Comparative Study Of Naphthalene Diogradation With Immobilized Cell And Immobilized Cell Under Low Intensity Ultrasound

This thesis applies ultrasonic wave to immobilized cell. This thesis firstly uses immobilized pseudomonas aeruginosa and immobilized pseudomonas aeruginosa under low intensity ultrasound to degrade naphthalene respectively. Then, this thesis contrasts the two results in order to offer references to application of ultrasound in immobilized cell technology.The main research contents and results of this thesis:1.Immobilized cell degrade naphthalene. After testifying the characteristic that pseudomonas aeruginosa degrade naphthalene, this thesis uses six kinds of methods to bury pseudomonas aeruginosa and choose the optimum immobilization method. Then, this thesis finds the optimum parameters of immobilization, including: immobilized time, concentration of naphthalene, PH of culture medium, the centigrade of culture box. Finding shows that: (1)The method of bury that use sodium alginate 3%,calcium carbonate 3%,silicon dioxide2% and calcium chloride2% is good(Table2.3). (2) the suitable immobilized parameters are: the immobilized time is 24 hours, the concentration of naphthalene is 0.05%, the PH of medium is 7.0, and the centigrade of culture box is 30℃(Table2.4,2.5,2.6,2.7).2. Immobilized cell degrades naphthalene under low intensity ultrasound. This thesis finds the stimulative optimum parameters with the orthogonal experiment. Findings are: power is 8w, frequency is 24kHz, ultrasonic time is 40s, interval is 10s (Table3.3). With the contrast experiments of various treatment time, this thesis testifies that the treatment time has little influence over degradation ratio of naphthalene in definite time. The treatment time chosen is 10 min (Table3.4). 3. The diameter of the immobilized cell under low intensity Ultrasound is made certain. The experiment testifies that under low intensity ultrasound, the highest degradation ratio of naphthalene is gained through the NO. 16 injector (Table3.5). Under low intensity ultrasound, the degradation of naphthalene firstly increases and then decreases with the increase of the concentration of naphthalene (Table3.6). According to the practice and the results of the experiment, 0.05 percent naphthalene is chosen.4.contrast the immobilized cell and immobilized cell under low intensity ultrasound in terms of their degradation of naphthalene. The finding shows that the degradation ratio of immobilized cell is 69.1%, and the degradation ratio of immobilized cell under low intensity ultrasound is 82%. The latter is 12.9% higher than the former (Figure4.1). 5. Mechanism is primarily discussed. According experiments, we draw the degradation curve. This degradation curve indicates that after the immobilized cell in lag phase and exponential phase have received the ultrasonic irradiation; the degradation ratio of naphthalene significantly increases. However, ultrasound has little influence over the immobilized cell in decay phase (Figure4.2,4.3,4.4,4.5,4.6).