Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 11.177
Filtrar
1.
Braz Dent J ; 33(2): 1-11, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35508031

RESUMO

The aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite solution [Ca(OCl)2], with or without surfactants. The surfactants benzalkonium chloride, cetrimide, Tween 80 and Triton X-100 were mixed at different concentrations with sodium hypochlorite solution (NaOCl), Ca(OCl)2 and distilled water (control). Once the critical micellar concentration (CMC) of the surfactants in Ca(OCl)2 and NaOCl was determined, pH, free chlorine, surface tension and free calcium ions were evaluated. The penetration into dentinal tubules of NaOCl and Ca(OCl)2, with or without benzalkonium chloride and Triton X-100 [surfactants that promoted the lowest surface tension of Ca(OCl)2], was assessed using human premolars stained with crystal violet. The statistical tests were one-way ANOVA and Tukey's post-test, Kruskal-Wallis and Dunn's post-test, two-way ANOVA and Bonferroni's post-test, and t-test; depending on the assay. The addition of surfactants reduced the surface tension of NaOCl and Ca(OCl)2, and did not alter the pH or the free available chlorine of either solution. The addition of all surfactants increased the availability of free calcium ions in Ca(OCl)2, especially benzalkonium chloride. Ca(OCl)2 exhibited lower penetration into dentinal tubules than NaOCl, and the addition of surfactants did not improve the penetration of Ca(OCl)2, but did increase the penetration of NaOCl. It can be concluded that the addition of surfactants to Ca(OCl)2 did not increase the penetration into dentinal tubules, but it did promote lower surface tension, without changing the pH or free available chlorine values, and higher availability of free calcium ions in Ca(OCl)2.


Assuntos
Irrigantes do Canal Radicular , Hipoclorito de Sódio , Compostos de Benzalcônio , Cálcio , Compostos de Cálcio , Cloro , Humanos , Octoxinol , Irrigantes do Canal Radicular/química , Hipoclorito de Sódio/química , Tensoativos/química
2.
Water Res ; 216: 118341, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35367942

RESUMO

The formation of undesirable chloro-organic byproducts is of great concern in the UV/chlorine process. In this study, chlorine dioxide (ClO2) pre-oxidation was applied to control the formation of chloro-organic byproducts and the toxicity in UV/chlorine-treated water. The molecular-level changes in dissolved organic matter (DOM) were tracked by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and ClO2 pre-oxidation was found to preferentially react with DOM moieties with high aromaticity level and with a carbon number of > 18, producing compounds with a higher degree of oxidation and lower aromaticity. The ClO2-treated DOM was found to be less susceptible to attack by radicals and free chlorine in the UV/chlorine process compared to the raw DOM. ClO2 pre-oxidation resulted in a significant decrease in the number of unknown chloro-organic byproducts (i.e., -17%) and the total intensity of organic chlorine detected by FT-ICR-MS (i.e., -31%). The molecular characteristics, such as O/C, aromaticity index, and the average number of chlorine atoms, of these unknown chloro-organic byproducts generated in the scenarios with and without ClO2 pre-oxidation were also different. Additionally, ClO2 pre-oxidation reduced the genotoxicity (SOS/umu test) and cytotoxicity (Hep G2 cytotoxicity assay) of UV/chlorine-treated water by 26% and 20%, respectively. The findings in this study highlight the merits of ClO2 pre-oxidation for controlling chloro-organic byproducts and reducing the toxicity of water treated by the UV/chlorine process in actual practice.


Assuntos
Compostos Clorados , Poluentes Químicos da Água , Purificação da Água , 2,5-Dimetoxi-4-Metilanfetamina , Cloretos , Cloro/análise , Desinfecção , Óxidos , Água , Poluentes Químicos da Água/análise
3.
Molecules ; 27(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35408687

RESUMO

The new technology development for municipal solid waste incineration fly ash treatment and reuse is urgent due to landfill shortage and environmental effect of leached hazardous substances. Chlorine (Cl) is worth considering due to its high levels in fly ash. In this study, a treatment process of ultrasound combined with organic acid was used to eliminate Cl from fly ash to enhance its properties for reuse. Taguchi methodology was implemented to design the experiments by controlling four impact factors and the contribution of each factor was evaluated by the ANOVA analysis of variance. Following two treatment steps within 5 min with a solid/liquid ratio of 1:10 at 165 kHz, 98.8% of Cl was eliminated. Solid/liquid ratio was the most prominent factor that contributed to the Cl removal with more than 90%, according to the ANOVA analysis of variance. Tert-butyl alcohol (tBuOH), an •OH radical scavenger, was utilized to examine different effects of ultrasonic cavitation on Cl removal efficiency. A 20 kHz ultrasound was used to explore the influence of multi-frequency ultrasound with different mechanical and sonochemical effects on the fly ash dechlorination. This ultrasonic-assisted organic acid treatment was found to be a time and cost-effective pathway for fly ash Cl removal.


Assuntos
Metais Pesados , Nanoporos , Eliminação de Resíduos , Carbono/química , Cloretos/análise , Cloro/análise , Cinza de Carvão/análise , Incineração , Metais Pesados/análise , Compostos Orgânicos/análise , Material Particulado , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise
4.
Environ Int ; 163: 107195, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35447436

RESUMO

Even though the chlorinated paraffins (CPs) have been on the environmental pollution agenda throughout the last 50 years it is a class of chemicals that only now is discussed in terms of an emerging issue with extensive annual publication rates. Major reviews on CPs have been produced, but a deeper understanding of the chemical fate of CPs, including formation of metabolites in animals and humans, is still missing. Thus, the present review aims to critically compile our present knowledge on the disposition, i.e. Adsorption, Disposition, Metabolism, and Excretion (ADME) of CPs in biota and to identify research needs. We conclude that CPs could be effectively absorbed from the gastro-intestinal tract (GI) tract, and probably also from the lungs, and transported to various organs. A biphasic elimination is suggested, with a rapid initial phase followed by a terminal phase, the latter (e.g., fat tissues) covering half-lives of weeks and months. CPs are metabolized in the liver and excreted mainly via the bile and faeces, and the metabolic rate and type of metabolites are dependent on chlorine content and chain length. Results that strengthen CP metabolism are in vivo findings of phase II metabolites in bile, and CP degradation to carbon fragments in experimental animals. Still the metabolic transformations of CPs are poorly studied, and no metabolic scheme has yet been presented. Further, toxicokinetic mass balance calculations suggest that a large part of a given dose (not found as parent compound) is transformation products of CPs, and in vitro metabolism studies present numerous CP metabolites (e.g., chloroalkenes, chlorinated ketones, aldehydes, and carboxylic acids).


Assuntos
Hidrocarbonetos Clorados , Animais , China , Cloro , Monitoramento Ambiental , Poluição Ambiental , Humanos , Hidrocarbonetos Clorados/análise , Parafina/análise
5.
Environ Sci Technol ; 56(9): 5808-5819, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35442653

RESUMO

Sulfidized nanoscale zerovalent iron (SNZVI) with desirable properties and reactivity has recently emerged as a promising groundwater remediation agent. However, little information is available on how the molecular structure of chlorinated ethenes (CEs) affects their dechlorination by SNZVI or whether the sulfur content of SNZVI can alter their dechlorination pathway and reactivity. Here, we show that the reactivity (up to 30-fold) and selectivity (up to 70-fold) improvements of SNZVI (compared to NZVI) toward CEs depended on the chlorine number, chlorine position, and sulfur content. Low CEs (i.e., vinyl chloride and cis-1,2-dichloroethene) and high CEs (perchloroethene) tended to be dechlorinated by SNZVI primarily via atomic H and direct electron transfer, respectively, while SNZVI could efficiently and selectively dechlorinate trichloroethene and trans-1,2-dichloroethene via both pathways. Increasing the sulfidation degree of SNZVI suppressed its ability to produce atomic H but promoted electron transfer and thus altered the relative contributions of atomic H and electron transfer to the CE dechlorination, resulting in different reactivities and selectivities. These were indicated by the correlations of CE dechlorination rates and improvements with CE molecular descriptors, H2 evolution rates, and electron transfer indicators of SNZVI. These mechanistic insights indicate the importance of determining the structure-specific properties and reactivity of both SNZVI materials and their target contaminants and can lead to a more rational design of SNZVI for in situ groundwater remediation of various CEs.


Assuntos
Ferro , Poluentes Químicos da Água , Cloro , Etilenos , Estrutura Molecular , Enxofre
6.
Dalton Trans ; 51(17): 6964-6975, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35452068

RESUMO

We developed a porous diamino group-functionalized Zr(IV) metal-organic framework (MOF). The synthesized MOF has a similar structure to DUT-52 (DUT = Dresden University of Technology), which has a face-centered cubic structure with an Fm3̄m space group. The synthesized material (DUT-52-(NH2)2-1) was solvent exchanged with methanol (MeOH) and activated at 100 °C overnight. Both the as-synthesized and activated materials (DUT-52-(NH2)2-1') are thermally stable until 300 °C. The Brunauer-Emmett-Teller (BET) surface area of DUT-52-(NH2)2-1' was found to be 413 m2 g-1. DUT-52-(NH2)2-1' showed a significant quenching of fluorescence response after coming in contact with free chlorine (ClO-) in an aqueous medium. The selectivity of DUT-52-(NH2)2-1' towards ClO- was not significantly hampered in the presence of any competitive ion. The limit of detection (LOD) value was found to be 0.08 µM in phosphate-buffered saline (PBS, pH = 7.4). DUT-52-(NH2)2-1' is recyclable and very sensitive towards ClO-. Moreover, the paper strip method was developed for onsite identification of ClO-. Furthermore, the catalytic activity of DUT-52-(NH2)2-1' was tested in the Knoevenagel condensation between benzaldehyde and cyanoacetamide. The experimental results clearly indicate that DUT-52-(NH2)2-1' exhibits high activity with very high selectivity towards condensation products. The solid was reusable three times with no decay in its activity, as evidenced by powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and fourier transform infrared (FT-IR).


Assuntos
Estruturas Metalorgânicas , Cloro , Halogênios , Limite de Detecção , Estruturas Metalorgânicas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
7.
Waste Manag ; 144: 376-386, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35452946

RESUMO

Polyvinyl chloride (PVC)-containing waste streams are difficult to recycle due to high chlorine content in PVC. Toxic dioxins or corrosive hydrogen chloride (HCl) vapor released from improper management of PVC-containing wastes can cause severe environmental pollution and human health problems. While PVC is usually treated as contamination and burden in waste recycling, a novel recycling approach was developed in this study to leverage PVC as an asset. Specifically, red oak and PVC were co-converted in γ-Valerolactone, a green biomass-derivable solvent. During the co-conversion, PVC-derived HCl in the solvent acted as an acid catalyst to produce up to 14.4% levoglucosenone and 14.3% furfural from red oak. On the other hand, dechlorinated PVC hydrocarbons and lignin fraction of red oak reacted each other to form chlorine-free solid fuels with high thermal stability. The higher heating value of the solids was up to 36.2 MJ/kg, which is even higher than the heating value of anthracite coal. After the co-conversion, more than 80% of PVC-contained chlorine turned into chloride ion and the rest formed 5-chlorovaleric acid. 5-chlorovaleric acid crystals were further recovered from the post-reaction liquid with a purity of 91.2%.


Assuntos
Cloro , Cloreto de Polivinila , Carvão Mineral , Humanos , Ácido Clorídrico , Reciclagem , Solventes , Madeira
8.
J Med Life ; 15(3): 313-318, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35449999

RESUMO

The COVID-19 pandemic has tremendously increased the production and sales of disinfectants. This study aimed to systematically review and analyze the efficacy and safety of chlorine dioxide as a disinfectant. The literature relating to the use of chlorine dioxide as a disinfectant was systematically reviewed in January 2021 using databases such as PubMed, Science Direct, and Google Scholar. Inclusion criteria were studies that investigated the use of chlorine dioxide to assess the efficacy, safety, and impact of chlorine dioxide as a disinfectant. Out of the 33 included studies, 14 studies focused on the disinfectant efficacy of chlorine dioxide, 8 studies expounded on the safety and toxicity in humans and animals, and 15 studies discussed the impact, such as water treatment disinfection using chlorine dioxide. Chlorine dioxide is a safe and effective disinfectant, even at concentrations as low as 20 to 30 mg/L. Moreover, the efficacy of chlorine dioxide is mostly independent of pH. Chlorine dioxide can be effectively used to disinfect drinking water without much alteration of palatability and can also be used to destroy pathogenic microbes, including viruses, bacteria, and fungi from vegetables and fruits. Our review confirms that chlorine dioxide is effective against the resistant Mycobacterium, H1N1, and other influenza viruses. Studies generally support the use of chlorine dioxide as a disinfectant. The concentration deemed safe for usage still needs to be determined on a case-by-case basis.


Assuntos
COVID-19 , Compostos Clorados/farmacologia , Desinfetantes , Vírus da Influenza A Subtipo H1N1 , Animais , Cloro , Desinfetantes/farmacologia , Humanos , Óxidos , Pandemias
9.
Food Res Int ; 155: 111026, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400423

RESUMO

Sanitation of water, food, and food contact surfaces is essential for the safety of food supply. Lack of stability of sanitizers in the presence of organic content and lack of targeted binding of sanitizers to biofilms can reduce effectiveness of sanitizers and increase the risk of contamination of food. Therefore, this study evaluated the development, characterization, and application of gelatin microgel based chlorine delivery system for improving both stability of chlorine based sanitizer and targeted binding of sanitizer to biofilms. The results illustrate that cross-linked gelatin microgels rapidly bind chlorine to form a halamine bond. The total chlorine loading was 5.05% per gram of gelatin microgels. Chlorine bound to gelatin microgels was stable in the presence of high organic content up to 2,000 mg/L and in a powder form for 5 weeks under refrigerated conditions. Gelatin microgel particles significantly improve the inactivation of bacteria in the presence of organic content compared to equivalent concentration of free chlorine. Gelatin microgel particles had affinity to bind biofilms with 26.5% and 22.9% to the L. innocua and E. coli O157:H7 biofilms, respectively. In bacterial biofilm models, more than 6 log CFU/cm2 of L. innocua and E. coli O157:H7 were inactivated within 60 min using chlorine charged gelatin microgel particles while equivalent free chlorine could only achieve 4 log CFU/cm2 inactivation during the same period. Overall, the results demonstrate potential of protein microgels for effective binding and delivery of chlorine to improve sanitation of wash water with suspended organics and food contact surfaces.


Assuntos
Desinfetantes , Escherichia coli O157 , Microgéis , Biofilmes , Cloro/farmacologia , Contagem de Colônia Microbiana , Desinfetantes/química , Desinfetantes/farmacologia , Contaminação de Alimentos , Gelatina , Água
10.
Int J Food Microbiol ; 370: 109668, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35410797

RESUMO

Sprout consumption has become more popular due to a new variety of sprouts being introduced to the market. However, sprout seeds are a major source of sprout contamination and have been linked to most sprout-associated foodborne outbreaks. This study investigated Salmonella reduction in sunflower and roselle seeds using various sanitizing agents including water, water at 55 °C, sodium hypochlorite (NaOCl), diluted vinegar, acidic electrolyzed water (ACEW), and alkaline electrolyzed water (ALEW). Diluted vinegar containing 1.25% (v/v) acetic acid was the most effective treatment to inactivate Salmonella in sunflower seeds, resulting in a 3.82 log reduction after 15-min treatment. High concentrations of NaOCl (available chlorine concentration (ACC) 1692 mg/L) and ACEW (pH 2.76, oxidation-reduction potential 1093 mV, ACC 48 mg/L) had significantly lower antimicrobial activity with 3.20 and 2.39 log reduction, respectively, after 15-min treatment. Disinfecting roselle seeds for 15 min with water at 55 °C and diluted vinegar had comparable efficacy to reduce Salmonella by 2.54 and 2.48 log, respectively. There were no significant changes in Salmonella reduction among the high and low concentrations of NaOCl containing ACC 79 and 1692 mg/L, respectively, and ACEW in roselle seeds during 5-15 min of exposure time. All tested treatment solutions had no negative impact on the percentage of seed germination with over 96% and 92.56-95.89% for sunflower and roselle seeds, respectively. Conversely, the fresh weight and length of sunflower and roselle sprouts were influenced significantly by the types of sanitizing agents used for decontaminating the seeds. Collectively, our findings may contribute to the development of effective seed sanitization measure for sunflower and roselle seeds to reduce the risk of Salmonella-associated outbreaks linked to sprout consumption.


Assuntos
Helianthus , Hibiscus , Ácido Acético/farmacologia , Cloro/farmacologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Germinação , Medicago sativa , Salmonella , Sementes , Água/farmacologia
11.
Anal Chim Acta ; 1204: 339618, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35397908

RESUMO

Halogenated organic compounds (HOCs) are a huge group of pollutants, which have caused severe environmental pollution worldwide. This study developed a nontarget analysis method for characterization of known and unknown HOCs in tap water, fly ash, soil and sediment using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) with aid of scripting data-processing approaches. The FT-ICR-MS was equipped with an electrospray ionization source operated in negative ion mode, and full scan at a mass resolution around 200,000 was applied. Data screening scripts were developed based on exact mass differences and abundance ratios between neighboring chlorine/bromine isotopologues. Cosine similarity analysis was applied to evaluating similarity between measured and simulated isotopologue distributions which were constituted by abundance ratios between neighboring isotopologues for identification of polychlorinated and polybrominated compounds. From huge amount of peaks in raw mass spectra, thousands of MS features of HOCs were screened out. In total 824 HOC formulae were finally identified, including 702 organochlorines, 108 organobromines, and 14 mix-chlorine/bromine-containing organic compounds (OClBrs), mainly being monochlorinated/monobrominated compounds (∼90%) whose abundances were also the most prominent. Dozens of HOCs were tentatively structurally elucidated, including halogenated phenols, carboxylic acids, benzenesulfonic acids, etc. Three novel OClBrs were structurally identified, i.e., bromochlorobenzoic acid, bromodichlorophenol and bromotrichlorophenol. The data-processing scripts and strategies can facilitate accurate and high-throughput nontarget analysis of both common and novel/emerging halogenated organic pollutants in complex matrices. The research results provide informative insights into pollution profiles of HOCs in the environment, suggesting that halogenated organic pollutants remain to be seriously concerned.


Assuntos
Cinza de Carvão , Poluentes Ambientais , Algoritmos , Bromo , Cloro/análise , Cinza de Carvão/análise , Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrometria de Massas , Compostos Orgânicos/análise , Solo/química , Água/análise
12.
Environ Monit Assess ; 194(5): 342, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35389102

RESUMO

The present study tracked the city-wide dynamics of severe acute respiratory syndrome-corona virus 2 ribonucleic acids (SARS-CoV-2 RNA) in the wastewater from nine different wastewater treatment plants (WWTPs) in Jaipur during the second wave of COVID-19 out-break in India. A total of 164 samples were collected weekly between February 19th and June 8th, 2021. SARS-CoV-2 was detected in 47.2% (52/110) influent samples and 37% (20/54) effluent samples. The increasing percentage of positive influent samples correlated with the city's increasing active clinical cases during the second wave of COVID-19 in Jaipur. Furthermore, wastewater-based epidemiology (WBE) evidence clearly showed early detection of about 20 days (9/9 samples reported positive on April 20th, 2021) before the maximum cases and maximum deaths reported in the city on May 8th, 2021. The present study further observed the presence of SARS-CoV-2 RNA in treated effluents at the time window of maximum active cases in the city even after tertiary disinfection treatments of ultraviolet (UV) and chlorine (Cl2) disinfection. The average genome concentration in the effluents and removal efficacy of six commonly used treatments, activated sludge process + chlorine disinfection (ASP + Cl2), moving bed biofilm reactor (MBBR) with ultraviolet radiations disinfection (MBBR + UV), MBBR + chlorine (Cl2), sequencing batch reactor (SBR), and SBR + Cl2, were compared with removal efficacy of SBR + Cl2 (81.2%) > MBBR + UV (68.8%) > SBR (57.1%) > ASP (50%) > MBBR + Cl2 (36.4%). The study observed the trends and prevalence of four genes (E, RdRp, N, and ORF1ab gene) based on two different kits and found that prevalence of N > ORF1ab > RdRp > E gene suggested that the effective genome concentration should be calculated based on the presence/absence of multiple genes. Hence, it is imperative to say that using a combination of different detection genes (E, N, RdRp, & ORF1ab genes) increases the sensitivity in WBE.


Assuntos
COVID-19 , Vigilância Epidemiológica Baseada em Águas Residuárias , Biofilmes , Reatores Biológicos , COVID-19/epidemiologia , Cloro , Monitoramento Ambiental , Humanos , RNA Viral , RNA Polimerase Dependente de RNA , SARS-CoV-2 , Águas Residuárias
13.
Water Res ; 216: 118305, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35334337

RESUMO

Despite the extensive application of electrochemical advanced oxidation processes (EAOPs) in wastewater treatment, the exact speciation of oxidants and their effects on pollutants removal efficiency, by-products formation, and effluent toxicity are largely unknown. In this study, galvanostatic steel anodes were used to drive the electrochemical activation of hydrogen peroxide (EAHP), persulfate (EAP), and free chlorine (EAFC), for industrial-scale treatment of municipal and livestock wastewater with a focus on micropollutants and transformation products (MTPs) and effluent toxicity. Response surface methodology determined the optimized conditions for each treatment towards total organic carbon ([TOC]0 = 180 mg/L) removal at pH 3.0: persulfate dose = 0.12 mmol/min, 26.5 mA/cm2; free chlorine dose = 0.29 mmol/min, 37.4 mA/cm2; H2O2 dose = 0.20 mmol/min, 45 mA/cm2. Probe-compound degradation revealed that HO•, SO4•- and FeIVO2+ species were simultaneously generated in EAP, whereas HO• and FeIVO2+ were the principal oxidants in EAHP and EAFC, respectively. Samples were analyzed via liquid and gas chromatography in non-target screening (NTS) mode to monitor the generation or removal of MTPs and by-products including compounds that have not been reported previously. The speciation of oxidants, shifted in presence of halide ions (Cl-, Br-) in real wastewater samples, significantly affected the mineralization efficiency and by-product formation. The production of halogenated by-products in EAFC and EAP substantially increased the effluent toxicity, whereas EAHP provided non-toxic effluent and the highest mineralization efficiency (75 - 80%) to be nominated as the best strategy.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Animais , Cloretos , Cloro/análise , Eletrodos , Halogênios , Peróxido de Hidrogênio/química , Gado , Oxidantes , Oxirredução , Aço , Águas Residuárias/química , Poluentes Químicos da Água/química
14.
Water Res ; 216: 118318, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35339968

RESUMO

Cupric oxide (CuO) is able to catalyze the reactions among disinfectant, extracellular polymeric substances (EPS) and bromide (Br-) in copper pipes, which may deteriorate the water quality. This study aimed to investigate the metabonomic and transcriptomic modulations of HepG2 cells caused by the CuO-catalyzed formation of disinfection byproducts (DBPs) from EPS. The presence of CuO favored the substitution reactions of chlorine and bromine with EPS, inducing a higher content of total organic halogen (TOX). In addition, DBPs were shifted from chlorinated species to brominated species. A total of 182 differential metabolites (DMs) and 437 differentially expressed genes (DEGs) were identified, which were jointly involved in 38 KEGG pathways. Topology analysis indicates that glycerophospholipid and purine metabolism were disturbed most obviously. During glycerophospholipid metabolism, the differential expression of genes GPATs, AGPATs, LPINs and DGKs impacted the conversion of glycerol-3-phosphate to 2-diacyl-sn-glycerol, which further affected the conversion among phosphatidylcholine, phosphatidylserine and phosphocholines. During purine metabolism, it was mainly the differential expression of genes POLRs, RPAs, RPBs, RPCs, ENTPDs and CDs that impacted the transformation of RNA into guanine-, xanthosine-, inosine- and adenosine monophosphate, which were further successively transformed into their corresponding nucleosides and purines. The study provides an omics perspective to assess the potential adverse effects of overall DBPs formed in copper pipes on human.


Assuntos
Desinfetantes , Poluentes Químicos da Água , Purificação da Água , Biofilmes , Catálise , Cloro/análise , Cobre/análise , Desinfetantes/análise , Desinfecção , Matriz Extracelular de Substâncias Poliméricas/química , Glicerol , Glicerofosfolipídeos , Halogenação , Halogênios , Células Hep G2 , Humanos , Transcriptoma , Poluentes Químicos da Água/análise
16.
Nature ; 603(7902): E18-E20, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35322245

Assuntos
Cloro
17.
Bioengineered ; 13(4): 8558-8566, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35322730

RESUMO

To observe the application of two instruments for the quantitative detection of total chlorine in the water in the hemodialysis industry, thereby evaluating the accuracy of the two tools and the consistency of their results, and evaluating their practical significance for the safety of hemodialysis treatment. Two methods, based on diethyl-p-phenylenediamine spectrophotometry and amperometric methods, were employed to detect the total chlorine concentration in running water and in activated carbon tank effluent. Correlation analysis was performed to evaluate the accuracy of the two instruments. The Bland-Altman test was used to evaluate the consistency of the two methods. The total chlorine tester showed high accuracy and good repeatability in terms of detecting the total chlorine concentration in running water and activated carbon tank effluent. The residual chlorine sensor had high accuracy and good repeatability for detecting the concentrations of total and free chlorine, respectively, in running water. When detecting the concentrations of total and free chlorine in the effluent of the activated carbon tank, the two test results showed a moderate correlation. The two detection methods had good consistency for the detection of total chlorine concentrations in running water and activated carbon tank effluent. The two reviewed methods can monitor changes in the total chlorine in running water and activated carbon tank effluent. It is important to take timely measures when the total chlorine concentration of the activated carbon tank effluent reaches a certain warning value, and therefore to better ensure the safety of hemodialysis treatment.


Assuntos
Cloro , Purificação da Água , Carvão Vegetal , Cloro/análise , Diálise Renal , Água , Purificação da Água/métodos
18.
Environ Sci Technol ; 56(9): 5796-5807, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35321543

RESUMO

Developing economic and applicable catalysts with elegant chlorine resistance and organic byproduct inhibition capability is of great significance for chlorinated volatile organic compounds (Cl-VOCs) eco-friendly purification. Here, ternary CexSr1-xTiO3 catalysts with tunable surface acidity and oxygen species mobility were creatively fabricated using the hollow tubular-structured fruit hair of Platanus (FHP; a widespread greenery waste) as the scaffolding biotemplate. It is shown that the oxygen vacancy (Ov) triggered by the presence of Ce can optimize the synergy between the Lewis acid sites (LAS) and Brønsted acid sites (BAS). High concentration of Ov and BAS promotes the C-Cl cleavage of chlorobenzene (CB) and accelerates the desorption of Cl• radicals as inorganic chlorine. Simultaneously, the strong electron transfer within Ti-Ce-Sr linkage increases the acidity of LAS, resulting in the superior reducibility of Ce0.4Sr0.6TiO3 and facilitating the deep oxidation of dechlorination intermediates. Additionally, the spatial confinement of the tubular structure remarkably accelerates the CB flow rate and reduces the residence time of byproducts over the prepared catalysts. Owing to these, CB can be efficiently destructed over Ce0.4Sr0.6TiO3 with selectivity of CO2 and inorganic chlorine dramatically enhanced, respectively, approximately 16 and 21 times at 275 °C compared to those of pure SrTiO3. The present work provides a feasible and promising strategy for engineering efficient catalysts for heterogeneous thermocatalytic reactions for industrial-scale Cl-CVOC destruction.


Assuntos
Cloro , Oxigênio , Catálise , Cloretos , Clorobenzenos/química , Oxirredução
19.
Environ Sci Technol ; 56(7): 4132-4141, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35302737

RESUMO

Identifying disinfection byproducts (DBPs) with high health risk is an unresolved challenge. In this study, six members of a new class of aromatic nitrogenous DBPs─2-chloroaniline, 2-bromoaniline, 2,4-dichloroaniline, 2-chloro-4-bromoaniline, 4-chloro-3-nitroaniline, and 2-chloro-4-nitroaniline─are reported as DBPs in drinking water for the first time. Haloanilines completely degraded within 1 h in the presence of chlorine (1 mg/L), while about 20% remained in the presence of chloramine (1 mg/L) after 120 h. Haloanilines showed high stability in the absence of disinfectants, with <30% degradation at pH 5-9 over 120 h. Eight haloanilines were determined in chloraminated finished water and tap water at total concentrations of up to 443 ng/L. The most abundant was 2-bromoaniline, with a median concentration of 104 ng/L. The cytotoxicity of eight haloanilines and regulated trichloromethane and dichloroacetic acid (DCAA) was evaluated using Hep G2 cell assay. The EC50 values of eight haloanilines were 1-2 orders of magnitude lower than those of the regulated DBPs. The lowest toxic concentration of 2-chloro-4-nitroaniline was 1 µM, 500 times lower than that of DCAA. The formation and control of haloanilines in drinking water warrant further investigation.


Assuntos
Desinfetantes , Água Potável , Poluentes Químicos da Água , Purificação da Água , Cloro , Desinfetantes/toxicidade , Desinfecção , Halogenação , Nitrogênio , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
20.
Int J Food Microbiol ; 369: 109632, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35299047

RESUMO

Chlorine dioxide (ClO2) is commonly generated by mixing sodium chlorite and acid. This study aimed to evaluate how acid affects the release kinetics and antimicrobial property of ClO2. Solutions made with weak acids released ClO2 more slowly and had higher stability than those made with hydrochloric acid. Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes were treated with 1, 2.5, and 5 ppm ClO2 for 3 or 5 min. Lettuce inoculated with the pathogenic bacteria were treated with 2.5 and 5 ppm ClO2 for 5 min. The effects of peptone load at 0.01% and 0.02% on the antimicrobial efficacy of ClO2 were investigated in S. Typhimurium cell suspensions. The contribution of acids alone at the pH of the ClO2 solutions to bacterial reduction was also evaluated. The 2.5 ppm ClO2 solutions made with citric acid, lactic acid, and malic acid showed higher reductions in all three bacteria than ClO2 made with hydrochloric acid and sodium bisulfate. The 5 ppm ClO2 solutions produced with organic acids reduced populations of all bacterial strains from 7 log CFU/mL to undetectable level in 3 min, except S. Typhimurium treated by ClO2 produced with lactic acid. On inoculated Romaine lettuce model, 5 ppm ClO2 produced with lactic acid and malic acid resulted in the highest reduction of E. coli O157:H7, S. Typhimurium, and L. monocytogenes of approximately 1.4, 1.7, and 2.4 log CFU/g, respectively. The antimicrobial efficacy of ClO2 made with HCl and NaHSO4 were affected by 0.01% and 0.02% peptone load, respectively. Food-grade organic acids produced aqueous ClO2 solutions with stronger antimicrobial properties than inorganic acids. The acids alone at the pH of ClO2 did not show significant bacterial reductions.


Assuntos
Anti-Infecciosos , Desinfetantes , Escherichia coli O157 , Listeria monocytogenes , Anti-Infecciosos/farmacologia , Cloro/farmacologia , Compostos Clorados , Contagem de Colônia Microbiana , Desinfetantes/farmacologia , Microbiologia de Alimentos , Óxidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...