Durability of nano-enhanced textiles through the life cycle: releases from landfilling after washing

Abstract

By taking a life cycle approach to study the potential for silver nanoparticle (AgNP) release from functionalized textiles, we can estimate the relative importance of different phases to the release of Ag over time. Alongside the fastness of the AgNPs during the use phase (e.g. washing), we further explored the release potential of NPs from fabrics disposed of in a landfill (i.e. the end of life stage). Three different laboratory-prepared nano-enhanced fabrics (60 nm and 100 nm citrate-capped Ag as reactive particles; 60 nm citrate-capped Au as a non-reactive control) were subjected to 1 or 10 washing cycles under different laundering conditions (detergents with and without oxidants). The total metal released varied significantly depending on NP incorporation and the washing pattern variant. Au served to contrast the mechanical release of NPs with the (additional) chemical release the detergents induced to the Ag textiles, where the Ag : Au ratio released from the fabric was as high as 3, suggesting more predominant chemical mechanisms for silver release in those cases. Textile disposal was simulated by the Toxicity Characteristic Leaching Procedure (TCLP), where pre-laundered fabrics were subjected to this sequential exposure. The results show that the active landfill environment cannot readily mobilize the NPs from the fabric surface as easily after washing compared to unwashed textiles. Without washing, simulated landfilling released between 35–45% of the total Ag incorporated into the fabric (and only 20% of Au), but after laundering, most variants released less than 0.5%. Therefore, larger releases of NPs from textiles were observed during the use phase of the life cycle rather than the disposal phase, where an important portion of the released NP was in the dissolved phase. Large variations in releases at the end of life stage are determined under pre-washing conditions, which proves the necessity of life-cycle aging sequences to properly assess the likelihood and characteristics of materials released from nano-enhanced textiles.