Photocatalytic efficiency of ZnFe-mixed metal oxides in correlation with reaction parameters

In the last decade, the interest for the photocatalytic phenomena has rapidly grown due to its great potential for the overall environmental decontamination. Photocatalysts based on ZnFe mixed oxides have been considered to be potentially photocatalyticly efficient in wastewater purification. This investigation is focused on the characterization of the synthesized and thermally treated photocatalysts, on their photocatalytic efficiency in the degradation process of organic dye pollutant Rhodamine B (RhB), as well as on the influence of process parameters on the photocatalytic efficiency. The results showed that the obtained mixed oxides are highly efficient in the RhB degradation. In addition, the pH effect of the reaction system on the photocatalytic activity was observed, which could be explained by the correlation with different textural and structural properties of the photocatalysts

Adsorption kinetics for the removal of methyl orange using adsorbents based on Zn Al-layered double hydroxides

The adsorption phenomena of adsorbents based on ZnAl layered double hydroxides was studied. Methyl orange was used as test pollutant. The emphasis of the study was the analysis of Methyl Orange removal kinetics. The synthesized and thermally treated adsorbents were characterized by X-ray diffraction. The analysis of adsorption kinetics was conducted using the pseudo-second order kinetic model. The results showed that the samples have adsorptive removal properties, particularly the adsorbent derived from thermally treated layered double hydroxides. The findings give an insight into the adsorption phenomena of ZnAl-layered double hydroxides based materials which could be considered as promising adsorbents for the removal of Methyl Orange in wastewaters

Surface modification of graphitic carbon nitride with copper nanoparticles

Two different synthetic routes were employed to modify surface of graphitic carbon nitride (gCN) with copper nanoparticles (CuNPs). Structure, morphology and CuNPs distribution on presynthesized g-CN surface are characterized by FT-IR, XRD and TEM. Results suggested that the simpler method based on mixing of precursors in inert atmosphere and room temperature, resulted in better CuNPs distribution compared to method which used refluxing as a step in synthesis

Possibilities to control solid uptake during osmotic dehydration of carrot slices in salt solutions

Aleksandar Jokić, Nataša Lukić, Jelena Dodić, Jovana Grahovac, Milica Hadnađev-Kostić, Tatjana Vuli

Mg-Cu-Al layered double hydroxides based catalysts for the reduction of nitrates in aqueous solutions

The secondary waste and bacterial contamination in physico-chemical and biological separation processes used today for nitrate removal from ground water make novel catalytic technologies that convert nitrates to unharmful gaseous nitrogen, very attractive for scientific research. The Mg-Cu-Al layered double hydroxide (LDH) based catalysts with different Mg/Al ratio were investigated in water denitrification reaction in the presence of hydrogen and with solely copper as an active phase. Since LDHs have ion exchange properties and their derived mixed oxides possess memory effect (restoration of layered structure after thermal decomposition), their adsorption capacity for nitrates was also measured in the same model system. All studied samples showed nitrate removal from 23% to 62% following the decrease in Al content, as well as the substantial adsorption capacity ranging from 18% to 38%. These results underlie the necessity to take into account the effects of the adsorption in all future investigations

Characterization of photocatalytically active coatings based on TiO2/Zn-Al layered double hydroxide on ceramic tiles

The self-cleaning function (photocatalytic activity and surface hydrophilicity/hydrophobicity) is of great importance for ceramic tiles from both economic and environmental point of view. This research is focused on the preparation of suitable photocatalytic suspensions studying the influence of the photocatalyst powder amount and the molecular mass of polyethylene glycol (PEG) on the self-cleaning properties of the suspensions deposited on the ceramic tile surface. Photocatalysts based on Zn-Al double layered hydroxides with TiO2 as active component, were synthesized and used for the preparation of the suspensions. The coated tiles prepared using smaller photocatalyst amount and the highest investigated molecular mass of PEG (PEG 4000) showed the highest photocatalytic activity in the Rhodamine B degradation reaction, as well as the appropriate surface properties. [Projekat Ministarstva nauke Republike Srbije, br. III45008

Photocatalytic properties of ZnFe-mixed oxides synthesized via a simple route for water remediation

ZnFe photocatalysts have been increasingly investigated for water remediation due to the high demands in this field, such as activity, toxicity, cost, and stability. The presented study was focused on the simple, safe, non-toxic, and eco-friendly synthesis and characterization of ZnFe-mixed metal oxides in correlation with their functional properties. Photocatalytic performance of these materials was evaluated by rhodamine B photodegradation under simulated solar light irradiation. The synthesized mixed oxides contained hexagonal wurtzite ZnO as the predominant phase, whereas, after thermal treatment, the formation of the spinel-structured ZnFe2O4 phase was observed. The photocatalysts with the additional spinel phase and thermally treated at 300°C and 500°C exhibited superior photocatalytic activity probably due to the highest amount of the ZnFe2O4 spinel phase, favourable mesoporous structure, and an optimal energy band gap of ∼2.30 eV that initiated higher light-harvesting efficiency. The rhodamine B photodegradation followed zero-order kinetics, indicating complete coverage of active sites by the pollutant substrate. Additionally, photocatalysts showed the highest efficiency at the natural pH (6.8), being in accordance with green synthesis principles. Simple, green route assembling synthesis method, high photodegradation efficiency, and good reusability make these ZnFe-mixed oxides great candidates for potential application in practical wastewater treatments