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Study On The Adsorptive Character Of Hydroxypropyl Chitosan- Fe(ⅱ) Complex

Posted on:2011-07-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:S Q YeFull Text:PDF
GTID:1101360308464361Subject:Sugar works
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Chitosan(CS) , (1,4)-2-amino-2-deoxy-β-D-glucan, is the product of partial deacetylation from natural chitin.Recently, much attention has been paid to chitosan because it has excellent properties such as biocompatibility, non-toxicity, bioactivity and physicochemical property. There is a vast vista of application for chitosan in water treatment, chemical industry, textile, food and medicine industry. However, by its crystalline structure, the application is restricted in some respects. It is an effective step to improve the applied properties with the modification of chitosan. The studies on the modification of chitosan and the properties of its derivatives using physical fields(magnetic field and ultrasonic field) for rising the reaction speed and reaction yield. The basic investigative data were provided for the development on the new high efficiency water treatment agent. The main contents and results of this thesis are as follows:1. Study on the Complex Reaction of Chitosan and Fe(II) Enhancing with Magnetic TreatmentMangnetic technology was used to enhance the synthesis of chitosan-Fe(II),mostly the reaction of chitosan and ammonium ferrous sulfate,then synthesizing chitosan- Fe(II) complex. The effects of power densities of magnetic field, magnetic treatment time, ratios of reactant, initial concentration of Fe2+, dosages of chitosan, temperature and pH value on the reactions were studied. The result showed that the coordination reaction could be enhanced by a constant magnetic fields with magnetic induction of 100 mT~150mT.The reaction rate and complex yield could be increased 23.0% and 24.0%under the optimized magnetic fields treatment conditions. The analysis showed that for the case of experiments, there was almost no influence on molecular weight, deacetylation degree and the basic structure of products by the treating with the magnetic field.2. Study on Etherification of Chitosan Enhancing with Ultrasonic FieldUltrasonic technology was introduced to study the complex reaction of chitosan with epoxypropane, the effects of power densities of ultrasonic field, ultrasonic irradiation time, ratios of reactant, temperature and pH value on the reactions were studied. The result showed that the reaction speed of the synthesis of O-(hydroxyl isopropy1) chitosan was quickened by the ultrasonic-assisted technology and the dosages of epoxypropane and catalyzer could be reduced.The experimental result of the optimumation for the preparation of O-(hydroxyl isopropy1) chitosan complex was as follow: the ratio of volumn of epoxypropane and catalyzer and the ratio of gram of chitosan is 10ml:0.8 ml:1g, at the temperature 60℃~70℃, radiating with ultrasound for 3 h, under a power ultrasound of 120kW. The improvement of obtain ratio and substitution degree was 13.6% and 12.9 %, respectively. The structure of the product was identified by iodoform reaction, Fourier infrared spectrum and X-ray diffractomer.3. Study on the Adsorptive Property of Hydroxylpropyl Chitosan-Fe(II) Complex Enhancing with Magnetic FieldThe magnetic field treatment technology was introduced in the researches of adsorption properties of hydroxylpropyl chitosan-Fe(II) complex. Three kinds of metal ions: Cr (VI), Cu (II), Pb (II) were selected. The study of adsorptive property of hydroxylpropyl chitosan-Fe(II) on the three metal ions under the constant magnetic field. The experimental result showed that adsorption effect could be influenced by power densities of magnetic field, metal ion pH value and initial concentration of solution. The absorptive quality and rate of the Cr (VI), Cu (II), Pb (II) by hydroxylpropyl chitosan-Fe(II) complex were both increased with the constant magnetic field intensity when magnetic induction from 200 mT to1000 mT.However, the acidity existed a adsorptive optimum value under pH4~pH5, and the initial concentration of metal ion solution would be controlled in 30mg/L~40 mg/L.4. Study on Adsorptive Kinetics of Hydroxypropyl Chitosan-Fe(II) ComplexThe adsorption kinetics were researched on chitosan and its derivatives on the three metal ions: Cr (VI), Cu (II), Pb (II) in magnetic field. The results showed the order of their adsorption properties for the three metal ions was Cu (II) > Pb (II) >Cr (VI). Classical isothermal equations were used to fit the adsorption equilibrium data of chitosan and its derivatives on Cr (VI), Cu (II) , Pb (II) and the experimental results showed that their adsorption behavior were interrelated well with Langmuir and Frundlich adsorption isothermal equation. The research showed that the suitable magnetic treatment could be enhanced significantly the adsorption properties of chitosan and its derivatives on matel ions according kinetic view.5. Study on Application of Hydroxypropyl Chitosan- Fe (II) Complex in Water TreatmentThe water treatment additive of derivative chitosan was prepared, the optimum conditions were researched for soften the hard water with the orthogonal experimental technique. The results showed that it could effective adsorb Ca2+ and Mg2+ in hard water with water treatment additive amount of 0.5%, with pH10, temperature at 20℃, reaction time for 25min, it could make water degree of hardness (by the CaCO3 amount) from 265.52 mg/L drops to 98.70 mg/L,Ca2+ and Mg2+ in hard water may be adsorbed by the rate of above 60%. Display using derivative chitosan as a hard water soften agent is effective and there are the very applications in the future.The adsorptive properties of hydroxypropyl chitosan-Fe(II) complex (HPCTS-Fe2+) for heavy metal ions were researched .The experiments showed that the removal efficiencies were 99.8%,78.8% respectively with using 1%(g/mL) of the HPCTS-Fe2+, pH5, initial concentration 1 mg/L Cu2+,0.1 mg/L Pb2+ respectively, absorption for 30min. It showed that HPCTS-Fe2+ might be used as a new high efficiency water treatment agent for absorbing heavy metal ions.Satisfactory results were also obtained in practical application of the abattoir wastewater treatment, hydroxypropyl chitosan-Fe(II) complex for water treatment agent combining with biological treatment method.
Keywords/Search Tags:chitosan modification, metal complex, magnetic field treatment, ultrasonic enhancing, adsorptive property
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