Co-Pyrolysis Behavior, Kinetic and Mechanism of Waste Printed Circuit Board with Biomass

Waste printed circuit boards (WPCBs) account for approximately 3-6 wt% of total electronic waste. Due to their content of thermosetting materials and added brominated fire retardants, their re-cycling and disposal is difficult and not eco-friendly. Pyrolysis as a thermal degradation process may assist in the solution of this problem. In addition, using biomass as an additive can upgrade the bio-oil and fix bromines in the char. In this study, cotton stalk (CS) is chosen as an additive and kinetic of the pyrolysis of three samples namely: PCB, CS, and CS:PCB (50:50) were investi-gated by thermogravimetric analyzer (TGA) at heating rates of 5, 10, and 15 K/min. Three non-isothermal methods: FWO, KAS, and Starink were found in good agreement with the TGA data; however, FWO method was more efficient in the description of the degradation mechanism of solid-state reactions. For CS and CS:PCB (50:50), α was increased from 0.2 to 0.9 with FWO method, and calculated Eα values were found in the range of 121.43 - 151.88 and 151.60 - 105.67 kJ/mol in the zone 1, while 197.06 - 79.22 and 115.90 -275.06 kJ/mol in the zone 2, respectively. Whereas, for PCB in the zone 1, Eα values found to be in the range of 190.23 - 93.88 kJ/mol. The possible decomposition mechanism was determined by Criado method, which was in agreement with mechanism model for reaction order n=3. The oil product was also analyzed using Fouri-er-Transform Infrared Spectroscopy analysis.