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1.
Int J Biol Macromol ; 263(Pt 2): 130273, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38368990

RESUMO

Blueberries are highly perishable after harvest, so a simple preservation method is needed to extend the shelf life of blueberries. In this study, sodium chlorite-loaded sepiolite was added to polylactide solution with tartaric acid to create a ClO2 gas slow-release fresh-keeping card. The fresh-keeping card absorbs moisture in the air, which causes tartaric acid to enter the sepiolite and react with sodium chlorite to release ClO2 gas slowly. The study investigated the impact of fresh-keeping cards on the quality attributes of blueberries, including appearance, decay rate, ethylene release rate, respiration rate, hardness, ascorbic acid content, and anthocyanin concentration. Low-field nuclear magnetic technology was used to analyze the water state and distribution of blueberries during storage. The results showed that the ClO2 gas released by the fresh-keeping card can destroy ethylene in the air and kill microorganisms in blueberries, thereby delaying fruit decay.


Assuntos
Cloretos , Compostos Clorados , Cloro , Conservação de Alimentos , Silicatos de Magnésio , Poliésteres , Tartaratos , Conservação de Alimentos/métodos , Óxidos , Etilenos
2.
Environ Sci Pollut Res Int ; 31(2): 2314-2326, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38057675

RESUMO

Water treatment for most public pools involves disinfection with active chlorine leading to the formation of disinfection by-products (DBPs). Among them, nitrogen-containing compounds (N-DBPs) having increased toxicity and adverse effects on human health are of the greatest concern. Being the major component of various body washers for swimmers, cocamidopropyl betaine (CAPB) represents a potential and still underestimated anthropogenic precursor of N-DBPs in pool water. The purpose of this study was to investigate CAPB transformation pathways and mechanisms under the aqueous chlorination conditions. High-performance liquid and two-dimensional gas chromatography hyphenated with high-resolution mass spectrometry were used for the search and tentative identification of the primary and final CAPB transformation products. A wide range of DBPs containing up to five chlorine atoms including these in combination with hydroxyl and additional carbonyl groups has been revealed in model chlorination experiments for the first time. The proposed mechanism of their formation involves nucleophilic substitution of the secondary amide hydrogen atom at the first stage with subsequent free radical and electrophilic addition reactions resulting in non-selective introduction of halogen atoms and hydroxyl groups in the alkyl chain. The deep transformation products include short-chain chlorinated hydrocarbons and their oxidation products as well as dimethylcarbamoyl chloride possessing high toxicity and carcinogenic properties. Targeted analysis of real swimming pool water samples confirmed the results of model experiments enabling semi-quantitative determination of CAPB (0.8 µg L-1) and 18 primary DBPs, including 10 chlorine-containing compounds with the total concentration of 0.1 µg L-1. Among them, monochloro (50%) and hydroxydichloro (25%) derivatives predominate. The toxicity and health of the main DBPs has been estimated using QSAR/QSTR approach. Thus, the possibility of formation of new classes of potentially toxic chlorine-containing DBPs associated with the widespread use of detergents and cosmetics was shown.


Assuntos
Betaína/análogos & derivados , Compostos Clorados , Desinfetantes , Hidrocarbonetos Clorados , Piscinas , Poluentes Químicos da Água , Purificação da Água , Humanos , Desinfecção , Desinfetantes/química , Cloro/química , Nitrogênio/análise , Hidrocarbonetos Clorados/análise , Compostos Clorados/análise , Halogenação , Compostos de Nitrogênio , Cloretos , Poluentes Químicos da Água/análise
3.
Int J Biol Macromol ; 258(Pt 1): 128662, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38065456

RESUMO

Polylactic acid (PLA)-based microcapsules, capable of releasing chlorine dioxide (ClO2) upon exposure to moisture, have been developed for fruits and vegetables preservation. The microcapsules were prepared by emulsion solvent evaporation, utilizing PLA as the wall material, and NaClO2 as the core material. After optimization, NaClO2 microcapsules exhibited an encapsulation efficiency of 55.75% and an average particle size of 498.08 µm. Citric acid microcapsules were prepared using the same process, but with citric acid as the core material. When the two kinds of microcapsules were mixed, gaseous ClO2 was released in a highly humid environment. The release rate could be adjusted by temperature and the ratio between the two microcapsules, and the release period could be as long as 17 days at 20 °C. With a certain amount of microcapsules placed in the package of cherry tomatoes, the decay rate and weight loss rate of the fruits were reduced by 63 % and 34 %, respectively, compared to the control group. The microcapsules also helped to maintain the good appearance, hardness, and the content of total soluble solid content and titratable acid content of cherry tomatoes. Therefore, the PLA-based microcapsules have satisfied convenience and effectiveness for application in fruit and vegetables preservation.


Assuntos
Compostos Clorados , Óxidos , Solanum lycopersicum , Cápsulas , Poliésteres , Ácido Cítrico
4.
Sci Rep ; 13(1): 22866, 2023 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-38129523

RESUMO

Chlorine dioxide is a powerful disinfectant with strong antibacterial properties. We conducted a study at different sites of the Lebanese American University Medical Center-Rizk Hospital to determine the efficacy of the ECOM air mask in decreasing the particle load. Air cultures were obtained from three different locations, namely the patients' elevator, visitors' elevator and mobile clinic and the number of colonies grown on each type of agar was determined. We also measured particle counts at the three sites both at baseline and after placement of the ECOM air mask. After 7 days of ECOM air mask use, the numbers of colonies grown on all types of media was decreased by 20-100% versus the baseline values. The counts of particles of different diameters (0.3, 0.5 and 5 µm) were decreased at all three sampled sites. This study highlighted the efficacy of the ECOM air mask. The utility of the gaseous form of ClO2 as an antiseptic in the hospital setting appears promising.


Assuntos
Compostos Clorados , Desinfetantes , Humanos , Desinfetantes/farmacologia , Gases , Compostos Clorados/farmacologia , Óxidos/farmacologia , Hospitais , Cloro/farmacologia
5.
BMC Oral Health ; 23(1): 930, 2023 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-38012605

RESUMO

OBJECTIVES: The study aimed to compare the antibacterial effect of a novel disinfectant, hyper-pure chlorine dioxide (hClO2) to sodium hypochlorite (NaOCl) in various depths of dentin tubules. MATERIALS AND METHODS: The distal root of the extracted lower molars was infected artificially with Enterococcus faecalis. The control group was rinsed with saline, and the test groups were irrigated with either 5% NaOCl or 0.12% hClO2. The longitudinally split teeth were stained by viability stain. The coronal third of the root was scanned with a confocal laser scanning microscope. The fluorescent intensities were measured, and the percentage of dead bacteria was calculated at depths up to 950 µm along the dentin tubules. The effect of penetration depth, irrigants, and their interaction on antimicrobial efficacy was determined by the linear mixed model. RESULTS: The percentage of dead bacteria was higher both in the NaOCl (45.1 ± 2.3%, p < 0.01) and in the hClO2 (44.6 ± 3.8%, p < 0.01) irrigant groups compared to saline (23 ± 4.5%); however, there was no difference between them. The percentage of killed bacteria was not correlated with the depths in any group (p = 0.633). CONCLUSIONS: Our results suggest that the functional penetration depth of NaOCl is at least 2-3 times more than published to date. There is no difference in disinfection effectiveness along the dentin tubules between NaOCl and hClO2 until at least the measured 950 µm. However, both were only able to eradicate the intratubular bacteria partially. CLINICAL RELEVANCE: Hyper-pure ClO2 could be used as an alternative or final adjuvant irrigant in endodontic treatment.


Assuntos
Anti-Infecciosos , Compostos Clorados , Humanos , Hipoclorito de Sódio/farmacologia , Dentina , Anti-Infecciosos/farmacologia , Compostos Clorados/farmacologia , Bactérias , Enterococcus faecalis , Irrigantes do Canal Radicular/farmacologia , Cavidade Pulpar/microbiologia , Biofilmes
6.
Environ Pollut ; 339: 122736, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37838321

RESUMO

Recently, it has been reported that chlorine dioxide (ClO2) and (bi)sulfite/ClO2 showed excellent performance in micropollutant removal from water; however, the degradation mechanisms and application boundaries of the two system have not been identified. In this study, bisphenol A (BPA) was chosen as the target contaminant to give multiple comparisons of ClO2 and S(IV)/ClO2 process regarding the degradation performance of contaminant, generation of reactive species, transformation of products and toxicity variation. Both ClO2 and S(IV)/ClO2 can degrade BPA within 3 min. The BPA degradation mechanism was mainly based on direct oxidation in ClO2 process while it was attributed to radicals (especially SO4·-) generation in S(IV)/ClO2 process. Meanwhile, the effect of pH and coexisting substances (Cl-, Br-, HCO3- and HA) were evaluated. It was found that ClO2 preferred the neutral and alkaline condition and S(IV)/ClO2 preferred the acidic condition for BPA degradation. An unexpected speed-up of BPA degradation was observed in ClO2 process in the presence of Br-, HCO3- and HA. In addition, the intermediate products in BPA degradation were identified. Three exclusive products were found in ClO2 process, in which p-benzoquinone was considered to be the reason of the acute toxicity increase in ClO2 process.


Assuntos
Compostos Clorados , Poluentes Químicos da Água , Purificação da Água , Óxidos/toxicidade , Óxidos/química , Compostos Clorados/toxicidade , Compostos Clorados/química , Fenóis/toxicidade , Oxirredução , Cloro/química , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise
7.
PLoS One ; 18(8): e0289534, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37561805

RESUMO

With the spread of coronavirus infections, the demand for disinfectants, such as a sodium chlorite solution, has increased worldwide. Sodium chlorite solution is a food additive and is used in a wide range of applications. There is evidence that chlorous acid or sodium chlorite is effective against various bacteria, but the actual mechanism is not well understood. One reason for this is that the composition of chlorine-based compounds contained in sodium chlorite solutions has not been clearly elucidated. The composition can vary greatly with pH. In addition, the conventional iodometric titration method, the N,N-diethyl-p-phenylenediamine sulfate (DPD) method and the absorption photometric method cannot clarify the composition. In this study, we attempted to elucidate the composition of a sodium chlorite solution using absorption spectrophotometry and ion chromatography (IC). IC is excellent for qualitative and quantitative analysis of trace ions. Through this, we aimed to develop an evaluation method that allows anyone to easily determine the bactericidal power of sodium chlorite. We found that commercially available sodium chlorite solution is 80% pure, with the remaining 20% potentially containing sodium hypochlorite solution. In addition, when sodium chlorite solution became acidified, its absorption spectrum exhibited a peak at 365 nm. Sodium chlorite solution is normally alkaline, and it cannot be measured by the DPD method, which is only applicable under acidic conditions. The presence of a peak at 365 nm indicates that the acidic sodium chlorite solution contains species with oxidizing power. On the other hand, the IC analysis showed a gradual decrease in chlorite ions in the acidic sodium chlorite solution. These results indicate that chlorite ions may not react with this DPD reagent, and other oxidizing species may be present in the acidic sodium chlorite solution. In summary, when a sodium chlorite solution becomes acidic, chlorine-based oxidizing species produce an absorption peak at 365 nm. Sodium hypochlorite and sodium chlorite solutions have completely different IC peak profiles. Although there are still many problems to be solved, we believe that the use of IC will facilitate the elucidation of the composition of sodium chlorite solution and its sterilization mechanism.


Assuntos
Compostos Clorados , Hipoclorito de Sódio , Cloro , Cloretos/química , Cromatografia
8.
Mar Pollut Bull ; 194(Pt B): 115357, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37579597

RESUMO

Since 2007, green tides have occurred almost every year in the Yellow Sea, and a method to prevent them and to control levels of attached Ulva prolifera is urgently needed. In this study, we measured the effects of different concentrations of citric acid-activated chlorine dioxide solution (0, 50, 100, 150, 200, and 250 mg/L of chlorine dioxide) on the morphology (macrostructure and microstructure), chlorophyll a content, chlorophyll b content, carotenoid content, and chlorophyll fluorescence parameters (Fv/Fm, Y (II), NPQ, and ETRmax) of U. prolifera. Micropropagules in the treatment filtrate were cultured to determine whether the solution reduced the number of micropropagules released during the treatment process. The results showed that citric acid-activated chlorine dioxide at the appropriate concentration can be applied to remove U. prolifera from Neopyropia cultivation rafts. Because U. prolifera and its micropropagules died in the 250 mg/L chlorine dioxide group, we recommend that the appropriate concentration of chlorine dioxide for removing green macroalgae is ≥250 mg/L. Our results provide a scientific basis for convenient collection of accurate data for the U. prolifera prevention trial organized by the Ministry of Natural Resources of the People's Republic of China.


Assuntos
Compostos Clorados , Ulva , Humanos , Clorofila A , Óxidos , China , Eutrofização
9.
Environ Sci Technol ; 57(32): 12063-12071, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37531609

RESUMO

The washwater used to wash produce within postharvest washing facilities frequently contains high chlorine concentrations to prevent pathogen cross-contamination. To address concerns regarding the formation and uptake of chlorate (ClO3-) into produce, this study evaluated whether switching to chlorine dioxide (ClO2) could reduce chlorate concentrations within the produce. Because ClO2 exhibits lower disinfectant demand than chlorine, substantially lower concentrations can be applied. However, ClO3- can form through several pathways, particularly by reactions between ClO2 and the chlorine used to generate ClO2 via reaction with chlorite (ClO2-) or chlorine that forms when ClO2 reacts with produce. This study demonstrates that purging ClO2 from the chlorine and ClO2- mixture used for its generation through a trap containing ClO2- can scavenge chlorine, substantially reducing ClO3- concentrations in ClO2 stock solutions. Addition of low concentrations of ammonia to the produce washwater further reduced ClO3- formation by binding the chlorine produced by ClO2 reactions with produce as inactive chloramines without scavenging ClO2. While chlorate concentrations in lettuce, kale, and broccoli exceeded regulatory guidelines during treatment with chlorine, ClO3- concentrations were below regulatory guidelines for each of these vegetables when treated with ClO2 together with these two purification measures. Switching to purified ClO2 also reduced the concentrations of lipid-bound oleic acid chlorohydrins and protein-bound chlorotyrosines, which are exemplars of halogenated byproducts formed from disinfectant reactions with biomolecules within produce.


Assuntos
Compostos Clorados , Desinfetantes , Purificação da Água , Desinfecção , Cloratos , Cloro , Compostos Clorados/química , Óxidos/química , Desinfetantes/química
10.
Environ Int ; 178: 108121, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37544266

RESUMO

Compared to individual UV or chlorine disinfection, the combined UV and chlorine (i.e., UV/chlorine) can substantially promote the degradation of antibiotic resistance genes (ARGs) in the effluent by generating radicals. However, the mechanisms of ARG degradation induced by radicals during UV/chlorine treatment remain largely unknown, limiting further enhancement of ARG degradation by process optimization. Herein, we aimed to uncover the role of different radicals in ARG degradation and the molecular mechanisms of ARG degradation by radicals in UV/chlorine process. The ClO was proven to be responsible for the enhanced ARG degradation during UV/chlorine treatment, while the other radicals (OH, Cl, and Cl2-) played a minor role. This is because ClO possessed both high steady-state concentration and high reactivity toward ARGs (rate constant: 4.29 × 1010 M-1 s-1). The ClO might collaborate with free chlorine to degrade ARG. The ClO degraded ARGs by selectively attacking guanine and thymine but failed to induce strand breakage, while chlorine could break the strand of ARGs. Ultimately, ClO cooperated with chlorine to degrade ARGs quickly by hydroxylation and chlorination of bases and produce many chlorine- and nitrogen-containing products as revealed by high-resolution mass spectrometry. The uncovered degradation mechanisms of ARGs by UV/chlorine provide useful guidelines for process optimization to achieve deep removal of effluent ARGs.


Assuntos
Compostos Clorados , Poluentes Químicos da Água , Purificação da Água , Antibacterianos , Cloro , Resistência Microbiana a Medicamentos/genética , Desinfecção , Cloretos , Purificação da Água/métodos , Raios Ultravioleta , Cinética , Poluentes Químicos da Água/análise , Oxirredução
11.
J Vet Med Sci ; 85(9): 950-955, 2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37482423

RESUMO

The efficacy of ClO2 gas, as surface disinfectant at around 1,000 ppb against avian orthoavulaviruses type 1 (AOAV-1), infectious bronchitis virus (IBV), Escherichia coli (EC), and Salmonella Enteritidis (SE) was evaluated at the required level (≥99.9% reduction) on various surfaces. Exposing the surfaces to ClO2 gas for 1 hr reduced AOAV-1, except for rayon sheets which required 3 hr. However, 1 hr of exposure did not effectively reduced IBV titer. In the case of EC, glass plates and plastic carriers needed 1 hr of exposure, while rayon sheets required 2 hr. SE on rayon sheets required 1 hr exposure, but on the other tested surfaces showed inadequate reduction. Overall, ClO2 gas is an effective disinfectant for poultry farms.


Assuntos
Compostos Clorados , Desinfetantes , Animais , Cloro , Óxidos/farmacologia , Compostos Clorados/farmacologia , Desinfetantes/farmacologia , Salmonella enteritidis
12.
J Appl Microbiol ; 134(7)2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37403321

RESUMO

Chlorine dioxide (ClO2) is a disinfectant gas with strong antifungal, antibacterial, and antiviral activities. Applied on hard, non-porous surfaces as an aqueous solution or gas, the ClO2 exerts antimicrobial activity through its interaction and destabilization of cell membrane proteins, as well as through DNA/RNA oxidation, triggering cell death. As for viruses, the ClO2 promotes protein denaturalization mechanisms, preventing the union between the human cells and the viral envelope. Currently, ClO2 has been pointed out as a potential anti-SARS-CoV-2 clinical treatment for use in humans with the ability to oxidize the cysteine residues in the spike protein of SARS-CoV-2, inhibiting the subsequent binding with the Angiotensin-converting enzyme type 2 receptor, located in the alveolar cells. Orally administered ClO2 reaches the gut tract and exacerbates the symptoms of COVID-19, generating a dysbiosis with gut inflammation and diarrhea as side effects, and once absorbed, produces toxic effects including methemoglobinemia and hemoglobinuria, which can trigger respiratory diseases. These effects are dose-dependent and may not be entirely consistent between individuals since the gut microbiota composition is highly heterogeneous. However, to support the use of ClO2 as an anti-SARS-CoV-2 agent, further studies focused on its effectiveness and safety both in healthy and immunocompromised individuals, are needed.


Assuntos
COVID-19 , Compostos Clorados , Desinfetantes , Microbioma Gastrointestinal , Humanos , SARS-CoV-2 , Óxidos/farmacologia , Óxidos/química , Desinfetantes/farmacologia , Compostos Clorados/farmacologia , Cloro
13.
Sci Total Environ ; 896: 165282, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37406691

RESUMO

Polyvinyl chloride (PVC) pipes are widely used as drinking water distribution pipes in rural areas of China. However, whether phthalate acid esters (PAEs) released from PVC pipes will affect tap water quality is still unknown. The influence of released PAEs on the water quality was analysed in this study, especially after ClO2 disinfection. The results indicated that ClO2 disinfection could control the growth of total coliforms and heterotrophic bacteria (HPC). However, when the ClO2 residual decreased to below 0.10 mg/L, HPC and opportunistic pathogens, including Mycobacterium avium and Pseudomonas aeruginosa, increased significantly. In addition, after ClO2 disinfection, PAEs concentrations increased from 10.6-22.2 µg/L to 21.2-58.8 µg/L in different sampling cites. Linear discriminant analysis (LDA) effect size (LEfSe) and statistical analysis of metagenomic profiles (Stamp) showed that ClO2 disinfection induced the enrichment of Pseudomonas, Bradyrhizobium, and Mycobacterium and functions related to human diseases, such as pathogenic Escherichia coli infection, shigellosis, Staphylococcus aureus infection, and Vibrio cholerae infection. The released PAEs not only promoted the growth of these ClO2-resistant bacterial genera but also enhanced their functions related to human diseases. Moreover, these PAEs also induced the enrichment of other bacterial genera, such as Blastomonas, Dechloromonas, and Kocuria, and their functions, such as chronic myeloid leukaemia, African trypanosomiasis, leishmaniasis, hepatitis C and human T-cell leukaemia virus 1 infection. The released PAEs enhanced the microbial risk of the drinking water. These results are meaningful for guaranteeing water quality in rural areas of China.


Assuntos
Compostos Clorados , Desinfetantes , Água Potável , Humanos , Desinfetantes/farmacologia , Cloreto de Polivinila , Compostos Clorados/farmacologia , Desinfecção/métodos , Bactérias , Ésteres , Cloro/farmacologia
14.
Water Res ; 241: 120159, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37290190

RESUMO

Aromatic polyamide (PA) based membranes are widely used for reverse osmosis (RO), but they can be degraded by free chlorine used for controlling the biofouling prior to RO treatment. Kinetics and mechanisms for the reactions of PA membrane model monomers, i.e., benzanilide (BA), and acetanilide (AC), with chlorine dioxide (ClO2) were investigated in this study. Rate constants for the reactions of ClO2 with BA and AC at pH 8.3 and 21°C were determined to be (4.1±0.1) × 10-1 M-1.24 s-1 and (6.0±0.1) × 10-3 M-1 s-1, respectively. These reactions are base assisted with a strong pH dependence. The activation energies of BA and AC degradation by ClO2 were 123.7 and 81.0 kJ mol-1, respectively. This indicates a relatively strong temperature dependence in the studied temperature range of 21-35 °C. The presence of bromide and natural organic matter does not promote the degradation of model monomers by ClO2. BA was degraded by ClO2 via two pathways: (1) the attack on the anilide moiety with the formation of benzamide (major pathway) and (2) oxidative hydrolysis to benzoic acid (minor pathway). A kinetic model was developed to simulate the degradation of BA and formation of byproducts during ClO2 pretreatment, and simulations agree well with the experimental data. Half-lives of BA treated by ClO2 were 1-5 orders of magnitude longer than chlorine under typical seawater treatment conditions. These novel findings suggest the potential application of ClO2 for controlling biofouling ahead of RO treatment at desalination treatments.


Assuntos
Compostos Clorados , Purificação da Água , Nylons , Cloro , Cinética , Óxidos , Cloretos
15.
Environ Sci Technol ; 57(47): 18846-18855, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37276343

RESUMO

Chlorine dioxide (ClO2) is an oxidant applied in water treatment processes that is very effective for disinfection and abatement of inorganic and organic pollutants. Thereby phenol is the most important reaction partner of ClO2 in reactions of natural organic matter (NOM) and in pollutant degradation. It was previously reported that with specific reaction partners (e.g., phenol), free available chlorine (FAC) could form as another byproduct next to chlorite (ClO2-). This study investigates the impact of different functional groups attached to the aromatic ring of phenol on the formation of inorganic byproducts (i.e., FAC, ClO2-, chloride, and chlorate) and the overall reaction mechanism. The majority of the investigated compounds reacted with a 2:1 stoichiometry and formed 50% ClO2- and 50% FAC, regardless of the position and kind of the groups attached to the aromatic ring. The only functional groups strongly influencing the FAC formation in the ClO2 reaction with phenols were hydroxyl- and amino-substituents in ortho- and para-positions, causing 100% ClO2- and 0% FAC formation. Additionally, this class of compounds showed a pH-dependent stoichiometric ratio due to pH-dependent autoxidation. Overall, FAC is an important secondary oxidant in ClO2 based treatment processes. Synergetic effects in pollutant control and disinfection might be observable; however, the formation of halogenated byproducts needs to be considered as well.


Assuntos
Compostos Clorados , Desinfetantes , Poluentes Ambientais , Poluentes Químicos da Água , Purificação da Água , Cloretos , Cloro , Fenol , Óxidos , Desinfecção , Fenóis , Oxidantes , Poluentes Químicos da Água/análise
16.
Water Res ; 242: 120231, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37385073

RESUMO

Chlorine dioxide (ClO2) is a widely used sterilizer and a disinfectant across a multitude of industries. When using ClO2, it is imperative to measure the ClO2 concentration to abide by the safety regulations. This study presents a novel, soft sensor method based on Fourier transform infrared spectroscopy (FTIR) spectroscopy for measurement of ClO2 concentration in different water samples varying from milli Q to wastewater. Six distinct artificial neural network models were constructed and evaluated based on three overarching statistical standards to select the optimal model. The OPLS-RF model outperformed all other models with R2, RMSE, and NRMSE values of 0.945, 0.24, and 0.063, respectively. The developed model demonstrated limit of detection and limit of quantification values of 0.1 and 0.25 ppm, respectively, for water. Furthermore, the model also exhibited good reproducibility and precision as measured by the BCMSEP (0.064). The soft sensor-based method presented in the study offers significant advantages in terms of simplicity and speedy detection. In summary, the study presents development of a soft sensor that is capable of predicting the trace content of chlorine dioxide ranging between 0.1 to 5 ppm in a water sample by connecting FTIR with an OPLS-RF model.


Assuntos
Compostos Clorados , Desinfetantes , Purificação da Água , Água , Reprodutibilidade dos Testes , Óxidos/química , Compostos Clorados/química , Cloro
17.
Health Secur ; 21(4): 303-309, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37289796

RESUMO

The pursuit of disinfecting porous materials or fomites to inactivate viral agents has special challenges. To address these challenges, a highly portable chlorine dioxide (ClO2) gas generation system was used to ascertain the ability of a gaseous preparation to inactivate a viral agent, the MS2 bacteriophage, when associated with potentially porous fomites of cloth, paper towel, and wood. The MS2 bacteriophage is increasingly used as a model to identify means of inactivating infectious viral agents of significance to humans. Studies showed that MS2 bacteriophage can be applied to and subsequently recovered from potential porous fomites such as cloth, paper towel, and wood. Paired with viral plaque assays, this provided a means for assessing the ability of gaseous ClO2 to inactivate bacteriophage associated with the porous materials. Notable results include 100% inactivation of 6 log bacteriophage after overnight exposure to 20 parts per million(ppm) ClO2. Reducing exposure time to 90 minutes and gas ppm to lower concentrations proved to remain effective in bacteriophage elimination in association with porous materials. Stepwise reduction in gas concentration from 76 ppm to 5 ppm consistently resulted in greater than 99.99% to 100% reduction of recoverable bacteriophage. This model suggests the potential of ClO2 gas deployment systems for use in the inactivation of viral agents associated with porous potential fomites. The ClO2 gas could prove especially helpful in disinfecting enclosed areas containing viral contaminated surfaces, rather than manually spraying and wiping them.


Assuntos
Bacteriófagos , Compostos Clorados , Desinfetantes , Humanos , Desinfecção , Cloro , Desinfetantes/farmacologia , Fômites , Porosidade , Óxidos/farmacologia , Compostos Clorados/farmacologia
18.
Water Res ; 238: 120030, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37150063

RESUMO

Polyethylene (PE) pipes have been widely used in drinking water distribution systems across the world. In many cases, chlorine dioxide (ClO2) is used to maintain a residual disinfectant concentration in potable water. Practical experiences have shown that the lifetime of PE pipes is significantly reduced due to exposure to drinking water with ClO2. Recently, many companies have proposed new PE pipes with a modified formulation, which are more resistant to chlorine dioxide. However, a standardized test method for evaluating the long-term performances of PE pipes is still missing. This literature review was performed to provide a description of chlorine dioxide uses and degradation mechanisms of polyethylene pipes in real water distribution systems. Current accelerated aging methods to evaluate long-term performances of PE pipes exposed to ClO2 are described and discussed along with the common technics used to characterize the specimens. Accelerate aging methods can be distinguished in immersion aging tests and pressurized pipe loop tests. Wide ranges of operational conditions (chlorine dioxide concentration, water pressure, water temperature, etc.) are applied, resulting in a great variety of results. It was concluded that pressurized looping tests applying semi-realistic operational conditions could better replicate the aging mechanisms occurring in service. Despite this, the acceleration and the evaluation of the long-term performance are still difficult to determine precisely. Further experimentation is needed to correlate chemical-mechanical characterization parameters of PE pipes with their lifetime in service.


Assuntos
Compostos Clorados , Desinfetantes , Água Potável , Purificação da Água , Polietileno , Abastecimento de Água , Óxidos , Cloro , Purificação da Água/métodos , Desinfecção
19.
J Water Health ; 21(5): 537-546, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37254903

RESUMO

Disinfectants, especially air disinfectants, are necessary to prevent the potential spread of pathogens (bacteria and viruses) in the pandemic era and minimize the spread of pathogens. Some of the commercial disinfectant products that are often used generally contain chlorine dioxide (ClO2) gas. This study tested the effectiveness of two different commercial disinfectants, a liquid stick disinfectant and a powder disinfection card, to carry out the disinfection of pathogenic bacteria in the environment. These two disinfectants were used as a medium for releasing chlorine dioxide gas which has a much stronger bactericidal effect. In the form of liquid stick, ClO2 is more effective in the disinfection process rather than in the form of powder. The effectiveness of the liquid disinfectant in inhibiting the growth of pathogenic bacteria is influenced by the temperature and the area of the open space covered. Considering that the release from both disinfectants used is very small (0.002 ppmv/h), it takes a small area to ensure that the disinfection process runs effectively.


Assuntos
Compostos Clorados , Desinfetantes , Desinfetantes/farmacologia , Cloro/farmacologia , Pós , Óxidos/farmacologia , Compostos Clorados/farmacologia , Desinfecção , Bactérias
20.
Environ Sci Pollut Res Int ; 30(28): 72675-72689, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37178295

RESUMO

Extensive application of reclaimed water alleviated water scarcity obviously. Bacterial proliferation in reclaimed water distribution systems (RWDSs) poses a threat to water safety. Disinfection is the most common method to control microbial growth. The present study investigated the efficiency and mechanisms of two widely used disinfectants: sodium hypochlorite (NaClO) and chlorine dioxide (ClO2) on the bacterial community and cell integrity in effluents of RWDSs through high-throughput sequencing (Hiseq) and flow cytometry, respectively. Results showed that a low disinfectant dose (1 mg/L) did not change the bacterial community basically, while an intermediate disinfectant dose (2 mg/L) reduced the biodiversity significantly. However, some tolerant species survived and multiplied in high disinfectant environments (4 mg/L). Additionally, the effect of disinfection on bacterial properties varied between effluents and biofilm, with changes in the abundance, bacterial community, and biodiversity. Results of flow cytometry showed that NaClO disturbed live bacterial cells rapidly, while ClO2 caused greater damage, stripping the bacterial membrane and exposing the cytoplasm. This research will provide valuable information for assessing the disinfection efficiency, biological stability control, and microbial risk management of reclaimed water supply systems.


Assuntos
Compostos Clorados , Desinfetantes , Purificação da Água , Água , Purificação da Água/métodos , Óxidos , Desinfecção/métodos , Hipoclorito de Sódio , Bactérias , Cloro
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