科研之友
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摘要
Dry cleaning of waste plastic is urgently required to substitute traditional wet cleaning, especially in arid areas. Nevertheless, it is still limited by relatively poor cleaning performance. This study reports a novel, effective and sustainable dry cleaning system for waste plastic purification in gas-solid media. An agitated fluidized bed and Geldart B silica sand were employed to fulfill the dry cleaning process without any consumption of water. With gravimetric and spectroscopic methods determining cleaning performance index, superficial gas velocity, bed height, temperature, agitation speed and cleaning time were investigated to evaluate their influence on dry cleaning performance. Under the moderate operating conditions, the gravimetric and spectroscopic indexes of the dry cleaning reached up to 98.4% and 95.0%, which were close to those of routine caustic washing (99.2% and 98.9%). Furthermore, the dry cleaning turned in a similar performance by visual inspection, as well as a similar surface transition of more hydrophilicity compared with caustic washing. Mechanism analysis indicated that mutual interaction between fluidization and agitation facilitated adhesion breaking and dispersing of contaminants into gas-solid media due to sufficient collisions and mass transfer. Triboelectrification that resulted in redeposition of fine powder should be avoided to further improve dry cleaning performance. This study provides theoretical and practical guidance for dry cleaning of contaminated waste plastics.
- 出版日期2018-1-10
- 单位中国科学院; 中国科学院大学
