Release of Titanium Dioxide from Textiles during Washing

Nano-TiO2 has the highest production of all nanomaterials, and pigment-TiO2 is a commodity used on the million tons/year scale. Information on the release of TiO2 from consumer products is therefore an important part of analyzing the potential environmental exposure to TiO2. For this study, we investigated the release of TiO2 from six different functional textiles during washing. TiO2 is used in textiles because of its UV-absorbing properties and as pigment. Analysis of fiber cross sections showed that the TiO2 was contained in the fiber matrix. The sun-protection textiles had Ultraviolet Protection Factors that were between 58 and 6100 after washing and therefore above the labeled factor of 50+. Five of the textiles (sun-protection clothes) released low amounts of Ti (0.01 to 0.06 wt % of total Ti) in one wash cycle. One textile (with antimicrobial functionality) released much higher amounts of Ti (5 mg/L, corresponding to 3.4 wt % of total Ti in one wash cycle). Size fractionation showed that about equal amounts were released as particles below and above 0.45 mu m. After 10 washings, only in two textiles significantly lower Ti contents were measured. Electron microscopy showed that the TiO2 particles released into washing solution had a roundish appearance with primary particle sizes between 60 and 350 nm that formed small aggregates with up to 20 particles. The results indicate that functional textiles release some TiO2 particles, but that the amounts are relatively low and mostly not in the nanoparticulate range.