Study On Recoverying Sericin From Cocoon-cooking Wastewater And Bio-chemical Treatment

Silk industry in Guangxi's has been developing rapidly in last ten years. The large quantities of waste water of silk industry brought on a series of environmental problems. The all kinds of treatment technologys of silk industry wastewater had been studying. In this paper, the study focused on the flocculation of sericin, and was successful in extending to recovery sericin from cocoon-cooking wasterwater by tannin. Therefore, Yugan tannin extract was attempted to flocculate cocoon wasterwater. And the attemption got better results. At the same time, a good result was achieved by using bio-chemical method to deal with the wasterwater of eliminating sericin, the effect was good. The main research contents and conclusions were as follows:1. Study on technology of the treatment of cocoon-cooking wasterwater by tannin. The experimental values agreed with this method, so tannin as a flocculation of cocoon-cooking was feasible.The main technology factors which affacted the recovery sericin from cocoon-cooking wasterwater by tannin were sifted by Plackett-Burman (P-B),The optimum conditions of flocculation of cocoon-cooking by tannin were determined to be the flocculation time 0.3h, the dosage of tannic 8mL, pH of wasterwater 4 and the dosage of cocoon-cooking wasterwater 14mL,the value of UV spectrum of tannin-sericin comlexing and removing CODcr from wasterwater were 2.3,82.5%, respectively.2. It was showed that the interaction of tannin and sericin lead to quench the fluorescence of sericin by fluorescence spectroscopy and ultraviolet pectroscopy. After analyzing the fluorescence quenching data, it was found that sericin had reacted with tannin and formed a certain new compound. It was static fluorescence quenching. The binding constants at 298 K, 305 K, and 308 K were calculated to be 4.56×104,4.39×104 and 4.13×104L-mol-1, respectively. The thermodynamic parameters obtained implied that electrostatic interaction should be the predominant intermolecular forces stabilizing the complex.3. The results of experiment indicated that vegetable tannin extract flocculated to cocoon wasterwater was feasible, and got better results. 4. The factor of DO, aeration time, deposition time affected to SBR, and were optimized--them by the experiment in SBR, then payed attention to the stable operation of effect and identity. And then the granular activated carbon was added into SBR. Experimental results showed that PAC-SBR had better treatment result than SBR.