Theoretical Study of Adsorption Sites on the (001) Surfaces of 1:1 Clay Minerals

Langmuir ◽  
2002 ◽  
Vol 18 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Daniel Tunega ◽  
Georg Haberhauer ◽  
Martin H. Gerzabek ◽  
Hans Lischka
Keyword(s):  
Clay Minerals ◽  
Theoretical Study ◽  
Adsorption Sites

A Theoretical Study of H2S Toxic Gas Adsorption on Pristine and Doped Monolayer (AlN)21 Using Density Functional Theory

2020 ◽  
Vol 12 (02) ◽  
pp. 99-111
Author(s):  
Jamal A. Shlaka ◽  
◽  
Abbas H. Abo Nasria
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Gas Adsorption ◽  
Aluminium Nitride ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Gas Molecules ◽  
Toxic Gas ◽  
Center Ring

Been studying the interactions between graphene - like aluminium nitride P(AlN)21 nano ribbons doped and defect (AlN)21Sheet, Molecules and small toxic gas molecules ( H2S), were built for two different adsorption sites on graphene like aluminium nitride P(AlN)21. this was done by employing B3LYP density functional theory (DFT) with 6-31G*(d,p) using Gaussian 09 program, Gaussian viw5.0 package of programs and Nanotube Modeller program 2018. the adsorptions of H2S on P(AlN)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C)atoms-doped P(AL-N)19 (on atom) with (Ead) (-0.468eV),(-0.473 eV), (-0.457 eV), (-0.4478 eV) and (-0.454 eV), respectively, (Ead) of H2S on the center ring of the P(AL-N)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C,B)atoms-doped P(AL-N)19 sheet are (-0.280 eV),(-0.465 eV), (-0.405 eV), (-0.468 eV) and -0.282 eV), respectively, are weak physisorption . However, the adsorptions of H2S, on the ((AlN)20 -B and D- (AlN)19 -B), (on atom N and center ring the sheet) are a strong chemisorption because of the (Ead) larger than -0.5 eV, due to the strong interaction, the ((AlN)20-B and D-(AlN)19-B), could catalyst or activate, through the results that we obtained, which are the improvement of the sheet P(AlN)21 by doping and per forming a defect in, it that can be used to design sensors. DOI: http://dx.doi.org/10.31257/2018/JKP/2020/120210

Dissociation of H2O molecule adsorbed on Si (001) 2×1 surface: a theoretical study

2008 ◽  
Vol 1145 ◽  
Author(s):  
Hyun-Chul Oh ◽  
Hwa-Il Seo ◽  
Yeong-Cheol Kim
Keyword(s):  
Water Molecule ◽  
Room Temperature ◽  
Surface Coverage ◽  
Theoretical Study ◽  
Surface Model ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Adsorption Sites ◽  
Adsorption Surface ◽  
Adsorption And Dissociation

AbstractThe adsorption and dissociation behavior of water molecule below and above the critical dissociation temperatures were studied by first principles calculations. We found that water-molecule adsorption (surface coverage, θ=0.25) on the down Si atom of a Si dimer in two dimers surface model was 0.26 eV more favorable than that on the up Si atom. The activation energies of water molecule on the down Si atom for interdimer and intradimer dissociations were 0.17 eV and 0.20 eV, respectively. Due to the lower activation energy, the water molecule splits into H and OH immediately once it adsorbs on down Si atom of the Si (001) surface at room temperature. There were three different adsorption sites among four sites of the two dimers for the second water molecule (θ=0.5): one was preoccupied by OH of the first water molecule; up Si atom of the same-dimer with 76.3 % probability, up Si atom of the adjacent-dimer with 23.6 % probability, and down Si atom of the adjacent-dimer with 0.1 % probability. Thus, ½ monolayer of OH sites on the Si (001) surface are irregularly distributed when water molecules are adsorbed and dissociated at room temperature.

The role of sorbate in the determination of preferential adsorption sites in zeolite HY: A theoretical study

2007 ◽  
Vol 103 (1-3) ◽  
pp. 280-283 ◽  
Author(s):  
Siricharn S. Jirapongphan ◽  
Juliusz Warzywoda ◽  
David E. Budil ◽  
Albert Sacco
Keyword(s):  
Theoretical Study ◽  
Adsorption Sites ◽  
Preferential Adsorption

The role of clay minerals in formation of the regolith-hosted heavy rare earth element deposits

2020 ◽  
Vol 105 (1) ◽  
pp. 92-108 ◽  
Author(s):  
Martin Yan Hei Li ◽  
Mei-Fu Zhou
Keyword(s):  
Rare Earth ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Rare Earth Element ◽  
Earth Element ◽  
Modern Society ◽  
Heavy Rare Earth ◽  
Heavy Rare Earth Element ◽  
Adsorption Sites ◽  
Shallow Soils

Abstract Rare earth elements (REEs) have become increasingly important to our modern society due to their strategical significance and numerous high technological applications. Regolith-hosted heavy rare earth element (HREE) deposits in South China are currently the main source of the HREEs, but the ore-forming processes are poorly understood. In these deposits, the REEs are postulated to accumulate in regolith through adsorption on clay minerals. In the Zudong deposit, the world's largest regolith-hosted HREE deposit, clay minerals are dominated by short, stubby, nanometer-scale halloysite tubes (either 10 or 7 Å) and microcrystalline kaolinite in the saprolite and lower pedolith and micrometer-sized vermicular kaolinite in the humic layer and upper pedolith. A critical transformation of the clay minerals in the upper pedolith is coalescence and unrolling of halloysite to form vermicular kaolinite. Microcrystalline kaolinite also transformed to large, well-crystalline vermicular kaolinite. This transformation could result in significant changes in different physicochemical properties of the clay assemblages. Halloysite-abundant clay assemblages in the deep regolith have specific surface area and porosity significantly higher than the kaolinite-dominant clay assemblages in the shallow soils. The crystallinity of clay minerals also increased, exemplified by decrease in Fe contents of the kaolinite group minerals (from ~1.2 wt% in the lower saprolite to ~0.35 wt% in the upper pedolith), thereby indicative of less availability of various types of adsorption sites. Hence, halloysite-abundant clay minerals of high adsorption capacity in deep regolith could efficiently retain the REEs released from weathering of the parent granite. Reduction in adsorption capacity during the clay transformation in shallow depth partially leads to REE desorption, and the released REEs would be subsequently transported to and adsorbed at deeper part of the soil profile. Hence, the clay-adsorbed REE concentration in the lower pedolith and saprolite (~2500 ppm on average) is much higher than the uppermost soils (~400 ppm on average). Therefore, weathering environments that favor the release of the REEs in the shallow soils but preservation of halloysite in the deep regolith can continuously adsorb REEs in the clay minerals to form economically valuable deposits.

Ab Initio Molecular Dynamics Study of Adsorption Sites on the (001) Surfaces of 1:1 Dioctahedral Clay Minerals

2002 ◽  
Vol 106 (44) ◽  
pp. 11515-11525 ◽  
Author(s):  
Daniel Tunega ◽  
Lubomir Benco ◽  
Georg Haberhauer ◽  
Martin H. Gerzabek ◽  
Hans Lischka
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Clay Minerals ◽  
Ab Initio Molecular Dynamics ◽  
Adsorption Sites

FRACTAL CHARACTERISTICS OF PORES IN TAIYUAN FORMATION SHALE FROM HEDONG COAL FIELD, CHINA

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840006 ◽  
Author(s):  
KUNJIE LI ◽  
FANGUI ZENG ◽  
JIANCHAO CAI ◽  
GUANGLONG SHENG ◽  
PENG XIA ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Clay Minerals ◽  
Fractal Dimensions ◽  
Methane Adsorption ◽  
Relative Pressure ◽  
Coal Field ◽  
Adsorption Sites ◽  
Taiyuan Formation ◽  
Pore Size Distributions ◽  
Fractal Characteristics

For the purpose of investigating the fractal characteristics of pores in Taiyuan formation shale, a series of qualitative and quantitative experiments were conducted on 17 shale samples from well HD-1 in Hedong coal field of North China. The results of geochemical experiments show that Total organic carbon (TOC) varies from 0.67% to 5.32% and the organic matters are in the high mature or over mature stage. The shale samples consist mainly of clay minerals and quartz with minor pyrite and carbonates. The FE-SEM images indicate that three types of pores, organic-related pores, inorganic-related pores and micro-fractures related pores, are developed well, and a certain number of intragranular pores are found inside quartz and carbonates formed by acid liquid corrosion. The pore size distributions (PSDs) broadly range from several to hundreds nanometers, but most pores are smaller than 10[Formula: see text]nm. As the result of different adsorption features at relative pressure (0–0.5) and (0.5–1) on the N2 adsorption isotherm, two fractal dimensions [Formula: see text] and [Formula: see text] were obtained with the Frenkel–Halsey–Hill (FHH) model. [Formula: see text] and [Formula: see text] vary from 2.4227 to 2.6219 and from 2.6049 to 2.7877, respectively. Both TOC and brittle minerals have positive effect on [Formula: see text] and [Formula: see text], whereas clay minerals, have a negative influence on them. The fractal dimensions are also influenced by the pore structure parameters, such as the specific surface area, BJH pore volume, etc. Shale samples with higher [Formula: see text] could provide more adsorption sites leading to a greater methane adsorption capacity, whereas shale samples with higher [Formula: see text] have little influence on methane adsorption capacity.

Specificity of virus adsorption to clay minerals

1985 ◽  
Vol 31 (1) ◽  
pp. 50-53 ◽  
Author(s):  
Steven M. Lipson ◽  
G. Stotzky
Keyword(s):  
Clay Minerals ◽  
Minimal Essential Medium ◽  
Adsorption Sites ◽  
Virus Adsorption ◽  
Serum Amino Acids ◽  
Soils And Sediments ◽  
Reovirus Type ◽  
Fetal Bovine ◽  
Type 3 ◽  
Positively Charged

Competitive adsorption studies indicated that reovirus type 3 and coliphage T1 did not share common adsorption sites on kaolinite and montmorillonite. Compounds in the minimal essential medium (e.g., fetal bovine serum, amino acids) in which the reovirus was maintained blocked adsorption of coliphage T1 to kaolinite and partially to montmorillonite in synthetic estuarine water, but they had no effect on coliphage adsorption to montmorillonite in distilled water or on the adsorption of the reovirus to either clay. The blockage of positively charged sites on kaolinite or montmorillonite by treatment of the clays with sodium metaphosphate or with the supernatants from montmorillonite or kaolinite, respectively, had no effect on adsorption of the reovirus. These data indicate that there was a specificity in adsorption sites for mixed populations of reovirus type 3 and coliphage T1 and emphasize the importance of using more than one type of virus, especially in combination, to predict virus behavior (e.g., adsorption, loss of infectivity) in soils and sediments containing clay minerals.

Theoretical Study of Microscopic Features of Gas-Phase Adsorption onto a Few Adsorption Sites of Silica Gel

1995 ◽  
Vol 99 (43) ◽  
pp. 15968-15972 ◽  
Author(s):  
Tetsuo Suzuki ◽  
Makoto Hirano ◽  
Hajime Tamon ◽  
Morio Okazaki
Keyword(s):  
Gas Phase ◽  
Silica Gel ◽  
Theoretical Study ◽  
Adsorption Sites ◽  
Gas Phase Adsorption ◽  
Microscopic Features
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