Dynamic, synergistic, and optimal emissions and kinetics of volatiles during co-pyrolysis of soil remediation plants with kaolin/modified kaolin

The post-harvest disposal of soil remediation plants (SRPs) needs to be eco-friendly for remediation techniques to be sustainable. Incorporating Al/Si-based materials as additives may prove to be an effective method for stabilizing heavy metals during the pyrolysis of Zn/Cd-enriched SRPs. Based on the coupling of thermogravimetry - Fourier-transform infrared spectrometry - mass spectrometry - two-dimensional correlation spectrum analyses (TG-FTIR-MS-2D-COS) and Gaussian modeling, this study aimed to quantify and unveil dynamic, synergistic, and optimal emissions and kinetics of volatile components in response to the co-pyrolysis of Pfaffia glomerata (PG) with kaolin (K) or modified kaolin (KH). The kinetic mechanism of the thermal decomposition stage of volatile components was best accounted for by the diffusion model (100-315 degrees C) and reaction order model (315-600 degrees C).The Al-OH group in K enhanced the evolution and emission of CO2, H2O, and CH4. PG mixed with 10 % K (PK91) reduced the average activation energy value of PG from 217.90 to 196.44 kJ/mol. Compared with K, KH demonstrated superior thermal stability and controlled the cleavage of carbonyl, ether, carboxyl, and methyl groups, thus reducing gaseous pollution. Specifically, PG mixed with 20 % KH (PKH82) minimized the mass loss of PG biochar by 112.81 %, while PG mixed with 10 % KH (PKH91) reduced the E-a value of PG to 155.91 kJ/mol. The sequential temperature dependency of volatiles in PG, identified through two-dimensional correlation spectroscopy, was altered by both K and KH. Given artificial neural network-based simulations, the simultaneously optimized reduction in total volatile emission and fuel mass was achieved with PKH91 but diminished with the rising temperature. These insights contribute to optimizing energy and controlling air pollution during the co-pyrolysis of SRPs with Al/Si-based materials.