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1.
Environ Res ; 213: 113737, 2022 10.
Article in English | MEDLINE | ID: covidwho-1907006

ABSTRACT

To keep COVID-19 at bay, most countries have mandated the use of face masks in public places and imposed heavy penalties for those who fail to do so. This has inadvertently created a huge demand for disposable face masks and worsened the problem of littering, where a large number of used masks are constantly discarded into the environment. As such, an efficient and innovative waste management strategy for the discarded face mask is urgently needed. This study presents the transformation of discarded face mask into catalyst termed 'mask waste ash catalyst (MWAC)' to synthesise bisindolylmethanes (BIMs), alkaloids that possess antibacterial, antioxidant and antiviral properties. Using commercially available aldehydes and indole, an excellent yield of reaction (62-94%) was achieved using the MWAC in the presence of water as the sole solvent. On the other hand, the FT-IR spectrum of MWAC showed the absorption bands at 2337 cm-1, 1415 cm-1 and 871 cm-1, which correspond to the signals of calcium oxide. It is then proposed that the calcium oxides mainly present in MWAC can protonate oxygen atoms in the carbonyl molecule of the aldehyde group, thus facilitating the nucleophile attack by indole which consequently improved the product yield. Moreover, the MWAC is also observed to facilitate the photodegradation of methylene blue with an efficiency of up to 94.55%. Our results showed the potential applications of the MWAC derived from discarded face masks as a sustainable catalyst for bioactive compound synthesis and photodegradation of dye compounds.


Subject(s)
COVID-19 , COVID-19/prevention & control , Humans , Indoles , Masks , Photolysis , Spectroscopy, Fourier Transform Infrared
2.
Chemosphere ; 302: 134837, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-1819450

ABSTRACT

The number of antibiotic compounds in wastewaters has been growing globally due to the covid-19 problem. Using antibiotics to treat the patients would produce larger amounts of these compounds into the environment with negative impacts. Hence, finding out the method for the elimination of toxic organic pollutants as well as antibiotics in water is urgent (In this study, the treatment of antibiotic pollutants including cefalexin (CF) and tetracycline (TC) was investigated by applying the advanced oxidation process based on Ni-doped TiO2 (Ni-TiO2). The characterizations technologies such as XRD, XPS, UV-vis, PL, and PC indicated that Ni doping would improve the photocatalytic performance of TiO2. In the photodegradation experiments, the Ni-TiO2 possessed high photocatalytic degradation efficiencies with 93.6% for CF and 82.5% for TC. Besides, the removal rates of antibiotics after five cycles are higher than 75%, implying excellent stability of Ni-TiO2 photocatalyst. The result from the treatment of wastewater samples revealed that the Ni-TiO2 photocatalytic had good performance for removal of CF and TC at a high level of 88.6 and 80.2%, respectively.


Subject(s)
COVID-19 , Environmental Pollutants , Water Pollutants, Chemical , Anti-Bacterial Agents , Catalysis , Humans , Photolysis , Tetracycline , Titanium , Waste Water
3.
J Photochem Photobiol B ; 229: 112415, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1712830

ABSTRACT

Noscapine (NSC) is a benzyl-isoquinoline alkaloid discovered in 1930 as an antitussive agent. Recently, NSC has also been reported to exhibit antitumor activity and, according to computational studies, it is able to attack the protease enzyme of Coronavirus (COVID-19) and thus could be used as antiviral for COVID-19 pandemic. Therefore, an increasing use of this drug could be envisaged in the coming years. NSC is readily metabolized with a half-life of 4.5 h giving rise to cotarnine, hydrocotarnine, and meconine, arising from the oxidative breaking of the CC bond between isoquinoline and phthalide moieties. Because of its potentially increasing use, high concentrations of NSC but also its metabolites will be delivered in the environment and potentially affect natural ecosystems. Thus, the aim of this work is to investigate the degradation of NSC in the presence of naturally occurring photocatalysts. As a matter of fact, the present contribution has demonstrated that NSC can be efficiently degraded in the presence of a derivative of the natural organic dye Riboflavin (RFTA) upon exposure to visible light. Indeed, a detailed study of the mechanism involved in the photodegradation revealed the similarities between the biomimetic and the photocatalyzed processes. In fact, the main photoproducts of NSC were identified as cotarnine and opianic acid based on a careful UPLC-MS2 analysis compared to the independently synthesized standards. The former is coincident with one of the main metabolites obtained in humans, whereas the latter is related to meconine, a second major metabolite of NSC. Photophysical experiments demonstrated that the observed oxidative cleavage is mediated mainly by singlet oxygen in a medium in which the lifetime of 1O2 is long enough, or by electron transfer to the triplet excited state of RFTA if the photodegradation occurs in aqueous media, where the 1O2 lifetime is very short.


Subject(s)
COVID-19 , Environmental Restoration and Remediation , Noscapine , Biomimetics , Chromatography, Liquid , Coloring Agents , Ecosystem , Humans , Light , Pandemics , Photolysis , Riboflavin/chemistry , Tandem Mass Spectrometry , Water/chemistry
4.
Int J Mol Sci ; 23(3)2022 Feb 02.
Article in English | MEDLINE | ID: covidwho-1686814

ABSTRACT

A chabazite-type zeolite was prepared by the hydrothermal method. Before ion exchange, the chabazite was activated with ammonium chloride (NH4Cl). The ion exchange process was carried out at a controlled temperature and constant stirring to obtain ion-exchanged chabazites of Ti4+ chabazite (TiCHA), Zn2+ chabazite (ZnCHA), Cu2+ chabazite (CuCHA), Ag+ chabazite (AgCHA) and Au3+ chabazite (AuCHA). Modified chabazite samples were characterized by X-ray diffraction (XRD), scanning electron microscope equipped with energy-dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), N2 adsorption methods and UV-visible diffuse reflectance spectroscopy (DRS). XRD results revealed that the chabazite structure did not undergo any modification during the exchange treatments. The photocatalytic activity of chabazite samples was evaluated by the degradation of methylene blue (MB) in the presence of H2O2 under ultraviolet (UV) light illumination. The photodegradation results showed a higher degradation efficiency of modified chabazites, compared to the synthesized chabazite. CuCHA showed an efficiency of 98.92% in MB degradation, with a constant of k = 0.0266 min-1 following a first-order kinetic mechanism. Then, it was demonstrated that the modified chabazites could be used for the photodegradation of dyes.


Subject(s)
Methylene Blue/chemistry , Water Pollutants, Chemical/chemistry , Zeolites/chemistry , Photolysis , Zeolites/chemical synthesis
5.
Environ Sci Technol ; 54(18): 11271-11281, 2020 09 15.
Article in English | MEDLINE | ID: covidwho-1373338

ABSTRACT

Ebselen (EBS), 2-phenyl-1,2-benzisoselenazol-3(2H)-one, is an organoselenium pharmaceutical with antioxidant and anti-inflammatory properties. Furthermore, EBS is an excellent scavenger of reactive oxygen species. This property complicates conventional protocols for sensitizing and quenching reactive species because of potential generation of active intermediates that quickly react with EBS. In this study, the photochemical reactivity of EBS was investigated in the presence of (1) 1O2 and •OH sensitizers [rose Bengal (RB), perinaphthanone, and H2O2] and (2) reactive species scavenging and quenching agents (sorbic acid, isopropanol, sodium azide, and tert-butanol) that are commonly employed to study photodegradation mechanisms and kinetics. The carbon analogue of EBS, namely, 2-phenyl-3H-isoindol-1-one, was included as a reference compound to confirm the impact of the selenium atom on EBS photochemical reactivity. EBS does not undergo acid dissociation, but pH-dependent kinetics were observed in RB-sensitized solutions, suggesting EBS reaction with active intermediates (3RB2-*, O2•-, and H2O2) that are not kinetically relevant for other compounds. In addition, the observed rate constant of EBS increased in the presence of sorbic acid, isopropanol, and sodium azide. These findings suggest that conventional reactive species sensitizers, scavengers, and quenchers need to be carefully applied to highly reactive organoselenium compounds to account for reactions that are typically slow for other organic contaminants.


Subject(s)
Hydrogen Peroxide , Organoselenium Compounds , Azoles , Isoindoles , Photolysis
6.
Biomed Chromatogr ; 35(12): e5212, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1349236

ABSTRACT

Remdesivir (RDV) is the first antiviral drug, approved by the Food and Drug Administration, to treat severe acute respiratory syndrome coronavirus 2. RDV is a relatively new chemical entity, 'ester prodrug', with no reported stability profile. Due to the urgency of its use and thus fast production, it is important to develop a stability-indicating method for its assay. Chromatographic separation was carried out on a C18 column (250 × 4.6 mm, 5 µm) with dual detection: diode array at 240 nm and fluorescence at λex/em 245/390 nm. Isocratic elution of acetonitrile and distilled water (acidified with phosphoric acid, pH 4) in the ratio of 55:45 (v/v), respectively, was used. The linearity range using HPLC-diode array detection was 0.1-15 µg/mL, whereas that using fluorimetric detection was 0.05-15 µg/mL. As per the International Conference on Harmonization guidelines, RDV has been degraded by accelerated alkaline, acidic, neutral hydrolysis, oxidative, heat, and photolytic stress conditions. Possible degradation hypothesis of the parent molecule has been suggested and illustrated. The proposed methods have achieved selective determination of the intact drug with no peaks overlapping in all assumptions. Extensive degradation confirms threatened drug stability at thermal and basic hydrolytic stressing. The developed methods were fully validated and proved suitable for quality control routine analysis of RDV in raw material and pharmaceutical dosage forms.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/chemistry , COVID-19/drug therapy , Prodrugs/chemistry , Acetonitriles/chemistry , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/pharmacology , Alanine/chemistry , Alanine/pharmacology , Antiviral Agents/pharmacology , Chromatography, High Pressure Liquid/methods , Chromatography, Reverse-Phase/methods , Drug Stability , Hot Temperature , Humans , Hydrolysis , Limit of Detection , Oxidation-Reduction , Photolysis
7.
Int J Mol Sci ; 22(8)2021 Apr 14.
Article in English | MEDLINE | ID: covidwho-1299443

ABSTRACT

Photodegradation of the aqueous solutions of acetylsalicylic acid, in the absence (ASA) and the presence of excipients (ASE), is demonstrated by the photoluminescence (PL). A shift of the PL bands from 342 and 338 nm to 358 and 361-397 nm for ASA and ASE in solid state and as aqueous solutions was reported. By exposure of the solution of ASA 0.3 M to UV light, a decrease in the PL band intensity was highlighted. This behavior was revealed for ASA in the presence of phosphate buffer (PB) having the pH equal to 6.4, 7, and 8 or by the interaction with NaOH 0.3 M. A different behavior was reported in the case of ASE. In the presence of PB, an increase in the intensity of the PL band of ASE simultaneously with a change of the ratio between the intensities of the bands at 361-364 and 394-397 nm was highlighted. The differences between PL spectra of ASA and ASE have their origin in the presence of salicylic acid (SAL). The interaction of ASE with NaOH induces a shift of the PL band at 405-407 nm. Arguments for the reaction of ASA with NaOH are shown by Raman scattering and FTIR spectroscopy.


Subject(s)
Aspirin/chemistry , Photolysis/radiation effects , Solutions/radiation effects , Water/chemistry , Aspirin/radiation effects , Cadmium Compounds/chemistry , Luminescence , Quantum Dots/chemistry , Spectrum Analysis, Raman , Ultraviolet Rays/adverse effects
8.
Water Res ; 198: 117165, 2021 Jun 15.
Article in English | MEDLINE | ID: covidwho-1199118

ABSTRACT

UV254 irradiation disinfection is a commonly used method to inactivate pathogenic viruses in water and wastewater treatment. Model prediction method can serve as a pre-screening tool to quickly estimate the effectiveness of UV254 irradiation on emerging or unculturable viruses. In this study, an improved prediction model was applied to estimate UV254 photolysis kinetics of viral genomes (kpred, genome) based on the genome sequences and their photoreactivity and to correlate with the experimental virus infectivity loss kinetics (kexp, infectivity). The UV254 inactivation data of 102 viruses (including 2 dsRNA, 65 ssRNA, 33 dsDNA and 2 ssDNA viruses) were collected from the published experimental data with kexp, infectivity ranging from 0.016 to 3.49 cm2 mJ-1. The model had fairly good performance in predicting the virus susceptibility to UV254 irradiation except dsRNA viruses (Pearson's correlation coefficient = 0.64) and 70% of kpred, genome fell in the range of 1/2 to 2 times of kexp, infectivity. The positive deviation of the model often occurred for photoresistant viruses with low kexp, infectivity less than 0.20 cm2 mJ-1 (e.g., Adenovirus, Papovaviridae and Retroviridae). We also applied this model to predict the UV254 inactivation rate of SARS-CoV-2 (kpred, genome = 3.168 cm2 mJ-1) and a UV dose of 3 mJ cm-2 seemed to be able to achieve a 2-log removal by conservative calculation using 1/2kpred, genome value. This prediction method can be used as a prescreening tool to assess the effectiveness of UV254 irradiation for emerging/unculturable viruses in water or wastewater treatment.


Subject(s)
COVID-19 , Virus Inactivation , Disinfection , Genome, Viral , Humans , Kinetics , Photolysis , SARS-CoV-2 , Ultraviolet Rays
9.
PLoS One ; 16(3): e0248487, 2021.
Article in English | MEDLINE | ID: covidwho-1140530

ABSTRACT

A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2-6% v/v) but was significantly (P<0.05) higher when H2O2 was introduced into the unit at 40 ml/min compared to 20 ml/min. A suitable treatment for N95 masks was identified as 3% v/v hydrogen peroxide delivered into the gAOP reactor at 40 ml/min with continuous introduction of ozone gas and a UV-C dose of 113 mJ/cm2 (30 s processing time). The treatment supported >6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (<1 ppm) in gAOP treated masks. The optimized gAOP treatment could also support >6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality.


Subject(s)
Decontamination/methods , Masks/virology , Gases/chemistry , Humans , Hydrogen Peroxide/chemistry , Hydroxyl Radical/chemistry , N95 Respirators/virology , Oxidation-Reduction , Ozone/chemistry , Photolysis
10.
Photochem Photobiol Sci ; 20(1): 183-188, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-1103608

ABSTRACT

A hypothesis is proposed to explain the increased detrimental effect of COVID-19 for Black, Asian and Minority Ethnic (BAME) men and women compared to Caucasian individuals. This is based on the differing photochemistry of phaeomelanin in fair skin and eumelanin in dark/black skin. It is suggested that a range of reactive oxygen species, including, singlet oxygen and the superoxide radical anion, derived via direct photolysis of phaeomelanin, may escape the melanocyte and cause subsequent damage to the SARS-CoV-2 virus. It is further suggested that (large) carbon and sulphur peroxy radicals, from oxygen addition to radicals formed by carbon-sulphur bond cleavage, may assist via damage to the cell membranes. It is also speculated that light absorption by phaeomelanin and the subsequent C-S bond cleavage, leads to release of pre-absorbed reactive oxygen species, such as singlet oxygen and free radicals, which may also contribute to an enhanced protective effect for fair-skinned people.


Subject(s)
COVID-19/pathology , Photochemical Processes , COVID-19/ethnology , COVID-19/virology , Carbon/chemistry , Female , Free Radicals/chemistry , Humans , Light , Male , Melanins/chemistry , Photolysis , SARS-CoV-2/isolation & purification , Singlet Oxygen/chemistry , Singlet Oxygen/metabolism , Skin/metabolism , Sulfur/chemistry , Superoxides/chemistry , Superoxides/metabolism
11.
Anal Chem ; 93(5): 2767-2775, 2021 02 09.
Article in English | MEDLINE | ID: covidwho-1039622

ABSTRACT

Clinical tissue specimens are often unscreened, and preparation of tissue sections for analysis by mass spectrometry imaging (MSI) can cause aerosolization of particles potentially carrying an infectious load. We here present a decontamination approach based on ultraviolet-C (UV-C) light to inactivate clinically relevant pathogens such as herpesviridae, papovaviridae human immunodeficiency virus, or SARS-CoV-2, which may be present in human tissue samples while preserving the biodistributions of analytes within the tissue. High doses of UV-C required for high-level disinfection were found to cause oxidation and photodegradation of endogenous species. Lower UV-C doses maintaining inactivation of clinically relevant pathogens to a level of increased operator safety were found to be less destructive to the tissue metabolome and xenobiotics. These doses caused less alterations of the tissue metabolome and allowed elucidation of the biodistribution of the endogenous metabolites. Additionally, we were able to determine the spatially integrated abundances of the ATR inhibitor ceralasertib from decontaminated human biopsies using desorption electrospray ionization-MSI (DESI-MSI).


Subject(s)
Decontamination/methods , Ultraviolet Rays , Animals , Azetidines/analysis , Azetidines/therapeutic use , COVID-19/pathology , COVID-19/virology , Head and Neck Neoplasms/chemistry , Head and Neck Neoplasms/drug therapy , Head and Neck Neoplasms/pathology , Humans , Male , Metabolome , Naphthalenes/analysis , Naphthalenes/therapeutic use , Photolysis/radiation effects , Rats , Rats, Wistar , SARS-CoV-2/isolation & purification , SARS-CoV-2/radiation effects , Spectrometry, Mass, Electrospray Ionization/methods , Terfenadine/chemistry , Virus Inactivation/radiation effects
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