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1

Do we still need a laboratory to study advanced oxidation processes? A review of the modelling of radical reactions used for water treatment

Wacławek Stanisław

Ecological Chemistry and Engineering. S

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2021

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Vol. 28, nr 1

11--28

EN

Environmental pollution due to humankind’s often irresponsible actions has become a serious concern in the last few decades. Numerous contaminants are anthropogenically produced and are being transformed in ecological systems, which creates pollutants with unknown chemical properties and toxicity. Such chemical pathways are usually examined in the laboratory, where hours are often needed to perform proper kinetic experiments and analytical procedures. Due to increased computing power, it becomes easier to use quantum chemistry computation approaches (QCC) for predicting reaction pathways, kinetics, and regioselectivity. This review paper presents QCC for describing the oxidative degradation of contaminants by advanced oxidation processes (AOP, i.e., techniques utilizing •OH for degradation of pollutants). Regioselectivity was discussed based on the Acid Blue 129 compound. Moreover, the forecasting of the mechanism of hydroxyl radical reaction with organic pollutants and the techniques of prediction of degradation kinetics was discussed. The reactions of •OH in various aqueous systems (explicit and implicit solvation) with water matrix constituents were reviewed. For example, possible singlet oxygen formation routes in the AOP systems were proposed. Furthermore, quantum chemical computation was shown to be an excellent tool for solving the controversies present in the field of environmental chemistry, such as the Fenton reaction debate [main species were determined to be: •OH < pH = 2.2 < oxoiron(IV)]. An ongoing discussion on such processes concerning similar reactions, e.g., associated with sulphate radical-based advanced oxidation processes (SR-AOP), could, in the future, be enriched by similar means. It can be concluded that, with the rapid growth of computational power, QCC can replace most of the experimental investigations related to the pollutant’s remediation in the future; at the same time, experiments could be pushed aside for quality assessment only.

2

System fotokatalityczny oparty na żelu krzemionkowym i magnez(II)-2,3-bis(1-adamantylosulfanylo)ftalocyjaninie i generujący tlen singletowy

Kryjewski M., Nowak M., Gośliński T., Mielcarek J.

Przemysł Chemiczny

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2018

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T. 97, nr 4

601--603

PL

Magnez(II) 2,3-bis(1-adamantylosulfanylo)ftalocyjaninę, związek z grupy makrocykli porfirynoidowych, wykazujący wysoką wydajność generowania tlenu singletowego w roztworach, osadzono na żelu krzemionkowym. Uzyskany kompozyt scharakteryzowano z wykorzystaniem spektroskopii fluorescencyjnej i mikroskopii elektronowej (SEM) oraz oceniono pod względem potencjalnego zastosowania jako katalizatora heterogenicznego w reakcjach fotochemicznych. Otrzymany kompozyt generuje tlen singletowy pod wpływem światła.

EN

Mg(II) 2,3-bis(1-adamantylsulfanyl)phthalocyjanine was deposited on SiO2 gel and characterized by fluorescence spectroscopy, electron microscopy and energy-dispersive X-ray spectroscopy. The composite material was able to generate singlet O2 quenched with 1,3-diphenyl-isobenzofurane.

3

Fenomen tlenu singletowego

Krukiewicz K.

Chemik

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2011

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Vol. 65, nr 11

1190-1192

PL

Tlen singletowy jest obiektem intensywnych badań już od prawie 80 lat. Jego niezwykłe właściwości, takie jak: wysoka reaktywność i silne właściwości utleniające, sprawiają, że uznawany jest za uniwersalny utleniacz. Za jedną z najwydajniejszych metod produkcji tlenu singletowego uważana jest fotogeneracja - z powodu krótkiego czasu życia tlenu singletowego przeprowadzana in situ. Tlen singletowy znajduje wiele zastosowań w różnych dziedzinach, zarówno przy oczyszczaniu ścieków jak i w medycynie.

EN

Singlet oxygen has been the subject of intensive research for almost 80 years. Its unusual properties, like high reactivity and oxidizing properties, make it a versatile chemical reagent. Photogeneration is considered as the most effective method of singlet oxygen formation, though it needs to be conducted in situ due to the short lifetime of that form of oxygen. Singlet oxygen has been already applied in the area of medicine and wastewater treatment.

4

Intermolecular interactions in plant cells reflected by ultraweak luminescence penomenon

Jaśkowska A., Dudziak A., Gospodarek M., Śpiewla E.

Materials Science Poland

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2006

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Vol. 24, No. 4

1115--1125

EN

It is commonly known that photons necessarily participate in atomic and molecular interactions. On the other hand, plant, animal and human cells spontaneously emit electromagnetic radiation. The universality of ultraweak cell luminescence is inherently associated with fundamental processes in living organisms. The majority of researchers think that this very weak radiation (10-105 photons/(cm2-s)) results from such radical reactions as, for instance, lipid peroxidation. Having at our disposal the spectra of ultraweak luminescence (UL) from intact Characeae cells and their particular cellular structures and fractions, we could confirm that the electron carriers of the mitochondrial respiration chain were active in cytoplasm and in the intact cells but not in the cell walls. We obtained a band of chlorophyll emission in UL spectra. The dark chlorophyll should not emit fluorescence, which we observed under illumination. Nevertheless in our experiments, in which plants were kept in darkness for ca. 12 hours prior to measurement, this emission was observed. The only way to account for this phenomenon is that the energy of excitation is transferred to chlorophyll by other molecules. In this ultraweak sensibilized luminescence, the excited carbonyl molecules 1,3(=C=O*) transfer their energy to chlorophyll molecules with a high quantum efficiency. As we found in the spectral analysis of UL, the intensity at the wavelength of 634 nm - corresponding to dimoles of singlet oxygen - markedly decreased when the cells were exposed to the action of ascorbic acid (AsA) and lignocaine, which are singlet oxygen quenchers.

5

Photosensitized oxidation as a tool for degradation of harmful substances in water solutions

Gryglik D., Miller J.S.

Chemia i Inżynieria Ekologiczna

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2005

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Vol. 12, nr 9

977-987

EN

The applicability of photochemical process involving singlet molecular oxygen (102) in the field of environmental protection was considered. 102 was generated via energy transfer from dye sensitizer excited by visible light to ground stale oxygen (302). The photosensitized oxidation was applied for degradation of 2-chlorophenol (2-CP), a common model organic pollutant, and ingredient of many pesticides. The 2-CP decomposition in, an aqueous solution was studied using various sensitizers in two types of reactions: in the homogeneous system with a solubilized sensitizer and in the heterogeneous system with a sensitizer immobilized in silane gel covering the glass reactor walls. In both systems the influence of various experimental conditions (light intensity, the amount of sensitizer, oxygen concentration) on the rate of 2-CP degradation was investigated. Finally, the possibility of using sunlight for decomposition of 2-CP in aqueous solutions both in homo- and heterogeneous system was demonstrated.

PL

Badano sensybilizowane fotoutleniania, pod kątem rozpoznania możliwości jego zastosowania do degradacji szkodliwych zanieczyszczeń w środowisku wodnym. W procesie zastosowano różne sensybilizatory w postaci roztworu oraz immobilizowane w żelu silanowym na szklanym podłożu. Efektywność procesu określano przez szybkość rozkładu 2-chlorofenolu w różnych warunkach natlenienia i naświetlania roztworu reakcyjnego. Sprawdzono również możliwość degradacji 2-chlorofenolu w procesie sensybilizowanego utleniania pod działaniem promieniowania słonecznego.

6

Wykorzystanie właściwości sensybilizacyjnych kompleksów ftalocyjaniny z metalami do generowania stanów wzbudzonych molekuł tlenu

Dyrda G., Słota R., Wacławek W.

Chemistry-Didactics-Ecology-Metrology

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2001

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R. 6, NR 1-2

31--34

PL

Aktywne stany wzbudzone molekuły tlenu mogą być generowane przez molekuły kompleksów ftalocyjaniny, sensybilizowane promieniowaniem z zakresu UV i VIS. Proces ten można wykorzystać do aktywacji różnorodnych układów reakcyjnych, zarówno typowych reakcji red-ox, jak i złożonych procesów biochemicznych. Przedstawione przykłady świadczą o dużym znaczeniu praktycznym zwłaszcza tlenu singletowego. Otrzymane wyniki badań układów ftalocyjanina – tlen wskazują, że wzbudzone molekuły tlenu mogą również powodować rozkład użytego jako sensybilizatora kompleksu Mpc (M = jon metalu, pc = C32H16N8 2- ligand ftalocyjaninowy), niezależnie od jego struktury molekularnej oraz użytego rozpuszczalnika.

EN

Reactive excited states of oxygen molecules may be generated by phthalocyanine complexes photosensitised by radiation from the UV and VIS range. This idea could be used in activating of versatile reaction systems, both typical red-ox reactions as well as complex biochemical processes. The cases shown have proved the practical application potential particularly of the singlet oxygen molecules. Results obtained in our investigations of phthtalocyanine – oxygen systems have revealed the excited oxygen molecules might also produce a decay of the Mpc complex, used as a photosensitiser, regardless of its molecular structure and the solvent applied (M = metal ion, pc = C32H16N8 2- phthalocyanine ligand).