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-toroll throughput with cost modelling to enable industrial adoption.