Search

The iron diet supplements: AproFER 1000 and AproTHEM were subjected to various chemical, microbial and magnetic analysis. The microbial analysis revealed no presence of pathogenic bacteria in the studied products. No significant changes in iron content or forms (bivalent/trivalent) were observed in EPR analysis of supplements stored at different conditions for a long period of time. The chemical and magnetic analysis showed that both AproFER 1000 and AproTHEM contain a high concentration of bivalent iron so they can be used as an iron diet supplements.

Selenium is one of the trace elements playing a crucial role in a proper function of living organisms. Selenium intake varies, largely based on the selenium content of food. The daily Se intake recommended for adults amounts to 55 μg per day. The mean level of selenium in the population varies considerably between countries. Recent studies on the selenium dietary intakes in Poland showed that it is not sufficient to meet the daily requirement for this microelement so it is strongly recommended to employ selenium supplementation. The commercial product SEL-BRCA1® being a selenium diet supplement was subjected to chemical and microbial analysis to determine its stability in storage time and conditions. Basing on the obtained results it can be stated that the stability of studied supplement, stored in the closed bottles, can be confirmed for the period of time up to 45 months after the production date and it is not recommended to store opened bottles for the period of time longer than 12 months. The studied supplement showed a very high microbial stability what underscores its usefulness as human medicines.

Pharmaceutical pollutants have been detected in many countries in surface and ground water after treatment in wastewater treatment plants. The presented studies concern the photocatalytic removal of one of SSRI antidepressants - sertraline from water using TiO2 photocatalyst. The process was conducted using two laboratory installations with periodic and flow reactors. Two forms of TiO2 was used in the photocatalytic reactions: suspended and supported onto a glass fabric. The studies shown that with increasing initial concentration of pharmaceutical, photoactivity decreases. For the initial concentration of 0.025 g/dm3, the best results – 94% removal – was achieved for the process conducted in the periodic reactor with TiO2 supported onto a glass fabric.

The photocatalytic activity of nanocrystalline titanium dioxide containing various phases (anatase, rutile) can be used for example for the splitting of water into H2 and O2 under ultraviolet light. In our study the suitability of magnetic Fe3O4–TiO2 nanostructures obtained by microwave-assisted solvothermal method was checked for degradation of phenol. The selected method for the synthesis of Fe3O4–TiO2 does not require the calcination process and could be effective below 170 °C. The average size of the crystallites of Fe3O4 was determined to be ~27 nm, while that of surrounding TiO2 particles equals to about 17 nm. High photoactivity in the phenol degradation process was confirmed for synthesized nanomaterials. Their activity can be controlled by the TiO2:Fe3O4 mass ratio. After 180 min of the reaction, the conversion of phenol was 100% over the commercial catalyst (P25) and 70% over the Fe3O4–TiO2(3 ml TBOT). Superparamagnetic behavior of the obtained nanostructures was evidenced with the finite size effects and superexchange interactions playing prominent role. Magnetic properties and chemical stability permitted easy separation of the obtained nanostructures from the solution after the photocatalytic degradation process and their re-use.

In this work, the glycerol fermentation was carried out using Citrobacter freundii bacteria. The influence of glycerol and metabolites concentrations, and the pH changes on the efficiency of 1,3-propanediol production, during batch and fed-batch processes, was presented. The nanofiltration was used for the separation of obtained post-fermentation solutions. The resulted 1,3-PD solutions were significantly desalted, which may facilitate further downstream processes during 1,3-PD production.

Titanate nanotubes (TNTs) were prepared from TiO 2 P25 via hydrothermal method. The reaction temperature was 130 or 140 °C and the reaction time was 24 or 48 h. The samples were characterized by transmission electron microscopy, X-ray diffraction, thermogravimetry and N 2 adsorption as well as Raman, FTIR-DRS and UV–vis/DR spectroscopy. The obtained samples exhibited similar properties, regardless of the preparation temperature and time. The most notable difference between properties of TNTs prepared under different conditions was observed in case of BET surface area, which was increasing from 386 to 478 m 2 /g along with increasing the reaction time and temperature. Based on TEM, XRD and TG measurements we have suggested that the structure of TNTs was H 2 Ti 2 O 4 (OH) 2 . The TEM and Raman spectroscopy measurements showed that the obtained products contained also low amount of anatase phase. The TNTs exhibited no photoactivity towards degradation of model azo dye Acid Red 18. However, TNTs were successfully applied for photocatalytic generation of CH 4 and H 2 in a solution of acetic acid. The amount of methane produced with application of TNTs synthesized at 140 °C was about 2.5 times higher than that generated with use of TiO 2 P25. To the best of our knowledge this is a first report on the photocatalytic generation of hydrocarbons using TNTs in the current state of the art.

The removal of azo dyes acid red 18 (AR18), direct green 99 (DG99) and acid yellow 36 (AY36) in hybrid photocatalysis/nanofiltration (NF) system was investigated. The photocatalytic reactions were conducted in the flow reactor with immobilized photocatalyst bed. A commercially available titanium dioxide (Aeroxide® P25, Degussa, Germany) was used as a photocatalyst. The solution after the photocatalytic reaction was applied as feed for NF process. The changes of various parameters, including concentration of dyes, pH and conductivity of the solution, total organic carbon (TOC) and total dissolved solids (TDS) content were analyzed during the process. It was found that azo dyes AR18, DG99 and AY36 solutions could be successfully decolorized in the quartz labyrinth flow reactor with immobilized photocatalyst bed. The rate of color removal can range as follows: AR18 > DG99 > AY36. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

The aim of the presented work was the investigation on the possibility of application of the hybrid photocatalysis/membrane processes systems for removal of azo dyes (Acid Red 18, Direct Green 99 and Acid Yellow 36) from water. The photocatalytic reactions were conducted in the flow reactor with immobilized photocatalyst bed and in the suspended system integrated with ultrafiltration. A commercially available titanium dioxide (Aeroxide® P25, Evonik (former Degussa), Germany) was used as a photocatalyst. The solution after the photocatalytic reaction was applied as a feed in nanofiltration or membrane distillation. The changes of various parameters, including concentration of dyes, pH and conductivity of the solution, TOC and TDS content were analyzed during the processes. It was found that the solutions containing the model azo dyes could be successfully decolorized during the photocatalytic processes applied in the studies. The application of ultrafiltration process results in separation of photocatalyst from the treated solutions whereas during nanofiltration and membrane distillation high retention of degradation products was obtained.

The aim of the presented work was the removal of organic impurities from water using a novel reactor with photoactive textile refill. Titanium dioxide was immobilized on the base textile as a thin layer using sodium silicate as a binding material. The results of studies revealed that the titania–silicate coatings show a high photocatalytic activity towards the azo-dye Acid Red 18 decomposition in water. The prepared coatings exhibit high stability in repeated cycles of water treatment

Water purification using a novel reactor with the photoactive refill The aim of the presented work was the removal of organic dye, Acid Red 18, from water using a novel reactor with the photoactive refill. Titanium dioxide was immobilized on the base material as a thin layer from the alcoholic suspension followed by thermal stabilization. The prepared coating exhibits high stability in repeated cycles of water treatment. The complete removal of colour was achieved in a relatively short time of 14 hours. The proposed reactor with the photoactive refill solves the problem of the necessity of the replacement of the reactor or parts of the reactor when the photocatalysts activity decreases. In the case of activity drop of the photocatalyst, only the photoactivve refill can be easily replaced.