British Journal of Science 109
September 2012, Vol. 6 (2)
© 2012 British Journals ISSN 2047-3745
Adsorption of Nickel Ions by Synthesized Chitosan
Angham G. Hadi
Babylon University, College of Science, Chemistry Department.
Abstract
Chitosan is an amino-polysaccharide with highly efficient properties for the binding of metal
ions. Uptake may occur through chelation on free amino functions (at near-neutral pH) or by
electrostatic attraction on protonated amino groups (in acidic solutions). Chitosan synthesation process
from fish shells involved four main stages as preconditioning, demineralization, deproteinization,
decolorization and deacetylation. Chitosan was characterized using Fourier Transform Infrared
Spectroscopy (FTIR) and solubility in 1% acetic acid. The affinity of chitosan for nickel was studied
using NiCl2.6H2O solution as the heavy metal solution containing Ni (II) ions.
Keywords: Adsorption, chitosan, nickel chloride, chitin ,precipitate.
1. Introduction
Contamination of aquatic media by heavy metal ions is a serious environmental problem,
mainly due to the discarding of industrial wastes [1]. Among the heavy metals chromium, cobalt, zinc,
copper, nickel and iron ingestion beyond permissible quantities, causes various chronic disorders in
human beings. It is well known that heavy metals can damage the nerves, liver and bones and they
block functional groups of essential enzymes [2]. The increasing demand for new processes for
wastewater treatment, more environmentally friendly and more competitive, has led to much research
on the use of biopolymers such as alginate and chitin/chitosan for the recovery of metal ions [3,4] or
organic compounds [5-8]. These biopolymers are characterized by high sorption capacities, easy
degradation routes (at the end of life cycle) and relatively low costs [9]. These properties make them
very promising for replacing conventional processes. Chitosan has a unique property among these
biopolymers: its cationicity in acidic solutions. This property is due to the presence of a large number
of amino groups, which are very reactive for (a) metal cations by chelation in near-neutral solutions,
and for (b) metal anions that can be bound to protonated amino groups in acidic solutions [4].
Chitin is the second most abundant natural polymer on the earth after cellulose. Chitin exist widely the
exoskeleton of insects and other marine crustaceans. It is of interest, not only as an underutilized
resource, but also as a new functional material of high potential in various fields [10]. Chitosan is a
biopolymer which is of interest to researchers concerning the adsorption of metal ions [11]. Chitosan is
the N-deacetylated product of chitin (Fig.1). Although a sharp nomenclature border does not exist
between chitin and chitosan, the term ‘chitosan’ usually represents copolymers of 2-amino-2-deoxy-Dglucopyranose
and 2-acetamido-2- deoxy-D-glucopyranose.
Figure 1. Structure of Chitin and Chitosan .
British Journal of Science 110
September 2012, Vol. 6 (2)
© 2012 British Journals ISSN 2047-3745
The objective of this study was the synthesis of the of chitosan and study of nickel recovery on chitosan by sorption (chitosan in solid state) The adsorption capability of chitosan was investigated using Ni(II) as the model metal contaminant because of its extensive environmental impacts.