Study of heavy metal Mn2+ Adsorption by Synthesized Chitosan
Angham G. Hadi
Babylon University, College of Science, Chemistry Department.
Abstract
In this research work natural bio polymer “chitosan” was synthesized using fish shells and adsorption of manganese by chitosan was studied. Synthesize of chitosan 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 manganese was studied using MnCl2.4H2O solution as the heavy metal solution containing Mn (II) ions.
The ability of chitosan as an adsorbent for Mn (II) ions in aqueous solution was studied. The capacity of chitosan to trap manganese ions in aqueous solution was carried out at 30oC using concentration as parameters. Our results show that the adsorption process is concentration-driven with high capacity of chitosan for the adsorption of these metal ions. The Infra red spectroscopic study on the chitosan and the metal-chitosan complexes reveal a metal coordination based on the observed characteristic band changes. At initial manganese concentrations of 3, 5 and 8 mg/L, the adsorbed manganese ion concentrations are 2.6136, 4.3954, and 7.3638 mg/L, respectively.
KEYWORDS: chitosan, heavy metal, bio-adsorption
1. INTRODUCTION
In the past century there has been a rapid expansion in industries. This has lead to an increase in the complexity of toxic effluents. Several industrial processes generate metal containing wastes. Heavy metal contamination has been a critical problem mainly because metals tend to persist and accumulate in the environment. Copper, Nickel, Mercury, lead, Zinc, manganese, Arsenic etc. are such toxic metals which are being widely used. They are generated by dental operation, electroplating, tanning, textile, paper and pulp industry and are potentially toxic to humans [1]. These heavy metals are used in many industries for different purposes and released to the environment with industrial wastage. Therefore the effluents being generated by these industries are rich in heavy metals should be treated before discharge in to the common waste water. On the other hand aquatic systems are particularly sensitive to pollution possibly due to the structure of their food chain. In many cases harmful substances enter the food chain and are concentrated in fish and other edible organisms. As they move from one ecological tropic level to another, metallic species start damaging the ecosystem. They also become difficult to track as they move up in tropic levels. They accumulate in living tissues throughout the food chain. Due to biomagnifications, human receive the maximum impact, since they are at the top of the food chain. Hence heavy metal contamination has been a critical problem [2]. The efficient removal of toxic metals from wastewater is an important matter and it is being studied. A number of technologies have been developed over the years to remove toxic metal from wastewater. The main sources of manganese pollution are mining, the iron and steel industry, fuel oil, incineration, coal and dry cell batteries. Continued exposure may lead to chronic manganese poisoning and manganese pneumonia."" Chronic manganese poisoning is clearly characterized as resulting from the inhalation of fumes or dusts of manganese [3]. The central nervous system is the chief site of damage. When well established, the disease results in permanent disability [4,5].
British Journal of Science 128
September 2012, Vol. 6 (2)
© 2012 British Journals ISSN 2047-3745
The aim of this study was to demonstrate the use of chitosan as a bio-adsorbent for uptake of heavy metal ion. The chitosan used in this work was derived from fish shells available in Babylon-Hilla.