Optical Properties of Titania Coatings Prepared by Inkjet Direct Patterning of a Reverse Micelles Sol-Gel Composition.

Thin layers of titanium dioxide were fabricated by direct inkjet patterning of a reverse micelles sol-gel composition onto soda-lime glass plates. Several series of variable thickness samples were produced by repeated overprinting and these were further calcined at different temperatures. The resulting layers were inspected by optical and scanning electronic microscopy and their optical properties were investigated by spectroscopic ellipsometry in the range of 200-1000 nm. Thus the influence of the calcination temperature on material as well as optical properties of the patterned micellar titania was studied. The additive nature of the deposition process was demonstrated by a linear dependence of total thickness on the number of printed layers without being significantly affected by the calcination temperature. The micellar imprints structure of the titania layer resulted into significant deviation of measured optical constants from the values reported for bulk titania. The introduction of a void layer into the ellipsometric model was found necessary for this particular type of titania and enabled correct ellipsometric determination of layer thickness, well matching the thickness values from mechanical profilometry.

A highly effective photochemical system for complex treatment of heavily contaminated wastewaters.

Significant efforts have been committed to the research and development of many advanced oxidation processes, including photocatalytic oxidations with titanium dioxide or the hydrogen peroxide and ferrous/ferric ion (H2O2/Fe2+(Fe3+)/UV (photo-assisted Fenton) process. This study reports the development of a novel photochemical system for complex treatment of heavily contaminated wastewaters based on the use of UV-C light and H2O2. Special attention was focused on the technology employed, including the reactor design, process controls, and performance optimization. The effects of process parameters were studied using 4-chlorophenol (4CP) as model compound, and verification of this treatment technology was assessed using actual contaminated water. Among the most influential parameters were the 4CP concentration, reaction mixture volume, H2O2 concentration, and irradiation intensity. In contrast, for H2O2 dosing (proportional continuous or cumulative one-time), the flow rate did not significantly affect process efficacy.

Polycyclic aromatic hydrocarbon accumulation in aged and unaged polyurethane microplastics in contaminated soil.

The interaction of microplastics (MPs) and common environmental organic pollutants has been a frequently discussed topic in recent years. Although the estimated contamination caused by MPs in terrestrial ecosystems is one order of magnitude higher than that in the oceans, experiments have been conducted solely in an aqueous matrix. Therefore, an experiment was carried out with two soils differing in their concentrations of polycyclic aromatic hydrocarbons (PAHs) and polyurethane foams used for scent fences along roads and crop fields. Two types of polyurethane foam (biodegradable and conventional in aged and unaged form) were exposed to soils containing PAHs that originated from historically contaminated localities. The exposure lasted 28 days, and a newly developed three-step procedure to separate MPs from soil was then applied. Biodegradable polyurethane MPs exhibited a strong tendency to accumulate PAHs after 7 days, and their concentrations significantly grew over time. In contrast, the sorption of PAHs on conventional polyurethane MPs was substantially lower (a maximum of 3.6 times higher concentration than that in the soil). Neither type of foam changed their sorption behaviors after the aging procedure. The results indicate that the flexibility of the polyurethane polymeric network could be the main driving factor for the sorption.