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Application Of Chitosan In The Dyeing Wastewater Treatment

Posted on:2011-11-01Degree:MasterType:Thesis
Country:ChinaCandidate:X H WeiFull Text:PDF
GTID:2191360308963061Subject:Textile Engineering
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Chitosan has a series of advantages such as absorbency, film forming property, non-toxicity, biocompatibility, biodegradability and so on. Its applications are studied in the treatment of printing and dyeing wastewater.With chitosan as the raw material, a new type of cross-linked chitosan resins was prepared through chemical cross-linking method and used as absorbents on treatment of printing and dyeing wastewater. The resins were characterized by weight-loss ratio, water content ratio, water retention rate, porosity ratio, SEM, infrared (IR). The results indicate that the physical and chemical properties of chitasan resin particles were stable in wastewater, with excellent acid and alkali resistance. The resins particle is characterized by good adsorption capacities because of a rough and uneven surface and a microporous structure. Differences in the IR spectrum of chitosan and cross-linked chitosan resins show that chemical cross-linking reaction took place between -NH2 existing in chitosan molecular and glutaraldehyde. A series of adsorption was carried out to investigate the adsorption capacities of reactive dyes by chitosan resins and regeneration resins. The results show that the cross-linked chitosan resins possess good adsorption capacity. Consumption of cross-linked chitosan resins and pH are important factors to initial adsorption rate. In the temperature range of 30-40℃and pH of 4.5-5.5, the best absorption, the chitosan resin has the best adsorptivity to reactive dye. When the adsorption reaches equilibrium, the absorptivity to three kinds of reactive dyes are 97%, 92% and 90%, respectively. The ratio of chitosan resin to reactive dye is about 50:1. The regeneration of chitosan resins are up to more than 5 times. The adsorption isotherm of the adsorption to reactive dye is Langmiur type. The kinetic equation of the adsorption to reactive dye can be expressed as a pseudo first-order dynamic process.N-acetylated chitosan films were prepared by the reaction of chitosan and acetican hydride in the medium of methanol and DCC. Their properties, such as mechanical property, welling property, crystal property, ultrastructure, sflux and rejection rating are studied. The results show that the chitosan has good film forming property, and the N-acety—Lated chitosan films have hydrophlicity to some extent, hygroscopicity and crystallinity to some extent, and good transparency and permeability. It is resolved by carrying out experiments how to strength the mechanical property of chitosan films. The chitosan films are studied by SEM, infrared (IR), x-ray diffraction. The results show that the surface of chitosan films is smooth and the structure is uniformity and the film has a crystallinity degree of 42%. The question how to improve chitosan films is resolved in the experiment.Printing and dyeing wastewater is treated by adsorption of chitosan resins-chitosan NF Theunion method. The results show that adsorption-NF method possesses the best effect, followed by direct treatment with the chitosan film and chitosan resins treatment. The decolorization rate of Three methods is 45.7571%,33.9891% and 48.9145%, respectively. The treatment effect is better when the pH of printing and dyeing wastewater, the decolorization rate is 54.4885%,41.023% and 64.231%, respectively.
Keywords/Search Tags:reactive dye, printing and dyeing wastewater, chitosan resins, adsorption, chitosan nanofiltration membrane
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