In-depth study of kinetics, thermodynamics, and reaction mechanism of catalytic pyrolysis of disposable face mask using spent adsorbent based catalysts

Millions of face mask has been converted to waste since the onset of COVID-19 virus. Hence, present study explores the feasibility of converting disposable face masks to energy through catalytic pyrolysis process using a low-cost waste (spent aluminum hydroxide/oxide nanoparticle adsorbent) derived catalyst. Thermogravimetric analysis of the non-catalytic and catalytic pyrolysis of disposable face mask was conducted at varied heating rates of 10 °C/min, 20 °C/min, 30 °C/min, 40 °C/min, and 50 °C/min, respectively. Iso-conversional methods, Kissinger Akahira Sunose (KAS) and Ozawa Flynn Wall (OFW) were used for the kinetic study. The reaction mechanism was analyzed using Criado's z-master plot (CZMP) method along with the determination of thermodynamic parameters of the process. Results found that the addition of a catalyst to the process benefits the overall efficacy of the process by reducing the activation energy (Ea) (without catalyst; OFW-Ea: 188.7 kJ/mol, KAS-Ea: 186.2 kJ/mol) as well as lowering the disordered state of the process. Metal doped catalyst (Ni/ γ-Al2O3) (OFW-Ea: 168.4 kJ/mol, KAS-Ea: 167.8 kJ/mol) shows a larger reduction in activation energy in comparison to bare alumina (γ-Al2O3) (OFW-Ea: 183.2 kJ/mol, KAS-Ea: 180.4 kJ/mol). The current study presented disposable face masks as reclaimable in terms of energy and waste-derived catalyst as a potent solution to be explored in place of high-cost commercial catalysts.