Multicomponent Cu-Mn-Fe silica supported catalysts to stimulate photo-Fenton-like water treatment under sunlightAndraž Šuligoj
, Ivalina Trendafilova
, Ksenija Maver
, Albin Pintar
, Alenka Ristić
, Goran Dražić
, Wael H. M. Abdelraheem
, Zvonko Jagličić
, Iztok Arčon
, Nataša Zabukovec Logar
, Dionysios D. Dionysiou
, Nataša Novak Tušar
, izvirni znanstveni članek
Ključne besede: Magnetic catalyst, Photocatalyst, Water treatment, Sunlight, Contaminants of emerging concern, Photo-Fenton-like systems, Cu, Mn, Fe, XANES, EXAFS
Objavljeno v RUNG: 06.07.2023; Ogledov: 1021; Prenosov: 4
Celotno besedilo (4,32 MB)
Photocatalytic sol-gel/P25 TiO [sub] 2 coatings for water treatment : degradation of 7 selected pharmaceuticals (CO3:IL02)Lev Matoh
, Boštjan Žener
, Marin Kovačić
, Hrvoje Kušić
, Iztok Arčon
, Meta Levstek
, Urška Lavrenčič Štangar
, 2022, izvirni znanstveni članek
Opis: The effect of different water matrices on the photocatalytic degradation of dissolved pharmaceuticals was
explored. The focus was on the degradation efficiencies in wastewater effluent from a bioreactor and water
effluent from a central wastewater treatment plant and comparing the results with degradation in deionized H2O.
The compounds tested included: oxytetracycline, marbofloxacin, ibuprofen, diclofenac, phenytoin, ciprofloxacin,
sulfamethoxazole. For the experiments performed in this study, a compact packed-bed photocatalytic reactor was
used in which the hybrid TiO2 photocatalyst (sol-gel/P25) was deposited on ~3 mm glass beads. As expected, the
reactions proceed more slowly in wastewater than in deionized water, yet it is shown that removal of the
compounds from the water is still possible even when other organic molecules are present. Total organic carbon
measurements have shown that complete mineralization takes place albeit at slower rates than the initial
degradation of parent compounds. The results show that an acidic pH can increase the reaction rates and the
adsorption on the photocatalyst surface. Analyses of the degradation intermediates were performed using tandem
liquid chromatography triple-quadrupole mass spectrometry system. Additionally, X-ray absorption spectroscopy
was applied to get insight into the local structure of the photocatalyst before and after use. Understanding the
effects that different wastewater compositions have on photocatalytic reactions will help to refine the potential
applications of the technology.
Ključne besede: titanium dioxide, sol-gel processes, functionla applications, water treatment
Objavljeno v RUNG: 30.09.2022; Ogledov: 1096; Prenosov: 0
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Study of water adsorption on EDTA dealuminated zeolite YO. L. Pliekhov
, Olena Pliekhova
, Iztok Arčon
, Federica Bondino
, Elena Magnano
, Gregor Mali
, Nataša Zabukovec Logar
, 2020, izvirni znanstveni članek
Opis: Zeolite Y was synthesized and modified with EDTA dealumination procedure. The modified zeolites were
analyzed by X-ray diffraction, X-ray absorption spectroscopy, chemical analysis and water adsorption measurements.
We demonstrated that dealumination with bulk organic acid such as EDTA is able to reduce the
original intense water affinity. Furthermore, it was found that dealumination with EDTA, in contrast with
steaming and HCl dealumination, provides fully controllable, predictable and secure process of Al removal from
the zeolites’ frameworks. The shift of the adsorption isotherm in the low partial pressure range represents an
interesting result for adsorption-based applications.
Ključne besede: Zeolite Y
Objavljeno v RUNG: 05.06.2020; Ogledov: 2831; Prenosov: 0
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Zr/Cu-TiO2 CATALYSTS FOR PHOTOCATALYTIC WATER TREATMENTOlena Pliekhova
, 2019, doktorska disertacija
Opis: This work entitled «Zr/Cu-TiO2 catalysts for photocatalytic water treatment» tackles a problem of tons of dyes discharged everyday mainly from textile industries. This is a huge concern because of dyes persistence, toxicity and potential to the bioaccumulation in living organisms. Here, a small contribution to overall problem is presented.
The research work consists of three main parts: Theoretical background, Experimental and Results and discussion. In the Theoretical background chapter the overall problem is identified and discussed. The main water treatment techniques are presented briefly with their advantages and drawbacks. Photocatalysis assisted with TiO2 is shown as an alternative additional technique with its own pros and cons. Further, a cursory overview of TiO2 modification techniques is made and advantages in using copper and zirconium oxides for TiO2 modification are presented. The reason and possible positive effect of using of two oxides simultaneously for TiO2 modification is indicated. Additionally, a positive impact of solar light for overall rate of dyes degradation assisted with TiO2 is discussed. Within the framework of photosensitization effect, the problem of using dyes for assessment of photocatalytic properties of materials under the visible light is touched on. Photothermal methods as possible beneficial techniques for this purpose are proposed.
In the Experimental chapter, all experimental techniques used in current research work with the technical details specific for the research work are presented. There are methods of materials preparation, photocatalytic tests under different conditions and varying model pollutants, and physico-chemical characterization techniques.
The Results and discussion chapter is divided by three subchapters. Each chapter is dedicated to one hypothesis, which was checked and confirmed or disproved. The first hypothesis is about beneficial loading of copper and zirconium oxides to TiO2. After numerous experiments held, it was concluded that the pair of copper and zirconium oxides is beneficial for simultaneous application on TiO2 surface to promote its performance.
The second subchapter is about zirconium distribution and its impact on the activity of studied materials towards the antraquinone dye Reactive Blue 19. Different techniques such as XRD, TEM, EXAFS and many others were used in order to characterize the materials and to understand the details of the processes taking place. The existence of upper limit of copper oxide loading for its beneficial effect on TiO2 performance was demonstrated. It was observed that zirconium species loading leads to improvement in performance of materials with higher copper loading, which otherwise lowers activity of TiO2 – this is in case when copper only above its optimal level is present. It was concluded that zirconium oxide containing species occupy rutile surface sites in mixed phase TiO2 and this way beneficially influence the material performance towards the dye removal.
The third subchapter is about the visible light TiO2 assisted dye degradation. It is well known that photosensitization mechanism of dye degradation appears under the visible and as a consequence under the solar light irradiation. This leads to the overall enhancement of dyes degradation, which is positive and may be used as a benefit for faster pollutant destruction. However, this fact leads to mishmash in the determination of real photocatalytic activity of materials towards the dye. It was hypothesized that the impact of photosensitization mechanism on the overall material performance against Reactive blue 19 dye (RB19) descends with the dye concentration lowering. Thermal lens spectrometry (TLS) which is sensitive to chemicals at low concentrations was used for hypothesis evaluation.
To summarize the research work achievements, the conclusions of the thesis are given at the end.
Ključne besede: titanium dioxide, photocatalysis, zirconium/copper, surface modification, water treatment, dyes
Objavljeno v RUNG: 03.12.2019; Ogledov: 5667; Prenosov: 134
Celotno besedilo (3,18 MB)
NOVEL METHODS FOR DETECTION AND REMOVAL OF POLLUTANTS FROM WATERSFranja Prosenc
, 2017, doktorska disertacija
Opis: Water security and quality are a global issue of concern, which have recently become alarming due to the growth of the human population, industrialisation and expanded agricultural activities. Biologically active compounds, such as pharmaceuticals and personal care products can have major adverse effects on aquatic organisms, and are therefore one of the biggest threats in water quality. Another major concern is the spread of waterborne pathogens, including multidrug resistant (MDR) bacteria, which can cause serious illnesses in humans. In order to maintain water abundance and quality, it is necessary that adequate wastewater treatment and analytical techniques allowing for sensitive and fast-response detection of water hazards are in place.
Conventional (waste)water treatment technologies often fail to adequately remove all of the water hazards detailed above. Moreover, conventional analytical techniques currently used in water quality control are, although highly selective and sensitive, time-extensive, with throughput of merely 2 to 3 samples per hour, excluding the time for sample preparation. With respect to these drawbacks, research was proposed to explore new approaches for degradation of recalcitrant compounds, inactivation of microorganisms, and fast screening methods, which are listed in the second chapter of this dissertation as research objectives.
In the third chapter, an extensive theoretical background on the hazards found in aquatic environment, namely pharmaceuticals and waterborne pathogens, is given. Pharmaceuticals enter the environment through several routes (disposal of unused medication via the toilet, pharmaceuticals passing through the human body unchanged/slightly transformed, animal excretions of pharmaceutically active compounds, insufficient wastewater treatment, etc.); therefore, traces of pharmaceuticals have repeatedly been reported in surface waters, groundwater, wastewater effluents, and even drinking water. Iodinated contrast agents (ICAs), as the compounds of interest in this project are further described. ICAs are eliminated from the human body practically unchanged; therefore a large proportion of them end up in municipal and hospital wastewater, where they can be present in concentrations of up to 2.4 g/L. Their ecotoxicity, degradation attempts, as well as detection monitoring in the environment are reviewed within the chapter. Additionally, waterborne pathogens, which account for 2.2 million deaths per year, are reviewed in this chapter, with emphasis on multidrug-resistant (MDR) bacteria. Although MDR infections are mostly prevalent in hospital environments, the presence of MDR bacteria in the environment is not a rarity. A high percentage of bacterial isolates in waters have been shown to be of an MDR phenotype. The theoretical background in analytical methods in water quality monitoring is also given in this chapter. Vanguard and rearguard techniques are explained, the first offering simple, cheap, and rapid sample screening, but sacrificing sensitivity and selectivity, whereas the second providing the highest quality information, excellent sensitivity and selectivity, but in expense of complicated and timely sample handling and high-cost instruments. By combining the two techniques the benefits of both can be exploited in a single system. The basic principles of thermal lens spectrometry (TLS) and its miniaturised version - the thermal lens microscopy (TLM) as fast screening methods providing high sensitivity are further explained, and their practical applications are reviewed. Furthermore, composite materials have recently been finding applications in water treatment technologies, as filter materials, adsorptives for pollutants, catalysts for degradation reactions, and disinfectants. The applications of three main types of composites: synthetic composites, biocomposites, and nanocomposites, are also reviewed within this chapter.
The core of this dissertation is presented in the fourth and the fifth chapter, which examine two separate approaches for water treatment, as well as analytical methods for fast screening purposes. The fourth chapter is investigating options for degradation of iodinated X-ray agents (ICAs), namely diatrizoate, through biodegradation with extracellular enzymes of white rot fungus Dichomitus squalens, and chemical oxidation with manganese(III) acetate. Enzymatic degradation with laccase (Lac) and manganese peroxidase (MnP) at low enzymatic activities was unsuccessful, whereas at approximately 3-times higher activities the enzymes were capable of 60 % degradation in 12 days. Chemical oxidation of diatrizoate with manganese(III) acetate resulted in 85 % degradation in 12 days. Moreover, the suitability of microfluidic flow injection analysis coupled with thermal lens microscopy (μFIA-TLM) as a fast screening method for diatrizoate degradation was examined. The degradation was monitored through the release of iodide from the diatrizoate molecule. μFIA-TLM proved to be a preferable method over UV-Vis spectrophotometry, due to its higher sensitivity, sample throughput, and simple sample handling. Limit of detection (LOD) for μFIA-TLM method was estimated to be 0.14 µM in a 100 µm channel, which is 9 times lower than LOD obtained in UV-Vis measurements. In addition to μFIA-TLM and UV-VIS, high-pressure liquid chromatography (HPLC) was used to monitor the remaining parent compound in the reaction mix.
In the fifth chapter, the second water treatment approach is described. This includes synthesis of biocomposite materials from cellulose (CEL) and keratin (KER), with metal (Ag0, AgCl, Au0) nanoparticles (NPs). Materials were characterised for presence, species, and size of NPs with X-ray diffraction (XRD) and with scanning electron microscopy (SEM). Nanoparticles were confirmed to be of expected species, with sizes as follows: 6.3 ± 0.5 nm for Au NPs, 12 ± 2 nm for Ag NPs, and 22 ± 1 nm for AgCl NPs. In order to evaluate antibacterial properties of the materials, contact tests with gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive bacteria (Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), and Vancomycin-resistant Enterococcus faecalis (VRE)) were conducted. Direct-contact assay over 24 hours showed a dose and species-dependent antibacterial activity of [CEL:KER + Ag NPs] materials. The highest potency against the selected bacteria (up to 6-log of reduction) was observed for the material with 500 mg of Ag NPs. AgCl NPs appeared to be less potent than Ag NPs, whereas Au NPs exhibited antibacterial activity only against MRSA and VRE. In addition, antiviral properties of materials were investigated on selected bacteriophages (MS2, phiX174, and fr). However, biocomposite materials with 500 mg of Ag NPs and AgCl NPs, as well as, 240 mg of Au NPs did not exhibit any activity against selected bacteriophages. Biocompatibility with human fibroblasts was evaluated through a direct contact assay for 3 and 7 days of exposure. High concentrations of metal NPs turned out to be cytotoxic for human fibroblasts, whereas the amount of 69 mg of Ag NPs in [CEL:KER] was low enough not to affect the viability of the fibroblasts after 3 days of exposure. Composites with Ag NPs and AgCl NPs were also tested for leachability of NPs out of the materials. Both types of NPs were leaching out in two different forms, as silver ions, and as colloidal silver. Leaching of ionic silver from both materials stabilised after 3 days, whereas colloidal silver was still leaching out on the 7th day. The overall percentage of the total silver (ionic + colloidal) leached was only 0.04 % of silver incorporated in the material.
In summary, this dissertation investigates alternative approaches for water treatment technologies, which could potentially serve as unit improvements of existing technologies, or as on-point pre-treatment technologies to facilitate further conventional water treatment techniques. It also demonstrates the suitability of μFIA-TLM for fast screening measurements in aquatic samples, offering high sample throughput, simple handling of the samples and superior sensitivity over the UV-Vis spectrophotometry.
Ključne besede: Antibacterial biocomposites, nanomaterials, water treatment technologies, multidrug-resistant bacteria, iodinated contrast agents, thermal lens microscopy, flow-injection analysis, microfluidics
Objavljeno v RUNG: 26.04.2017; Ogledov: 6075; Prenosov: 208
Celotno besedilo (27,08 MB)
Solar-driven photocatalytic treatment of diclofenac using immobilized TiO2-based zeolite compositesMarin Kovacic
, Subhan Salaeh
, Hrvoje Kušić
, Andraz Suligoj
, Marko Kete
, Mattia Fanetti
, Urška Lavrenčič Štangar
, Dionysios D. Dionysiou
, Ana Lončarić Božić
, 2016, izvirni znanstveni članek
Opis: The study is aimed at evaluating the potential of
immobilized TiO2-based zeolite composite for solar-driven
photocatalytic water treatment. In that purpose, TiO2-iron-exchanged
zeolite (FeZ) composite was prepared using commercial
Aeroxide TiO2 P25 and iron-exchanged zeolite of ZSM5
type, FeZ. The activity of TiO2-FeZ, immobilized on glass
support, was evaluated under solar irradiation for removal of
diclofenac (DCF) in water. TiO2-FeZ immobilized in a form
of thin film was characterized for its morphology, structure,
and composition using scanning electron microscopy/energydispersive
x-ray spectroscopy (SEM/EDX). Diffuse reflectance
spectroscopy (DRS) was used to determine potential
changes in band gaps of prepared TiO2-FeZ in comparison
to pure TiO2. The influence of pH, concentration of hydrogen
peroxide, FeZ wt% within the composite, and photocatalyst
dosage on DCF removal and conversion efficiency by solar/
TiO2-FeZ/H2O2 process was investigated. TiO2-FeZ demonstrated
higher photocatalytic activity than pure TiO2 under
solar irradiation in acidic conditions and presence of H2O2.
Ključne besede: Photocatalysis, Thin films, TiO2-FeZ, Solar irradiation, Diclofenac, Water Treatment
Objavljeno v RUNG: 22.07.2016; Ogledov: 5944; Prenosov: 0
Gradivo ima več datotek! Več...