Ankica Šarić

Bio: Ankica Šarić is an academic researcher. The author has contributed to research in topics: Crystallite & Zinc. The author has an hindex of 12, co-authored 29 publications receiving 425 citations.

Microstructural properties of Fe–oxide powders obtained by precipitation from FeCl3 solutions

Abstract: The precipitation of Fe–oxides was performed by adding NaOH or urotropin to FeCl3 solutions and aging the precipitation systems at 90°C. Phase composition and microstructural properties of Fe–oxide powders were investigated using Fourier transform infrared spectroscopy, Mossbauer spectroscopy, X-ray diffraction and transmission electron microscopy. β-FeOOH was obtained in all precipitation systems with final pH values up to 1.80. However, when the precipitation was for a long time at pH≤1.80 the appearance of α-Fe2O3 phase was also observed. In the presence of urotropin the size of submicrometer β-FeOOH rods increased with time of aging thus forming a fibril structure of near micrometer size. The crystallite size of β-FeOOH varied between 7 and 11 nm and this indicated that β-FeOOH fibrils possessed a substructure. After 30 days of aging, the presence of a α-Fe2O3 phase was also detected by XRD. α-Fe2O3 was obtained as a single phase by precipitation with NaOH at pH 4.20–4.40 and aging of the precipitation systems up to 3 days. When the pH of precipitation was increased to 6.00–6.50 the formation of α-FeOOH particles, in addition to α-Fe2O3, was observed. TEM showed that the size and morphology of particles strongly depended on the precipitation conditions. The mechanism of the formation of Fe–oxide phases is discussed.

A review of ZnO nanoparticles as solar photocatalysts: Synthesis, mechanisms and applications

Abstract: Persistent organic pollutants (POPs) are carbon-based chemical substances that are resistant to environmental degradation and may not be completely removed through treatment processes. Their persistence can contribute to adverse health impacts on wild-life and human beings. Thus, the solar photocatalysis process has received increasing attention due to its great potential as a green and eco-friendly process for the elimination of POPs to increase the security of clean water. In this context, ZnO nanostructures have been shown to be prominent photocatalyst candidates to be used in photodegradation owing to the facts that they are low-cost, non-toxic and more efficient in the absorption across a large fraction of the solar spectrum compared to TiO 2 . There are several aspects, however, need to be taken into consideration for further development. The purpose of this paper is to review the photo-degradation mechanisms of POPs and the recent progress in ZnO nanostructured fabrication methods including doping, heterojunction and modification techniques as well as improvements of ZnO as a photocatalyst. The second objective of this review is to evaluate the immobilization of photocatalyst and suspension systems while looking into their future challenges and prospects.

Synthesis and applications of nano-structured iron oxides/hydroxides - a review

Abstract: The nano iron oxides have been synthesized by almost all the known wet chemical methods which include precipitation at ambient/elevated temperatures, surfactant mediation, emulsion/micro-emulsion, electro-deposition etc. Iron oxides in nano-scale have exhibited great potential for their applications as catalytic materials, wastewater treatment adsorbents, pigments, flocculants, coatings, gas sensors, ion exchangers, magnetic recording devices, magnetic data storage devices, toners and inks for xerography, magnetic resonance imaging, bioseparation and medicine. Nano sized magnetite Fe3O4, and maghemite γ-Fe2O3 exhibiting excellent magnetic properties find applications for biomedical purposes and as soft ferrites. Iron hydroxides and oxyhydroxides such as ferrihydrite, goethite, akaganeite, lepidocrocite are being evaluated for their applications in water purification for the removal of toxic ions. Hematite, α-Fe2O3 in the nano range has been used to obtain transparent paints. In catalysis both iron oxides and hydroxides find application in numerous synthesis processes. This review outlines the work being carried out on synthesis of iron oxides in nano form and their various applications.