scholarly journals Zavádění analytické metody pro kvalitativní stanovení mikroplastů ve vodách

Entecho ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
Robert Kvaček ◽  
Pavla Šmejkalová ◽  
Soňa Hermanová
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Structure ◽  
Drinking Water Treatment ◽  
Infrared Analysis ◽  
Health It ◽  
Qualitative And Quantitative ◽  
Naked Eye ◽  
Plastics Recycling ◽  
Insufficient Amount ◽  
Harmful Effects

CZ: Přítomnost reziduí plastů v životním prostředí je v poslední době diskutována napříč společností kvůli zamořování oceánů a nedostatečné recyklaci plastových výrobků. Okem nepostřehnutelné mikroplasty, které se do vody dostávají užíváním produktů osobní péče a rozkladem syntetických polymerů nejsou v současnosti dostatečně odstraňovány při úpravě vody a mohou se dostávat do trávicího traktu konzumentů. Zdravotní rizika pro člověka nejsou doposud známá, přesto lze předpokládat, že bude výskyt mikroplastů ve vodách monitorován. Naším cílem bylo vypracování finančně dostupné a dostatečně přesné metody pro následnou analýzu mikroplastů ve vodách, jež by mohla být rutinně prováděna v kontrolních laboratořích. Vzorky vláken byly podrobeny předúpravě sloužící k izolaci syntetických mikrovláken od ostatních materiálů, které mohou způsobit zkreslení kvantitativní analýzy mikroplastů. Byla sledována reakce dvou testovaných materiálů na jejich expozici různým teplotním a oxidačním podmínkám s využitím peroxidu vodíku jako oxidačního činidla a změna barvy vláken. Jako optimální se jeví osmihodinová expozice vzorku v 30% roztoku peroxidu vodíku při teplotě 60 °C s následnou analýzou mikroplastů infračervenou spektroskopií (ATR-IR). Naše výsledky by mohly být využity při vytváření komplexní metodiky kvalitativního a kvantitativního hodnocení mikroplastů. EN: Occurrence of plastics in the natural environment is one of the hot topics in the area of environmental studies due to the ocean contamination and insufficient amount of plastics' recycling. Microplastics which cannot be seen by the naked eye are not effectively removed from the water during drinking water treatment and afterwards they enter the human body through the digestive tract. Even though there is no evidence of harmful effects on health, it is assumed that the presence of microplastics in water will be monitored. Our work was aimed on the development of a methodology for the pretreatment of synthetic microfibers based microplastics followed by their subsequent infrared analysis, which can be routine performed in laboratories. Microfibers were subjected to various thermal and oxidative conditions, where hydrogen peroxide was used as an oxidizing agent. Effects of the exposure on changes in chemical structure and colour of fibres were analysed. Optimal exposure conditions for plastic microfibers' pretreatment concerns the exposure in 30% solution of hydrogen peroxide at 60 °C for 8 hours followed by infrared spectroscopy (ATR-IR). We believe that our results can be utilized for the creating complex methodology of qualitative and quantitative microplastics' evaluation.

A Two-step Electrodeposition of Pd-Cu/Cu2O Nanocomposite on FTO Substrate for Non-enzymatic Hydrogen Peroxide Sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Huan ◽  
Li Tang ◽  
Dongmei Deng ◽  
Huan Wang ◽  
Xiaojing Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pd Nanoparticles ◽  
Optimal Conditions ◽  
Potential Oscillation ◽  
X Ray Diffraction ◽  
X Ray

Background: Hydrogen peroxide (H2O2) is a common reagent in the production and living, but excessive H2O2 may enhance the danger to the human body. Consequently, it is very important to develop economical, fast and accurate techniques for detecting H2O2. Methods: A simple two-step electrodeposition process was applied to synthesize Pd-Cu/Cu2O nanocomposite for non-enzymatic H2O2 sensor. Cu/Cu2O nanomaterial was firstly electrodeposited on FTO by potential oscillation technique, and then Pd nanoparticles were electrodeposited on Cu/Cu2O nanomaterial by cyclic voltammetry. The chemical structure, component, and morphology of the synthesized Pd-Cu/Cu2O nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of Pd-Cu/Cu2O nanocomposite were studied by cyclic voltammetry and amperometry. Results: Under optimal conditions, the as-fabricated sensor displayed a broad linear range (5-4000 µM) and low detection limit (1.8 µM) for the determination of H2O2. The proposed sensor showed good selectivity and reproducibility. Meanwhile, the proposed sensor has been successfully applied to detect H2O2 in milk. Conclusion: The Pd-Cu/Cu2O/FTO biosensor exhibits excellent electrochemical activity for H2O2 reduction, which has great potential application in the field of food safety.

Destruction of Pollutants and Microorganisms in Water by UV Light and Hydrogen Peroxide

1992 ◽  
Vol 27 (1) ◽  
pp. 57-68 ◽  
Author(s):  
D.W. Sundstrom ◽  
B.A. Weir ◽  
T. A. Barber ◽  
H. E. Klei
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Compounds ◽  
Chemical Structure ◽  
Uv Light ◽  
Liquid Films ◽  
Strong Interactions ◽  
Order Kinetic ◽  
E Coli ◽  
Order Kinetic Model ◽  
Catalyzed Oxidation

Abstract This project investigated the destruction of organic compounds and microorganisms in water by ultraviolet catalyzed oxidation using hydrogen peroxide as the oxidizing agent. The combination of UV light and hydrogen peroxide was effective in decomposing all of the organic compounds studied. The rates of destruction increased with increasing peroxide concentration and UV light intensity, and were highly dependent on chemical structure. The destruction of mixtures of organic compounds showed strong interactions between reacting components. The inactivation of E. coli and B. subtilis spores by UV light and/or hydrogen peroxide was studied in flat plate reactors. By using thin liquid films, the combination of UV light and peroxide greatly increased the rates of inactivation of both microorganisms. The results were correlated by a mixed second order kinetic model.

scholarly journals Modelling and optimization of zinc recovery from Enyigba sphalerite in a binary solution of hydrochloric acid and hydrogen peroxide

2020 ◽  
Vol 120 (11) ◽  
Author(s):  
I.A. Nnanwube ◽  
O.D. Onukwuli
Keyword(s):  
Genetic Algorithm ◽  
Hydrogen Peroxide ◽  
Response Surface Methodology ◽  
Hydrochloric Acid ◽  
Response Surface ◽  
Binary Solution ◽  
Infrared Analysis ◽  
Zinc Recovery ◽  
X Ray ◽  
Stirring Rate

SYNOPSIS This work focused on the prediction of optimal conditions for zinc recovery from sphalerite in a binary solution of hydrochloric acid and hydrogen peroxide. The sphalerite sample was characterized with X-ray fluorescence spectrometry (XRF), X-ray diffractometry, and Fourier transform infrared analysis (FTIR). The central composite design of response surface methodology (RSM) developed in Design Expert software and the genetic algorithm (GA) tool in matlab, were deployed for the optimization exercise. The leaching temperature, acid concentration, stirring rate, leaching time, and hydrogen peroxide concentration were defined as input variables, while zinc yield was the response. An ideal zinc yield of 90.89% could be obtained with a leaching temperature of 84.17°C, HCl concentration of 3.14 M, stirring rate of 453.08 r/min, leaching time of 107.55 minutes, and hydrogen peroxide concentration of 3.93 M using RSM; while a yield of 87.73% was obtained using GA. Analysis of the post-leaching residue revealed the presence of sulphur, zircon, fluorite, gahnite, anatase, and sylvite. Keywords: sphalerite leaching, genetic algorithm, optimization, response surface methodology.

Plasticization of Rubber in the Form of Latex

1954 ◽  
Vol 27 (1) ◽  
pp. 271-276 ◽  
Author(s):  
Marc Conté
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Reactions ◽  
Room Temperature ◽  
Ph Value ◽  
Inhibitory Effect ◽  
Rubber Latex ◽  
Adhesive Properties ◽  
Harmful Effects ◽  
Latex Rubber

Abstract When in the form of latex, rubber can be oxidized by thiols under hot conditions. The reaction apparently proceeds by the same mechanism as that characteristic in the action of peptizing agents on rubber during mastication. The results obtained confirm the hypothesis that the thiol is transformed quantitatively into the corresponding disulfide, with resultant oxidation of the rubbert. This transformation is a function of the pH value, and the best results are obtained when the pH value is around 4 and in the absence of NH4 ions (which have an inhibitory effect). Latex preparations of this type can be utilized for studying the chemical reactions of rubber in emulsion and for the preparation of rubber derivatives which are more soluble than those prepared from rubber latex which has not been degraded. In addition, such latex preparations are excellent adhesives which, in contrast to already known products (latex treated with hydrogen peroxide or other peroxides), give a sticky film by simple drying at room temperature. In this way heating can be avoided in cases where it has harmful effects and where the use of an oven is inconvenient. Finally, this type of latex is more adaptable to certain direct applications, both because of the superior adhesive properties of the rubber and because, with a relatively plastic coagulum, mastication is easier.

Oxidation-triggered aggregation of gold nanoparticles for naked-eye detection of hydrogen peroxide

2016 ◽  
Vol 52 (17) ◽  
pp. 3508-3511 ◽  
Author(s):  
Shaojue Wu ◽  
Si Yu Tan ◽  
Chung Yen Ang ◽  
Zhong Luo ◽  
Yanli Zhao
Keyword(s):  
Hydrogen Peroxide ◽  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Eye Detection ◽  
Surface Hydrophilicity ◽  
Naked Eye ◽  
Naked Eye Detection

A gold nanoparticle-based platform for naked-eye detection of H2O2 was realized by changing the surface hydrophilicity.

scholarly journals Evaluation of Enzymes Production Activity of Trichoderma, Aspergillus and Rhizopus Species in Paraeforce (Herbicide) Degradation

2020 ◽  
pp. 1-7
Author(s):  
F. I. Onianwah ◽  
H. O. Stanley ◽  
V. C. Eze ◽  
V. O. Ifeanyi ◽  
C. J. Ugboma
Keyword(s):  
Hydrogen Peroxide ◽  
Soil Samples ◽  
Laccase Production ◽  
Methyl Red ◽  
Aerobic Incubation ◽  
Fungal Isolation ◽  
Qualitative And Quantitative ◽  
Herbicide Degradation ◽  
Production Activity ◽  
Catalase Peroxidase

The study aims to evaluate enzymes that facilitate fungal degradation of paraeforce. Soil samples for fungal isolation were collected from impacted sites and inoculated on potato dextrose agar (PDA). The isolates were screened for growth and tolerance to paraefoce in 50 mg/l concentration of the test herbicides. Trichoderma, Aspergillus and Rhizopus species were found to grow in paraeforce supplemented PDA. Qualitative and quantitative assay for different enzyme production in hydrogen peroxide, methyl red, guaiacol and hydrogen peroxide-pyrogallol complex proved potential for catalase, lignin peroxidase, laccase and manganese peroxidase production, respectively. The results showed that these three fungi have great potential for catalase, peroxidase and laccase production after six days aerobic incubation in paraeforce and these enzymes facilitated the utilization of the paraeforce.  

scholarly journals Using Advanced Spectroscopy and Organic Matter Characterization to Evaluate the Impact of Oxidation on Cyanobacteria

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 278 ◽  
Author(s):  
Saber Moradinejad ◽  
Caitlin M. Glover ◽  
Jacinthe Mailly ◽  
Tahere Zadfathollah Seighalani ◽  
Sigrid Peldszus ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Potassium Permanganate ◽  
Drinking Water Treatment ◽  
Carbon And Nitrogen ◽  
Toxic Cyanobacteria ◽  
Nitrogen Detection ◽  
Algal Organic Matter ◽  
Organic Matter Fractions ◽  
The Impact

Drinking water treatment plants throughout the world are increasingly facing the presence of toxic cyanobacteria in their source waters. During treatment, the oxidation of cyanobacteria changes cell morphology and can potentially lyse cells, releasing intracellular metabolites. In this study, a combination of techniques was applied to better understand the effect of oxidation with chlorine, ozone, potassium permanganate, and hydrogen peroxide on two cell cultures (Microcystis, Dolichospermum) in Lake Champlain water. The discrepancy observed between flow cytometry cell viability and cell count numbers was more pronounced for hydrogen peroxide and potassium permanganate than ozone and chlorine. Liquid chromatography with organic carbon and nitrogen detection was applied to monitor the changes in dissolved organic matter fractions following oxidation. Increases in the biopolymer fraction after oxidation with chlorine and ozone were attributed to the release of intracellular algal organic matter and/or fragmentation of the cell membrane. A novel technique, Enhanced Darkfield Microscopy with Hyperspectral Imaging, was applied to chlorinated and ozonated samples. Significant changes in the peak maxima and number of peaks were observed for the cell walls post-oxidation, but this effect was muted for the cell-bound material, which remained relatively unaltered.

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