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1

The River System Pollutant Migration in the Context of the Sudden One-Time Discharge with Consideration of the Bottom Sediments Influence (Case of Benzene Migration in the Stryi River, Ukraine)

Kuzyk Andriy, Karabyn Vasyl, Shuryhin Vladyslav, Sushko Yulia, Stepova Kateryna, Karabyn Oksana

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 1

46--54

EN

Basing on the mathematical model developed with the account of influence of bottom sediments, the parameters of benzene migration in the river caused by one-time discharge into the Stryi River were investigated. The mathematical model of migration consists of two equations that describe the movement of pollutants in the river system, taking into account the flow rate, diffusion, sorption and desorption of the pollutant by the bottom sediments of the river. The parameters of benzene distribution in the "water-bottom sediments" system were experimentally determined under laboratory conditions. With the help of computer modeling, the temporal and spatial distributions of benzene in water and bottom sediments were obtained. The regularities of benzene concentration change depending on the composition of the bottom sediments of the river have been established. The dependencies can be extrapolated to other river systems and pollutants.

2

Prediction of Benzene Migration Parameters Resulting from Continuous Flow in a Mountain River

Shuryhin Vladyslav, Karabyn Vasyl, Kuzyk Andriy

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

73--81

EN

Using a mathematical model that includes the influence of bottom sediments, a comprehensive study of the migration of benzene (C6H6) as a result of its continuous release into a mountain river was conducted. The adopted migration model consists of two equations that accurately describe the movement of pollutants within the river system, considering crucial factors such as flow velocity, diffusion, sorption, and desorption by river sediments. Through meticulous laboratory experiments, the distribution parameters that govern the behavior of benzene (C6H6) within the water-sediment system were successfulully determined. Leveraging advanced computer modeling techniques, intricate spatiotemporal profiles illustrating benzene (C6H6) concentrations in both water and sediments were generated. Furthermore, consistent patterns in the fluctuations of benzene (C6H6) concentrations that exhibit strong correlation with the specific composition of river sediments were identified. Importantly, these foundational relationships can be extrapolated to diverse river systems and various categories of pollutants.

3

Analiza i ocena składu toksycznych grup związków emitowanych w spalinach pojazdów zgodnych z normą Euro 6

Kęska Aleksandra

Przemysł Chemiczny

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2022

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T. 101, nr 8

606- 610

PL

Badano gazy spalinowe emitowane z pojazdów osobowych wyposażonych w silniki o zapłonie iskrowym (ZI) oraz samoczynnym (ZS), spełniających normę Euro 6. Wykonano analizę jakościowo-ilościową lotnych związków organicznych oraz wielopierścieniowych węglowodorów aromatycznych za pomocą chromatografii gazowej. Poziom benzenu był ponad kilkudziesięciokrotnie wyższy w pojeździe z silnikiem ZS. Stwierdzono, że wprowadzane restrykcje prawne oraz stosowane metody kontroli w obecnej formie nie wpływają w sposób wystarczający na zmniejszenie emisji toksycznych związków, a tym samym na poprawę zdrowia ludzi.

EN

The exhaust gases emitted from 2 identical passenger car models meeting the Euro 6 emission std., equipped with engines (i) with spark ignition (SI) and (ii) with compression ignition (CI) were tested. Samples were taken at idle speed. The qual. and quant. anal. of PAH and VOC in the exhaust gases were carried out by GC. The benzene content was several dozen times higher in the exhaust gases coming out from the CI engines.

4

Benzen. Dokumentacja proponowanych dopuszczalnych wielkości narażenia zawodowego

Szymańska Jadwiga, Frydrych Barbara, Bruchajzer Elżbieta

Podstawy i Metody Oceny Środowiska Pracy

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2022

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Nr 3 (113)

21-117

EN

Benzene is a colorless to slightly yellow liquid with the characteristic odor. Gases emitted from volcanoes and forest fires as well as petroleum products are natural sources of benzene. It is used primarily as a solvent and a starting material in the synthesis of many chemicals. In 2020 Poland, 28 people were exposed to benzene in concentrations exceeding the current TLV value. Benzene is a narcotic under the severe poisoning conditions. The liquid is irritating. Haematological changes in the blood and neoplasms, including acute myeloid leukemia, have been observed in humans after chronic exposure. Similar effects were seen in laboratory animals. Benzene and/or its metabolites are genotoxic. Such an effect of benzene was demonstrated in people occupationally exposed to the compound at a concentration of < 3.2 mg/m³ (< 1 ppm). Benzene is not an animal teratogen. As the value of TLV for benzene, it is proposed to adopt the concentration recommended in the Directive of the European Parliament and of the Council amending Directive 2004/37/EC, i.e. 0.66 mg/m3 . The risk of leukemia at employees professionally exposed to benzene at a concentration of 0.66 mg/m3 is within the range from 2.7 • 10−4 to 1 • 10−3. It is also proposed to add the following notations: “Carc. 1A” (carcinogenic substance of hazard category 1A); “Skin” (the absorption of substances through the skin may be as important as for inhalation exposure); “Muta. 1B” (germ cell mutagenicity, hazard category 1B). Benzene concentration of 2.5 µg/l of urine and the concentration of S-phenylmercapturic acid (S-PMA) at the level of 9.0 µg/g of creatinine in urine were proposed as biomarkers of occupational exposure to benzene. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

5

A novel application of building demolition waste for removal benzene from aqueous solutions

Alquzweeni Saif S., Hassan Afrah A., Alkizwini Rasha S.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2021

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Vol. 30, No. 1

86--97

EN

A novel application of building demolition waste for removal benzene from aqueous solutions. In this research, demolition waste from buildings has been studied for possible use as benzene removal adsorbent from aquatic solution. The effect of adsorbent dosage, contact time, initial benzene concentration, and initial pH on benzene adsorption capacity have been investigated in the batch adsorption experiments. The adsorption effects initially happened very rapidly and achieved equilibrium within 180 min. Benzene removal was observed to decrease by an increase in the initial concentration of benzene of 300–700 mg·L–1, an increase in the adsorbent dose of 0.4–2.4 g per 100 mL, where an optimum adsorbent dose equal to 1.2 g per 100 mL was found. The potential of adsorption increases with pH 3.0–7.0 to reach the maximum removal efficiency at pH 6.0. The findings showed that equilibrium data were adequately adapted and correlated with the Freundlich isotherm models. The average percentage of the removal at room temperature was about 98%. Results suggest that building demolition waste can be used effectively in industrial wastewater treatment for the removal of aromatic hydrocarbon, benzene, as a low-cost option.

6

SAW Sensor with Langmuir-Blodgett Layer for Detection of Benzene and its Derivatives

Balcerzak Andrzej, Kiełczyński Piotr, Szalewski Marek, Wieja Krzysztof

Archives of Acoustics

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2021

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Vol. 46, No. 1

25--30

EN

Vapors of benzene and its derivatives are harmful and toxic for human beings and natural environment. Their detection has fundamental importance. For this purpose authors propose surface acoustic wave (SAW) sensor with skeletonized layer deposited by Langmuir-Blodgett (L-B) method. This layer was obtained by depositing a binary equimolar mixture of 5-[[1,3-dioxo-3-[4-(1-oxooctadecyl) phenyl]propyl]amino]-1,3-benzenedicarboxylic acid with cetylamine. The skeletonized sensor layer has been obtained by removing cetylamine. Response of this sensor depends mainly of the electrical dipole momentum of molecule. Among the tested compounds, benzene has a zero dipole moment and gives the smallest sensor response, and nitrobenzene has the largest dipole moment and the sensor reacts most strongly to its vapor.

7

Volatile organic compounds in motor vehicle interiors under various conditions and their effect on human health

Verner Jan, Sejkorová Marie, Veselík Petr

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

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z. 107

205--216

EN

The aim of this paper is to estimate the mass concentrations of volatile organic compounds (VOCs) such as benzene (B), toluene (T), ethylbenzene (E) and m-, p-, o-xylenes (X) inside of the driver-compartment of motor vehicles. The results were compared with the Czech limits for indoor environments and the external concentrations. The experiments were carried out on various routes with different methods of ventilation. The volatile emissions detected inside the vehicle were investigated in the city of Brno, Czech Republic. Cabin air was collected using desorption tubes and the samples were analysed by thermal desorption gas chromatography with a flame ionisation detector coupled with a mass detector. VOC concentrations detected in the cabin of the vehicle ranged from 2.93 µg.m-3 to 7.96 µg.m-3 for benzene, 1.42 µg.m-3 to 4.38 µg.m-3. for toluene, 44.06 µg.m-3 to 152.00 µg.m-3 for ethylbenzene and 63.07 µg.m-3 to 479.62 µg.m-3 for xylenes. The indoor limit value for benzene, according to the Czech standard, is 7 µg.m-3. Levels of toluene were consistently below the Czech hourly standard, whose value according to the Czech standard is 300 µg.m-3. According to our findings, various methods of ventilation are an important factor influencing the BTEX pollution levels within the interior of the vehicle. In addition, this paper presents the influence results of benzene on the health of passengers inside the cabin of the vehicle. The results show that all age categories, especially children under the age of two, are exposed to increased health risks.

8

Benzen i metan jako wzorce przesunięcia chemicznego 1 H I 13 C NMR w obliczeniach teoretycznych

Rzepiela Kacper, Gajda Tomasz, Buczek Aneta, Broda Małgorzta A., Kupka Teobalt

Wiadomości Chemiczne

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2020

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[Z] 74, 9-10

609--627

EN

NMR spectroscopy belongs to the most versatile techniques used in chemical laboratory for testing the presence of various compounds and elucidation of their structure. In case of more complex natural products chemical intuition and experience applied to analysis of experimental spectra is often supported by theoretical modeling of NMR spectra. However, theoretical predictions should be reliable and the errors associated with the approximations inherent to the existing methods minimized. In this respect, systematic errors, present in calculation of isotropic nuclear magnetic shieldings of the studied molecule need to be minimized. Conversion of nuclear shieldings of the studied molecule to the corresponding chemical shifts is performed by using a calculated reference molecule. This way systematic errors partly cancel and the remaining inaccuracies are efficiently decreased by using a properly selected theoretical reference molecule. In this work we demonstrate the impact of calculation method (selected density functional) and basis set on the predicted isotropic nuclear magnetic shieldings of free benzene and methane in vacuum and in popular solvents using a simple PCM approach. We propose the use of B3LYP, OPBE density functionals and recently designed xOPBE one in combination with Pople’s and Dunning’s basis sets, as well as with the modified STO-3G one. The new, STO(1M)-3G basis set was designed by Leszczyński and co-workers for efficient prediction of 13C NMR parameters in large organic molecules. Two molecules were selected to demonstrate the performance of GIAO B3LYP, OPBE and xOPBE for prediction of 1H and 13C NMR chemical shifts in vacuum and solution in comparison with available experimental data.

9

Chlorinated benzenes and benzene degradation in aerobic pyrite suspension

Pham Hoa Thi, Chihiro Inoue

Archives of Environmental Protection

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2019

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Vol. 45, no. 1

115--125

EN

The focus of this study is to investigate the applicability of natural mineral iron disulfide (pyrite) in degradation of aromatic compounds including benzene and several chlorinated benzenes (from mono-chlorinated benzene (CB), di-chlorinated benzenes (di-CBs) to tri-chlorobenzenes (tri-CBs) in aerobic pyrite suspension by using laboratory batch experiments at 25°C and room pressure. At first, chlorobenzene was studied as a model compound for all considered aromatic compounds. CB was degraded in aerobic pyrite suspension, transformed to several organic acids and finally to CO2 and Clˉ. Transformations of remaining aromatic compounds were pursued by measuring their degradation rates and CO2 and Clˉ released with time. Transformation kinetics was fitted to the pseudo-first-order reactions to calculate degradation rate constant of each compound. Degradation rates of the aromatic compounds were different depending on their chemical structures, specifically the number and position of chlorine substituents on the benzene ring in this study. Compounds with the highest number of chlorine substituent at m-positions have highest degradation rate (1,3,5-triCB > 1,3-diCB > others). Three chlorine substituents closed together (1,2,3-triCB) generated steric hindrance effects. Therefore 1,2,3-triCB was the least degraded compound The degradation rates of all compounds were in the following order: 1,3,5-triCB > 1,3-diCB > 1,2,4-triCB ≅1,2-diCB ≅CB ≅benzene > 1,4-diCB > 1,2,3-triCB. The final products of the transformations were CO2 and Clˉ. Oxygen was the common oxidant for pyrite and aromatic compounds. The presence of aromatic compounds reduced the oxidation rate of pyrite, which reduced the amount of ferrous and sulfate ions release to aqueous solution.

10

Evaluation of the efficiency of the three-way catalytic converter of a spark ignition engine of the chosen aromatic hydrocarbons removing

Skrętowicz M., Woźniak J., Wróbel R.

Combustion Engines

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2017

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R. 56, nr 2

83--86

EN

In the paper the results of measurement of the most popular aromatic hydrocarbons (benzene, toluene and xylenes) in the exhaust of spark ignition engine before and after three-way catalytic reactor were presented. The investigations have been conducted at fixed rotational speed, 2500 rpm and at a few different values of torque in range 0 – 80 Nm, every 10 Nm. Based on obtained results, the calculations of catalytic reactor efficiency in removing analysed components have been made. The measurements showed high efficiency of the catalytic converter in reduction of that pollutants in exhaust gases.

11

Produkcja cykloheksanonu : od fenolu do benzenu i z powrotem?

Krzysztoforski A., Rygiel S.

Przemysł Chemiczny

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2016

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T. 95, nr 6

1055--1060

12

Chemizm wód podziemnych w rejonie ujęcia „Lipce” i „Grodza Kamienna” w Gdańsku

Pasierowska B., Tarnawska E., Lidzbarski M., Kordalski Z.

Przegląd Geologiczny

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2016

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Vol. 64, nr 6

418--426

EN

The article presents the results of groundwater chemistry studies in the area around the “Lipce” and “Grodza Kamienna” intakes in Gdańsk. In the northern part of the “Lipce” intake the groundwater quality has been low for the last few years; therefore it was necessary to pump water from two wells directly into drainage ditches. Currently, the benzene concentration in the groundwater exceeds the maximum permissible limit for drinking water (>1μg/dm3). Groundwater quality is also lowered by the presence of phenol, PAH and vinyl chloride (PVC). The studies showed variability of the benzene and phenol concentrations in the upper and bottom parts of the Holocene-Pleistocene aquifer. Chemical analysis of soil taken from drainage ditches revealed contamination caused by illegal sewage discharge emitted from a nearby factory, producing tar in the past.

13

Analiza chromatograficzna wybranych produktów rozkładu termicznego mas rdzeniowych wykonanych w technologii cold-box

Żymankowska-Kumon S., Kolczyk J.

Prace Instytutu Odlewnictwa

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2016

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Vol. 56, no. 4

369--378

PL

Sypkie masy szybkoutwardzalne z żywicami syntetycznymi, nazywane zwyczajowo technologiami cold-box, zdominowały proces wytwarzania rdzeni odlewniczych. Charakterystyczną cechą tych technologii jest sposób przygotowywania masy, którą sporządza się bez dodatku utwardzacza. Środek utwardzający (w postaci zgazowanej) wprowadza się poprzez przegazowywanie go do zagęszczonego rdzenia. W grupie tych technologii największe znaczenie posiada fenolowy proces cold-box (Ashland-cold-box, Pur-cold-box). Ocena szkodliwości tych mas rdzeniowych dla otoczenia wymaga uwzględnienia ilości i toksyczności wydzielanych gazów. Głównym hamulcem ograniczającym technologię cold-box z udziałem aminy jest problem związany z jej neutralizacją i obawy dotyczące szkodliwości dla otoczenia. Do oceny ekologiczności spoiw odlewniczych nadają się badania pirolityczne w połączeniu z metodą chromatografii gazowej sprzężonej ze spektrometrią mas (Py-GC/MS). W artykule przedstawiono wyniki badań chromatograficznych wybranych produktów rozkładu termicznego (BTEX – głównie benzen, toluen oraz fenol) masy rdzeniowej wykonanej w klasycznej technologii cold-box. Badania przeprowadzono w atmosferze obojętnej, w temperaturze 500°C i 1200°C.

EN

Loose rapid hardening masses with synthetic resins, customarily called cold-box technologies, have dominated the process of casting core production. A distinguishing feature of these technologies is the manner of mass preparation without the use of a hardener. The hardening agent (in the gaseous form) is introduced by way of its gasification into the condensed core. In the group of these technologies, the most significant one is the phenol cold-box process (Ashland-cold-box, Pur-cold-box). The evaluation of the harmfulness of these core sands to the environment requires consideration of the amount and toxicity of the released gases. The main limitation of the cold-box technology with the participation of amine is connected with its neutralization and its harmfulness to the environment. For the evaluation of environmental performance of casting binders, it is suitable to apply pyrolytic testing in combination with the gas chromatography method (Py-GC/MS). The article presents the results of chromatographic tests of selected products of thermal decomposition (BTEX – mainly benzene, toluene and phenol) of core sand made in the classic cold-box technology. The investigations were performed in inert atmosphere, at the temperature of 500°C and 1200°C.

14

Historyczny rozwój koncepcji aromatyczności

Ciesielski A., Krygowski T. M., Cyrański M. K.

Wiadomości Chemiczne

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2015

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[Z] 69, 9-10

789--808

EN

Aromaticity is one of the most important terms used in organic chemistry. It has been called as a “as a cornerstone of heterocyclic chemistry” or “a theoretical concept of immese practical importance”. The concept, in chemical sense, has been introduced by Friedrich August Kekulé von Stradonitz 150 ago. The paper presents the contribution to its development of many outstanding scientists: Emil Erlenmayer, Albert Ladenburg, Adolf von Baeyer, Victor Meyer, Heinrich Limpricht, Artur Hantzsch, Eugen Bamberger, Richard Willstätter, Ernest Crocker, James W. Armit, Robert Robinson, Erich Hückel, Artur Frost, Boris Musulin, Linus Pauling, Kathleen Lonsdale, Eric Clar, Haruo Hosoya, Henry Edward Armstrong, George W. Wheland, Fritz W. London, John Pople, Paul von Ragué Schleyer and others. Aromaticity is defined on the basis of four main criteria: energetic, geometric, magnetic and reactivity. Two modern definitions of the term are presented in chapter 2 (both are given in English).

15

Charakterystyka stężeń wybranych zanieczyszczeń powietrza na obszarze Warszawy (Poland)

Rozbicka K., Michalak M.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2015

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Vol. 24, No. 2

193--206

PL

Celem pracy jest charakterystyka czasowego i przestrzennego rozkładu zanieczyszczeń komunikacyjnych (NO2, PM10, O3, C6H6) na trzech stacjach monitoringu jakości powietrza na obszarze Warszawy. Analizowany okres to 2011–2013. Uzyskano wyższe stężenia na stacji Komunikacyjna niż na stacjach referencyjnych: Targówek i Ursynów. Wzrost stężeń zanieczyszczeń komunikacyjnych był obserwowany w godzinach szczytu: porannego o 7–11 oraz popołudniowego o 15–20 spowodowanego wzrostem natężenia ruchu drogowego na badanym obszarze. Określono również związek między wartościami stężenia analizowanych zanieczyszczeń i warunkami meteorologicznymi.

EN

The aim of this work was to characterize the temporary and spatial distribution of traffic related air pollutants (NO2, PM10, O3, C6H6) and assessment of the relationship between meteorological conditions and air pollution concentration from three monitoring stations in Warsaw area. In the period from 2011 to 2013 average annual values of concentration NO2 were exceeded on all considered stations Warsaw (i.e. Komunikacyjna, Warszawa- -Ursynów and Warszawa-Targówek). The values varied from 114 do 141% of permissible values (40 μg·m–3 ). In case of PM10 concentration permissible concentration of annual average value was exceeded on two stations and in case of ozone and benzene excesses not occurred. The greatest concentration values for analyzed pollutants were recorded on Komunikacyjna station situated in the city center in close proximity of communication routes. The least concentration values were recorded for city suburb areas Ursynów and Targówek situated in greater distance from the biggest traffic streets than Komunikacyjna station. Statistical analysis shows the relationship between logical conditions and high concentration of ozone during episode days and between particular meteorological elements and the concentration of analyzed air pollutants.

16

Two-step treatment of harmful industrial wastewater: an analysis of microbial reactor with integrated membrane retention for benzene and toluene removal

Trusek-Holownia A., Noworyta A.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 4

15--22

EN

Standards for highly toxic and carcinogenic pollutants impose strict guidelines, requiring values close to zero, regarding the degradation of such pollutants in industrial streams. In many cases, classic bioremoval processes fail. Therefore, we proposed a stream leaving the microbial membrane bioreactor (MBR) that is directed to an additional membrane separation mode (NF/RO). Under certain conditions, the integrated process not only benefits the environment but may also increase the profitability of the bioreactor operation. An appropriate model was developed and tested in which the bioremoval of benzene and toluene by Pseudomonas fluorescens was used as an example. This paper presents equations for selecting the operation parameters of the integrated system to achieve the expected degree of industrial wastewater purification.

17

Preparation of iron oxide nanocatalysts and application in the liquid phase oxidation of benzene

Lokhat D., Oliver M., Carsky M.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 2

43--46

EN

A series of iron oxide nanocatalysts were prepared using an ultrasonically assisted co-precipitation technique. Molybdenum promoted Fe3O4 and Fe2O3 were prepared from the original materials by wet impregnation using a solution of ammonium molybdate. The catalysts were tested in the liquid phase oxidation of benzene at atmospheric pressure and at 60°C using molecular oxygen. Phenol yields between 7% and 14.5% were obtained. The major products were pyrogallol and catechol.

18

Zastosowanie inwersyjnej chromatografii gazowej do charakterystyki właściwości adsorpcyjnych uporządkowanych węgli mezoporowatych

Jedynak K., Zdenkowski J., Święcicka A., Choma J.

Ochrona Środowiska

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2015

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Vol. 37, nr 2

3--10

PL

Badano właściwości adsorpcyjne uporządkowanych mezoporowatych węgli za pomocą inwersyjnej chromatografii gazowej (IGC). Wykorzystano cztery adsorbenty otrzymane metodą miękkiego odwzorowania w obecności kwasu solnego lub octowego, przy czym dwa z nich zawierały cząstki złota lub srebra. Przedstawiono charakterystykę struktury porowatej tych węgli na podstawie doświadczalnych izoterm adsorpcji azotu wyznaczając standardowe parametry oraz funkcje rozkładu objętości porów metodą opartą na teorii funkcjonału gęstości (DFT). Dodatkowo metodą IGC wyznaczono izotermy adsorpcji n-heksanu, benzenu oraz trichloroetenu. Stwierdzono, że na większości badanych węgli najlepiej adsorbował się n-heksan, kolejno benzen, a najsłabiej trichloroeten. Związki te były najlepiej adsorbowane przez mezoporowate węgle zawierające cząstki złota i srebra. Można sądzić, że było to wynikiem najsilniejszego oddziaływania cząsteczek adsorbatów z powierzchnią tych węgli. Świadczy o tym położenie maksimów funkcji rozkładu potencjału adsorpcyjnego otrzymane w badaniach adsorpcji n-heksanu, benzenu i trichloroetenu.

EN

Adsorption properties of ordered mesoporous carbons were studied using inverse gas chromatography (IGC). Four different adsorbents obtained by soft templating with hydrochloric or acetic acid were used, two of them containing particles of silver or gold. Porous structure characteristics of the studied carbons was presented on the basis of experimental isotherms of nitrogen adsorption. Standard parameters and functions of pore volume distribution were determined by Density Functional Theory method (DFT). Additionally, adsorption isotherms of n-hexane, benzene and trichloroethene were determined by IGC method. The highest adsorption for most of the examined carbons was observed for n-hexane, then benzene, while the lowest adsorption was determined for trichloroethene. The mesoporous carbons with silver and gold particles showed the highest adsorption of the tested compounds. This could be related to the strongest interactions between the adsorbate molecules and the carbon surface, determined on the basis of location of maximums of adsorption potential distribution functions for n-hexane, benzene and trichloroethene.

19

Laboratory studies on benzene sorption processes in clay formations

Wołowiec K., Malina G.

Geology, Geophysics and Environment

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2015

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Vol. 41, no. 1

43--51

EN

The presented studies focused on benzene sorption mechanisms in the semi-permeable geological formations (aquitards). Clay formations were taken under consideration as not well investigated so far. Natural clay samples artificially contaminated with benzene were used in batch and column experiments to determine benzene partitioning and retardation in the studied clay material, and to reflect natural groundwater flow conditions. Column tests were carried out under controlled water flow conditions and using undisturbed clay samples. Benzene concentrations in tested samples (water and soil) were determined by gas chromatography (GC-FID). The linear sorption isotherm was used to fit the experimental data, as well as calculate the distribution coefficient (K d = 0,042) and the retardation factor (R = 1.21) of benzene in the studied clay material. These parameters are important for mathematical modelling of the fate and transport of benzene through the semi-permeable formations (clays) to assess the associated risk and to prevent groundwater resources from contamination.

20

Benzene propagation during turbulent flow in PEHD water supply pipes

Musz A., Widomski M. K., Kowalska B.

Environment Protection Engineering

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2015

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Vol. 41, nr 4

5--16

EN

The results of laboratory and numerical studies of benzene propagation migrating from PEHD pipe to water in turbulent flow conditions have been presented. Laboratory studies were performed on 30 meter long closed-loop installation consisting of PEHD 80 32×3.0 mm polyethylene pipes during the 168 h of experiment. Measurements of benzene concentration in water were conducted by the gas chromatography-mass spectroscopy (GC-MS) method. Numerical calculations of benzene propagation in water were performed with the Fluent, Ansys Inc. Our studies showed a clear increase of benzene concentration in water resulting from its migration to water from the pipe material. The developed numerical model was positively validated.