Water purification from metal ions using carbon
nanoparticle-conjugated polymer nanocomposites
Rashid A. Khaydarov*, Renat R. Khaydarov, Olga Gapurova
Institute of Nuclear Physics, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
article info
Article history:
Received 28 June 2009
Received in revised form
19 November 2009
Accepted 20 November 2009
Available online 3 December 2009
Keywords:
Carbon
Nanoparticle
Polyethylenimine
Water treatment
Metal ion
abstract
The paper deals with a novel method of obtaining nanocarbon-conjugated polymer
nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for
water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical
characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of
interaction of metal ions with NCPC, ability of removing metal ions from water by NCPC
against pH have been studied. NCPC has a bonding capacity of 4.0–5.7 mmol/g at pH 6 for
most of the divalent metal ions. Percent of sorption of Zn
2þ
,Cd
2þ
,Cu
2þ
,Hg
2þ
,Ni
2þ
,
Cr
6þ
ions is higher than 99%. Lifetime of NCPC before coagulation in the treated water is
1 s–1000 min and depends on the ratio of polymeric molecules and carbon nanoparticle
concentrations. Results of laboratory tests of the method are described.
ª 2009 Elsevier Ltd. All rights reserved.
1. Introduction
An extensive use of metals and chemicals in process industry
has resulted in generation of a large amount of effluent con-
taining high levels of toxic heavy metals. Furthermore mining
and mineral processing procedures are known to generate
toxic liquid waste. The presence of different organic and
heavy metal contaminants in waste water has a large envi-
ronmental, public health and economic impact. Most of the
traditional methods such as solvent extraction, activated
carbon adsorption, ion exchange, biological degradation and
precipitation techniques are rather efficient, but often are
costly and/or time-consuming. Rumeau et al. (1992) were the
first to introduce the method of separation by coupling
ultrafiltration and complexation of metallic species with
industrial water-soluble polymers. This approach implies that
polymeric molecules operate as a sorbent and a carrier of
metal ions. In the method metal ions are primarily bound to
water-soluble polymers. The unbound ions pass through the
membrane, whereas the polymers and their complexes are
retained. Within this approach various weakly basic, water-
soluble polymers including chitosan, polyethylenimine (PEI),
poly(diallyldimethylammonium chloride), sodium poly-
styrene sulfonate (PSS) etc. have been used for removal of
metal ions from water (Juang and Chiou, 2000; Molinari et al.,
2004; Vieira et al., 2001; Steenkamp et al., 2002; Abderrahim
et al., 2006). The main advantages of the method lie in rela-
tively low energy requirements of the ultrafiltration process
and high removal efficiency due to effective binding of metal
ions with polymers (Juang and Shiau, 2000). On the other
hand, there is a difficulty of removal of the carrier of metal
ions from concentrated solution and the separation of poly-
meric molecules and metal ions.
Application of carbon nanoparticles and nanotubes for
removal of metal ions (Cd
2þ
,Cu
2þ
,Ni
2þ
,Pb
2þ
,Zn
2þ
, etc.) from
water have been described recently (Rao et al., 2007; Hudson
* Corresponding author. Tel.: þ998 712893144; fax: þ998 711503080.
E-mail address: renat2@gmail.com (R.A. Khaydarov).
Available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/watres
water research 44 (2010) 1927–1933
0043-1354/$ – see front matter ª 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.watres.2009.11.041