There is an increasing need for the development of probes for the detection of hexavalent chromium since it is a known carcinogen, which can cause adverse effects on human health. Metal-organic frameworks (MOFs) have shown successful detection and removal of hazardous substances from aqueous media. This work presents the use of simple organic ligands such as 3-pyridinecarboxaldehyde and trimesic acid with Zn(II) ion to fabricate a new MOF that exhibits sensitive and selective luminescence quenching response towards CrO4
2− and Cr2O7
2− species in aqueous solution. The MOF showed a detection limit of 0.67 μM (0.078 ppm) as CrO4
2− species and 1.91 μM (0.41 ppm) as Cr2O7
2− species. Results reveal that the as-synthesized MOF could serve as a good luminescent sensor for CrO4
2− and Cr2O7
2− species in the contaminated aqueous phase.
The effect of volatile organic compounds (VOCs) on chromium-containing atmospheric particles remains obscured because of difficulties in experimental measurements. Moreover, several ambiguities exist in the literature related to accurate measurements of atmospheric chromium concentration to evaluate its toxicity. We investigated the interaction energies and diffusivity for several VOCs in chromium (III)-containing atmospheric particles using classical molecular dynamics simulations. We analyzed xylene, toluene, ascorbic acid, carbon tetrachloride, styrene, methyl ethyl ketone, naphthalene, and anthracene in Cr(III) solutions, with and without air, to compare their effects on solution chemistry. The interaction energy between Cr(III) and water changed from 48 to 180% for different VOCs, with the highest change with anthracene and the lowest change with naphthalene. The results revealed no direct interactions between Cr(III) particles and the analyzed volatile organic compounds, except ascorbic acid. Interactions of Cr(III) and ascorbic acid differ significantly between the solution phase and the particulate phase. The diffusion of Cr(III) and all the VOCs also were observed in a similar order of magnitude (~ 10−5 cm2/s). The results can further assist in exploring the variation in chromium chemistry and reaction rates in the atmospheric particles in the presence of VOCs.
People spend most of their time indoors (80-90%), which are mainly schools, homes, and workplaces. 1 Thus, investigating the air quality in such environments is of utmost importance. Ultrafine particles (UFPs) (particles smaller than 100 nm) were reported to be present in different indoor environments including homes, schools, offices, and aged care facilities, 2 which could be due to the presence of different indoor sources such as heating, cooking, tobacco smoking, candle burning, hair ironing, copying machines, printers. [3][4][5] These sources are linked to different indoor activities, equipment usage, and household property. 1,6 Outdoor sources contributing to UFPs are mostly traffic and industries. 7 Outdoor UFPs can penetrate indoors and play a major role in exposure to indoor UFPs if a major source is not present indoors. 2 Several studies were conducted to examine the air quality in the primary schools and schools in different countries including Portugal, South Korea, and the USA [8][9][10][11][12] ). Nevertheless, few investigations have been done in preschools to study the exposure of the occupants to fine, UFPs and black carbon. Simultaneous
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