Colloids and Surfaces A: Physicochem. Eng. Aspects 440 (2014) 202–207
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Colloids and Surfaces A: Physicochemical and
Engineering Aspects
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Electrokinetic properties of detonation nanodiamond aggregates in
aqueous KCl solutions
F. Gareeva
a
, N. Petrova
b
, O. Shenderova
c
, A. Zhukov
a,∗
a
St. Petersburg State University, St. Petersburg, Russia
b
South Ural State University, Chelyabinsk, Russia
c
International Technology Center, Raleigh, USA
h i g h l i g h t s
Electrophoretic mobility of porous
aggregates of detonation nanodia-
mond was measured.
-potential values were calculated
using different equations of the the-
ory of electrophoresis.
Miller formula should provide the
most accurate -potential values for
these aggregates.
Conductivity of these porous aggre-
gates in KCl solutions was measured.
This conductivity is one or two orders
of magnitude higher than that of
solutions.
g r a p h i c a l a b s t r a c t
a r t i c l e i n f o
Article history:
Received 29 June 2012
Received in revised form 11 August 2012
Accepted 13 August 2012
Available online 2 September 2012
Keywords:
Zeta potential
Electrophoretic mobility
Detonation nanodiamond
Porous aggregates
Particle conductivity
a b s t r a c t
Electrophoretic mobility of porous aggregates of detonation nanodiamond (DND) particles was mea-
sured using the laser Doppler electrophoresis technique in aqueous KCl solutions. Corresponding values
of -potential were calculated as functions of pH and KCl concentration using different equations of
the theory of electrophoresis. It is suggested that use of the Miller formula, which takes into account
the electromigration fluxes of ions and electroosmotic flows of solutions in pores of dispersed particles,
should provide the most accurate -potential values for DND aggregates. The hydrosols of DND purified
from non-diamond carbon with nitric acid were additionally characterized by acid–base potentiometric
titrations and conductometric measurements. The dependences of surface charge density and conduc-
tivity of the aggregates on the pH = 3.5–10.5 of aqueous 0.0001–0.1 M KCl solutions were obtained. The
optimal values were determined for the reaction constants of ionization of acidic carboxyl ( COOH) and
amphoteric hydroxyl ( COH) groups, predominant on the DND surface. It is revealed that the effective
conductivity of the porous aggregates is one or two orders of magnitude higher than the conductivity of
the equilibrium solutions.
© 2012 Elsevier B.V. All rights reserved.
1. Introduction
During the last two decades the industrial production of det-
onation nanodiamond (DND) powders on a commercial scale has
∗
Corresponding author.
E-mail address: zhuk@AZ1038.spb.edu (A. Zhukov).
steadily increased due to the appearance of new applications [1–4].
It is known that the detonation of a mixture of carbon-containing
explosives, such as trinitrotoluene and cyclonite, in a confined
space and non-oxidizing environment gives rise to the formation of
nanoporous aggregates of DND ranging in sizes from tens to several
hundred of nanometers and specific surface areas of 200–350 m
2
/g.
The aggregates consist of primary nanoparticles with a crystalline
diamond lattice and very narrow size distribution in the range of
0927-7757/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.colsurfa.2012.08.055