Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 15

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Ionizing radiation intensity data and estimation of equivalent absorbed doses from solid and liquid samples from prospecting shale gas and oil at select sites in Pomerania are presented. Naturally occurring radioactive materials (NORM) are associated with geological formations or fluids and can be enhanced during oil and gas production. They appear in e.g. drilling cuttings, flow-back water, produced water, scale, and sludge. In this study only gamma rays were detected and their intensity was comparable to the background radiation, which is 20.0±4.6 [min-1]. The highest value of 27.3 [min-1] was detected in solid residue from evaporated flow-back fluid after hydraulic fracturing. The equivalent absorbed dose from this sample was ~ 2 Sv/a, which is lower than the global average dose from 2.4 Sv/a background radiation. In this regard, workers and others in the vicinity of drilling well sites will not be exposed to external or internal ionizing radiation.
The aim of our research was to develop an immobilization method for photocatalysts that is an alternative to the sol-gel or dip-coating methods and can be simply scaled up for technical applications. The investigated photocatalyst was TiO₂, which was electrochemically deposited onto a cathode made of stainless steel. This deposited film was photocatalytically active. In order to enhance the photoactivity of the TiO₂ film, commercially available P25 photocatalyst nanoparticles were occluded into the film. The effect of deposition current density as well as the amount of occluded nanoparticles on the photocatalytic activity and photoelectrochemical behavior was investigated. The photocatalytic activity was evaluated in a UV-LED reactor. The decomposition rate of toluene and cyclohexane in air was examined for all prepared stainless steel-photocatalyst composites. It was observed that deposits prepared with 5 g dm⁻³ of P25 in the deposition bath showed the best photocatalytic activity and highest photocurrent.
A sol-gel process followed by hydrothermal reaction was used to prepare coupled WO₃-TiO₂ photocatalysts with varying amounts of WO₃ in respect to TiO₂ (3 mol% and 5 mol% respectively). Additionally, photocatalysts have been subjected to different calcination temperatures of 400ºC and 800ºC, which allowed us to compare how these affect photodegradation efficiency. Photocatalysts were characterized under a scanning electron microscope, x-ray diffraction, and by measuring BET surface area. Photocatalytic tests have been carried out following the degradation of toluene and cyclohexane in the gas phase under LED UV light (375 nm). Elevated calcination temperature turned to enhance photocatalytical efficiency of coupled WO₃-TiO₂ while degrading the model pollutant cyclohexane. It was demonstrated that light emitting diodes (LEDs) can be used effectively as a source of illumination in photoreactors, sufficient to obtain 90% compound elimination from the air during 15 minutes of illumination while applying a well-matched photocatalyst.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.