The non-stoichiometry of pink zinc oxide

1975 ◽  
Vol 28 (2) ◽  
pp. 229
Author(s):  
VJ Norman
Keyword(s):  
Carbon Dioxide ◽  
Zinc Oxide ◽  
Specific Surface ◽  
Nitrogen Content ◽  
Surface Area ◽  
Total Nitrogen ◽  
Reactive Oxygen ◽  
Surface Concentration ◽  
Controlled Environment ◽  
Interstitial Zinc

A highly coloured pink zinc oxide, having a total nitrogen content of 0.054%, has been prepared by heating white zinc oxide and ammonium carbamate in an atmosphere of ammonia and carbon dioxide at 200�. The preparation results in a marked increase in the specific surface area of the zinc oxide. ��� The non-stoichiometry of the pink zinc oxide has been determined, and it is shown that the amount of reactive oxygen chemisorbed on the surface increases with time. The maximum chemisorption amounted to 52 p.p.m. by weight (1.1 x 1025 ion m-3) after exposure for 35 days in a controlled environment. The surface concentration of interstitial zinc has been estimated indirectly from the reactive oxygen results. The concentration of the non-stoichiometric species in pink zinc oxide is more than an order higher than that of the white zinc oxide from which it was prepared. The results support the mechanism tentatively proposed by previous workers for the incorporation of nitrogen in zinc oxide.

Carbon nanomaterials based on interpolyelectrolyte complex lignosulfonate-chitosan

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Olga Brovko ◽  
Irina Palamarchuk ◽  
Konstantin Bogolitsyn ◽  
Nikolay Bogdanovich ◽  
Artem Ivakhnov ◽  
...  
Keyword(s):  
Specific Surface ◽  
Nitrogen Content ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Nanomaterials ◽  
Electron Pair ◽  
Spherical Geometry ◽  
Processing Conditions ◽  
Interpolyelectrolyte Complex ◽  
New Approach

AbstractA new approach to the formation of “fullerene-like” carbon-nitrogen carbogels based on the interpolyelectrolyte complex lignosulfonate-chitosan (IPEC LSNa-CT) was developed. It was established that carbogel maintained the morphology of the precursor complex, i.e. the spherical geometry and the particle size of its main fractions (40–55 nm) were stored in the carbonizate. The influence of pyrolysis (Py) temperature was studied in the range of 500–1000°C on the structure of carbonizate. Carbogels obtained under different processing conditions have a well-developed microporous structure. The specific surface area of carbogels reduced with increasing Py temperature according to their nitrogen content. The maximum specific surface area (438.3 m2g−1) corresponds to the carbogel obtained at 600°C, while the maximum nitrogen content of this sample is 4.4%. The internal porosity of the material and the volume of supermicropores are reduced with increasing Py temperature due to the accumulation of double and triple carbon bonds in the carbogel. Apparently, the structure-forming N-atoms participate in the formation of condensed nitrogen-containing and cyclic structures as a donor of the electron pair and as such they accelerate the carbonization process.

Effect of ZnO Particle Size on the Curing of Carboxylated NBR and Carboxylated SBR

2004 ◽  
Vol 77 (2) ◽  
pp. 214-226 ◽  
Author(s):  
G. R. Hamed ◽  
K.-C. Hua
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Cure Rate ◽  
Surface Areas ◽  
Diffusion Limited ◽  
Rate Of Dissolution ◽  
Oxide Particles ◽  
And Diffusion

Abstract A carboxylated nitrile rubber (XNBR) and a carboxylated SBR (XSBR) were mixed with zinc oxide particles of different specific surface areas (“S”, 35 m2/g; “M”, 3.5m2/g; “L”, 0.5 m2/g) and cure behavior at 165 ºC studied using oscillating disc rheometry. Without added zinc oxide, both raw rubbers slowly stiffen over many hours of heating. This is probably due to condensation of carboxyl groups to form anhydride crosslinks. XNBR compositions containing the finely divided “S” crosslink much more rapidly. Full cure is reached after about 10 minutes of heating. Cure rate decreases markedly as the specific surface area of the ZnO decreases. A composition containing “M” at twice stoichiometry requires about an hour to cure well, while with “L”, about 10 hours are required. In contrast, curing of the XSBR depends little on the specific surface area of the ZnO, either with “S” or “L”, curing is essentially complete after 30 minutes. After simply mixing ZnO into either rubber, it remains as a dispersed particulate. With XNBR, curing appears to be controlled by the rate of dissolution and diffusion of ZnO, while, with XSBR, reaction is not diffusion limited and may be confined to regions near particle surfaces.

scholarly journals Carbon Dioxide Absorption and Release Properties of Pyrolysis Products of Dolomite Calcined in Vacuum Atmosphere

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Fei Wang ◽  
Toshihiro Kuzuya ◽  
Shinji Hirai ◽  
Jihua Li ◽  
Te Li
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Micropore Volume ◽  
Carbon Dioxide Absorption ◽  
Pyrolysis Products ◽  
Vacuum Atmosphere

The decomposition of dolomite into CaO and MgO was performed at 1073 K in vacuum and at 1273 K in an Ar atmosphere. The dolomite calcined in vacuum was found to have a higher specific surface area and a higher micropore volume when compared to the dolomite calcined in the Ar atmosphere. These pyrolysis products of dolomite were reacted with CO2at 673 K for 21.6 ks. On the absorption of CO2, the formation of CaCO3was observed. The degree of absorption of the dolomite calcined in vacuum was determined to be above 50%, which was higher than the degree of absorption of the dolomite calcined in the Ar atmosphere. The CO2absorption and release procedures were repeated three times for the dolomite calcined in vacuum. The specific surface area and micropore volume of calcined dolomite decreased with successive repetitions of the CO2absorption and release cycles leading to a decrease in the degree of absorption of CO2.

Influence of Zinc Oxide Nanograins on Properties of Epoxidized Natural Rubber Vulcanizates

2017 ◽  
Vol 748 ◽  
pp. 79-83 ◽  
Author(s):  
Rudeerat Suntako
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Epoxidized Natural Rubber ◽  
Precipitation Method ◽  
Cure Characteristics ◽  
Permanent Set

Zinc oxide (ZnO) nanograins are synthesized by precipitation method filled epoxidized natural rubber compared to conventional ZnO. The synthesized ZnO nanograins are characterized by X-ray diffraction and transmission electron microscopy and found that average primary size of ZnO synthesized around 40 nm and the specific surface area of 28.72 m2 g-1. Furthermore, the cure characteristics, rubber mechanical properties and permanent set were investigated. The obtained results are found that the ZnO nanograins significantly affected to cure characteristics, rubber mechanical properties and permanent set. This is due to small grain size and large specific surface area.

scholarly journals W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 836
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Alessia Amodio ◽  
Mauro Mazzocchi ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Gas Sensing ◽  
Molar Fraction ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

Study on the Preparing of Nanowhite Carbon Black by Silica Fume

2013 ◽  
Vol 423-426 ◽  
pp. 554-559 ◽  
Author(s):  
Xin Zhi ◽  
Zhan Cheng Guo
Keyword(s):  
Carbon Dioxide ◽  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Silica Fume ◽  
Specific Surface Area ◽  
Particle Diameter ◽  
Complete Response ◽  
High Specific Surface Area ◽  
Precipitated Silica

This research through the study on the properties of silicon dust, put forward in combination with lime kiln tail gas recycling carbon dioxide, preparation of precipitated silica (nanoWhite Carbon Black) of high value utilization technology, and studied and summarized process of the dissolution and precipitation by carbon dioxide. The silica fume is in amorphous form, and it has some special powder properties such as ultra fine grain size and high specific surface area and high chemical activity, these provide favorable foundation for low energy consumption process of recycling the powder. In the dissolution stage, the optimization reaction time is about 40 minutes, this time to complete the process of the reaction more than 90%. And the reaction is the fastest in the first 20 minutes, complete response 75% of the reaction. In the stage of carbonization, with increase of the concentration of the precursor, the particle diameter becomes larger, but the specific surface area of the powder will reduce, the porosity and the surface activity of it will reduce corresponding.

scholarly journals Activated carbons from common nettle as potential adsorbents for CO2 capture

2019 ◽  
Vol 21 (1) ◽  
pp. 59-66
Author(s):  
Alicja Szymańska ◽  
Amelia Skoczek ◽  
Jacek Przepiórski
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Characterization ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Dft Method ◽  
Nitrogen Atmosphere ◽  
Adsorption Desorption

Abstract Activated carbons (ACs) prepared from common nettle (Urtica Dioica L.) were studied in terms of carbon dioxide adsorption. ACs were prepared by KOH chemical activation in a nitrogen atmosphere at temperatures (ranging from 500 to 850°C). The pore structure and the surface characterization of the ACs were specified based on adsorption-desorption isotherms of nitrogen measured at –196°C and carbon dioxide at 0°C. The specific surface area was calculated according to the BET equation. The pore volume was estimated using the DFT method. The highest values of the specific surface area (SSA) showed activated carbons produced at higher carbonization temperatures. All samples revealed presence of micropores and mesopores with a diameter range of 0.3–10 nm. The highest value of the CO2 adsorption, 4.22 mmol/g, was found for the material activated at 700°C.

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