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The structural transformation of metal-organic frameworks (MOFs) has attracted increasing interests, which has not only produced various new structures but also served as a fantastic platform for MOF-based kinetic analysis. Multiple reaction conditions have been documented to cause structural transformation; nevertheless, central metal-induced topological alteration of MOFs is rare. Herein, we reported a structural transformation of a 2D layered Cd-MOF driven by Cd(II) ions. After being submerged in the aqueous solution of cadmium nitrate, the twofold interpenetrated 2D network of [Cd(hsb-2)(bdc)·5H2O]n [HSB-W10; bdc: 1,4-benzenedicarboxylate; hsb-2:1,2-bis(4'-pyridylmethylamino)-ethane] was converted into a novel noninterpenetrated 2D network [Cd1.5(hsb-2)(bdc)1.5(H2O)2·H2O]n (HSB-W16). This partial dissolution-recrystallization process was investigated by integrating controlled experiments, 1H NMR spectra, and photographic tracking analysis. Furthermore, a novel strategy combining in situ multicomponent dye encapsulation and central metal-triggered structural transformation was developed for the fabrication of MOF materials with white-light emission. By adopting this strategy, different dye guest molecules were concurrently introduced into the HSB-W16 host matrix, leading to a range of white-light-emitting MOF composites. This work will enable detailed studies of solid-state transformations and demonstrate a promising application prospect for structural transformation.
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Cobalt sulfide is deemed a promising anode material, owing to its high theoretical capacity (630 mAh g-1 ). Due to its low conductivity, fast energy decay, and the huge volume change during the lithiation process limits its practical application. In this work, a simple and large-scale method are developed to prepare Co1-x S nanoparticles embedding in N-doped carbon/graphene (CSCG). At a current density of 0.2 C, the reversible discharge capacity of CSCG maintains 937 mAh g-1 after 200 cycles. The discharge capacity of CSCG maintains at 596 mAh g-1 after 500 cycles at the high current density of 2.0 C. The excellent performance of CSCG is due to its unique structural features. The addition of rGO buffered volume changes while preventing Co1-x S from crushing/aggregating during the cycle, resulting in multiplier charge-discharge and long cycle life. The N-doped carbon provides a simple and easy way to achieve excellent performance in practical applications. Combined with density functional theory calculation, the presence of Co-vacancies(Co1-x ) increases more active site. Moreover, N-doping carbon is beneficial to the improve adsorption energy. This work presents a simple and effective structural engineering strategy and also provides a new idea to improve the performance of Li-ion batteries.
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Recent research has primarily focused on the utilization of reductants as activators for Fe(VI) to generate high-valent iron species (Fe(IV)/Fe(V)) for the degradation of emerging organic contaminants (EOCs). However, a significant drawback of this approach arises from the reaction between reductants and ferrates, leading to a decrease in oxidation capacity. This study introduces a novel discovery that highlights the potential of the iron(III)-(1,10-phenanthroline) (Fe(III)-Phen) complex as an activator, effectively enhancing the degradation of EOCs by Fe(VI) and augmenting the overall oxidation capacity of Fe(VI). The degradation of EOCs in the Fe(VI)/Fe(III)-Phen system is facilitated through two mechanisms: a direct electron transfer (DET) process and electron shuttle action. The DET process involves the formation of a Phen-Fe(III)-Fe(VI)* complex, which exhibits a stronger oxidation ability than Fe(VI) alone and can accept electrons directly from EOCs. On the other hand, the electron shuttle process utilizes Fe(III)-Phen as a redox mediator to transfer electrons from EOCs to Fe(VI) through the Fe(IV)/Fe(III) or Fe(IV)/Fe(II)/Fe(III) cycle. Moreover, the Fe(III)-Phen complex can improve the utilization efficiency of Fe(V) by preventing its self-decay. This study's findings may present a viable option for utilizing an effective catalyst to enhance the oxidation of EOCs by Fe(VI) and Fe(V).
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Poluentes Químicos da Água , Purificação da Água , Compostos Férricos , Elétrons , Substâncias Redutoras , Oxirredução , FerroRESUMO
Fe(IV) and Fe(V) are promising oxidants for the selective removal of emerging organic contaminants (EOCs) from water under near-neutral conditions. The Fe(III)-assisted electrochemical oxidation system with a BDD anode (Fe(III)-EOS-BDD system) has been employed to generate Fe(VI), while the generation and contributions of Fe(IV) and Fe(V) have been largely ignored. Thus, we examined the feasibility and involved mechanisms of the selective degradation of EOCs in the Fe(III)-EOS-BDD system under near-neutral conditions. It was found that Fe(III) application selectively accelerated the electro-oxidation of phenolic and sulfonamide organics and made the oxidation system be resistant to interference from Cl-, HCO3-, and humic acid. Several lines of evidence indicated that EOCs were decomposed via direct electron-transfer process on the BDD anode and by Fe(IV) and Fe(V) but not Fe(VI), besides HOâ¢. Fe(VI) was not generated until the exhaustion of EOCs. Furthermore, the overall contributions of Fe(IV) and Fe(V) to the oxidation of phenolic and sulfonamide organics were over 45%. Our results also revealed that Fe(III) was oxidized primarily by HO⢠to Fe(IV) and Fe(V) in the Fe(III)-EOS-BDD system. This study advances the understanding of the roles of Fe(IV) and Fe(V) in the Fe(III)-EOS-BDD system and provides an alternative for utilizing Fe(IV) and Fe(V) under near-neutral conditions.
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Diamante , Poluentes Químicos da Água , Boro , Compostos Férricos , Água , Oxidantes , Oxirredução , EletrodosRESUMO
Despite decades of research on phenols oxidation by permanganate, there are still considerable uncertainties regarding the mechanisms accounting for the unexpected parabolic pH-dependent oxidation rate. Herein, the pH effect on phenols oxidation was reinvestigated experimentally and theoretically by highlighting the previously unappreciated proton transfer. The results revealed that the oxidation of protonated phenols occurred via proton-coupled electron transfer (PCET) pathways, which can switch from ETPT (electron transfer followed by proton transfer) to CEPT (concerted electron-proton transfer) or PTET (proton transfer followed by electron transfer) with an increase in pH. A PCET-based model was thus established, and it could fit the kinetic data of phenols oxidation by permanganate well. In contrast with what was previously thought, both the simulating results and the density functional theory calculation indicated the rate of CEPT reaction of protonated phenols with OH- as the proton acceptor was much higher than that of deprotonated phenols, which could account for the pH-rate profiles for phenols oxidation. Analysis of the quantitative structure-activity relationships among the modeled rate constants, Hammett constants, and pKa values of phenols further supports the idea that the oxidation of protonated phenols is dominated by PCET. This study improves our understanding of permanganate oxidation and suggests a new pattern of reactivity that may be applicable to other systems.
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Elétrons , Prótons , Concentração de Íons de Hidrogênio , Oxirredução , Transporte de Elétrons , Fenóis , CinéticaRESUMO
Current techniques for identifying and quantifying sulfate radicals (SO4·-) in SO4·--based advanced oxidation processes (SR-AOPs) are unsatisfactory due to their low selectivity, poor reliability, and limited feasibility for real-time quantification. In this study, naproxen (NAP) was employed as a turn-on luminescent probe for real-time quantification of SO4·- in SR-AOPs. The chemiluminescence(CL) yield (ΦCL) of the reaction of NAP with SO4·- was first determined to be 1.49 × 10-5 E mol-1 with the bisulfite activation by cerium(IV) [Ce(IV)/BS] process. Then, the maximum peak concentrations of SO4·- in the Ce(IV)/BS-NAP process was quantified to be â¼10-11 M based on the derived equation. Since ΦCL of the reaction of NAP with SO4·- was much greater than that with other reactive oxidizing species (ROS), the developed CL method worked well in selective quantification of SO4·- in various SR-AOPs (e.g., the activation of peroxymonosulfate and persulfate by iron processes). Finally, the electron transfer from NAP to SO4·- was proposed to be the critical step for CL production. This work provides a novel CL method for real-time quantification of SO4·-, which facilitates the development of SR-AOPs and their application in water and wastewater treatment.
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Poluentes Químicos da Água , Purificação da Água , Naproxeno , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Oxirredução , SulfatosRESUMO
The poor oxidation capacity of the Fe(II)/S2O82- [Fe(II)/PDS] system at pH > 3.0 has limited its wide application in water treatment. To unravel the underlying mechanism, this study systematically evaluated the possible influencing factors over the pH range of 1.0-8.0 and developed a mathematical model to quantify these effects. Results showed that â¼82% of the generated Fe(IV) could be used for pollutant degradation at pH 1.0, whereas negligible Fe(IV) contribution was observed at pH 7.5. This dramatic decline of Fe(IV) contribution with increasing pH dominantly accounted for the pH-dependent performance of the Fe(II)/PDS process. Unexpectedly, Fe(II) could consume â¼80% of the generated SO4â¢- non-productively under both acidic and near-neutral conditions, while the larger formation of Fe(III) precipitates at high pH inhibited the SO4â¢- contribution mildly. Moreover, the strong Fe(II) scavenging effect was difficult to be compensated for by slowing down the Fe(II) dosing rate. The competition of dissolved oxygen with PDS for Fe(II) was insignificant at pH ≤ 7.5, where the second-order rate constants for reactions of Fe(II) with oxygen were much lower than or comparable to that between Fe(II) and PDS. These findings could advance our understanding of the chemistry and application of the Fe(II)/PDS process.
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Poluentes Ambientais , Poluentes Químicos da Água , Compostos Férricos , Compostos Ferrosos , Concentração de Íons de Hidrogênio , Oxirredução , Oxigênio , Poluentes Químicos da Água/análiseRESUMO
Although periodate-based advanced oxidation processes have been proven to be efficient in abating organic contaminants, the activation properties of different periodate species remain largely unclear. Herein, by highlighting the role of H4IO6-, we reinvestigated the pH effect on the decontamination performance of the H2O2/periodate process. Results revealed that elevating pH from 2.0 to 10.0 could markedly accelerate the rates of organic contaminant decay but decrease the amounts of organic contaminant removal. This pH-dependent trend of organic contaminant degradation corresponded well with the HO· yield and the variation of periodate species. Specifically, although 1O2 could be detected at pH 9.0, HO· was determined to be the major reactive oxidizing species in the H2O2/periodate process under all the tested pH levels. Furthermore, it was suggested that only H4IO6- and H2I2O104- could serve as the precursors of HO·. The second-order rate constant for the reaction of H2I2O104- species with H2O2 was determined to be â¼1199.5 M-1 s-1 at pH 9.0, which was two orders of magnitude greater than that of H4IO6- (â¼2.2 M-1 s-1 at pH 3.0). Taken together, the reaction pathways of H2O2 with different periodate species were proposed. These fundamental findings could improve our understanding of the periodate-based advanced oxidation processes.
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Peróxido de Hidrogênio , Poluentes Químicos da Água , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Ácido Periódico , Raios Ultravioleta , Poluentes Químicos da Água/químicaRESUMO
The iron(II)-activated peroxymonosulfate [Fe(II)/PMS] process is effective in degrading organic contaminants with a rapid oxidation stage followed by a slow one. Nevertheless, prior studies have greatly underestimated the degradation rates of organic contaminants in the rapid oxidation stage and ignored the differences in the kinetics and mechanism of organic contaminants degradation in these two oxidation stages. In this work, we investigated the kinetics and mechanisms of organic contaminants in this process under acidic conditions by combining the stopped-flow spectrophotometric method and batch experiments. The organic contaminants were rapidly oxidized with rate constants of 0.18-2.9 s-1 in the rapid oxidation stage. Meanwhile, both Fe(IV) and SO4â¢- were active oxidants and contributed differently to the degradation of different organic contaminants in this stage. Additionally, the presence of Cl- promoted the degradation of both phenol and estradiol but the effects of Br- and humic acid on phenol degradation differed from those on estradiol degradation in the rapid oxidation stage. In contrast, the degradation of phenol and estradiol was slow and the amounts of Fe(IV) and SO4â¢- generated were small in the slow oxidation stage. This work updates the fundamental understanding of the degradation of organic contaminants in this process.
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Ferro , Peróxidos , Compostos Ferrosos , OxirreduçãoRESUMO
Literature works reported that organic cocontaminants could be degraded during Cr(VI), a contaminant, reduction by sulfite (Cr(VI)/sulfite process). However, the role of Cr(V) and Cr(IV) intermediates in the Cr(VI)/sulfite process has been overlooked. In this study, we confirmed the generation of Cr(V) and proposed a new mechanism for the decomposition of coexisting organic contaminants during Cr(VI)/sulfite reactions occurring in oxygenated solutions at pHini 4.0 with the molar ratio of sulfite to Cr(VI) of 10.0. UV-visible and electron paramagnetic resonance (EPR) spectra indicate that Cr(V) was the predominant Cr intermediates in oxygenated solutions, while Cr(IV) accumulated in deoxygenated solutions. The contribution of Cr(V) to the degradation of organic contaminants was verified by the EPR spectra collected at 2 K and using methyl phenyl sulfoxide as a probe compound. Both Cr(V) and SO4â¢- contributed to the decomposition of organic contaminants in oxygenated solutions, with the relative contributions from each species being strongly dependent on properties of the target organic cocontaminants. The key mechanisms responsible for Cr(V) accumulation were supported by DFT calculations, and the degradation kinetics of organic cocontaminants was simulated with the program Kintecus 6.51. This work advances the fundamental understanding of the oxidative transformation of coexisting organic contaminants in this process.
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Cromo , Sulfitos , Espectroscopia de Ressonância de Spin Eletrônica , Cinética , OxirreduçãoRESUMO
Fe(VI) has received increasing attention since it can decompose a wide range of trace organic contaminants (TrOCs) in water treatment. However, the role of short-lived Fe(IV) and Fe(V) in TrOC decomposition by Fe(VI) has been overlooked. Using methyl phenyl sulfoxide (PMSO), carbamazepine, and caffeine as probe TrOCs, we observed that the apparent second-order rate constants (kapp) between TrOCs and Fe(VI) determined with the initial kinetics data were strongly dependent on the initial molar ratios of TrOCs to Fe(VI). Furthermore, the kapp value increases gradually as the reaction proceeds. Several lines of evidence suggested that these phenomena were ascribed to the accumulation of Fe(IV) and Fe(V) arising from Fe(VI) decay. Kinetic models were built and employed to simulate the kinetics of Fe(VI) self-decay and the kinetics of PMSO degradation by Fe(VI). The modeling results revealed that PMSO was mainly degraded by Fe(IV) and Fe(V) rather than by Fe(VI) per se and Fe(V) played a dominant role, which was also supported by the density functional theory calculation results. Given that Fe(IV) and Fe(V) have much greater oxidizing reactivity than Fe(VI), this work urges the development of Fe(V)/Fe(IV)-based oxidation technology for efficient degradation of TrOCs.
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Poluentes Químicos da Água , Purificação da Água , Ferro , Cinética , OxirreduçãoRESUMO
The present work describes the monitoring system of the real-time strain response on the curing process of epoxy resin from the initial point of curing to the end, and the change in strain during temperature changes. A simple mould was designed to embed the strain gauge, thermometer, and quartz standard sample into the epoxy resin, so that the strain and the temperature were simultaneously measured and recorded. A cryogenic-grade epoxy resin was tested and the Differential Scanning Calorimetry (DSC) was used to analyse the curing process. Based on the DSC results, three curing processes were adopted to investigate their influence on strain response as well as residual strain of the epoxy resin. Moreover, impact strength of the epoxy resin with various curing temperatures were tested and the results indicate that the curing plays a crucial role on the mechanical properties. The method will find cryogenic application of epoxy adhesives and epoxy resin based composites to monitor the strain during the curing process as well as the cryogenic service.
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Here, an RNA-sequencing assay revealed long noncoding RNAs (lncRNAs) with an ectopic expression between colon cancer (CC) and normal colon epithelial cells, in which lncRNA B4GALT1-AS1 exhibited the highest change. A 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay indicated that B4GALT1-AS1 knockdown had no effect on CC cell viability, however, cell clone formation analysis showed that B4GALT1-AS1 knockdown attenuated the capacity of cell clone formation. Additionally, gene set enrichment analysis of this data set revealed that positive enrichment of stem cell-differentiated signatures and negative embryonic stem cell function and adult tissue stem module were observed in CC cells with B4GALT1-AS1 knockdown. Furthermore, B4GALT1-AS1 knockdown suppressed the stemness-marker expression, the ability of cell spheroid formation, and ALDH1 activity in CC cells. Mechanistically, RNA-sequencing data found that the Hippo pathway in cancer was shown on pathways mostly upregulated by B4GALT1-AS1 knockdown, and B4GALT1-AS1 directly bound to the yes-associated protein (YAP), a downstream executor of the Hippo pathway, and B4GALT1-AS1 knockdown promoted the nuclear cytoplasm translocation of YAP and decreased YAP transcriptional activity. Notably, YAP overexpression attenuated the inhibitory effects mediated by B4GALT1-AS1 knockdown. Our results identify the direct binding of lncRNA B4GALT1-AS1 to YAP, which is responsible for CC cell stemness.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Movimento Celular/genética , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Células-Tronco Neoplásicas/metabolismo , RNA Longo não Codificante/metabolismo , Fatores de Transcrição/genética , Transcrição Gênica , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Sobrevivência Celular , Células Clonais , Transição Epitelial-Mesenquimal , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica , RNA Longo não Codificante/genética , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAPRESUMO
In this work, the kinetics and mechanisms of the reductive removal of BrO3- by sulfite in air atmosphere were determined. BrO3- could be effectively reduced by sulfite at pHini 3.0-6.0, and the reduction rate of BrO3- increased with decreasing pH. The coexisting organic contaminants with electron-rich moieties could be degraded, accompanied with BrO3- reduction by sulfite. The reaction stoichiometries of -Δ[sulfite]/Δ[bromate] were determined to be 3.33 and 15.63 in the absence and presence of O2, respectively. Many lines of evidence verified that the main reactions in the BrO3-/sulfite system in air atmosphere included the reduction of BrO3- to HOBr and its further reduction to Br-, as well as the oxidation of H2SO3 by BrO3- to form SO3·- and its further transformation to SO4·-. Moreover, SO4·- rather than HOBr was determined to be the major active oxidant in the BrO3-/sulfite system. SO3·- played a key role in the over-stoichiometric sulfite consumption because of its rapid reaction with dissolved oxygen. However, the formed SO3·- was further oxidized by BrO3- in the N2 atmosphere. BrO3- reduction by sulfite is an alternative for controlling BrO3- in water treatment because it was effective in real water at pHini ≤ 6.0.
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Poluentes Químicos da Água , Purificação da Água , Bromatos , Oxirredução , Sulfitos , EnxofreRESUMO
Although the Fe(VI)-sulfite process has shown great potential for the rapid removal of organic contaminants, the major active oxidants (Fe(IV)/Fe(V) versus SO4â¢-/â¢OH) involved in this process are still under debate. By employing sparingly soluble CaSO3 as a slow-releasing source of SO32-, this study evaluated the oxidation performance of the Fe(VI)-CaSO3 process and identified the active oxidants involved in this process. The process exhibited efficient oxidation of a variety of compounds, including antibiotics, pharmaceuticals, and pesticides, at rates that were 6.1-173.7-fold faster than those measured for Fe(VI) alone, depending on pH, CaSO3 dosage, and the properties of organic contaminants. Many lines of evidence verified that neither SO4â¢- nor â¢OH was the active species in the Fe(VI)-CaSO3 process. The accelerating effect of CaSO3 was ascribed to the direct generation of Fe(IV)/Fe(V) species from the reaction of Fe(VI) with soluble SO32- via one-electron steps as well as the indirect generation of Fe(IV)/Fe(V) species from the self-decay of Fe(VI) and Fe(VI) reaction with H2O2, which could be catalyzed by uncomplexed Fe(III). Besides, the Fe(VI)-CaSO3 process exhibited satisfactory removal of organic contaminants in real water, and inorganic anions showed negligible effects on organic contaminant decomposition in this process. Thus, the Fe(VI)-CaSO3 process with Fe(IV)/Fe(V) as reactive oxidants may be a promising method for abating various micropollutants in water treatment.
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Poluentes Químicos da Água , Purificação da Água , Cálcio , Compostos Férricos , Peróxido de Hidrogênio , Ferro , Oxirredução , SulfitosRESUMO
RE (Radiation enteritis) has been characterized by the inflammation reaction, and in this study, we aim to explore inflammatory cytokines and underlying mechanism involved in the pathogenesis of RE. Luciferase assay was performed to explore whether polymorphism affected the expression of let-7, and also validated let-7 directly regulated f IL-6 expression. Then Elisa was performed to study the mechanism of rs13293512 polymorphism associated with enteritis occurrence. And Western-blot and real-time PCR were performed to verify the relationship between let-7 and IL-6. 380 colorectal cancer patients were recruited, and all participants were genotyped. We found that occurrence probability of enteritis patients carried CC genotype (32%) was much higher than that in TT and TC groups (15%). In addition, we showed that the presence of the minor (C) allele of the polymorphism in the promoter region of let-7 substantially reduced the transcription activity of let-7, furthermore, we validated that let-7 directly regulated IL-6 expression by using luciferase reporter system. Moreover, IL-6 was highly expressed in peripheral blood and colonic mucosa samples genotyped as CC compared to those in TT and TC groups, furthermore, IL-6 was highly expressed in peripheral blood and colonic mucosa samples from participants with enteritis than without enteritis, whereas let-7 was highly expressed in peripheral blood and colonic mucosa samples genotyped as TT and TC compared to those in CC groups. Let-7 polymorphism (rs13293512) was associated with risk of RE in the colorectal cancer patients who received radiotherapy.
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Neoplasias Colorretais , Enterite , MicroRNAs , Polimorfismo Genético , Regiões Promotoras Genéticas , RNA Neoplásico , Lesões por Radiação , Idoso , Povo Asiático/genética , Colo/metabolismo , Colo/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Neoplasias Colorretais/radioterapia , Enterite/genética , Enterite/metabolismo , Enterite/patologia , Feminino , Humanos , Interleucina-6/biossíntese , Interleucina-6/genética , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , MicroRNAs/biossíntese , MicroRNAs/genética , Pessoa de Meia-Idade , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Lesões por Radiação/genética , Lesões por Radiação/metabolismo , Lesões por Radiação/patologiaRESUMO
Permanganate can be activated by bisulfite to generate soluble Mn(III) (noncomplexed with ligands other than H2O and OH(-)) which oxidizes organic contaminants at extraordinarily high rates. However, the generation of Mn(III) in the permanganate/bisulfite (PM/BS) process and the reactivity of Mn(III) toward emerging contaminants have never been quantified. In this work, Mn(III) generated in the PM/BS process was shown to absorb at 230-290 nm for the first time and disproportionated more easily at higher pH, and thus, the utilization rate of Mn(III) for decomposing organic contaminant was low under alkaline conditions. A Mn(III) generation and utilization model was developed to get the second-order reaction rate parameters of benzene oxidation by soluble Mn(III), and then, benzene was chosen as the reference probe to build a competition kinetics method, which was employed to obtain the second-order rate constants of organic contaminants oxidation by soluble Mn(III). The results revealed that the second-order rate constants of aniline and bisphenol A oxidation by soluble Mn(III) were in the range of 10(5)-10(6) M(-1) s(-1). With the presence of soluble Mn(III) at micromolar concentration, contaminants could be oxidized with the observed rates several orders of magnitude higher than those by common oxidation processes, implying the great potential application of the PM/BS process in water and wastewater treatment.
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Compostos de Manganês/química , Manganês/química , Óxidos/química , Sulfitos/química , Poluentes Químicos da Água/química , Compostos de Anilina/química , Compostos Benzidrílicos/química , Cinética , Oxirredução , Fenóis/química , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodosRESUMO
Nanomaterials with superhydrophobic properties are promising as drag-reducing coatings. However, debates regarding whether superhydrophobic surfaces are favorable for drag reduction require further clarification. A quantified water adhesive force measurement is proposed as a metric and its effectiveness demonstrated using three typical superhydrophobic coatings on model ships with in situ sailing tests.
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In this study, modified polyamide fibers were used as biocarriers to enrich dense biofilms in a multi-stage biological contact oxidation reactor (MBCOR) in which partitioned wastewater treatment zone (WTZ) and bioaugmentation zone (BAZ) were established to enhance the removal of methyl orange (MO) and its metabolites while minimizing sludge yields. WTZ exhibited high biomass loading capacity (5.75 ± 0.31 g/g filler), achieving MO removal rate ranging from 68 % to 86 % under different aeration condition within 8 h in which the most dominant genus Chlorobium played an important role. In the BAZ, Pseudoxanthomonas was the dominant genus while carbon starvation stimulated the enrichment of chemoheterotrophy and aerobic_chemoheterotrophy genes thereby enhanced the microbial utilization of cell-released substrates, MO as well as its metabolic intermediates. These results revealed the mechanism bioaugmentation on MBCOR in effectively eliminating both MO and its metabolites.
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Biodegradação Ambiental , Reatores Biológicos , Corantes , Oxirredução , Águas Residuárias , Purificação da Água , Águas Residuárias/química , Corantes/metabolismo , Corantes/química , Purificação da Água/métodos , Compostos Azo/metabolismo , Compostos Azo/química , Têxteis , Indústria Têxtil , Poluentes Químicos da Água/metabolismo , Biomassa , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodosRESUMO
Electrochemical advanced oxidation processes (EAOPs) have shown great promise for treating industrial wastewater contaminated with phenolic compounds. However, the presence of chloride in the wastewater leads to the production of undesirable chlorinated organic and inorganic byproducts, limiting the application of EAOPs. To address this challenge, we investigated the potential of incorporating Fe(II) and Fe(III) into the EAOPs with a boron-doped diamond (BDD) anode under near-neutral conditions. Our findings revealed that both Fe(II) and Fe(III) facilitated the generation of high-valent iron-oxo species (Fe(IV) and Fe(V)) in the anodic compartment, thereby reducing the oxidation contribution of reactive chlorine species. Remarkably, the addition of 1000 µM Fe(II) under high chloride conditions resulted in over a 2.8-fold increase in the oxidation rate of 50 µM phenolic contaminants at pH 6.5. Furthermore, 1000 µM Fe(II) contributed to a reduction of more than 66% in the formation of chlorinated byproducts, consequently enhancing the biodegradability of the treated water. Additionally, transitioning from batch mode to continuous flow mode further amplified the positive effects of Fe(II) on the EAOPs. Overall, this study presents a modified electrochemical approach that simultaneously enhanced the degradation of phenolic contaminants and improved the biodegradability of wastewater with high chloride concentrations.