Wyniki wyszukiwania - BazTech

1

Zastosowanie utleniaczy do usuwania tlenków azotu w instalacjach odsiarczania spalin dla instalacji typu MCP

Łuszkiewicz Dariusz, Świerczok Arkadiusz, Jędrusik Maria

Rynek Energii

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2025

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Nr 2

86--92

PL

W artykule przedstawiono problematykę związaną z dostosowaniem istniejących źródeł spalania paliw do wymagań dyrektywy MCP (Medium Combustion Plants). W Polsce funkcjonuje ok. 4 800 obiektów sklasyfikowanych jako MCP o mocy od 1 do 50 MW termicznych, źródła te będą musiały spełniać wymagania odnośnie do poziomów emisji dla pyłów, SO2 i NOx. Z uwagi na specyfikę zakładów posiadających małe źródła emisji poszukiwane będą rozwiązania pozwalające na dotrzymanie standardów emisyjnych przy zrównoważonych kosztach eksploatacyjnych i inwestycyjnych, co otwiera drogę do zastosowania metod oksydacyjnych jednoczesnego usuwania tlenków azotu i dwutlenku siarki ze spalin. Naukowcy z Politechniki Wrocławskiej posiadają bogate doświadczenie z prac badawczych nad metodami oksydacyjnymi prowadzonych w przemyśle energetycznym. Na przestrzeni lat w warunkach przemysłowych testowane były następujące utleniacze NO: ozon, woda utleniona, chloryn sodu. Zastosowanie wtrysku utleniaczy przed instalacjami odsiarczania spalin może być alternatywnym rozwiązaniem (w stosunku do instalacji SNCR) w kontekście ograniczenia emisji NOx szczególnie tam, gdzie wykorzystywane są instalacje odsiarczania spalin metodą półsuchą lub mokrą.

EN

The article presents the issues related to adapting existing fuel combustion sources to the requirements of the MCP (Medium Combustion Plants) directive. In Poland, there are approximately 4,800 facilities classiﬁed as MCP with a capacity of 1 to 50 MW thermal, these sources will have to meet the requirements regarding to emissions for dust, 802 and NOX. Due to the specificity of small emission sources, solutions will be sought that will allow for compliance with emission standards at balanced operating and investment costs, which opens the way to the use of oxidation methods for the simultaneous removal of nitrogen oxides and sulfur dioxide from ﬂue gases. Scientists from the Wroclaw University of Science and Technology have extensive experience in research on oxidative methods conducted in the energy industry. Over the years, the following NO oxidants have been tested in industrial conditions: ozone, hydrogen peroxide, sodium chlorite. The use of oxidant injection before ﬂue gas desulfurization installations may be an alternative solution in the context of reducing NOX emissions, especially where semi-dry or wet ﬂue gas desulfurization installations were used.

2

Ocena morfologii próbek materiałów wysokoenergetycznych otrzymanych na bazie saletry amonowej oraz mieszaniny oleju napędowego z nadtlenkiem wodoru

Biessikirski Andrzej, Dworzak Michał, Ziąbka Magdalena, Polak Krzysztof, Pytlik Mateusz, Napruszewska Bogna D., Kuterasiński Łukasz

Przemysł Chemiczny

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2025

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T. 104, nr 9

872--878

PL

Przedstawiono wstępną ocenę możliwości zastosowania mieszaniny oleju napędowego z nadtlenkiem wodoru (FOHP) do otrzymywania próbek materiałów wysokoenergetycznych na bazie azotanu(V) amonu (AN). Przeanalizowano potencjalny wpływ obecności nadtlenku wodoru na właściwości morfologiczne uzyskanych próbek. Analiza mikroskopii skaningowej (SEM) wykazała brak negatywnego oddziaływania nadtlenku wodoru na powierzchnię krystaliczną azotanu(V) amonu. Zaobserwowano, że mieszanina FOHP tworzy cienką warstwę filmu olejowo-nadtlenkowego, pokrywającą zarówno powierzchnię krystaliczną AN, jak i obecne na niej defekty strukturalne. Badania dyfrakcji rentgenowskiej (XRD) potwierdziły, że obecność nadtlenku wodoru nie wpływa na strukturę krystaliczną azotanu(V) amonu. Analiza termograwimetryczna i różnicowa analiza kalorymetryczna (TG/ DSC) ujawniły dodatkowy efekt endotermiczny w temperaturze ok. 80°C w próbkach zawierających nadtlenek wodoru. Zarówno badania morfologii strukturalnej, jak i obliczenia termodynamiczne potencjalnych właściwości detonacyjnych analizowanych próbek wskazują na możliwość zastosowania nadtlenku wodoru jako dodatku w produkcji materiałów wysokoenergetycznych.

EN

High-energy materials were prepared by adding a mixt. of diesel fuel and H₂O₂ (FOHP) to NH₄NO₃. The effect of H₂O₂ on the physicochem. properties of the obtained materials was analyzed using SEM, XRD, and TG/DSC. SEM anal. showed no adverse effect of H₂O₂ on the crystal surface of NH₄NO₃. XRD anal. confirmed that H₂O₂ did not change the crystal structure of NH₄NO₃. TG/DSC anal. showed the presence of an addnl. endothermic effect at a temp. of approx. 80°C in samples contg. H₂O₂. Both the morphol. evaluation of the structure and the thermodynamic calcns. of the potential detonation properties of the analyzed samples suggest that H₂O₂ additives may be useful in the production of high-energy materials.

3

Development and validation of a method for studying Relugolix and its impurities by UPLC-MS

Thrinath S.R., Lakshmi K.S., Krishnan Manikandan

Acta Chromatographica

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2025

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Vol. 37, no. 2

164--175

EN

In accordance with the International Coordinating Committee’s recommendations, an acceptable UPLC-MS method is being developed for analyzing Relugolix stability under various stress scenarios. Stress conditions included exposure to 0.1 and 1 N acid, alkali, hydrolysis, peroxide, light, reduction, and heat. The mobile phase for this analysis was prepared by blending acetonitrile and a 0.1% orthophosphate solution in a 50:50 (v/v) ratio. A C18 Column with dimensions of 100x2.1mm and a particle size of 1.7 μm was employed as the stationary phase. The wavelength at which detection was performed was 247 nm, and the flow rate was maintained stable at 0.5 mL min-1. Strong linearity was shown by this method across a concentration range of 1.25 μg mL-1 to 7.5 μg mL-1. The method’s reliability was shown by ensuring all of the validation parameters fell within the acceptable range. Furthermore, forced degradation studies were conducted using standard drugs. Different stress conditions led to the formation of degradation products, which were successfully separated from Relugolix using the C18 column in combination with an auto-purification mass spectrometer. Among the stress conditions, alkaline conditions showed a lower degradation rate. Interestingly, seven distinct types of degradation products were identified from the degradation studies under acid, alkali, hydrolysis, hydrogen peroxide, light, reduction, and thermal conditions. Remarkably, these seven degradation products have not been reported in previous literature, making this study the first to document their existence.

4

Concept of a green propulsion system for IOSHEX, designed to perform in-orbit rendezvous and docking

Surmacz Paweł, Parzybut Adrian, Gramatyka Jakub, Bodych Daria, Rugor Łucja, Uwarowa Inna, Mariani Marco, Guerzoni Marco

Transactions on Aerospace Research

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2024

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Nr 3 (276)

58--76

EN

Recent challenges in space access include cost optimization and space debris reduction. The European Space Agency has envisioned the evolution of in-orbit transportation involving re-usable service vehicles, moving payloads from high parking orbits to their target orbits. This concept for orbital infrastructure requires de-risking activities and the development of building blocks, such as standardized interfaces and communication. Mastery of close-proximity operations and docking is essential for the new transportation system. This new branch of space operations represents a good opportunity to introduce more sustainable propulsion solutions, especially given the high costs and uncertain future of hydrazine and its derivatives. IOSHEX, a service spacecraft to be equipped with a green propulsion system utilizing 98% hydrogen peroxide, serves as a reference. This paper presents a design concept for this propulsion system, including trade-off analyses, calculations, and a three-dimensional model integrated with IOSHEX.

5

Bezpośrednie bielenie masy celulozowej siarczanowej sosnowej papierniczej normalnej nadtlenkiem wodoru

Danielewicz Dariusz

Przegląd Papierniczy

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2024

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R. 80, nr 4

210--217

PL

Głównym celem niniejszej pracy było sprawdzenie możliwości uzyskania pełnego wybielenia (tj. do białości >88%) masy celulozowej siarczanowej (Sa) sosnowej papierniczej normalnej (tj. przeznaczonej do bielenia) o liczbie Kappa 26,9 nadtlenkiem bezpośrednio, tj. bez zastosowania procesu delignifikacji tlenowej. Badania wykazały możliwość uzyskania takiej białości masy wdwóch wariantach procesu, tj. QP1PaP2 oraz QP1P2 z odpowiednio dobranymi parametrami procesów. Wykonane próby bielenia wybranej do badań masy celulozowej umożliwiły również przedstawienie wpływu kilku czynników na wyniki jej bielenia, takich jak: początkowe pH cieczy bielącej (pHP), ilość H2O2 dozowanego w procesie bielenia, regulacja pH zawiesiny włóknistej masy w trakcie bielenia, wstępna obróbka masy środkiem chelatującym (jedno i dwustopniowa) (Q) oraz rozcieńczonym kwasem siarkowym (A), użycie międzystopniowej obróbki masy kwasem nadoctowym oraz podwyższenie stężenia masy zawiesiny włóknistej z 10 do 16% w stopniu bielenia nadtlenkowego.

EN

The main aim of this work was to check the possibility of obtaining fully- -bleached (i.e., of a brightness of >88%) of pine regular grade kraft pulp with the Kappa number of 26.9 using hydrogen peroxide directly, i.e., without the use of the oxygen delignification process. The tests showed the possibility of obtaining such brightness of the pulp in two process variants, i.e., QP1PaP2 and QP1P2 with appropriately selected process parameters. The bleaching tests performed on the pulp selected for testing also made it possible to present the influence of several factors on the bleaching results, such as: initial pH of the bleaching liquid (pHP); the amount of H2O2 dosed in the bleaching process; pH regulation of the fibrous pulp suspension during bleaching; pre-treatment of the pulp with a chelating agent (one- and two-stage) (Q) and dilute sulfuric acid (A); the use of inter-stage pulp treatment with peracetic acid; and increasing the pulp concentration of the fibrous suspension from 10 to 16% in the peroxide bleaching stage.

6

Compressive Strength and Water Flux Performance of Type C and Type F Fly Ash-Based Geopolymer Membrane

Nurlina Nurlina, Alief Mohammad Naufal, Rahmawati Zeni, Nurherdiana Silvana Dwi, Susanto Tri Eddy, Fansuri Hamzah

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

1107--1113

EN

This study explains the influence of fly ash type C and type F on the properties of membrane geopolymer. The geopolymer paste was synthesized through a mix of fly ash (FA) and an alkaline activator (AA) (2:1 mass ratio of FA:AA). The alkali activator was prepared from sodium silicate and 12 M sodium hydroxide solution in a mass ratio of 1.6. Hydrogen peroxide 3 wt.% was applied as the pore-forming agent, and 4 wt.% glass fiber was employed for reinforcement. The properties of the geopolymer were investigated via Fourier-transform infrared, X-ray diffraction, and scanning electron microscopy. The compressive strength confirmed the higher performance of the type C fly ash-based geopolymer membrane (CFAGM) over the type F fly ash-based geopolymer membrane (FFAGM). On the other hand, FFAGM exhibited an enhanced water permeation flux owing to the larger pore diameter. These results affirmed the excellent performance compared to the previous study.

7

Fotokatalizatory i fotoelektrokatalizatory w procesach wytwarzania nadtlenku wodoru

Gańczarczyk Roman M.

Wiadomości Chemiczne

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2023

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[Z] 77, 11-12

1017--1040

EN

A significant contemporary challenge in the field of science and technology pertains to the development of innovative and sustainable methods for energy acquisition. The dynamic advancement of solar energy conversion techniques has led to the swift commercialization of photovoltaic cell technology, concomitantly creating a demand for cost-effective energy conversion and storage systems. An interesting solution to this challenge lies in the application of photocatalytic and photoelectrocatalytic synthesis to produce energy-rich molecules. One of the possible solutions under consideration in this context is hydrogen peroxide artificial photosynthesis. In recent years, several research efforts have been dedicated to the photo-assisted generation of hydrogen peroxide through oxygen reduction and water oxidation. In this brief review, the fundamental aspects related to photocatalytic and photoelectrocatalytic processes have been presented. Particular attention was paid to issues related to various groups of active photo(electro)catalysts used in the synthesis of hydrogen peroxide, and the latest trends in the molecular engineering of these compounds were highlighted.

8

Rozkład nadtlenku wodoru podczas katalitycznego epoksydowania propylenu

Lina Wang, Cheng Shen, Yingfeng Duan, Wei Du, Yagang Zhang, Wenying Li

Przemysł Chemiczny

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2023

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T. 102, nr 10

1018--1021

PL

Jako katalizator epoksydowania propylenu za pomocą nadtlenku wodoru w wodnym roztworze metanolu zastosowano sito molekularne TS-1 (krzemian tytanu). Zbadano szybkość samoistnego rozkładu nadtlenku wodoru wtemp. 30-50°C. Znaleziono optymalne warunki (temp. reakcji 43°C, stężenie nadtlenku wodoru 10,3% mas., zawartość metanolu 65% mas.). Ustalono, że rozkład nadtlenku wodoru jest reakcją pierwszego rzędu. Wyznaczono stałą szybkości tej reakcji i jej energię aktywacji.

EN

Ti silicalite mol. sieve (TS-1) was used as catalyst for propylene epoxidation with H₂O₂ in aq. MeOH soln. The H₂O₂ self-decompn. rate at 30-50°C was studied. The optimum conditions were found (reaction temp. 43°C, H₂O₂ concn. 10.3% by mass, MeOH concn. 65% by mass). The H₂O₂ selfdecompn. was the first-order reaction. Its reaction rate const. and activation energy were detd.

9

Analiza przeglądowa metod i urządzeń pomiarowych oraz projekt inteligentnego systemu elektronicznego do badania stężeń szkodliwych środków chemicznych w powietrzu w przemyśle spożywczym

Jędrusiak Zbigniew, Wymysłowski Artur

Przegląd Elektrotechniczny

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2023

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R. 99, nr 11

292--297

PL

W publikacji prezentowana jest analiza przeglądowa w zakresie metod i urządzeń pomiarowych dotyczących detekcji szkodliwych lub potencjalnie niebezpiecznych substancji chemicznych w zakładach przemysłowych. Szczególną uwagę poświęcono procedurom identyfikacji popularnych środków dezynfekujących, takich jak kwas nadoctowy, kwas octowy i nadtlenek wodoru, których rosnące zastosowanie w przemyśle spożywczym napędza implementację coraz bardziej rygorystycznych regulacji dotyczących ich zawartości w powietrzu. Opracowanie zawiera również opis projektowanego systemu elektronicznego, który ma na celu umożliwienie efektywnego monitorowania i regulacji obecności tych substancji w czasie rzeczywistym.

EN

The publication presents a thorough analysis of the current state of knowledge regarding the methods of detection of harmful or potentially dangerous chemical substances in industrial facilities. Particular focus has been placed on the procedures for identifying popular disinfectants, such as peracetic acid, acetic acid, and hydrogen peroxide, the increasing use of which in the food industry drives the implementation of increasingly stringent regulations regarding their content in the air. The study also includes a description of a proposed electronic system intended to enable effective monitoring and regulation of the presence of these substances.

10

New insights into pyrite-hydrogen peroxide interactions during froth flotation : experimental and DFT study

Cao Qinbo, Yan Wenchao, Wen Shuming, Liu Dianwen, Li Yanjun

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 157409

EN

Hydrogen peroxide (H2O2) is an efficient depressant for pyrite (FeS2) flotation. However, the depressing mechanism of H2O2 is not fully understood. In this paper, the depressing capacity of H2O2 for pyrite was examined by flotation tests. Results revealed that pyrite flotation could be inhibited by H2O2 at pH 6.4. The pyrite powder in H2O2 solution enhanced the release of O2 from H2O2. However, the O2 concentration in the solution was less than that of H2O2; thus, H2O2 is the major oxidant in the solution. Moreover, density functional theory calculations were performed to study the interactions between H2O2 and hydrated pyrite (100) surface. The H2O2 molecule tended to react with the pyrite surface to generate one S=O bond and an H2O molecule. The possible binding models of O2 molecules on the pyrite (100) surface were also studied for comparison. The O2 dissociation on the pyrite surface was more favorable than the adsorption of O2 as a whole. In addition, the orbital interaction in the S=O bond raised from the reaction of H2O2/O2 with the pyrite surface was also investigated by the density states analysis. These results provide some insights into the oxidizing effect of H2O2 in pyrite flotation.

11

A new environmentally friendly chemical mechanical polishing method applied for surface finishing Ti-6Al-4V alloy

Quang Nguyen Minh, Quan Nguyen Ngoc, Mai Nguyen Trong, Thanh Le Thi Phuong, Tung Nguyen Tien, Tan Tran Ngoc, Hai Ha Thanh, Trinh Nguyen Duy

Journal of Machine Engineering

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2023

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Vol. 23, No. 4

64--76

EN

A new eco-friendly slurry has been developed for the chemical mechanical polishing process with a solution of malic acid, deionized water, and an oxidizing agent hydrogen peroxide (H2O2). The surface quality of Ti-6Al-4V workpieces with the proposed chemical mechanical polishing slurry with optimal parameters include oxidizers (H2O2), colloidal (SiO2) slurry, and deionized water by weight 8%, 45%, and 47% respectively, the pH concentration is adjusted 4 through the malic acid content present in the slurry. Experimental results obtained with the proposed chemical mechanical polishing method show a more improved surface quality than previous studies when applying for polishing Ti-6Al-4V alloy. The developed chemical mechanical polishing method's polishing results under optimal conditions obtain an ultra-fine surface quality with Ra = 0.696 nm over a measuring area of 53×70 μm2. X-ray photoelectron (XPS) and electrochemical measurements were used to study the chemical reaction mechanisms in the proposed chemical mechanical polishing process. The chemical mechanical polishing processes for the surface of the Ti-6Al-4V alloy workpiece with the H2O2 oxidizing agent showed high suitability with the reactants formed on the surface such as Ti, V, and Al oxide. With the proposed oxidant and the established chemical mechanical polishing slurry, the feasibility and surface quality of the super smooth Ti-6Al-4V workpiece formed after polishing were demonstrated. The established chemical mechanical polishing method shows high applicability in environmental protection and Ti-6Al-4V alloy ultra-precision machining industries.

12

The Influence of Foaming Agent Towards Metakaolin Based Alkali Activated Materials Properties and Cu2+ Adsorption

Ibrahim Masdiyana, Ibrahim Wan Mastura Wan, Abdullah Mohd Mustafa Al Bakri, Mahamud L. H., Tajuddin Muhammad Noorfadzlin Najmi, Yahya Nur Faezah

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

1077--1086

EN

The performance of adsorbent synthesized by alkali activation of aluminosilicate precursor metakaolin with sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as well as the foaming agent was studied for copper ions adsorption from aqueous solution. This paper investigated the effect of adding hydrogen peroxide (H2O2) and aluminium powder as foaming agents to an alkali activated materials slurry. The experimental range included 0.50 wt%, 0.75 wt%, and 1.00 wt% hydrogen peroxide and 0.02 wt%, 0.04 wt%, and 0.06 wt% aluminium powder. A control sample without a foaming agent was also created for comparison. The specific surface area, water absorption, density, compressive strength and microstructure of metakaolin based alkali activated materials were evaluated. The adsorption capability of Cu2+ with addition of hydrogen peroxide and aluminium powder was then tested. Results indicate hydrogen peroxide addition had superior pore size distribution and homogeneous porosity than aluminium powder, implying improved copper ion elimination. Cu2+ adsorption capability reached 98% with 0.75 wt% hydrogen peroxide and 24.6076 m2/g surface area. The results demonstrating that low cost metakaolin-based AAMs are the most effective adsorbent for removing copper ions.

13

Wykorzystanie gazowego nadtlenku wodoru do biodekontaminacji materiałów z zanieczyszczeń mikrobiologicznych

Furtak Elwira, Cichocka Wioletta, Kisielińska-Kot Edyta

Przemysł Chemiczny

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2021

|

T. 100, nr 3

240--245

PL

Sterylizacja nadtlenkiem wodoru jest bardzo skuteczną metodą pozbywania się mikroorganizmów oraz ich form przetrwalnikowych z zanieczyszczonych powierzchni. Zbadano skuteczność procesu sterylizacji różnych materiałów skażonych zawiesiną grzybów pleśniowych oraz wpływ nadtlenku wodoru na fizykomechaniczne właściwości tych materiałów. Zastosowanie nadtlenku wodoru w formie gazowej dało zadowalające efekty w usuwaniu mikroorganizmów, nie powodując zmian właściwości sterylizowanego materiału.

EN

Many materials (filtration paper, uniform textile, leather) were contaminated with mould spores and then sterilized with H₂O₂ vapors at 40°C for 5–60 min. Full removal of spores was achieved. No changes of color, hydrophobicity and mechanical strength were obsd.

14

Nadtlenek wodoru : metoda oznaczania w powietrzu na stanowiskach pracy metodą spektrofotometryczną

Mysur Wioletta, Kucharska Nadia, Bonczarowska Marzena, Brzeźnicki Sławomir

Podstawy i Metody Oceny Środowiska Pracy

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2021

|

Nr 3 (109)

161-171

PL

Nadtlenek wodoru w temperaturze pokojowej występuje w postaci bezbarwnej, przejrzystej cieczy, o słabym zapachu ozonu. Nadtlenek wodoru jest wykorzystywany jako wybielacz w przemyśle papierniczym, spożywczym i kosmetycznym oraz do produkcji paliwa rakietowego. Właściwości utleniające nadtlenku wodoru są wykorzystywane w procesie oczyszczania ścieków oraz w medycynie do odkażania ran (woda utleniona). W chemii analitycznej związek ten wykorzystywany jest w oznaczeniach śladowych ilości metali. Szkodliwe działanie nadtlenku wodoru polega na działaniu drażniącym na skórę, błony śluzowe oczu i górnych dróg oddechowych. Celem prac badawczych było opracowanie i walidacja metody oznaczania nadtlenku wodoru w powietrzu na stanowiskach pracy. Opracowana metoda oznaczania polega na pochłanianiu nadtlenku wodoru w wodzie, a następnie na spektrofotometrycznym oznaczeniu kompleksu oranżu ksylenolowego z utlenionymi przez nadtlenek wodoru jonami żelaza (Fe III). Do badań wykorzystano spektro¬fotometr UNICAM umożliwiający wykonanie oznaczeń przy długości fali 560 nm. Opracowana metoda jest liniowa w zakresie stężeń 0,02 ÷ 0,4 μg/ml, co odpowiada zakresowi 0,04 ÷ 0,8 mg/m³ dla próbki powietrza o objętości 10 l. Opracowana metoda umożliwia oznaczanie nadtlenku wodoru w powietrzu na stanowiskach pracy w obecności substancji współwystępujących. Metoda charakteryzuje się dobrą precyzją i dokładnością i spełnia wymagania normy PN-EN 482 dla procedur dotyczących oznaczania czynników chemicznych. Opracowana metoda oznaczania nadtlenku wodoru w powietrzu na stanowiskach pracy została zapisana w postaci procedury analitycznej, którą zamieszczono w załączniku. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.

EN

Hydrogen peroxide at room temperature is a colourless clear liquid with weak ozone like odour. It is used as a bleach in paper, food and cosmetics industry and in rocket fuel production. It is also used in waste water and waste gas treatment and as a disinfectant in wounds treatment. In analytical chemistry, hydrogen peroxide is used to determine trace amounts of metals. Hydrogen peroxide may cause irritation of eyes, skin, and respiratory tract. The goal of this research was to develop and validate a method for determining hydrogen peroxide in workplace air. Developed method is based on the collection of hydrogen peroxide with water filled bubbler and spectrophotometric determination of xylenol orange and ferrum (III) ions complex. Developed method is linear in the concentration range of 0.2-4.0 µg/ml, which corresponds to the range of 0.04-0.8 mg/m³ for 10-L air sample. The analytical method described in this paper makes it possible to determine hydrogen peroxide in workplace air in the presence of other substances. The method is precise, accurate and it meets the criteria for procedures for determining chemical agents listed in Standard No. PN-EN 482. The developed method of determining hydrogen peroxide in workplace air has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

15

Degradation of toluene using UV/hydrogen peroxide process

Cai Shaokang, Sun Yue, Gao Canzhu, Li Pengfei, Cheng Zhongfa

Environment Protection Engineering

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2021

|

Vol. 47, nr 1

5-15

EN

Toluene in wastewater is volatile and difficult to degrade, and the longer it stays in the water, the higher is the risk. An advanced oxidation process (AOPs) has been used to degrade toluene rapidly and efficiently in wastewater by using ultraviolet light and hydrogen peroxide. Toluene in solution (initial concentration – 180 mg/dm3) with hydrogen peroxide (H2O2 dose – 2022 mg/dm3) was almost decomposed within 150 min. pH as well as the presence of various ions in waste water did not affect the degradation process. However, under strongly acidic conditions (pH less than 3), the chloride ions reduced the degradation efficiency of toluene. Based on the UV spectrophotometer and GC-MS analyses, the degradation pathways were observed: first, the methyl group was oxidized leading to the generation of benzoic acid, the benzene ring was subsequently opened by the action of hydroxyl radical, followed by the gradual decomposition of the intermediate products into small molecules such as water and carbon dioxide.

16

Modification of the Detonation Parameters of Mining Explosives Containing Hydrogen Peroxide and Aluminium Powder

Paszula Józef, Maranda Andrzej, Nikolczuk Karolina, Giercuszkiewicz Agnieszka

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 4

477--491

EN

Presently, due to rising environmental consciousness, numerous actions are being taken to prevent devastation of the natural environment. If explosive mixtures are manufactured in an insufficiently controlled manner, they contain too much ammonium nitrate and generate nitrogen oxides (NOx), which are both harmful for living organism and responsible for negative weather phenomena. However, the products from decomposition of hydrogen peroxide are only oxygen and hydrogen, which are both environmentally friendly. This paper presents the results of research on the impact of two types of aluminium powder on the detonation parameters of mining explosives containing hydrogen peroxide 60% as an oxidiser. The detonation velocities were measured by means of short circuit sensors. Direct measurement of the blast wave overpressure was performed with piezoelectric sensors and the positive phase impulse was analyzed. Measurement of the explosive strength was made by the ballistic pendulum method for 10 g samples. The results of these experiments showed that the addition of both types of aluminium, as well as their content in the explosive mixture, have a significant impact on all of the measured parameters.

17

Thermodynamics and kinetics of thermal deactivation of catalase Aspergillus niger

Miłek Justyna

Polish Journal of Chemical Technology

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2020

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Vol. 22, nr 2

67--72

EN

The thermal stability of enzyme-based biosensors is crucial in economic feasibility. In this study, thermal deactivation profiles of catalase Aspergillus niger were obtained at different temperatures in the range of 35° C to 70° C. It has been shown that the thermal deactivation of catalase Aspergillus niger follows the first-order model. The half-life time t 1/2 of catalase Aspergillus niger at pH 7.0 and the temperature of 35° C and 70° C were 197 h and 1.3 h respectively. Additionally, t 1/2 of catalase Aspergillus niger at the temperature of 5° C was calculated 58 months. Thermodynamic parameters the change in enthalpy ΔH*, the change in entropy ΔS* and the change Gibbs free energy ΔG* for the deactivation of catalase at different temperatures in the range of 35° C to 70° C were estimated. Catalase Aspergillus niger is predisposed to be used in biosensors by thermodynamics parameters obtained.

18

Seasonal variability of antibiotic resistance and biodiversity of tap water bacteria in Wrocław, Poland

Siedlecka Agata, Wolf-Baca Mirela, Piekarska Katarzyna

Environment Protection Engineering

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2020

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Vol. 46, nr 2

93--109

EN

Antibiotic resistance of bacteria has become a worldwide problem. Drinking water distribution systems (DWDSs) can be regarded as reservoirs of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study aims to provide a preliminary evaluation of seasonal changes in the occurrence of ARB and ARGs in Wrocław tap water samples. It also investigates the biodiversity of bacterial communities dwelling in Wrocław DWDS and compares them with worldwide literature reports. Third generation cephalosporins resistant bacteria were present in each season, with relative abundances reaching from 40.46% in spring to 99.86% in summer. β-lactams and tetracyclines resistant bacteria were present only in spring and autumn samples, with relative abundances reaching from 0.51% to 3.80%. Relative abundances of ARB fluctuated across the year, and no season-dependent trend was found. This suggests that other factors influenced the resistance phenomenon in Wrocław tap water. The investigated resistomes were represented only by several ARGs (qnrB, tetW, ermB,qacEΔ1). Class 1 integrons gene intI1 was also detected. Biodiversity of bacteria collected from large amounts of tap water was similar to that reported previously for Wrocław and worldwide DWDSs, with a prevalence of Proteobacteria, followed by Actinobacteria, Cyanobacteria, and Firmicutes.

19

Effects of plant extracts and disinfectant Huva-San TR 50 on the quality of carrot (Daucus carota L.) seeds

Górski Romuald, Szopińska Dorota, Dorna Hanna, Rosińska Agnieszka, Stefańska Zuzanna, Lisiecka Jolanta

Ecological Chemistry and Engineering. S

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2020

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Vol. 27, nr 4

617--628

EN

The aim of the study was to determine the effect of Aloe vera (L.) Burm.f. (Aloe) and Morinda citrifolia L. (Indian mulberry) plant extracts and disinfectant Huva-San TR 50 (hydrogen peroxide stabilized with silver ions) on carrot seed quality. The seeds of two carrot cultivars Amsterdam (sample I) and Berlikumer 2 (sample II), were soaked in solutions of Aloe and Indian mulberry extracts and Huva-San TR 50 at concentrations of 0.025 %, 0.05 % and 0.1 % for 30 min. Untreated seeds and seeds soaked in distilled water for 30 min were used as controls. Seed germination was assessed after 7 and 14 days of incubation. The speed and uniformity of seed germination (vigour) were evaluated. Mycological analysis was performed using a deep-freeze blotter test. Sample I was characterized by lower germination at the first and the final counts than sample II and higher seed infestation with Alternaria radicina. Treating seeds of sample I with Morinda citrifolia plant extract at concentrations of 0.025 and 0.05 % reduced their infestation with Alternaria alternata and A. radicina, increased germination at the first and the final counts, and did not affect seed vigour. The effects of Aloe extract and disinfectant Huva-San TR 50 on seed quality parameters varied depending on their concentration. Hence, further studies are necessary to establish the optimal conditions for carrot seed treatment.

20

The effect of electrolyte composition on the plasma electrolyte oxidation and phase composition of oxide ceramic coatings formed on 2024 aluminium alloy

Posuvailo V. M., Kulyk V. V., Duriagina Z. A., Koval’chuck I. V., Student M. M., Vasyliv B. D.

Archives of Materials Science and Engineering

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2020

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Vol. 105, nr 2

49--55

EN

Purpose: Purpose of this work is to analyse the process of synthesis of oxide ceramic coatings in plasma electrolytes on 2024 aluminium alloy and to form an electrolyte which allows to reduce energy consumption for the coating formation. Design/methodology/approach: The oxide ceramic coatings were synthesized on 2024 aluminium alloy. The coatings were formed by the alternate application of anode and cathode pulses to the sample. X-ray diffraction analysis of coatings was performed on a DRON-3.0 X-ray diffractometer using CuKa radiation. The thickness of the coatings was determined using a CHY TG-05 thickness gauge. The porosity of the coatings was investigated by analysing the micrographs of the plasma electrolyte oxidation (PEO) coatings obtained on a scanning electron microscope at x500 magnification using the image processing technique. Findings: The electrolyte with 5 g/l H2O2 additive have been elaborated as an optimal composition for synthesis of a coating with an increased content of corundum (a-Al2O3) as compared to a coating synthesized in the same mode in the 3KOH+2Na2SiO3 electrolyte without H2O2. This synthesis mode allows obtaining a coating with a high corundum content at low energy consumption. Research limitations/implications: For further optimization of the synthesis modes, it is necessary to analyse the influence of the phase composition and porosity of the obtained oxide ceramic coatings on their microhardness, wear resistance, and corrosion resistance. Practical implications: Based on the developed modes of synthesis of the coatings, it will be possible to obtain wear and corrosion resistant oxide ceramic coatings with predetermined functional properties and to reduce energy consumption for their formation. Originality/value: Methods for accelerating the formation of coatings have been proposed and tested, in particular, by adding various amounts of hydrogen peroxide to the electrolyte. The content of oxides in the obtained coatings, in particular, their ratios at various concentrations of hydrogen peroxide in the electrolyte, were determined by X-ray phase analysis. The modes of synthesis of the coatings were developed which allow obtaining a continuous coating without cracks with simultaneous decreasing porosity from 4.32% to 3.55-3.53%.