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1.
J Hazard Mater ; 467: 133705, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38335618

RESUMO

Generation of sulfate radicals (SO4•-) from sulfite activation has emerged as a promising method for abatement of organic pollutants in the water and wastewater treatment. Co(II) has garnered attention due to its high catalytic activity in the sulfite activation, which is compromised by the slow Co(II)/Co(III) redox cycling. Regarding the regulation of Co(II) electronic structure via the complexation effect, monoethanolamine (MEA), a common chelator, is introduced into the Co(II)/sulfite system. MEA addition results in a significant improvement in iohexol abatement efficiency, increasing from 40% to 92%. The superior iohexol abatement relies on the involvement of SO4•-, hydroxyl radicals (HO•) and Co(IV). Hydrogen radical (•H) is unexpectedly detected, acting as a strong reducing agent, contributing to the reduction of Co(III). This enhancement of sulfite activation by MEA is due to the formation of the Co(II)-MEA complex, in which the complexation ratio of Co(II) and MEA is critical. Electrochemical characterization and theoretical calculations demonstrate that the complexation can facilitate the Co(II)/Co(III) redox cycling with the concomitant enhancement of sulfite activation. This work provides a new insight into the Co(II)/sulfite system in the presence of organic ligands.

2.
Environ Sci Pollut Res Int ; 30(12): 34827-34839, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36520295

RESUMO

Nano-zero-valent copper (nZVC) is a superior molecular oxygen (O2) activator for the abatement of organic pollutants due to its high electron utilization rate. However, the activation efficiency of O2 is compromised by the agglomeration tendency of nZVC particles and the concomitant reduction of the available active sites. To address this problem, the biochar (BC) with porous structure and abundant surface functional groups is utilized to disperse and stabilize nZVC for O2 activation (simplified as the nZVC/BC/O2 system) for efficient removal of tetracycline (TC). The nZVC/BC composite possesses a high specific area with well-distributed nZVC particles on the BC surface, which guarantees the superior dispersion and high reactivity in the activation of O2. The efficacy of the nZVC/BC/O2 system for TC abatement is evaluated and the underlying mechanism is elucidated. The results show that nZVC/BC/O2 system can achieve excellent removal of TC with the efficiencies of more than 85% in the pH range of 4.0-9.0, which originated from the combined action of complexation and degradation. The degradation is dominated by reactive oxygen species (ROS) including •OH, •O2- and 1O2 generated by Cu0/Cu+ activated O2 while the generation of Cu2+ via oxygen oxidation on the surface of nZVC/BC can remove TC by complexation adsorption. This study highlights the complexation and degradation in the removal of TC and can be expected to exhibit application prospects in the water and wastewater treatment.


Assuntos
Cobre , Poluentes Químicos da Água , Cobre/química , Carvão Vegetal/química , Tetraciclina/análise , Antibacterianos , Oxigênio , Poluentes Químicos da Água/análise , Adsorção
3.
Water Res ; 222: 118930, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35944409

RESUMO

Recently, iron-based heterogenous catalysts have received much attention in the activation of peracetic acid (PAA) for generating reactive radicals to degrade organic pollutants, yet the PAA activation efficiency is compromised by the slow transformation from Fe(III) to Fe(II). Herein, considering the electron-donating ability of reducing sulfur species, a novel advanced oxidation process by combining pyrite and PAA (simplified as pyrite/PAA) for the abatement of tetracycline (TC) is proposed in this study. In the pyrite/PAA process, TC can be completely removed within 30 min under neutral conditions by the synergy of homogeneous and heterogenous Fe(II) species. CH3C(O)OO• is the main radical generated from the pyrite/PAA process responsible for TC abatement. The excellent activation properties of pyrite can be attributed to the superior electron-donating ability of reducing sulfur species to facilitate the reduction of Fe(III). Meanwhile, the complexation of leached Fe2+ with TC favors PAA activation and concomitant TC abatement. In addition, the degradation pathways of TC and the toxicity of the degradation intermediates are analyzed. The pyrite/PAA process shows an excellent TC abatement efficacy in the pH range of 4.0∼10.0. The coexistence of Cl-, HCO3-, and HPO42- exhibits negligible effect on TC abatement, while the HA slightly inhibits the abatement rate of TC. This study highlights the efficient activation of PAA by pyrite and the important role of sulfur in promoting the conversion of Fe(III) to Fe(II) in the pyrite/PAA process.


Assuntos
Ácido Peracético , Poluentes Químicos da Água , Compostos Férricos , Compostos Ferrosos , Peróxido de Hidrogênio/química , Ferro/química , Oxirredução , Sulfetos , Enxofre , Tetraciclina
4.
J Hazard Mater ; 424(Pt D): 127653, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34801301

RESUMO

Peracetic acid (PAA) is an excellent oxidant that can produce multiple carbon-centered radicals (R•C). A novel advanced oxidation process (AOP) that combines PAA and nanoscale zero-valent iron (i.e. nZVI/PAA) is constructed to evaluate its performance toward tetracycline (TC) abatement. The nZVI/PAA process shows excellent abatement efficacy for TC in the pH range of 3.5-7.5. The presence of humic acid, HPO42- and HCO3- exerts inhibitory effects on TC abatement, while the presence of Cl- displays negligible influence in the nZVI/PAA process. Nanoscale zero-valent iron (nZVI) exhibits excellent reusability with no apparent variation in crystallinity. CH3C(O)OO• is the predominant active radical that contributes to TC abatement, in which leakage of Fe(II) from the nZVI surface is crucial for a radical generation. Due to the strong complexation tendency of TC towards Fe(II), the Fe(II)-TC complexes are formed, which significantly accelerates the PAA decomposition and TC abatement compared to free Fe(II). In addition, the degradation intermediates of TC are identified, and a possible degradation pathway is proposed. These results will be useful for the application of PAA-based AOPs in the treatment of water containing organic micropollutants.


Assuntos
Ácido Peracético , Poluentes Químicos da Água , Compostos Ferrosos , Ferro , Tetraciclina , Poluentes Químicos da Água/análise
5.
Environ Sci Pollut Res Int ; 27(21): 26965-26973, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32385823

RESUMO

Amino-functionalized ionic liquid biphasic solvents present excellent absorption capacity, regeneration ability, and energy consumption savings, which make them a possible candidate for CO2 capture. The kinetics and regeneration heat duty of the [TETAH][Lys]-ethanol-water system capturing CO2 were investigated in this work. The mass transfer and kinetic parameters, including the overall reaction rate constant (kov), the reaction rate constant (k2), and the enhancement factor (E), were assessed at diverse concentrations and temperatures. At 303.15 K, the k2 of CO2 capture into the [TETAH][Lys]-ethanol-water solution was 58,907.30 m3 kmol-1 s-1. The Arrhenius equation was introduced to evaluate the relations between k2 and the reaction temperature, which can be presented as [Formula: see text] The regeneration heat duty of the novel biphasic solvent was 35.5 and 62.39% lower than those of [TETAH][Lys]-water and the benchmark monoethanolamine solution, respectively. An efficient absorption performance and lower energy requirement indicate the great potential for this application.


Assuntos
Dióxido de Carbono , Líquidos Iônicos , Temperatura Alta , Cinética , Solventes
6.
Environ Sci Technol ; 54(10): 6281-6288, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32320224

RESUMO

To address the problems of high viscosity and difficult regeneration of the rich phase solution, a dual-functionalized ionic liquid ([DETAH][Tz]) was dissolved into a 1-propanol-water solvent to form a novel biphasic solvent for CO2 capture. The rich phase kept 96% of the total CO2 loading (1.713 mol mol-1) but only 44% of the total volume, and its viscosity was only 2.57 mPa s. As a regeneration promoter, 1-propanol helped the rich phase to maintain 90% of its initial loading after fifth regeneration. The high number of amine functional groups into [DETAH]+ and the equimolar reaction of [Tz]- provided the high CO2 loading, while [Tz]-H and 1-propanol ensured the high regeneration efficiency of the rich solution by enhancing the hydrolysis of RNCOO- to form HCO3-/CO32- and propyl carbonate. Due to a stronger polar and an aggregation of the CO2 absorption products in water, the CO2 products were enriched into the lower water phase while most of the 1-propanol was in the upper phase. The heat duty of [DETAH][Tz]-1-propanol-water was approximately 29.93% lower than [DETAH][Tz]-water (2.84 GJ ton-1 CO2) and 47.63% lower than MEA (3.80 GJ ton-1 CO2), which would be a promising candidate for CO2 capture.


Assuntos
Dióxido de Carbono , Líquidos Iônicos , Aminas , Solventes , Água
7.
Environ Sci Pollut Res Int ; 27(20): 25197-25208, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32347496

RESUMO

Sustainable management of dyeing industry is of paramount importance in order to minimize resource consumption and reduce related environmental impacts. Herein, an environmental study is conducted wherein life cycle assessment (LCA) is applied to a two-scenario process for Disperse blue 60 production with short and long processing chains with different (a) material types, (b) consumptions, (c) processes, and (d) functional units with yields of 300 t/a. The most important influenced substances of the two scenarios were sodium cyanide and electricity next. Results proved that the largest damage of the dye production was attributed to resources and reached 46 and 62 kPt in the two scenarios. Compared with the conventional coal-fired power generation, damaged values of electricity from nature gas (NG) could reduce from 102 to 86 kPt in scenarios 1 and from 123 to 104 kPt in scenarios 2, respectively. When the electricity switched from NG to solar power, the values of the two scenarios could further decrease by 17 and 27 kPt, respectively. Therefore, the process of scenario 1 with the short process chain was more environmentally friendly for the production of Disperse blue 60 owing to the more efficient process and lower resource consumption. Graphic abstract.


Assuntos
Carvão Mineral , Meio Ambiente , Eletricidade , Gás Natural
8.
Environ Pollut ; 260: 114038, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31995773

RESUMO

Copper ferrite (denoted as CuFe2O4MOF), prepared via a complexation reaction to obtain bimetal-organic frameworks (Cu/Fe bi-MOFs), followed by a combustion process to remove the MOF template, is employed as a heterogeneous activator to promote sulfite autoxidation for the removal of organic contaminants. At pH 8.0, more than 80% of the recalcitrant organic contaminant iohexol (10 µM) can be removed within 2 min by the activation of sulfite (500 µM) with CuFe2O4MOF (0.1 g L-1). CuFe2O4MOF exhibits more pronounced catalytic activity in accelerating sulfite autoxidation for iohexol abatement compared to that fabricated by hydrothermal and sol-gel combustion methods. Radical quenching studies suggest that the sulfate radical (SO4•-) is the main reactive species responsible for iohexol abatement. The performance of CuFe2O4MOF/sulfite for iohexol abatement can be affected by several critical influencing factors, including the solution pH and the presence of humic acid, Cl-, and HCO3-. The effect of the ionic strength and the results of the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis indicate that sulfite autoxidation in the presence of CuFe2O4MOF involves an inner-sphere interaction with the surface Cu(II) sites of CuFe2O4MOF. X-ray photoelectron spectroscopy (XPS) characterization suggests that the surface Cu(II)-Cu(I)-Cu(II) redox cycle is responsible for efficient SO4•- production from sulfite. Overall, CuFe2O4MOF can be considered an alternative activator for sulfite autoxidation for potential application in the treatment of organic-contaminated water.


Assuntos
Poluentes Ambientais , Iohexol , Estruturas Metalorgânicas , Sulfitos , Cobre , Oxirredução
9.
Sci Total Environ ; 695: 133836, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31756865

RESUMO

Sulfite has been recently emerging as an appealing sulfate radical (SO4•-) precursor for efficient treatment of organic contaminants. Due to the negligible autoxidation of sulfite, activators are often introduced to accelerate sulfite autoxidation and the concomitant generation of SO4•-. Present heterogeneous activators are mostly not very effective under mild conditions (pH 7.0-8.0). In this work, efficient activation of sulfite with copper oxides including Cu2O and CuO for iohexol degradation under mild pH conditions is proposed. In a comparison of iohexol degradation efficiency by sulfite autoxidation activated with different metal oxides (Co3O4, CoO, α-Fe2O3, γ-Fe2O3, CuO and Cu2O), CuO and Cu2O with lower toxicity are efficient activators and removal efficiencies of ~95% can be obtained at pH 8.0. SO4•- is identified to be the major species contributing to the removal of iohexol by electron paramagnetic resonance (EPR) spectroscopy and quenching experiment. Based on the effect of ionic strength and copper leaching, sulfite is proposed to interact with copper oxides via inner-sphere coordination. Effect of critical influencing parameters and efficacy of copper oxides in real water matrixes are investigated. The results suggest that using copper oxides as activators is a new alternative to promote sulfite autoxidation process for rapid contaminants degradation.

10.
Chemosphere ; 218: 458-467, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30485829

RESUMO

A novel amino-functionalized vermiculite (AVT)-supported nanoscale zero-valent iron (AVT-nZVI) was successfully synthesized for Cr(VI) removal from simulated electroplating rinse wastewater. Since the agglomeration and oxidation of nZVI could be weakened and the reaction rate between Cr(VI) and nZVI could be enhanced for the novel AVT-nZVI, an efficient Cr(VI) removal could be achieved. The experimental results showed that 100% of Cr(VI) removal was obtained with AVT-nZVI, whereas only 87.5% was achieved by nZVI after reacting for 60 min with 20.0 mg L-1 Cr(VI) (pH = 5.0). After four cycles, the removal efficiency of Cr(VI) by AVT-nZVI still maintained at above 70%, suggesting that AVT-nZVI exhibited a good performance of reusability. The stability of AVT-nZVI particles was better than nZVI, which was confirmed by the steady-state polarization measurements. Furthermore, the removal of Cr(VI) by AVT-nZVI was proved to be in accordance with the pseudo-second-order adsorption kinetics and Langmuir model. Based on the experiments and characterization, the reaction mechanism of Cr(VI) removal by AVT-nZVI was clarified. The protonated amino groups (-NH3+) on the AVT promoted negative Cr(VI) species to be adsorbed on AVT-nZVI surface. Besides, Cr(VI) was reduced by Fe (0) to Cr(III), which was eventually adsorbed on the surface of AVT-nZVI particles as the Cr(III)-Fe(III) co-precipitates.


Assuntos
Silicatos de Alumínio/química , Cromo/isolamento & purificação , Ferro/química , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cromo/química , Galvanoplastia , Cinética , Microscopia Eletrônica de Transmissão , Nanoestruturas/química , Oxirredução , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química , Difração de Raios X
11.
Chemosphere ; 160: 332-41, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27393969

RESUMO

Highly active Fe/Ni bimetallic nanocomposites were prepared by using the liquid-phase reduction method, and they were proven to be effective for Cr(VI) removal coupled with US irradiation. The US-assisted Fe/Ni bimetallic system could maintain a good performance for Cr(VI) removal at a wide pH range of 3-9. Based on the characterization of the Fe/Ni nanoparticles before and after reaction, the high efficiency of the mixed system could attribute to the synergistic effects of the catalysis of Ni(0) and US cavitation. Ni(0) could facilitate the Cr(VI) reduction through electron transfer and catalytic hydrogenation. Meanwhile, US could fluidize the Fe/Ni nanoparticles to increase the actual reactive surface area and clean off the co-precipitated Fe(III)-Cr(III) hydroxides to maintain the active sites on the surface of the Fe/Ni nanoparticles. Thus, compared with shaking, the US-assisted Fe/Ni system was more efficient on Cr(VI) removal, which achieved 94.7% removal efficiency of Cr(VI) within 10 min. The pseudo-first-order rate constant (kobs) in US-assisted Fe/Ni system (0.5075 min(-1)) was over 5 times higher than that under shaking (0.0972 min(-1)). Moreover, the Fe/Ni nanoparticles still have a good performance under US irradiation after 26 days aging as well as regeneration.


Assuntos
Cromo/análise , Ferro/química , Nanopartículas/química , Níquel/química , Ondas Ultrassônicas , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Cromo/química , Modelos Teóricos , Oxirredução , Propriedades de Superfície , Poluentes Químicos da Água/química
12.
Environ Sci Technol ; 49(17): 10728-35, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26236921

RESUMO

Though the mechanism of MEA-CO2 system has been widely studied, there is few literature on the detailed mechanism of CO2 capture into MEA solution with different CO2 loading during absorption/desorption processes. To get a clear picture of the process mechanism, (13)C nuclear magnetic resonance (NMR) was used to analyze the reaction intermediates under different CO2 loadings and detailed mechanism on CO2 absorption and desorption in MEA was evaluated in this work. The results demonstrated that the CO2 absorption in MEA started with the formation of carbamate according to the zwitterion mechanism, followed by the hydration of CO2 to form HCO3(-)/CO3(2-), and accompanied by the hydrolysis of carbamate. It is interesting to find that the existence of carbamate will be influenced by CO2 loading and that it is rather unstable at high CO2 loading. At low CO2 loading, carbamate is formed fast by the reaction between CO2 and MEA. At high CO2 loading, it is formed by the reaction of CO3(-)/CO3(2-) with MEA, and the formed carbamate can be easily hydrolyzed by H(+). Moreover, CO2 desorption from the CO2-saturated MEA solution was proved to be a reverse process of absorption. Initially, some HCO3(-) were heated to release CO2 and other HCO3(-) were reacted with carbamic acid (MEAH(+)) to form carbamate, and the carbamate was then decomposed to MEA and CO2.


Assuntos
Dióxido de Carbono/química , Etanolamina/análise , Absorção Fisico-Química , Adsorção , Aminas/química , Carbamatos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Hidrólise , Soluções
13.
Int J Biol Macromol ; 79: 719-25, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26038102

RESUMO

New materials of Fe3O4 magnetic microspheres were functionalized with carboxyl and prepared for carbonic anhydrase (CA) immobilization to capture CO2. The optimum conditions for immobilization, such as carrier dose, enzyme dose, pH, shaking speed, temperature and contact time, were determined. The pH and thermal stability of the free and the immobilized CA were compared. The results presented that the immobilized CA had a better enzyme activity, a higher pH and thermal stability than that of the free CA. Meanwhile, CO2 capture was respectively enhanced by the free and the immobilized CA in tris(hydroxymethyl) aminomethane (Tris) buffer solution. Moreover, the immobilized CA maintained 58.5% of its initial catalytic ability even after ten recovery cycles due to the protest of the magnetic microspheres. All the results confirmed the potential use of the carboxyl-functionalized Fe3O4 magnetic microspheres immobilized CA to remove CO2 from air or flue gas.


Assuntos
Dióxido de Carbono/química , Anidrases Carbônicas/química , Enzimas Imobilizadas/química , Óxido Ferroso-Férrico/química , Adsorção , Animais , Dióxido de Carbono/isolamento & purificação , Bovinos , Estabilidade Enzimática , Reutilização de Equipamento , Concentração de Íons de Hidrogênio , Soluções , Temperatura , Fatores de Tempo
14.
Bioresour Technol ; 172: 1-7, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25216123

RESUMO

Fe3O4 poly (styrene-glycidyl methacrylate) magnetic porous microspheres (MPPMs) were introduced to immobilize Klebsiella sp. FD-3, an iron-reducing bacterium applied to reduce Fe(III)EDTA. The effects of potential inhibitors (S(2-), SO3(2-), NO3(-), NO2(-) and Fe(II)EDTA-NO) on Fe(III)EDTA reduction were investigated. S(2-) reacted with Fe(III)EDTA as an electron-shuttling compound and enhanced the reduction. But Fe(III)EDTA reduction was inhibited by SO3(2-) and Fe(II)EDTA-NO due to their toxic to microorganisms. Low concentrations of NO3(-) and NO2(-) accelerated Fe(III)EDTA reduction, but high concentrations inhibited the reduction, whether by free or immobilized FD-3. The immobilized FD-3 performed better than freely-suspended style. The substrate mass transfer and diffusion kinetics in the porous microspheres were calculated. The value of Thiele modulus and effectiveness factors showed that the intraparticle diffusion was fairly small and neglected in this carrier. Fe(III)EDTA reduction fitted first-order model at low Fe(III)EDTA concentration, and changed to zero-order model at high concentrations.


Assuntos
Ácido Edético/metabolismo , Compostos Férricos/farmacologia , Compostos Inorgânicos/farmacologia , Klebsiella/metabolismo , Magnetismo , Microesferas , Ácidos Polimetacrílicos/farmacologia , Biodegradação Ambiental/efeitos dos fármacos , Células Imobilizadas/efeitos dos fármacos , Células Imobilizadas/metabolismo , Difusão , Cinética , Klebsiella/efeitos dos fármacos , Nitratos/farmacologia , Nitritos/farmacologia , Oxirredução/efeitos dos fármacos , Porosidade , Sulfitos/farmacologia
15.
Proteomics Clin Appl ; 7(11-12): 850-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24115602

RESUMO

PURPOSE: To identify biochemical markers in men with idiopathic infertility and normal sperm counts. EXPERIMENTAL DESIGN: We obtained proteomic profiling proteins in human spermatozoa following successful or unsuccessful pregnancy via assisted reproductive technology (ART) using 6-plex tandem mass tag (TMT) isobaric mass spectrometry. Our study design consisted of two groups: 1. The semen of 6 men whose sperm resulted in a clinical pregnancy following ART and 6 men whose semen did not result in a clinical pregnancy following ART. The results of differentiated mass spectrometry were validated by Western blotting. RESULTS AND DISCUSSION: A total of 2,045 proteins were detected in our cohort. 21 proteins were found to be differentially expressed (>1.2-fold) in men whose sperm resulted in a clinical pregnancy and those that did not. Using the results of bioinformatics analysis and Western Blotting, three proteins (A2LD1, ATP1B3 and FBXO2) were shown to have the same differential pattern (p<0.05) that was observed in the mass spectrometry analysis. CONCLUSIONS AND CLINICAL RELEVANCE: Proteomics may help identity a select cohort of men with abnormal semen parameters and aide infertility diagnoses.


Assuntos
Proteômica , Espermatozoides/metabolismo , Proteínas de Ciclo Celular/análise , Proteínas de Ciclo Celular/metabolismo , Cromatografia Líquida de Alta Pressão , Proteínas F-Box/análise , Proteínas F-Box/metabolismo , Feminino , Fertilização in vitro , Humanos , Inseminação Artificial Heteróloga , Masculino , Proteínas do Tecido Nervoso/análise , Proteínas do Tecido Nervoso/metabolismo , Gravidez , ATPase Trocadora de Sódio-Potássio/análise , ATPase Trocadora de Sódio-Potássio/metabolismo , Espectrometria de Massas em Tandem , gama-Glutamilciclotransferase/análise , gama-Glutamilciclotransferase/metabolismo
16.
Bioresour Technol ; 132: 210-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23411450

RESUMO

Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxides (NOx) removal by the integrated chemical absorption-biological reduction method, which determines the concentration of Fe(II) in the scrubbing liquid. A new Fe(III)EDTA reduction strain, named as FD-3, was isolated from mixed cultures used in the integrated NOx removal process and identified as Klebsiella sp. by 16S rDNA sequence analysis. The reduction abilities of FD-3 and the influence of nitrogen-containing compounds (Fe(II)EDTA-NO, NO3(-) and NO2(-)) and sulfur-containing compounds (SO4(2-), SO3(2-)) on the Fe(III)EDTA reduction were investigated. The results indicated that strain FD-3 could reduce Fe(III)EDTA efficiently. NO3(-), NO2(-) and Fe(II)EDTA-NO inhibit the reduction of Fe(III)EDTA and could also serve as electron acceptor for strain FD-3. SO3(2-) inhibited Fe(III)EDTA reduction while SO4(2-) had no obviously effect on Fe(III)EDTA reduction. The relationship between cell growth and Fe(III)EDTA reduction could be described by the models based on Logistic equation.


Assuntos
Biotecnologia/métodos , Compostos Férricos/metabolismo , Klebsiella/metabolismo , Óxidos de Nitrogênio/isolamento & purificação , DNA Ribossômico/genética , Ácido Edético/metabolismo , Klebsiella/genética , Modelos Biológicos , Óxidos de Nitrogênio/metabolismo , Oxirredução , Análise de Sequência de DNA , Especificidade da Espécie , Espectrofotometria Ultravioleta
17.
Bioresour Technol ; 130: 750-6, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23334160

RESUMO

Magnetic poly(styrene-glycidyl methacrylate) porous microspheres (MPPM) with high magnetic contents were prepared by surfactant reverse micelles and emulsion polymerization of monomers, in which the well-dispersed Fe(3)O(4) nanoparticles were modified by polyethylene glycol (PEG) and oleic acid (OA) respectively. The characterizations showed that both of the OA-MPPM and the PEG-MPPM were ferromagnetic, however, the OA-MPPM was used to immobilize the bacteria for more advantages. Therefore, the effects of monomer ratio, surfactant, crosslinker and amount of Fe(3)O(4) on the structure, morphology and magnetic contents of the OA-MPPM were investigated. Then, the OA-MPPM was utilized to immobilize Klebsiella sp. FD-3, an iron-reducing bacterium for Fe(III)EDTA reduction applied in NO(x) removal. Compared with free bacteria, the immobilized FD-3 showed a better tolerance to the unbeneficial pH and temperature conditions.


Assuntos
Compostos Férricos/metabolismo , Óxido Ferroso-Férrico/química , Klebsiella/metabolismo , Microesferas , Ácidos Polimetacrílicos/química , Células Imobilizadas/microbiologia , Reagentes de Ligações Cruzadas , Ácido Edético/metabolismo , Hexoses/química , Concentração de Íons de Hidrogênio , Óxidos de Nitrogênio , Ácido Oleico/química , Tamanho da Partícula , Polietilenoglicóis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios X
18.
Bioresour Technol ; 108: 169-75, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22281145

RESUMO

Magnetic Fe(3)O(4)-chitosan microspheres were prepared by co-precipitating of Fe(2+) and Fe(3+) ions with NaOH in the presence of chitosan. The saturated magnetization of the resulting material was 20.0 emu/g. Then these magnetic microspheres were employed to immobilize iron-reducing bacteria to improve the biological reduction of Fe(III)EDTA(-), which was one of the key steps in nitrogen oxides (NO(x)) removal by the integrated chemical absorption-biological reduction process. The immobilized bacteria performed well on Fe(III)EDTA(-) reduction than free bacteria, even under unfavorable pH and temperatures. Furthermore, the effects of NO(2)(-), NO(3)(-), SO(3)(-), and S(2-), the potential inhibition compounds in the scrubber solution, on the reduction of Fe(III)EDTA(-) by the immobilized and free bacteria were also studied.


Assuntos
Poluição do Ar/prevenção & controle , Bactérias/metabolismo , Quitosana/metabolismo , Compostos Férricos/metabolismo , Microesferas , Óxidos de Nitrogênio/metabolismo , Ácido Edético/metabolismo , Concentração de Íons de Hidrogênio , Magnetismo , Oxirredução , Temperatura
19.
Chemosphere ; 86(1): 76-82, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22014469

RESUMO

The acute toxicity of 13 quaternary ammonium compounds (QACs) to Chlorella pyrenoidosa and Scenedesmus quadricauda was investigated in the present study. Significant inhibition on algae biomass was observed and 96 h EC(50)-value of 13 QACs was tested. Sixteen physicochemical and quantum chemical parameters of the QACs were calculated using the semi-empirical MOPAC AMI method. The multiple linear regression (MLR) was employed to derive the quantitative structure-activity relationship (QSAR) models, by which the calculated parameters were correlated to the toxicity of QACs on the two green algaes. Results showed that the alkyl chain lengths (CL) and total connectivity (T(Con)) were the main descriptors in governing the log (1/EC(50)) values of the QACs in the two QSAR models. The two models had high predictive ability and stability, and two parameters were proved to have the general applicability in QSAR study of QACs congeners.


Assuntos
Chlorella/efeitos dos fármacos , Compostos de Amônio Quaternário/toxicidade , Scenedesmus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Análise dos Mínimos Quadrados , Dose Letal Mediana , Modelos Lineares , Modelos Estatísticos , Relação Quantitativa Estrutura-Atividade , Compostos de Amônio Quaternário/química , Especificidade da Espécie , Poluentes Químicos da Água/química
20.
Zhonghua Nan Ke Xue ; 17(9): 771-4, 2011 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-21961234

RESUMO

OBJECTIVE: To compare the outcomes of intracytoplasmic sperm injection (ICSI) for infertile males with Y-chromosome microdeletions and for those with azoospermia or severe oligospermia but without Y-chromosome microdeletions. METHODS: We retrospectively analyzed 56 cycles of ICSI for 48 infertile cases with Y microdeletions (Group A) and 94 cycles for 90 cases with azoospermia or severe oligospermia but without Y-chromosome microdeletions (Group B) during the same period. We compared the two groups in the females' age, duration of infertility, males' age, number of oocytes retrieved, number of ICSI oocytes, fertilization rate, good embryo rate, number of embryos transferred, implantation rate, clinical pregnancy rate, abortion rate, live birth rate and babies' sexes. RESULTS: There were no significant differences between Groups A and B in the females' age, duration of infertility, males' age, number of oocytes retrieved, number of ICSI oocytes and number of embryos transferred (P > 0.05), nor in the rates of fertilization (69.0% vs 73.2%), good embryos (53.3% vs 48.7%), implantation (24.0% vs 30.3%), biochemical pregnancy (41.1% vs 44.7%), clinical pregnancy (37.5% vs 35.1%), early abortion (4.8% vs 6.1%) and live birth (35.7% vs 29.2%) (P > 0.05). CONCLUSION: Y-chromosome microdeletions do not affect the outcomes of ICSI. The affected couples should be informed of the necessity of prenatal genetic diagnosis before embryo implantation and the inevitability of vertical transmission to male offspring.


Assuntos
Azoospermia/terapia , Infertilidade Masculina/terapia , Oligospermia/terapia , Transtornos do Cromossomo Sexual no Desenvolvimento Sexual/terapia , Adulto , Azoospermia/genética , Deleção Cromossômica , Cromossomos Humanos Y/genética , Feminino , Humanos , Infertilidade Masculina/genética , Masculino , Oligospermia/genética , Gravidez , Taxa de Gravidez , Estudos Retrospectivos , Aberrações dos Cromossomos Sexuais , Transtornos do Cromossomo Sexual no Desenvolvimento Sexual/genética , Injeções de Esperma Intracitoplásmicas , Resultado do Tratamento
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