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1.
Ozonation of amoxicillin and ciprofloxacin in model hospital wastewater to increase biotreatability
Severina Aleksić, Andreja Žgajnar Gotvajn, Katarina Premzl, Mitja Kolar, Sonja Šostar-Turk, 2021, izvirni znanstveni članek

Opis: Amoxicillin (AMX) and Ciprofloxacin (CIP) are antibiotics commonly used in human medicine with high environmental toxicity and poor biodegradability. They have been found in various hospital effluents and groundwater, and their environmental impact is still not fully understood. In this work, we investigated the possibility of treating model wastewaters containing the antibiotics AMX and CIP using ozonation, with the addition of H$_2$O$_2$ under various conditions, including different pH values, H$_2$O$_2$, and ozone dosages. The quantification of and treatment efficacy for antibiotic removal were determined via solid phase extraction followed by chromatographic separation by liquid chromatography coupled with tandem triple quadrupole mass spectrometry (LC/MS/MS). This analytical system is quite efficient for the detection of all major antibiotic classes, even if they are present at very low concentrations. The efficiency of ozonation was determined by measuring the TOC (Total Organic Carbon) changes after ozonation of the model wastewater and by measuring the concentration of the two antibiotics. In a sequential activated sludge process of ozone-treated model wastewater, almost complete TOC removal and an overwhelming decrease in antibiotic concentrations (up to 99%) were observed. Ozonation resulted in complete removal of AMX and CIP in less than 30 and 120 min, respectively. The results of this work indicate that ozonation could be a suitable pretreatment method to reduce the toxicity of contaminants (AMX and CIP) and improve the biodegradability of hospital wastewater.
Ključne besede: antibiotics, amoxicillin, AMX, ciprofloxacin, CIP, hospital wastewater, hydrogen peroxide, ozone, sludge, water treatment
Objavljeno v DKUM: 06.08.2024; Ogledov: 75; Prenosov: 14
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Preharvest treatments with low-risk plant protection products can help apple growers fulfill the demands of supermarket chains regarding pesticide residues and marketing apples under 0-residue brands
Andrej Paušič, Mihaela Roškarič, Mario Lešnik, 2023, izvirni znanstveni članek

Opis: As a result of worried consumer pressure, European supermarket chains (ESC) have developed very strict rules about the number and concentration of pesticide active substance residues (AS) accepted in fruits. So-called fruit quality toxicological burden indicators were developed. If fruit suppliers do not comply with ESC requirements, their fruit is often rejected. It is becoming increasingly difficult for apple producers to meet all the requirements of the ESC, so they need new residue reduction tools. One of the options to lower the concentrations of residue on apples is a preharvest application of low-risk preparations (LRP) based on potassium bicarbonate (KHCO3) = PBC, coconut di-ethanol amide ((CH3(CH2)nC(=O)N(CH2CH2OH)2) = DEA, hydrogen peroxide (H2O2) = HP, and a mixture of microbes (EM) that have the ability to dissolve or disintegrate the AS residue. Trials were carried out to test the concept mentioned above. The application of LRP during the last four weeks of preharvest significantly reduced the residue concentration of pesticide AS in apples. Reduction rates among 25 active substances ranged from 0 to 100%, depending on the combination of LRP and AS. HP had the highest capacity to accelerate AS degradation, PB was the second most efficient, and DEA and EM displayed a low residue disintegration ability. The application of the tested LRP can enable apple growers to produce fruits with significantly lower residue concentrations and allows them to comply more successfully with strict ESC rules based on the calculations of toxicological burden indicators.
Ključne besede: hydrogen peroxide, potassium bicarbonate, effective microbes, detergent, pesticide residues, fruit marketing rules
Objavljeno v DKUM: 19.04.2024; Ogledov: 253; Prenosov: 4
.pdf Celotno besedilo (330,68 KB)
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Converting waste into products and energy using complete circular economy and the hydrogen effect technique to reduce dependence on natural gas
Anita Kovač Kralj, 2023, izvirni znanstveni članek

Opis: Conversion of waste into products and energy has the potential to reduce CO2 emis-sion through implementation of a complete circular economy and utilisation of the hy-drogen effect technique. This study considers the novelties of the hydrogen effect tech-nique, which incorporates an upgraded input unit mathematical model. It includes real-simulated results obtained using an Aspen Plus & REG; simulator, and enlarged production. This technique is developed for optimal municipal solid waste (MSW) combustion, gas-ification, and reforming, presented as an upgraded input unit for syngas production, which can reduce CO2 emissions by 3 & BULL;106 kmol a-1. This approach is exemplified by utilizing existing methanol and dimethyl ether production processes from natural gas, as they can be achieved and exceeded using MSW with varying hydrogen amounts. The optimal upgraded methanol and dimethyl ether production processes can increase pro-duction by 47 % and 16 %, including only the upgraded input unit, as well as decrease the temperature in the product reactors by 30 & DEG;C.
Ključne besede: waste gasification, flue gas, syngas, hydrogen, circular economy, combustion
Objavljeno v DKUM: 13.02.2024; Ogledov: 320; Prenosov: 28
.pdf Celotno besedilo (524,98 KB)
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A review of the use of Rankine cycle systems for hydrogen production
Urška Novosel, Jurij Avsec, 2020, izvirni znanstveni članek

Opis: The vast majority of steam power plants in the world are based on the Rankine cycle. It is a wellknown, trustworthy process that uses water or water vapour as a working medium, which supplies heat from various primary energy sources: fossil fuels, renewable energy sources (solar energy, energy from wood biomass, etc.) or a combination of both. With the Rankine cycle, energy sources other than electricity can be produced, which can be used as the primary energy source for various applications. The present article focuses on the production of hydrogen in addition to electricity; therefore, two energy sources are obtained from the same system with a few modifications of the existing power plant for further exploitation. There are several processes for hydrogen production using the Rankine cycle; in the present article, two processes are focused on: using part of the electricity produced and obtaining hydrogen by electrolysis of water or using part of high quality steam (basically heat energy) in combination with electricity and obtaining hydrogen by a thermochemical copper-chlorine process. Each of these processes has its advantages and disadvantages, which are presented in the present article with an example model of a power plant.
Ključne besede: Rankine cycle, hydrogen production, electrolysis, thermochemical process
Objavljeno v DKUM: 01.12.2023; Ogledov: 483; Prenosov: 5
.pdf Celotno besedilo (894,90 KB)
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Impacts of zero-emission powertrains based on hydrogen technologies in public transport
Niko Natek, Boštjan Krajnc, 2020, izvirni znanstveni članek

Opis: This article reviews the development potentials and environmental impact of introducing category M3 vehicles (for passenger transport/buses) with fuel cell electric powertrains to an urban and inter-urban public transport service (PTS) to be operated in the Savinjsko-Šaleška region. The main focus is the demonstration of the PTS modelling and preliminary environmental impact assessment of the operation compared to conventional (modern) diesel-powered internal combustion engines.
Ključne besede: Hydrogen, Fuel Cell, Transport, Energy efficiency, Green-house gas emissions, Energy transition, Environment, Public transport service, Internal combustion Engine, CO2
Objavljeno v DKUM: 15.11.2023; Ogledov: 415; Prenosov: 6
.pdf Celotno besedilo (1,66 MB)
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Energy analysis of hydrogen use in road transport of the Republic of Croatia
Franco Krog, Jurij Avsec, 2022, strokovni članek

Opis: In this paper, we will calculate the needs for hydrogen if all traffic in Croatia was driven by hydrogen. In the article, we will determine the required amount in several ways. First, we will briefly describe fuel cell cars and the extent to which the amount of exhaust gases would be reduced. We will then explain the ways of obtaining hydrogen, its transport and what the purchase costs would be. Finally, we will compare the results and draw some conclusions.
Ključne besede: hydrogen, hydrogen technologies, hydrogen acquisition, transport
Objavljeno v DKUM: 30.10.2023; Ogledov: 466; Prenosov: 9
.pdf Celotno besedilo (832,04 KB)
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