Removal of methyl orange using combined ZnO/Fe2O3/ZnO Zn composite coated to the aluminium foil in the presence of simulated solar radiation

Four immobilized ZnO/Fe2O3 photocatalysts with different mоlar ratiоs оf Zn to Fe (0.42, 0.84, 1.68, and 3.36) were synthesized viа the chemicаl precipitatiоn methоd on optimized electrochemically synthesized ZnO-Zn coating on aluminium foil support (ZnAF). The efficiency оf these catalysts for methyl orange removal in the presence оf simulated solar radiation (SSR) was investigated. The оptimal mоlar ratiо of Zn towards Fe, in the presence оf the SSR, was 1.68. The pоssibility оf potential reusing the catalyst was examined six times in a row. It was determined thаt the application of the 1.68Zn/Fe/ZnAF/H2O2/SSR system after the dye removal generates hydrogen at a rate of 186.5 μmol g-1 after 6 h. Using the HPLC method for 1.68Zn/Fe/ZnAF/SSR system, five primary intermediates were found to be formed.XII YuCorr International Conference, September 13-16, 2021, Tara Mountain, Serbia, [http://sitzam.org.rs/YUCORR/

Molecular manipulations of a utility nitrogen-heterocyclic carbene by sodium magnesiate complexes and transmetallation chemistry with gold complexes

Expanding the scope and applications of anionic N‐heterocyclic carbenes (NCHs), a novel series of magnesium NHC complexes is reported using a mixed‐sodium‐magnesium approach. Sequential reactivity of classical imidazol‐2‐ylidene carbene IPr with NaR and MgR2 (R= CH2SiMe3) affords [(THF)3Na(μ‐IPr─)MgR2(THF)] (2) [IPr─ = :C{[N(2,6‐iPr2C6H3)]2CHC] containing an anionic NHC ligand, whereas surprisingly sodium magnesiate [NaMgR3] fails to deprotonate IPr affording instead the redistribution coordination adduct [IPr2Na2MgR4] (1). Compound 2 undergoes selective C2‐methylation when treated with MeOTf furnishing novel abnormal NHC complex [{aIPrMeMgR2}2] (3). Dissolving 3 in THF led to the dissociation of this complex into MgR2 and aIPrMe with the latter isomerizing to the olefinic NHC IPr=CH2. The ability of 2 and 3 to transfer their anionic and abnormal NHC ligands respectively to Au(I) metal fragments has been investigated allowing the isolation and structural characterization of [RAu(μ‐IPr─)MgR(THF)2] (4) and [aIPrMeAuR] (5) respectively. In both cases transfer of an alkyl R group is observed. However while 3 can also transfer its abnormal NHC ligand to give 5, in 4 the anionic NHC still remains coordinated to Mg via its C4 position, whereas the {AuR} fragment occupies the C2 position previously filled by a donor‐solvated {Na(THF)3}+ cation

Zirconia based photocatalysts in degradation of selected herbicides

Hydrothermally synthesized zirconia nanopowders: pure and doped with Si4+ ions were spectroscopically characterized and used as photocatalysts for degradation of herbicides sulcotrione and fluroxypyr. Zirconia is wide band gap ceramic (Eg ~ 5 eV) however, synthesized nanopowders showed unexpected, modest absorbance in visible light range. That fact inspired photocatalytical degradation of herbicides with wide utilization, using solar irradiation (SI) in laboratory conditions. In the scope of this study, degradation of herbicides was only slightly achieved (irradiation time 2h).XV International Conference on Fundamental and Applied Aspects of Physical Chemistry : Proceedings. Vol. 1, September 20-24,2021, Belgrad

Alkali metal effects in trans-metal-trapping (TMT) : comparing LiTMP with NaTMP in cooperative MTMP/Ga(CH2SiMe3)3 metalation reactions

Stepwise metalation and trapping, so called trans-metal-trapping (TMT), of anisole is studied using LiTMP as base and Ga(CH2SiMe3)3 as trap. The isolated "trapped" intermediate is also assessed in C-C bond forming reactions, highlighting the inherent advantages and remaining challenges of this system. The same base trap mixture is found to metalate N-Me bonds of the diamines TMEDA and PMDETA. Comparative studies replacing LiTMP by NaTMP have found significant alkali metal effects on the extent of both base-trap cocomplexation and onward reactivities of TMT products

Stress and worry in the 2020 coronavirus pandemic: Relationships to trust and compliance with preventive measures across 48 countries in the COVIDiSTRESS global survey

The COVIDiSTRESS global survey collects data on early human responses to the 2020 COVID-19 pandemic from 173 429 respondents in 48 countries. The open science study was co-designed by an international consortium of researchers to investigate how psychological responses differ across countries and cultures, and how this has impacted behaviour, coping and trust in government efforts to slow the spread of the virus. Starting in March 2020, COVIDiSTRESS leveraged the convenience of unpaid online recruitment to generate public data. The objective of the present analysis is to understand relationships between psychological responses in the early months of global coronavirus restrictions and help understand how different government measures succeed or fail in changing public behaviour. There were variations between and within countries. Although Western Europeans registered as more concerned over COVID-19, more stressed, and having slightly more trust in the governments' efforts, there was no clear geographical pattern in compliance with behavioural measures. Detailed plots illustrating between-countries differences are provided. Using both traditional and Bayesian analyses, we found that individuals who worried about getting sick worked harder to protect themselves and others. However, concern about the coronavirus itself did not account for all of the variances in experienced stress during the early months of COVID-19 restrictions. More alarmingly, such stress was associated with less compliance. Further, those most concerned over the coronavirus trusted in government measures primarily where policies were strict. While concern over a disease is a source of mental distress, other factors including strictness of protective measures, social support and personal lockdown conditions must also be taken into consideration to fully appreciate the psychological impact of COVID-19 and to understand why some people fail to follow behavioural guidelines intended to protect themselves and others from infection. The Stage 1 manuscript associated with this submission received in-principle acceptance (IPA) on 18 May 2020. Following IPA, the accepted Stage 1 version of the manuscript was preregistered on the Open Science Framework at https://osf.io/g2t3b. This preregistration was performed prior to data analysis

Ružička days : International conference 16th Ružička Days “Today Science – Tomorrow Industry” : Proceedings

Proceedings contains articles presented at Conference divided into sections: open lecture (1), chemical analysis and synthesis (3), chemical and biochemical engineering (8), food technology and biotechnology (8), medical chemistry and pharmacy (3), environmental protection (11) and meeting of young chemists (2)

Removal of methyl orange using combined ZnO/Fe2O3/ZnO-Zn composite coated to the aluminium foil in the presence of simulated solar radiation

In this paper, the optimal preparative conditions (current density, deposition temperature, calcination temperature) for the original electrochemical synthesis of ZnO-Zn coating on aluminum foil support (ZnAF) were examined and determined the application for the removal of methyl orange (MO). Optimal application conditions for removing MO (volume and concentration of a treated solution) were also determined. In the following, four immobilized ZnO/Fe2O3 photocatalysts with different molar ratios of Zn to Fe (0.42, 0.84, 1.68, and 3.36) were synthesized via the chemical precipitation method on optimized electrochemically synthesized ZnAF support. Characterization studies of synthesized materials included SEM–EDS and Raman scattering analyses. The efficiency of these catalysts for MO removal in the presence/absence of simulated solar radiation (SSR) was investigated. The adsorption isotherms were investigated, and the results show that the adsorption data were best fitted with the Freundlich adsorption isotherm model. Assessment of the thermodynamic parameters showed that although the adsorption process was weakly endothermic over the range of temperatures studied, the relatively high entropy change gave an overall negative change in Gibbs free energy making the processes spontaneous. In the presence of SSR, the optimal molar ratio of Zn to Fe was determined to be 1.68. The possibility of potential reusing the catalyst was examined six times in a row. The possibility for multiple uses of suspension, which is used for immobilization, was also examined. It was also determined that the application of the 1.68Zn/Fe/ZnAF/H2O2/SSR system after the dye removal generates hydrogen at a rate of 186.5 μmol g−1 after 6 h. Furthermore, in the presence of SSR and using a suspended form of catalyst, the removal efficiency was 1.6 times higher than the efficiency achieved with immobilized ZnO/Fe2O3 catalyst. Using the HPLC method for 1.68Zn/Fe/ZnAF/SSR system, five primary intermediates were found to be formed. The applicability of ZnO/Fe2O3/ZnAF for removal of other dyes was also examined. Graphical abstract: [Figure not available: see fulltext.