دانلود رایگان مقاله انگلیسی استفاده از جداسازی تربو الکترواستاتیک در بازیافت ضایعات پلاستیکی - الزویر 2018

ABSTRACT

In the last decades, increasing industrial development has led to huge consumption of plastic materials, due to their versatility and low cost. Therefore, the implementation of efficient and environmentally friendly recycling technologies is of great importance. This study proposes an alternative separation process for recycling mixtures of plastic wastes, using a tribo-electrostatic separation process. The methodology adopted in this work was firstly characterization of the polymeric wastes, followed by preparation of the wastes using different unit operation processes (washing, drying, and comminution), tribocharging, and electrostatic separation of different combinations of plastics (HDPE/PP, LDPE/PP, and PET/PVC). Various parameters were evaluated in the tribo-charging process and the electrostatic deflection. Separation of a mixture of HDPE and PP achieved PP recovery of 92.8% (purity of 95.7%) and HDPE recovery of 95.9% (purity of 93.1%). Recovery and purity values higher than 90.2% and 95.9% were obtained for PP/LDPE and PET/PVC mixtures, respectively. These results demonstrated that tribo-electrostatic separation is a promising and efficient method for use in the recycling of plastic wastes. The process studied enabled significant recoveries of the components at high levels of purity.

4. CONCLUSIONS

Recycling is one strategy for the end-of-life waste management of plastic products. In this work, characterization of the different plastics using DSC analyses confirmed the compositions of HDPE, LDPE, PP, PET, and PVC. The best mechanism of tribo-charging for the separation was a fluidized bed, rather than the vibration method. The relative humidity strongly affected the tribo-charging process and needed to be kept at low levels. The best conditions for the tribo-charging and electrostatic separation process were successfully defined. Satisfactory separations of the plastics mixtures were achieved, with recovery and purity values exceeding 90.2% for all the separations studied, demonstrating the effectiveness of the tribo-electrostatic process in separating a mixture of polymers. The results showed that was possible to obtain fractions with high purity, in addition to high recovery. Therefore, the tribo-electrostatic separation process is fully feasible for the recovery of plastics from selective waste collection. This process offers a good alternative to mechanical segregation and recycling of plastics from MSW.