Unusual Nature of Fingerprints and the Implications for Easy-to-Clean Coatings.

Irrespective of the technology, we now rely on touch to interact with devices such as smart phones, tablet computers, and control panels. As a result, touch screen technologies are frequently in contact with body grease. Hence, surface deposition arises from localized inhomogeneous finger-derived contaminants adhering to a surface, impairing the visual/optical experience of the user. In this study, we examined the contamination itself in order to understand its static and dynamic behavior with respect to deposition and cleaning. A process for standardized deposition of fingerprints was developed. Artificial sebum was used in this process to enable reproducibility for quantitative analysis. Fingerprint contamination was shown to be hygroscopic and to possess temperature- and shear-dependent properties. These results have implications for the design of easily cleanable surfaces.

In situ formation of pyromorphite is not required for the reduction of in vivo pb relative bioavailability in contaminated soils.

The effect of phosphate treatment on lead relative bioavailability (Pb RBA) was assessed in three distinct Pb-contaminated soils. Phosphoric acid (PA) or rock phosphate were added to smelter (PP2), nonferrous slag (SH15), and shooting range (SR01) impacted soils at a P:Pb molar ratio of 5:1. In all of the phosphate amended soils, Pb RBA decreased compared to that in untreated soils when assessed using an in vivo mouse model. Treatment effect ratios (i.e., the ratio of Pb RBA in treated soil divided by Pb RBA in untreated soil) ranged from 0.39 to 0.67, 0.48 to 0.90, and 0.03 to 0.19 for PP2, SH15, and SR01, respectively. The decrease in Pb RBA following phosphate amendment was attributed to the formation of poorly soluble Pb phosphates (i.e., chloropyromorphite, hydroxypyromorphite, and Pb phosphate) that were identified by X-ray absorption spectroscopy (XAS). However, a similar decrease in Pb RBA was also observed in untreated soils following the sequential gavage of phosphate amendments. This suggests that in vivo processes may also facilitate the formation of poorly soluble Pb phosphates, which decreases Pb absorption. Furthermore, XAS analysis of PA-treated PP2 indicated further in vivo changes in Pb speciation as it moved through the gastrointestinal tract, which resulted in the transformation of hydroxypyromorphite to chloropyromorphite.

Transformation of four silver/silver chloride nanoparticles during anaerobic treatment of wastewater and post-processing of sewage sludge.

The increasing use of silver (Ag) nanoparticles [containing either elemental Ag (Ag-NPs) or AgCl (AgCl-NPs)] in commercial products such as textiles will most likely result in these materials reaching wastewater treatment plants. Previous studies indicate that a conversion of Ag-NPs to Ag2S is to be expected during wastewater transport/treatment. However, the influence of surface functionality, the nature of the core structure and the effect of post-processing on Ag speciation in sewage sludge/biosolids has not been investigated. This study aims at closing these knowledge gaps using bench scale anaerobic digesters spiked with Ag nitrate, three different types of Ag-NPs, and AgCl-NPs at environmentally realistic concentrations. The results indicate that neither surface functionality nor the different compositions of the NP prevented the formation of Ag2S. Silver sulfides, unlike the sulfides of other metals present in sewage sludge, were stable over a six month period simulating composting/stockpiling.