In order to explore the resistance mechanism of polymer ultrafiltration membranes to ozone, polyvinyl chloride(PVC)membranes and polyvinylidene fluoride(PVDF)membranes as representatives were used, and systematically evaluated the effects of ozone on the water permeability, pollutant retention capacity and mechanical properties of the membranes by simulating 0.1mg/L ozone exposure for 0.5 years, and analyzed the changes in chemical properties. The results showed that the water permeability of the PVC membrane significantly increased under the action of ozone for 36 hours, up to more than 4times that of the new membrane, while the retention capacity of humic acid(HA)decreased by about 27.6%. The water permeability and retention performance continued to decrease with the extension of exposure time. The water permeability of PVDF membranes increased significantly in the initial stage, with the HA retention performance decreasing by about 40.2% after 36hours of aging. However, the performance tended to stabilize after 1 hour of aging. Ozone aging led to a decrease in the hydrophilicity of the two membranes, but the hydrophilicity of PVC membranes decreased to a lesser extent, showing their relative advantages in maintaining hydrophilic properties. The analysis of the membrane structure mechanism showed that ozone mainly damaged the membrane performance through oxidation and the loss of the hydrophilic additive polyvinyl pyrrolidone(PVP), and the membrane matrix itself remained intact, which was also confirmed by SEM observations. The mechanical properties of the two membranes decreased after aging, but the PVDF membrane showed relatively high mechanical strength. A comprehensive comparison of the ozone resistance of PVC, and PVDF, showed that PVC had relative advantages in ozone aging resistance in terms of retention, anti-pollution, hydrophilic, and mechanical properties, followed by PVDF. These findings provide an experimental basis and theoretical reference for the application and optimization of polymer ultrafiltration membranes in ozone-containing water treatment environment.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |