Synergetic Effects of Pulsed Electric Field and Ozone Treatments on the Degradation of High Molecular Weight Chitosan

摘要

A synergetic method integrating both pulsed electric field (PEF) and ozone treatment was developed as a novel approach to investigate the degradation of high molecular weight chitosan (Mw=4.5×105 Da). A device integrating both components was designed and assembled for the experiments. Results showed that the highest degradation percentage of chitosan was achieved with PEF/ozone co-treatment generated at experimental conditions of 1.2 L/min of ozone flow rate, 100 mL/min of 0.6% (w/v) chitosan solution flow rate, and 26.7 kV/cm of PEF intensity. The degradation percentage after 60 min PEF treatment was 24.89%, whereas it was improved to 94.89% by ozone treatment for 60 min. Combining the two treatments resulted in enhanced degradation percentage of 99.56%, with low molecular weights sample (Mw< 2,500 Da) obtained. FTIR analysis demonstrated that the amide structure of the degradation products was minimally affected by the co-treatment. XRD pattern indicated that the crystallinity of the degradation products decreased. In addition, it could complete dissolve in water after 60 min PEF/ozone co-treatment. These results demonstrated the synergetic PEF/ozone co-treatment as an effective method for degradation of high molecular weight chitosan.