Title 2.
Reception nanowires silica particles under conditions pyrogenic synthesis
1.
Myronyuk I.F. Chemical aspects of silica fumed synthesis // Chemistry, Physics and
Technology of Surface, v.3, pp. 15-20 (2001).
2.
Gun'ko V.M., Voronin E.F., Mironyuk I.F., Leboda R., Scubiszewska-Zieba J., Pakhlov
E.M., Guzenko N.V., Chuiko A.A. The effect of heat, adsorption and mechanochemical
treatments on stuck structure and adsorption properties of fumed silicas // Colloids and
Surfaces A: Physicochemical and Engineering Aspects, Volume 218, Issues 1-3, 29 May
2003, Pages 125-135.
The structural characteristics of fumed silicas synthesised under varied conditions and standard
fumed silicas subjected to different types of pre-treatment, such as heating, suspending–ball-milling–
drying, ball-milling of dry powder, and immobilisation of polymers, were studied using adsorption–
desorption methods. Variations of preparation conditions and applied treatments influence the
structure of finished samples in respect of both micropores and mesopores in primary particle
swarms (aggregates, agglomerates) dependent on the treatment time nonlinearly. However, pretreatments change the mesopore parameters of final adsorbents to a greater extent than those of
micropores due to significant rearrangement of the primary particle agglomerates and gaps between
aggregates. Application of the regularisation procedure to compute the pore size distributions using
overall adsorption equation based on the combination of the Kelvin equation and the statistical
adsorbed film thickness allows us to study the dependence of the structural characteristics of fumed
silicas on treatment conditions in details.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFR-489440T3&_user=10&_coverDate=05%2F29%2F2003&_alid=1048574834&_rdoc=2&_fmt=high&_orig
=search&_cdi=5233&_sort=r&_docanchor=&view=c&_ct=4&_acct=C000050221&_version=1&
_urlVersion=0&_userid=10&md5=cbf0e9ba66949aa86a8cf4cbf679116b
3.
Gun'ko V.M., Zarko V.I., Turov V.V., Voronin E.F., Goncharuk E.V., Mironyuk I.F.,
Chuiko A.A., Janusz W., Leboda R. and Chibowski S. Connection between Structural and
Adsorptive Characteristics of Fumed Oxides and Their Efficiency in Environmental and
Human Protection Applications, The Second International Conference "Interfaces Against
Population", University of Miskolc, Hungary, May 25-30, 2002. NATO Science Series,
Kluwer, 2003, pp. 445-455.
4.
Gun'ko V.M., Scubiszewska-Zieba J., Leboda R., Khomenko K.N., Kazakova O.A.,
Povazhnyak M.O., and Mironyuk I.F. Influence of Morphology and Composition of Fumed
Oxides on Changes in Their Structural and Adsorptive Characteristics on Hydrothermal
Treatment at Different Temperatures // Journal of Colloid and Interface Science, Volume
269, Issue 2, 15 January 2004, Pages 403-424.
A series of fumed oxides such as silica, titania, alumina, silica/alumina (SA), silica/titania (ST), and
alumina/silica/titania (AST), initial and hydrothermally treated (HTT) in the steam phase at
THTT=150, 250, and 350 °C was studied by adsorption, AFM, XRD, FTIR, and theoretical methods.
Diminution of the size of primary particles (corresponding to increasing SBET) of initial silica and
mixed oxides results in enhancement of their structural changes on HTT with elevating THTT and
increasing density of packing of primary particles in the secondary structures. Relative changes in
the texture of treated fumed silicas are smaller than those of mesoporous silica gels occurring under
similar HTT conditions. On HTT, aggregates of primary particles and their agglomerates become
denser but their surface layers become looser because of transfer of silica fragments from one
particle to another, and the smaller the initial primary particles, the greater the relative diminution
of the specific surface area SBET for the same type of primary particle packing in aggregates.
Relative changes in the pore volume Vp (or VBJHd) on HTT are more complex than that of SBET, as for
many samples the Vp value increases especially at THTT=150 °C. Alumina and titania partially inhibit
structural changes on HTT, which decrease in the series silica > SA > AST ≈ ST.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WHR-49HDPY68&_user=10&_coverDate=01%2F15%2F2004&_alid=1048560818&_rdoc=3&_fmt=high&_orig
=search&_cdi=6857&_sort=r&_docanchor=&view=c&_ct=4&_acct=C000050221&_version=1&
_urlVersion=0&_userid=10&md5=cd7c4f1f634e53c08ad944619226b1bd
5.
Gun'ko V.M., Zarko V.I., Mironyuk I.F., Goncharuk E.V., Guzenko N.V., Borysenko M.V.,
Janusz W., Leboda R., Scubiszewska-Zieba J., Gregorczyk W., Charmas B., Matysek M.
and Chibowski S. Surface electric and titration behavior of fumed oxides // Colloids and
Surfaces A: Physicochemical and Engineering Aspects, Volume 240, Issues 1-3, 15 June
2004, Pages 9-25.
Adsorption of Pb(II), Sr(II), and Cs(I) on fumed silica, alumina, titania, silica/titania (ST),
silica/alumina (SA), and alumina/silica/titania (AST) reveals that mixed oxides containing titania
have a greater adsorptive capability in respect to metal cations than individual and SA oxides.
Pyrocarbon deposits on fumed oxides enhance the adsorption of metal ions. Calculations of
electrophoretic potential (ζ) with consideration for the porosity of aggregates of primary particles of
AST show a significant influence of surface alumina (at pH<8) and titania and silica (at pH>8) on
the ζ values. The effective diameter of particles (Def) of fumed oxides in aqueous media depends on
pH for AST stronger than for ST (between isoelectric points (IEPs) of titania and alumina). A
significant difference in the pH values of IEP and point of zero charge is observed for AST samples.
A pyrocarbon influence on the ζ potential depends on the type of oxide matrix, since ζ increases for
certain samples but for others it decreases. These changes depend nonlinearly on pH as well as the
secondary particle size distributions (SPSDs) and Def.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFR-4CBW5YC2&_user=10&_coverDate=06%2F15%2F2004&_alid=1048574834&_rdoc=1&_fmt=high&_orig
=search&_cdi=5233&_sort=r&_docanchor=&view=c&_ct=4&_acct=C000050221&_version=1&
_urlVersion=0&_userid=10&md5=27383221afe49dd157fb99c6cbf5278d
6.
V.M. Gun’ko, I.F. Mironyuk, V.I. Zarko, E.F. Voronin, V.V. Turow, E.M. Pakhlow,
E.V. Goncharuk, Y.M. Niciporuk, N.N. Vlasova, P.P. Gorbik, O.A. Mishchuk, A.A. Chuiko,
T.V. Kulik, B.B. Palyanytsya, S.V. Pakhovchishin, J. Skubiszewska-Zięba, W. Janusz,
A.V. Turov, R. Leboda. Morphology and surface properties of fumed silicas // Journal of
Colloid and Interface Science, Volume 289, Issue 2, 15 September 2005, Pages 427-445.
Several series of fumed silicas and mixed fumed oxides produced and treated under different
conditions were studied in gaseous and liquid media using nitrogen and water adsorption–
desorption, mass spectrometry, FTIR, NMR, thermally stimulated depolarization current (TSDC),
photon correlation spectroscopy (PCS), zeta potential, potentiometric titration, and Auger electron
spectroscopy methods. Aggregation of primary particles and adsorption capacity (Vp) decrease and
hysteresis loops of nitrogen adsorption–desorption isotherms becomes shorter with decreasing
specific surface area (SBET). However, the shape of nitrogen adsorption–desorption isotherms can be
assigned to the same type independent of SBET value. The main maximum of pore size distribution
(gaps between primary nonporous particles in aggregates and agglomerates) shifts toward larger
pore size and its intensity decreases with decreasing SBET value. The water adsorption increases with
increasing SBET value; however, the opposite effect is observed for the content of surface hydroxyls
(in mmol/m2). Associative desorption of water (2( Si OH) → Si O Si + H2O) depends
on both the morphology and synthesis conditions of fumed silica. The silica dissolution rate
increases with increasing SBET and pH values. However, surface charge density and the modulus of
zeta-potential increase with decreasing SBET value. The PCS, 1H NMR, and TSDC spectra
demonstrate rearrangement of the fumed silica dispersion depending on the SBET value and the silica
concentration (CSiO2) in the aqueous suspensions. A specific state of the dispersion is observed at the
CSiO2 values corresponding to the bulk density of the initial silica powder.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WHR-4GMS99Y4&_user=10&_coverDate=09%2F15%2F2005&_alid=1048560818&_rdoc=1&_fmt=high&_orig
=search&_cdi=6857&_sort=r&_docanchor=&view=c&_ct=4&_acct=C000050221&_version=1&
_urlVersion=0&_userid=10&md5=a2eaf0cc49659163bb35b0aa8a33b76c
7.
I.F. Myronyuk; V.I. Mandzyuk; T.V. Gergel. Dimensions Effects in Fumed Silica
Nanoparticles // Physics and Chemistry of Solid State, v.6, #1, 2005, pp. 34-38.
The investigation of fumed silica by means the infrared Fourier spectroscopy method allowed find
out that the length of siloxane bond increase in Si–O–Si chains with the decreasing of nanoparticles
average diameter, thus bonds feel the most lengthening in surface globule interlayer. The globule
“swelling” related to considerable Laplace pressure within small particles. There is the band in
SiO2 – spectra with the maximum absorption at 978-964 sm-1, which belong to dissymmetric atom
oscillations of siloxane bond of surface globule interlayer. The decreasing of concentration of
hydroxyl groups and absorbed water concentration in small particles reduction of concentration is
conditioned by reduction of number of surface silicon atoms in re-calculation per unit of area.
http://www.pu.if.ua/inst/phys_che/start/pcss/vol6/0601-03.pdf
Figure. Picture of needle-shaped particles with the diameter of 10-20 nm, with the
length of 1000-3000 nm.