Synthesis of chitosan-phytic acid/TiO2 antioxidant composites for coal spontaneous combustion prevention

Traditional coal mine fire suppression methods face critical limitations, including short-term efficacy, poor penetration in concealed coal seams, and environmental risks from chemical residues. To address these challenges, this study developed a biomaterial-based composite inhibitor integrating physical isolation, free radical quenching, and antioxidant slow release for sustainable prevention of spontaneous coal combustion. A novel antioxidant-loaded composite was synthesized using hollow mesoporous TiO 2 nanoparticles (HM-TiO 2 ) as carriers, which were functionalized via layer-by-layer self-assembly (LBL) of chitosan (CS) and phytic acid (PA) to encapsulate tea polyphenol (TP). This design enables the TP antioxidant activity and low release while leveraging CS/PA’s catalytic char-forming capacity. The chemical composition and micromorphology of the composite were systematically characterized through FTIR, XRD, SEM, and TEM analyses. Programmed temperature oxidation experiments combined with thermogravimetric (TG) and thermogravimetric-Fourier Transform Infrared Spectroscopy (TG-FTIR) measurements were conducted to evaluate inhibition performance by tracking mass loss, characteristic gas emissions, and radical intermediates. Key findings demonstrate that the composite inhibitor: Prolongs coal ignition delay by 48 % compared to untreated coal, attributed to the synergistic barrier effect of the TiO 2 @CS-PA framework and TP’s radical scavenging activity; Reduces CO, CO 2 , CH 4 and H 2 O emissions during low-temperature oxidation; Maintains structural stability above 400 °C, with TiO 2 catalyzing dense char layers to isolate oxygen diffusion. This multifunctional composite overcomes the trade-off between inhibition longevity and environmental compatibility observed in conventional inhibitors (e.g., MgCl 2 , KMnO 4 ), offering a scalable solution for fire prevention in high-level mining areas. The bio-based components (CS, PA, TP) further ensure ecological safety, aligning with green mining initiatives.