72
4 Investigation into the Adsorption of Cadmium and Lead …
the mining, smelting, metal plating, battery and phosphorus companies [5, 6]. Lead on
the other hand poses health risks like iron deficiency, brain trauma, kidney and liver
dysfunction, pregnancy complications [7–9] is manufactured in industrial sectors
including coatings, battery packs, combustion, pesticides and herbicides, plastic
materials, water systems, food, beverages, sweetener and flavouring balms and curative mixtures. The current maximum limit given by the US environmental protection
agency (USEPA) for cadmium and lead is 0.005 and 0.05 mg/L correspondingly.
Because of the stringent regulations on the release in water sources of such toxic
metals, it then becomes necessary to promote new methods which would reduce
or eliminate such contaminants to their acceptable levels. In the past, technologies
including chemical coagulation, layer separation, reverse osmosis and electrodialysis
have been used to remove ions from materials. Consequently, previous findings have
suggested that adsorption is perhaps the most optimistic method of removing toxic
metals due to its effectiveness, ease of handling, simple design, could remove various
kinds of pollution, and it can be regenerated by certain process of desorption [3, 10].
Ali et al. [11] reported that the procedure of adsorption can eliminate up to 99.9%
of contaminants found in wastewater.
Chitosan has proved to be an important adsorbent among the numerous adsorbent’s materials, possessing particular attributes including antibacterial properties,
processability, non-toxicity and relatively cheap [11]. Chitosan is a product of Ndeacetylation of chitin, a polymer which occurs naturally in sea creatures, i.e. snails
and crabs, and fungal biomass [12]. The availability of amine and hydroxyl group
in the backbone of chitosan provides the polymer its excellent adsorption ability.
Chitosan can eliminate concentration levels of metallic ions to extremely low concentration [13]. The distinctiveness of chitosan allows for better improvements of the
polymer in an attempt to modify or boost the adsorption properties of chitosan.
Polymer chains transformation of chitosan appears to make the polymer impermeable in acidic environment, thus boosting the chemical and mechanical steadiness.
Many researches have found these procedure to have a detrimental impact on adsorption potential owing to the fact that the amine group of chitosan is participating in the
cross-linking mechanism [14], and thus, it becomes necessary to graft the crosslinked
beads to boost the metal adsorption characteristics of the target group [10].
This report presents the use of crosslinked chitosan beads with polyaniline graft to
extract cadmium and lead from aqueous solution. Because there is an amine group in
polyaniline which is effective in absorbing metallic ions, it is, however, important to
create an adsorbent that will adsorb metallic ions significantly faster than any other
chitosan composite materials. Chitosan beads were cross-linked with hydrochloric
acid and then grafted with polyaniline. Characterization of the beads was based on
scanning electron microscope (SEM) and X-ray diffraction (XRD). It examined the
effect of pH, adsorbent dosage, initial concentration, contact time, and cadmium and
lead adsorption. The models of Langmuir and Freundlich have been used to interpret
isotherms of equilibrium for cadmium adsorption and lead to cross-linked and grafted
beads. The adsorption thermodynamics of both metallic ions on grafted crosslinked
beads were represented by quantities including standard Gibbs free energy change
4 Investigation into the Adsorption of Cadmium and Lead …
the mining, smelting, metal plating, battery and phosphorus companies [5, 6]. Lead on
the other hand poses health risks like iron deficiency, brain trauma, kidney and liver
dysfunction, pregnancy complications [7–9] is manufactured in industrial sectors
including coatings, battery packs, combustion, pesticides and herbicides, plastic
materials, water systems, food, beverages, sweetener and flavouring balms and curative mixtures. The current maximum limit given by the US environmental protection
agency (USEPA) for cadmium and lead is 0.005 and 0.05 mg/L correspondingly.
Because of the stringent regulations on the release in water sources of such toxic
metals, it then becomes necessary to promote new methods which would reduce
or eliminate such contaminants to their acceptable levels. In the past, technologies
including chemical coagulation, layer separation, reverse osmosis and electrodialysis
have been used to remove ions from materials. Consequently, previous findings have
suggested that adsorption is perhaps the most optimistic method of removing toxic
metals due to its effectiveness, ease of handling, simple design, could remove various
kinds of pollution, and it can be regenerated by certain process of desorption [3, 10].
Ali et al. [11] reported that the procedure of adsorption can eliminate up to 99.9%
of contaminants found in wastewater.
Chitosan has proved to be an important adsorbent among the numerous adsorbent’s materials, possessing particular attributes including antibacterial properties,
processability, non-toxicity and relatively cheap [11]. Chitosan is a product of Ndeacetylation of chitin, a polymer which occurs naturally in sea creatures, i.e. snails
and crabs, and fungal biomass [12]. The availability of amine and hydroxyl group
in the backbone of chitosan provides the polymer its excellent adsorption ability.
Chitosan can eliminate concentration levels of metallic ions to extremely low concentration [13]. The distinctiveness of chitosan allows for better improvements of the
polymer in an attempt to modify or boost the adsorption properties of chitosan.
Polymer chains transformation of chitosan appears to make the polymer impermeable in acidic environment, thus boosting the chemical and mechanical steadiness.
Many researches have found these procedure to have a detrimental impact on adsorption potential owing to the fact that the amine group of chitosan is participating in the
cross-linking mechanism [14], and thus, it becomes necessary to graft the crosslinked
beads to boost the metal adsorption characteristics of the target group [10].
This report presents the use of crosslinked chitosan beads with polyaniline graft to
extract cadmium and lead from aqueous solution. Because there is an amine group in
polyaniline which is effective in absorbing metallic ions, it is, however, important to
create an adsorbent that will adsorb metallic ions significantly faster than any other
chitosan composite materials. Chitosan beads were cross-linked with hydrochloric
acid and then grafted with polyaniline. Characterization of the beads was based on
scanning electron microscope (SEM) and X-ray diffraction (XRD). It examined the
effect of pH, adsorbent dosage, initial concentration, contact time, and cadmium and
lead adsorption. The models of Langmuir and Freundlich have been used to interpret
isotherms of equilibrium for cadmium adsorption and lead to cross-linked and grafted
beads. The adsorption thermodynamics of both metallic ions on grafted crosslinked
beads were represented by quantities including standard Gibbs free energy change