Acid-base and adsorption properties of the porous microdispersed detonation nanodiamond

Abstract

It is necessary to choose the sorbent, which would provide a selective extraction and quantification
of polar compounds from aqueous solutions, for the effective implementation of the method of sorption concentration.
In recent years as potential adsorbents are increasingly attracting attention carbon sorbents based
on detonation nanodiamond that possess a number of unique physical and chemical properties. Detonation
nanodiamonds used directly in liquid chromatography impossible. Porous microdispersed detonation nanodiamonds
(PMDN) are suitable for these purposes. The presence on the surface of various polar functional
groups indicating that this sorbent is polar, which could promote increase the selectivity of the sorption of
polar compounds. The purpose of this work was to study the physicochemical patterns of adsorption of polar
sorbates having the properties of acids, bases and amphoteric compounds on porous microdispersed detonation
nanodiamonds. It has been shown that treatment of PMDN with acid or base does not affect the surface
area of the sorbent. Average values of specific surface area and pore diameter equal to 256 m2
/g and 3.8 nm,
respectively. The amount of acidic and basic groups on the sorbent surface were determined by method of
acid-base titration and Boehm titration. It is shown that the treatment of PMDN with acid or base leads to a
reproducible amounts of basic and acidic groups. This may indicate that the obtained results are reliable. The
data on adsorption of acidic and basic dyes on the surface of PMDN have shown that the surface of the sorbent
contains both basic and acidic groups. Treatment of the initial sample with acid or base leads to a decrease
of adsorption of acidic and basic dyes, which may be due to the removal of impurities from the PMDN
surface.