Evidence for the contribution of methane in the formation of aromatics and soot in fuel-rich pre-mixed combustion

Experimental results from an isothermal laminar flow reactor at atmospheric pressure are presented on the chemical composition in the post-oxidative region of two sooting fuel-rich pre-mixed mixtures diluted in nitrogen. A base case composed of n-heptane and O2 in N2 at 1425 K with a C/O of 2.85 was perturbed by substituting 10% of the carbon in n-heptane with carbon as CH4. While these changes would intuitively reduce aromatics and soot formation by increasing H2 and decreasing C2H2 concentrations, we observe the opposite. The concentrations of individual aromatic species are observed to actually increase by up to 50% and the soot yield increases by 80%.     

Guest dechlorination and covalent capture following photoexcitation of inclusion complexes in water

Photoexcitation of complexes between cyclophane 1 and 1- or 2-chloronaphthalene in aqueous solution leads to rapid dechlorination of the guest, a reaction driven by electron transfer from host to excited guest. The main photoproducts contain a naphthyl group covalently attached to the host framework. The results may lead to new approaches for remediating water contaminated with chlorinated aromatic compounds.     

Remediation of s-triazines contaminated water in a laboratory scale apparatus using zero-valent iron powder

Atrazine, propazine and simazine were tested separately and in mixture by batch procedure in a laboratory-constructed apparatus. 3.75 l of a buffered s-triazines pesticide solution was treated at room temperature by 325-mesh zero-valent iron powder (ZVIP) (20 g/l). High performance liquid chromatography was used to separate by-products and study the decline in the pesticide’s concentrations. Results obtained show that the order of degradation was simazine, atrazine and then propazine. The half-lives (t_1/2) of the s-triazines pesticides are, respectively, 7.4, 9.0 and 10.6 min when they are treated separately, and 9.8, 11.2 and 13.7 min when they are treated together under the same conditions. The final by-product obtained after 50 min of contact of simazine with ZVIP shows a shift to longer wavelength in its UV spectrum. A similar phenomenon is shown for atrazine and propazine. Identical primary by-products are produced and subsequently degraded to 4,6-(diamino)-s-triazine, which seems to be the major by-product of the reductive treatment process. Pathways for the degradation of the studied s-triazines by ZVIP are proposed.     

Solar photocatalytic mineralization of commercial pesticides: acrinathrin

A comparative study of the degradation of commercial acrinathrin spiked in water using TiO2 photocatalysis and photolysis under sunlight was performed. Samples were analysed by liquid chromatography-diode array detector (HPLC-DAD) and gas chromatography-ion trap-mass spectrometric detector (GC-ITMS). Additional total organic carbon (TOC) analyses were carried out to evaluate the mineralisation rates. One photoproduct, 2-phenoxy benzaldehyde, was unequivocally identified and evaluated by GC-ITMS during the processes. Although acrinathrin is almost destroyed when exposed to irradiation for more than 400 h, photocatalysis with TiO2 noticeably reduced degradation to a few hours. In this case, with the additional presence of peroxydisulphate, in less than 2 h acrinathrin is completely destroyed. Mineralisation of acrinathrin, without catalyst, was only around 50% after 400 h of irradiation.     

Semiconductor-assisted photocatalytic degradation of reactive dyes in aqueous solution

This work reports the semiconductor-assisted photochemical degradation of reactive dyes. In an oxygenated-UV-ZnO system almost total decolorization of Remazol Brilliant Blue R, Remazol Black B, Reactive Blue 221 and Reactive Blue 222 was observed in reaction times of about 60 min. Extending the photochemical treatment up to 120 min, mineralization higher than 80% for all the dyes was observed. During the same period, the residual acute toxicity was significantly reduced only for Remazol Black B. A systematic optimization study carried out by factorial design showed that for the reactive dyes tested, the ZnO semiconductor exhibits a better efficiency than that observed with anatase TiO2. A synergistic effect in the coupled TiO2-ZnO system was not observed.     

Potential protective effects of Spirulina platensis on liver,kidney, and brain acrylamide toxicity in rats

Environmental Science and Pollution Research - Acrylamide (AA) is a hazardous chemical that is widely used in industrial practices. Spirulina platensis (SP) is a blue green alga that is rich in...     

Innovative aspects of environmental chemistry and technology regarding air,water, and soil pollution

Environmental Science and Pollution Research -     

Artificial light at night (ALAN) causes variable dose-responses in a sandy beach isopod

Artificial Light at Night (ALAN) is expanding worldwide, and the study of its influence remains limited mainly to documenting impacts, overlooking the variation in key characteristics of the artificial light such as its intensity. The potential dose–response of fitness-related traits to different light intensities has not been assessed in sandy beach organisms. Hence, this study explored dose-responses to ALAN by exposing the intertidal sandy beach isopod Tylos spinulosus to a range of light intensities at night: 0 (control), 20, 40, 60, 80 and 100 lx. We quantified the response of this species at the molecular (RNA:DNA ratios), physiological (absorption efficiency) and organismal (growth rate) levels. Linear and non-linear regressions were used to explore the relationship between light intensity and the isopod response. The regressions showed that increasing light intensity caused an overall?~?threefold decline in RNA:DNA ratios and a?~?threefold increase in absorption efficiency, with strong dose-dependent effects. For both response variables, non-linear regressions also identified likely thresholds at 80 lx (RNA:DNA) and 40 lx (absorption efficiency). By contrast, isopod growth rates were unrelated (unaltered) by the increase in light intensity at night. We suggest that ALAN is detrimental for the condition of the isopods, likely by reducing the activity and feeding of these nocturnal organisms, and that the isopods compensate this by absorbing nutrients more efficiently in order to maintain growth levels.

     

Umbelliferone ameliorates ulcerative colitis induced by acetic acid via modulation of TLR4/NF-κB-p65/iNOS and SIRT1/PPARγ signaling pathways in rats

Environmental Science and Pollution Research - Ulcerative colitis (UC) is a common chronic, idiopathic inflammatory bowel disease associated with inflammatory perturbation and oxidative stress....     

Appraisal of kinetin spraying strategy to alleviate the harmful effects of UVC stress on tomato plants

Environmental Science and Pollution Research - Increasing ultraviolet (UV) radiation is causing oxidative stress that accounts for growth and yield losses in the present era of climate change....