A Comparative Study on Metal AdsorptionProperties of Different Forms of Chitosan (original) (raw)
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A Review on Chitosan for the Removal of Heavy Metals Ions
Journal of Fiber Bioengineering and Informatics, 2019
There has recently been an increasing interest in water treatment methods as a result of growing concerns over shortages of clean water. This paper aims to review the past and present researches on chitosan for the adsorption of heavy metals from the wastewater. Adsorption is considered to be the most efficient method for the removal of metal impurities from drinking water. Chitosan, a deacetylated derivative of chitin, has many commercial applications due to its biocompatibility, nontoxicity, and biodegradability. Moreover, amine groups are present on the backbone of chitosan. For this reason, chitosan has been used for the adsorption of heavy metals. To begin with, mechanism of adsorption of heavy metal ions on chitosan and disadvantages of heavy metal ions were reviewed. Further, a detailed review had been done on the adsorption capacities of crosslinked chitosan, chitosan nanofibers, chitosan nanoparticles, chitosan composites, modified/pure chitosan, and porous chitosan. Lastly, research gaps and future recommendations were given for further development and accurate results of adsorption.
Treatment of industrial wastewater containing copper and cobalt ions using modified chitosan
Journal of Industrial and Engineering Chemistry, 2014
Heavy metal water pollution is the contamination of water in natural resources by heavy metals . Traditional treatment methods including: chemical precipitation [2], electrochemical deposition , ion exchange, and membrane separation have been applied. Adsorption method using natural biosorbents is alternative to these methods. Numerous studies have demonstrated the effectiveness of chitosan and derived products in the uptake of metal cations such as lead, cadmium, copper, and nickel and the uptake of oxyanions as well as complexed metal ions [5-9,1]. Chitosan is undoubtedly one of the most popular adsorbents for metal ions removal from aqueous solution and is widely used in waste treatment applications . The binding ability of chitosan for metal cations is mainly due to the amine groups (-NH 2 ) on the chitosan chain which can serve as coordination sites for many metals. The extent of metal adsorption depends on the source of chitosan , the degree of deacetylation , the nature of the metal ion , and solution conditions such as pH . In spite of its prolific use, the adsorption ability of chitosan has not been realized to a satisfying level. In recent years, attention focused on several adsorbents which have metal-binding capacities and high selectivity to remove heavy metals from contaminated water . In order to improve the sorption selectivity and adsorption ability of chitosan for metal ions, a great number of chitosan derivatives have been prepared by grafting new functional groups such as histidine [16], heparin [17], succinic anhydride [18], N,O-carboxymethyl [19] through a crosslinked chitosan back bone. Further, chemical modifications of chitosan were made to improve the selectivity and the capacities toward heavy metal ions . Substituted chitosan was prepared and regarded as a simple and effective process to facilitate the adsorption ability of chitosan with heavy metals . In the present study, two chitosan derivatives were prepared and characterized. Their adsorption efficiency and mechanism of adsorption were determined and discussed.
Chitosan Based Adsorbent : A Remedy to Handle Industrial Waste Water
2017
A healthy environment is chief requirement of modern society and to make the surroundings to live, especially firstly needed water must be pollution free. Adsorption is one of the best wastewaters treatment process. Keeping in view, we have reviewed the utility of chitosan as an adsorbent for the removal of dyes and metals from aqueous solution, which is a non toxic, biocompatible, positively charged, biodegradable natural polymer and obtained by alkaline deacetylation of chitin. To introduce desired characteristics and broaden the scope of the potential applications of chitosan as an adsorbent, physical and chemical modifications have been carried out and obtained various chitosan based materials. Our review article produced an evidence that chitosan based beads, have outstanding adsorption efficiencies for metals and dyes and can be auspicious substitute for conventional adsorbents for removing pollutants.
Heavy Metal Ion Adsorbent in Aqueous Solution: A Review on Chitosan and Chitosan Composites
Journal of Advanced Research in Micro and Nano Engineering, 2024
One prominent contributor to environmental degradation is the presence of heavy metal ions, which are commonly introduced into ecosystems through diverse channels, including mining operations, paint manufacturing, battery production, and agricultural practises. The unprocessed waste from these industries typically undergoes direct discharge into rivers and seas, thereby adversely influencing the potable water supply and marine ecosystem. This results in the accumulation of heavy metals within living organisms and subsequent environmental degradation that poses a significant risk to human health, as their prolonged consumption can harm various organs and the nervous system. Therefore, the United States Environmental Protection Agency (US-EPA) and the World Health Organisation (WHO) have established stringent regulations regarding the allowable levels of heavy metal intake, particularly concerning potable water consumption. The imperative lies in surmounting this challenge by discovering the optimal technique for extracting heavy metals. This paper examines the primary methods of eliminating heavy metal ions using chitosan-based materials. Specifically, the methods under scrutiny include electrocoagulation (E.C.), bioremediation, ionexchange, membrane filtration (purification), and adsorption. Adsorption, as a highly efficient method, presents itself as a viable strategy for the remediation of dyes in textile wastewater due to its advantageous characteristics. Notably, this approach obviates the need for extensive spatial requirements and exhibits a commendably swift treatment duration. Chitosan exhibits promising adsorptive characteristics owing to its advantageous physical attributes, including crystalline structure, porous nature, and particle dimensions, all of which synergistically enhance the adsorption capacity of chitosan. Research findings indicate that the adsorption characteristics of chitosan are subject to variation contingent upon the distinct heavy metal ions under consideration and the specific experimental parameters employed. Hence, optimising these parameters becomes imperative to attain enhanced chitosan adsorption capabilities for heavy metal ion removal.
Bulletin of Materials Science
The purpose of this study is to evaluate the newly prepared modified chitosan, a new environmentally friendly adsorbent, in the field of wastewater treatment. Chitosan (CS) reacted with 3-chloro-2,4-pentanedione to give CS derivatives, CS-CPD. Modified CS with O-O and NO chelating centres was treated with aqueous solution containing different metal ions to investigate its metal uptake and selectivity. The concentration of metal ions in aqueous solution was measured by inductively coupled plasma-optical emission spectrometry. The structure of the complex was identified by elemental analysis, infrared and solid-nuclear magnetic resonance. In addition, the chelating centres were determined by X-ray photoelectron spectroscopy. The morphology of the modified polymer and its metal complexes was studied to show a dramatic change in cases of the CS-CPD-Pb, CS-CPD-Hg, CS-CPD-Cr and CS-CPD-Co complexes.
Chitosan obtained by deacetylation of second most abundant natural biopolymer 'Chitin' is found as the most reasonable material in the adsorption due to presence of the amino functional groups as well as hydroxyl groups in its molecule. These functional groups act as adsorbent sites for various types of organic like dyes, pesticides, phenols, drugs etc. as well as inorganic pollutants like heavy metal ions and others. The amino and hydroxyl groups on chitosan can be modified (grafting, cross-linking, etc.) to enhance physical, mechanical and adsorption qualities of this material. Related to the knowledge obtained from research papers published previously in literature, scientists have done many modifications of chitosan molecule by reacting with suitable reagents that react with the functional groups on this molecule to increase number of binding sites and adsorption capacity. This review compiles the research work of the last few years showing modifications in chitosan and its adsorption capacity towards various pollutants in water bodies.
Adsorption and Desorption Studies on Reusing Chitosan as an Efficient Adsorbent
World Congress on Civil, Structural, and Environmental Engineering, 2018
This paper describes the adsorption and desorption of copper sulfate ions on chitosan as adsorbent material. The recirculation of the biopolymer chitosan is an important feature for an adsorbent. Chitosan possesses the characteristic to adsorb copper ions as well as sulfate ions simultaneously. The verification is carried out by means of AAS and SEM. The adsorbed copper sulfate ions were removed from chitosan by treatment with sulfuric acid. Therefore, it is possible to reuse chitosan as an adsorbent several times.
Preparation of Fully Deacetylated Chitosan for Adsorption of Hg(II) Ion from Aqueous Solution
In this work, the fully deacetylated chitosan (FCS) was obtained from the deacetylation process of chitosan (= 31%) in 5% NaOH solution. The structure of FCS was characterized by nuclear magnetic resonance (NMR) spectroscopy, X-Ray diffraction and Bruauer-Emment-Teller (BET) analysis. The FCS was used to adsorb Hg(II) ion from aqueous solutions. The influences of various operating parameters such as pH, temperature, initial concentration of Hg(II) ion and contact time on the adsorption capacity of FCS have been investigated. The results showed that the adsorption capacity of FCS for Hg(II) ion rapidly reached equilibrium within 60 min and strongly depended on pH and temperature. Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. It was shown that the FCS had given good correlation with Langmuir isotherm model and the adsorption kinetics of Hg(II) ion could be best described by the pseudo-second-order model.