Evaluation of an Ozone Chamber as a Routine Method to Decontaminate Firefighters’ PPE

Ozone chambers have emerged as an alternative method to decontaminate firefighters’ Personal Protective Equipment (PPE) from toxic fire residues. This work evaluated the efficiency of using an ozone chamber to clean firefighters’ PPE. This was achieved by studying the degradation of pyrene and 9-methylanthracene polycyclic aromatic hydrocarbons (PAHs). The following experiments were performed: (i) insufflating ozone into PAH solutions (homogeneous setup), and (ii) exposing pieces of PPE impregnated with the PAHs to an ozone atmosphere for up to one hour (heterogeneous setup). The ozonolysis products were assessed by Fourier Transform Infrared Spectroscopy (FTIR), Thin-Layer Chromatography (TLC), and Mass Spectrometry (MS) analysis. In the homogeneous experiments, compounds of a higher molecular weight were produced due to the incorporation of oxygen into the PAH structures. Some of these new compounds included 4-oxapyren-5-one (m/z 220) and phenanthrene-4,5-dicarboxaldehyde (m/z 234) from pyrene; or 9-anthracenecarboxaldehyde (m/z 207) and hydroxy-9,10-anthracenedione (m/z 225) from 9-methylanthracene. In the heterogeneous experiments, a lower oxidation was revealed, since no byproducts were detected using FTIR and TLC, but only using MS. However, in both experiments, significant amounts of the original PAHs were still present even after one hour of ozone treatment. Thus, although some partial chemical degradation was observed, the remaining PAH and the new oxygenated-PAH compounds (equally or more toxic than the initial molecules) alerted us of the risks to firefighters’ health when using an ozone chamber as a unique decontamination method. These results do not prove the ozone-advertised efficiency of the ozone chambers for decontaminating (degrading the toxic combustion residues into innocuous compounds) firefighters’ PPE.

Arugula and pre-converted arugula extract as natural Nitrate/Nitrite sources for heat-treated sausages

The aim of this study was to investigate using arugula or pre-converted extracts as nitrite alternatives in heat-treated fermented sausages. Sausages with nitrite, 150 mg/kg of NaNO2, 1.2% arugula extract, and 1.5% pre-converted arugula extract were formulated. Natural nitrate sources added resulted in significantly lower oxidation content compared to negative control groups at initial storage. The addition of natural nitrate sources influenced colour, pigments, and conversion rate of sausages. Pre-converted arugula extract showed little effect on the residual nitrite content. The result of colour, oxidation, and nitrite analysis suggest pre-converted arugula is a potential nitrite replacer, but arugula as a nitrate source is limited to provide the functions of nitrite.

Effects of Frying Processes on the Nutritional and Sensory Characteristics of Different Mackerel Products

Studies have reported the impact of frying on the nutritional and sensory properties of mackerel. However, no study has reviewed this topic. This study reviewed the effects of different frying processes on the nutritional and sensory characteristics of mackerel, with and without batter, marinade, and spice. MEDLINE, Web of Science, PubMed, and ScienceDirect were used as online databases to find relevant articles. We found that the nutritional, physicochemical, and sensory properties of fried mackerel without treatment were influenced by frying methods. Deep frying affected the oxidation of lipids and degradation of proteins, while air frying increased the overall acceptance score. Frying can reduce perfluorinated compounds (PFCs), eliminate some toxins, lower the trypsin inhibitor (TI), and increase the sensory parameters of mackerel with batter, marinade, and spice treatment. The different ingredients of minced mackerel products preserved their nutritional and sensory parameters after frying. Interestingly, vacuum frying resulted in lower oxidation and maintenance of nutritional and sensory parameters of fried mackerel (with or without treatment) and minced mackerel products. Further research is needed to reveal the effectiveness of vacuum frying in maintaining the nutritional and sensory properties of fried and minced mackerel products.

Rate constants of dichloride radical anion reactions with molecules of environmental interest in aqueous solution: a review

Natural waters, water droplets in the air at coastal regions and wastewaters usually contain chloride ions (Cl-) in relatively high concentrations in the milimolar range. In the reactions of highly oxidizing radicals (e.g., •OH, •NO3, or SO4•-) in the nature or during wastewater treatment in advanced oxidation processes the chloride ions easily transform to chlorine containing radicals, such as Cl•, Cl2•-, and ClO•. This transformation basically affects the degradation of organic molecules. In this review about 400 rate constants of the dichloride radical anion (Cl2•-) with about 300 organic molecules is discussed together with the reaction mechanisms. The reactions with phenols, anilines, sulfur compounds (with sulfur atom in lower oxidation state), and molecules with conjugated electron systems are suggested to take place with electron transfer mechanism. The rate constant is high (107–109 M-1 s-1) when the reduction potential the one-electron oxidized species/molecule couple is well below that of the Cl2•-/2Cl- couple.

Regulating the species and the counter-ions size of proton acids to prepare novel poly(4-aminodiphenylamine) nanomaterials towards supercapacitor

Poly(4-aminodiphenylamine) (P(4-ADPA)) is a kind of polyaniline derivative and is promising as one of the alternatives to polyaniline because its monomer has a lower oxidation standard potential for the oxidation...

Fe-Al-Si Alloys for Applications in Internal Combustion Engines

Iron aluminides have been considered as materials resistant against high temperature oxidation in air and sulphur-containing environments. Previous research of our team proved that the oxidation resistance in the air can be significantly improved by the addition of silicon. Fe-Al-Si alloys have also very good mechanical properties at high temperatures. However, the resistance in the environments simulating combustion gasses have not been studied yet. This work focuses on the oxidation resistance in carbon dioxide, which is the main component of the combustion gasses. It was found that the Fe-Al-Si, Fe-Al-Si-Ni and Fe-Al-Si-Ti alloys have lower oxidation resistance in carbon dioxide containing atmosphere than in the air due to carbon diffusion to the material and even to the formation of carbides below the oxide layer. It leads to the spallation of the oxide layer, especially in FeAl20Si20Ni20 alloy.

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

We report on the synthesis of composite nanobeads with antibacterial properties. The particles consist of polystyrene cores that are surrounded by sulfonic gel shells with embedded silver nanoparticles. The nanocomposite beads are prepared by sulfonation of polystyrene particles followed by accumulation of silver ions in the shell layer and subsequent reduction with sodium borohydride. The resulting material has been characterized by electron microscopy, vibrational and X-ray photoelectron spectroscopy and several other experimental techniques. It was shown that sodium borohydride reduces silver ions embedded in the gel layer producing silver nanoparticles but also transforms a fraction of sulfonic groups in the polymer to moieties with sulfur in a lower oxidation state, likely thiols. It is hypothesized that the generated thiol groups are anchoring the nanoparticles in the gel shell of the nanobeads stabilizing the whole structure. The silver-decorated nanobeads appear to be a promising material with considerable antimicrobial activity and were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. The determined minimum inhibitory (MIC) and minimum biofilm inhibitory (MBIC) concentrations are comparable to those of non-incorporated silver nanoparticles.

Preconcentration And Determination Of Precious Metals Using Silica Gel Chemically Modified With Products Of Interaction Of O- or p-Aminotiophenols With g-(Trietoxisilane)Propylisocyanate

The synthesis of new complexing adsorbents with thiophenol (MPhS) and aminobenzthiazolpropyl (ABTS) groups grafted onto the surface of silica gels are considered. The extraction of precious metals (Au(III), Ag(I), Pd(II), Pt(II,IV), Rh(III), Ir(IV), Ru(IV), Os(IV)) from solutions of hydrochloric acid by MPhS and ABTS adsorbents. Contact time, acidity, temperature (25 – 95 °C), and the presence of a labilization agent tin(II) chloride is examined. It is shown that the adsorption properties of MPhS for precious metals are better than ABTS. It was proved by luminescence spectroscopy that gold, silver and platinum in the surface complexes with sulfur-containing groups are in lower oxidation states; and by the EPR method it was proved that ruthenium and osmium in surface complexes are in oxidation state +3. The formation of luminescent Ag(I), Au(I) and Pt(II) complexes on the surface of the MPhS, colored Ru(III) complexes on the surface of MPhS and ABTS, and mixed-ligand complexes of Pt(II) with surface aminobenzthiazole groups and Michler’s thioketone were used for developing methods of their adsorption luminescent, adsorption-photometric and test determinatio