RESEARCH ARTICLE
Polyvinyl alcohol-based nanocomposite hydrogels containing magnetic
laponite RD to remove cadmium
Sara Mola ali abasiyan
1
&
Gholam Reza Mahdavinia
2
Received: 19 October 2017 / Accepted: 4 February 2018 / Published online: 17 March 2018
#
Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
In this study, magnetic nanocomposite hydrogels based on polyvinyl alcohol were synthesized. Magnetic polyvinyl
alcohol/laponite RD (PVA-mLap) nanocomposites were characterized by scanning electron microscopy, X-ray dif-
fraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results indicated that
PVA-mLap had desirable magnetic-sorption properties and magnetic-laponite nanoparticles were successfully synthe-
sized and added to polyvinyl alcohol. The present nanocomposites were applied to remove Cd
2+
from aqueous
solution. The influence of initial Cd
2+
concentration, magnetic-laponite concentration, pH, and ionic strength on
adsorption isotherm was investigated. Heterogeneity of adsorption sites was intensified by increasing magnetic
concentration of adsorbents and by rising pH value. Results of ionic strength studies indicated that by increasing
ionic strength more than four times, the adsorption of Cd
2+
has only decreased around 15%. According to the
results, the dominant mechanism of Cd
2+
sorption by the present adsorbents was determined chemical and specific
sorption. Therefore, the use of the present nanocomposites as a powerful adsorbent of Cd
2+
in the wastewater
treatment is suggested. Isotherm data were described by using Freundlich and Langmuir models, and better fitting
was introduced Langmuir model.
Keywords Polyvinyl alcohol
.
Magnetic
.
Laponite RD
.
Removal
.
Cadmium
Introduction
Heavy metal ion pollution of water systems is a serious issue
that requires our attention. Heavy metal ions such as cadmi-
um, lead, arsenic, and mercury ions are very harmful to human
beings as well as the environment, even at low concentration
levels in water. Water pollution by cadmium is one of the
prevalent contaminants. The main sources of cadmium leak
into the environment is related to man-made ways such as
using of phosphate fertilizers, presence in sewage sludge,
and various industrial uses, e.g., pigments, plastics, and
NiCd batteries (Benguella and Benaissa 2002). For this rea-
son, the treatment of cadmium pollution in water has received
an extensive concern and become a hot topic in environmental
research. Several methods have been reported for the removal
of heavy metals from aqueous solution and industrial effluent
such as ion exchange (Dabrowski et al. 2004), chemical pre-
cipitation (Alvarez et al. 2007), flotation (Medina et al. 2005),
ultrafiltration (Landaburu-Aguirre et al. 2009), nanofiltration
membranes (Kheriji et al. 2015), reverse osmosis (Kheriji
et al. 2015), and electrocoagulation (Escobar et al. 2006).
Among the mentioned methods, adsorption is known as a
major technique due to ease of operation, low-cost services,
and high efficiency (Pan et al. 2009). Cadmium adsorption
was also investigated using chemical sorbents such as activat-
ed carbon (Kadirvelu et al. 2001), soil (Calace et al. 2009),
iron oxides and hydroxides (Davis and Bhatnagar 1995), hu-
mic substances (Murphy and Zachara 1995), chitosan (Chu
2002), and alginate (Klimiuk and Kuczajowska-Zadrozna
2002). Also, different types of modified/unmodified
biopolymer-based adsorbents have been constructed and used
Responsible editor: Guilherme L. Dotto
* Sara Mola ali abasiyan
abasiyan@maragheh.ac.ir
1
Soil Chemistry Laboratory, Department of Soil Science, Faculty of
Agriculture, University of Maragheh, P. O. Box 55181-83111,
Maragheh, Iran
2
Polymer Research Laboratory, Department of Chemistry, Faculty of
Science, University of Maragheh, Maragheh, Iran
Environmental Science and Pollution Research (2018) 25:14977–14988
https://doi.org/10.1007/s11356-018-1485-5
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