Reusing Waste Titanium Dioxide Spray Coating Solution for Manufacturing Antimicrobial Fabric Using Roll-to-Roll Technology

Introduction: This study evaluates the feasibility of reclaiming waste titanium dioxide (TiO₂) spray-coating solution as a feedstock for manufacturing antimicrobial cotton fabrics using a continuous roll-to-roll (R2R) process. Waste TiO₂ was collected, purified, and applied to cotton fabrics through an R2R coating process. Methods: Waste TiO₂ was collected from an industrial spray line, purified, and reconstituted before R2R application onto cotton. Coated fabrics were characterized by SEM/EDS, and antibacterial activity was assessed per ISO 20743:2013 against Escherichia coli and Staphylococcus aureus. Results: The TiO₂-finished cotton achieved ≥99.8 percent bacterial reduction for both organisms, with high durability maintained after 40 laundering cycles; SEM/EDS confirmed persistent TiO₂ on the fibre surfaces after washing. Discussion: These results demonstrate that reclaimed TiO₂ waste can serve as an effective antimicrobial finish compatible with scalable R2R manufacturing, offering a pathway to reduce virgin TiO₂ use and divert waste. Conclusion: Within the limits of this study, the approach provides a practical route to circularity in antimicrobial textiles. Future work should quantify environmental and economic impacts and benchmark against virgin TiO₂ formulations. Beyond demonstrating ISO 20743 antibacterial efficacy on cotton, we standardize protocols for multi-substrate coating and an expanded microbial panel, present mechanistic evidence for fibre–TiO₂ interactions and photocatalysis, and report pilot roll-to-roll throughput with cost modelling to enable industrial adoption.