UV-photochemical vapor generation of tellurium in a thin-film photoreactor with fast stripping of volatile compounds
Abstract
UV-photochemical vapor generation (UV-PVG) of tetravalent tellurium was investigated in a continuous flow mode using a special experimental setup of the photoreactor where the flow of a carrier gas was admitted upstream of the photoreactor. This was reflected in formation of a thin film of the reaction medium, leading to more effective penetration of UV radiation into the liquid medium as well as release of generated volatile compounds of Te.
The aim of the study was to investigate the effect of this unconventional PVG arrangement on the optimal conditions and performance of the method. Only 4 mol dm(-3) acetic acid as the reaction medium at a flow rate of 2.8 cm(3) min(-1) was found optimal for UV-PVG of Te(IV) in this photoreactor.
Addition of H(2) and temperatures higher than 900 °C were required for efficient atomization in a quartz tube atomizer indicating molecular nature of volatile species. The limit of detection and repeatability obtained for the coupling of UV-PVG with a high-resolution continuum source atomic absorption spectrometry (AAS) were 0.85 µg dm(-3) and 1.2% (n= 10) at 250 µg dm(-3) Te(IV), respectively.
The overall generation efficiency of approximately 8% at UV-PVG conditions optimal for AAS measurements was determined. The differences, similarities and performance of the two generator arrangements are discussed.