSPHATE NANOCOMPOSITE DOPED BY SILICATE AND CARBONATE ANIONS

2020 ◽  
Vol 5 (10) ◽  
pp. 47-56
Author(s):  
M. Troubitsin ◽  
Viet Hung Hoang ◽  
L. Furda
Keyword(s):  
Calcium Phosphate ◽  
Specific Surface ◽  
Crystallite Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Average Pore Size ◽  
Average Crystallite Size ◽  
Average Pore ◽  
The Impact

The object of our investigation is a biomimetic calcium-phosphate nanocomposite doped by silicate and carbonate anions (BMHAP) synthesized by chemical deposition from aqueous solutions. The obtained samples are investigated using X-ray phase analysis (XRD), FTIR spectroscopy, and low-temperature nitrogen adsorption (BET method). The influence of the techno chemical synthesis parameters on the products characteristics (including phase composition, crystal lattice parameters, average crystallite size, specific surface area) is evaluated. The study on the effect of the synthesis temperature shows that with increasing in temperature from 22°C to 80°C, reveals a slight increase in the parameters of unit cells a and c, which leads to an increase in its volume. There is also a tendency towards a decrease in the average size of coherent scattering regions of crystallites (from 7,52 to 4,65 nm) and specific surface area (from 192,51 to 74,72 m2/g), but the pore volume and average pore diameter of the synthesized powders increases. The effect of the aging time of the sediment in the mother liquor is studied from 0,5 to 24 hours. It is found that with an increase in the maturation time of the sediment, the percent crystallinity of the powders improves by 1,7 times, an increase in the specific surface area from 163,43 to 192,51 m2/g and a slight decrease in the pore volume and average pore size of the samples are observed. The impact of the stirring rate of the reagents is investigated. An increase in speed from 300 to 1300 rpm has been shown to decrease the average crystallite size from 8,80 to 6,41 nm, and as a result, to increase the specific surface area of the synthesized samples from 178,58 to 192,51 m2/g, respectively.

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