Extraction Of Collagen, Preparation Of Membrane Based Collagen And Its Adsorption Of Tannin

This paper studied the process of extracting collagen from Channel catfish skin and then optimizationed the technical parameters of film based on collagen. Finally, the collagen membrane was used as a adsorption material to adsorb tannic acid.First, the collagen was extracted from Channel catfish skin by pepsin and acetic acid. The basic properties of the extracted collagen were characterized through UV-VIS, FT-IR, amino acid analyzer and DSC. The paper studied the optimization technology of the extraction of collagen from Channel catfish skin through orthogonal tests. Experiment results showed that the optimal enzymolysis condition were: 0.5mol/L acetic acid and 1104U/mL pepsin in use, hydrolysis 54h at 4℃with intermission stir, Channel catfish skin: acetic acid=1:100(g/mL).Under the optimal extraction conditions, the extracting ratio of collagen was 65.16% and its denaturation temperature was 33.0℃.Besides, the extracted collagen has the typical amino acid composition of type and it has helix structure intact.Secondly, Collagen filming conditions were studied in this paper such as : the select of solvent, the ration of collagen and solvent, the film medium and the ways of filming. Experiment results showed that the best film forming conditions were: 0.1mol/L acetic acid as solvent, the ration of collagen and solvent were 1.5:100(g/mL), dissolve for 12h in 10℃, Ultrasonic degassing 10min,use organic glass as film medium, dried 24h in 30℃and 50% humidity. Stored in the desiccator,under the condition of 25℃and 50% humidity. Because of the collagen membrane water imbibition deformation, expansive and poor mechanical properties and biological and chemical stability, experiment through such as glutaraldehyde, glycerin, pva on membrane post-crosslinking and blending modified to improve its properties. In various characteristics ,we choice tensile strength , elongation , euphotic rate ,scanning electron microscope, solubility as evaluation indexes to investigate the effect of membrane performance. The optimum modification membrane technology parameters were collagen: acetic acid=1.5:100(g/mL), glycerin0.2%, PVA 0.6% and glutaraldehyde 0.2%.Finally, the modified collagen membrane was used as a adsorption material to adsorb tannic acid in water. We studied adsorption dosage, time, pH, temperature,adsorption balance and adsorption kinetics,etc. Results showed that: the tannic acid concentration for 100mg/L, modification membrane for 4g/L, time of adsorption equilibrium for 2h. In 100 ~ 200mg/L concentration range, modification membrane for the removal rate of tannic acid, can achieve 70% .At 35℃and 45℃,the adsorption of tannic acid can better fitting the Langmuir curve. In addition, the effect of tannic acid desorption with 50% alcohol was good, and collagen membrane may reuse.