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1.
Bioresour Technol ; 404: 130916, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38823560

RESUMO

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.


Assuntos
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/métodos
2.
Sci Total Environ ; 866: 161275, 2023 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-36587705

RESUMO

Environmental pollution has become an issue of increasing concern in China, owing to the country's rapid economic development. Atmospheric particulate matter (PM) is known to be an important parameter in air quality monitoring; further, bioaerosol forms a crucial component of PM. As the climatic environments in the north and south of Xinjiang, China, are significantly different, here, atmospheric PM samples collected from three cities, Shihezi, Yining, and Tumushuk, located in different directions, were analysed for a better understanding of the spatial distribution patterns of microbial community composition of Xinjiang. The16s rDNA and 18 s rDNA were used to locate bacteria and fungi in PM2.5, PM10, and total suspended particulate matter (TSP) at the species level and genus level, and the microbial communities with the top 15 abundances were selected for analysis. The reports indicate that the most abundant group in Shihezi and Yining was Cenchrus_americanus, which belongs to Proteobacteria. The remaining 14 dominant species had their own distribution pattern in each city. The most dominant strain in Tumushuk was Bacillus_taeanensis, but this strain was not detected in Yining and Shihezi. Similarly, the most predominant fungus in Tumushuk (Microdorylaimus_miser under Myriophyllum) was not detected in the other two cities. The analysis of the effect of environmental impact factors on bacteria and fungi revealed that the impact factors such as temperature, humidity, and wind speed had a greater effect on microorganisms, while O3 had a negative correlation with most microorganisms, owing to its toxicity. Overall, the results of this study show that short-range transported air masses have a greater impact on local pollutants and microorganisms.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Microbiota , Material Particulado/análise , Cidades , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Bactérias , Fungos , Estações do Ano , Monitoramento Ambiental/métodos
3.
Chemosphere ; 313: 137504, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36513205

RESUMO

In this work, different synthetic methods of polymeric aluminum silicate sulfate (PASS) and their coagulability to oily sewage were comparatively studied. PASS was synthesized by two methods: gravity supercritical method and basic titration method, denoted as PASS-B and PASS-S, respectively. The results show that the PASS prepared by gravity supercritical method has better Alb and stability. By applying two coagulants to oily sewage, it was found that PASS-B exhibited better turbidity and oil removal. It was found that PASS-B still has good coagulation by testing its coagulation after placing the coagulant for 2 months. In acidic test water, PASS-B exhibited stronger deprotonation ability. Finally, the polymerization mechanism and coagulation mechanism of PASS-B were analyzed in combination with Al morphology distribution and coagulation experiments. Gravity supercritical method as a new polymerization method may replace the traditional preparation method of inorganic polymer coagulants in the future, especially in large-scale applications.


Assuntos
Esgotos , Purificação da Água , Sulfatos , Silicatos , Silicatos de Alumínio , Água , Purificação da Água/métodos , Floculação
4.
Toxics ; 10(7)2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35878247

RESUMO

Environmentally persistent free radicals (EPFRs) are a kind of hazardous substance that exist stably in the atmosphere for a long time. EPFRs combined with fine particulate matter (PM2.5) can enter the human respiratory tract through respiration, causing oxidative stress and DNA damage, and they are also closely related to lung cancer. In this study, the inhalation risk for EPFRs in PM2.5 and factors influencing this risk were assessed using the equivalent number of cigarette tar EPFRs. The daily inhalation exposure for EPFRs in PM2.5 was estimated to be equivalent to 0.66-8.40 cigarette tar EPFRs per day. The concentration level and species characteristics were investigated using electron paramagnetic resonance spectroscopy. The concentration of EPFRs in the study ranged from 1.353-4.653 × 1013 spins/g, and the types of EPFRs were mainly oxygen- or carbon-centered semiquinone-type radicals. Our study showed that there is a strong correlation between the concentrations of EPFRs and conventional pollutants, except for sulfur dioxide. The major factors influencing EPFR concentration in the atmosphere were temperature and wind speed; the higher the temperature and wind speed, the lower the concentration of EPFRs. The findings of this study provide an important basis for further research on the formation mechanism and health effects of EPFRs.

5.
Environ Sci Pollut Res Int ; 29(39): 59403-59413, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35384536

RESUMO

The problems are associated with microplastic (MP) pollution of global concern. However, little is known about the pollution characteristics and sources of MPs in urban green-belt soils. Therefore, this study investigated MP pollution in 11 sampling sites (22 green belts) in Shihezi City. The results showed that the abundance of MPs (0.02-5.00 mm) ranged from 287 ± 100 items/kg dw to 3227 ± 155 items/kg dw (mean + SD). Fibers (69.9%) accounted for the majority of MPs, and the MPs were mainly black (36.7%) and 0.02-0.5 mm (64.8%). The main types of MPs were polystyrene (PS) and polyethylene (PE). Compared with agricultural soil, the color and composition of green-belt soil MPs are diverse, which means that the source of green-belt soil MPs is more diverse. In different types of green-belt soil, MP pollution of industrial green land is more serious. Through cluster analysis and spatial distribution, fragments and fibers were found to have similar sources, mainly originating from food and textile industrial activities. This study provides important information for revealing MP pollutions in urban green-belt soils.


Assuntos
Microplásticos , Poluentes Químicos da Água , China , Monitoramento Ambiental , Plásticos , Solo , Poluentes Químicos da Água/análise
6.
J Hazard Mater ; 427: 128166, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-34996000

RESUMO

The electrochemical degradation performance of sulfamethoxazole (SMX) was studied in the presence of humic acid (HA) by using a Ti/Ti4O7/ß-PbO2 anode. The electrochemical degradation efficiency of SMX decreased from 93.4% to 45.8% in 50 min after the addition of 25 mg L-1 HA. The pseudo-first-order kinetic rate constant decreased by 71.4%, and the EEO value increased from 63.8 Wh L-1 to 90.9 Wh L-1. HA and its degradation intermediates could compete for free radicals, especially for ·OH, with SMX. The analytical results obtained using UPLC-ESI-Q-TOF-MS showed that 18 degradation intermediates were identified in the coexistence of SMX and HA. Four imine intermediates were formed through the reactions between the aniline moieties of SMX and quinone groups in the HA structure through covalent bonds. Furthermore, the relative abundances of the intermediates demonstrated that the imine intermediates were complex and stable during electrochemical degradation.


Assuntos
Sulfametoxazol , Poluentes Químicos da Água , Substâncias Húmicas , Iminas , Cinética , Oxirredução , Poluentes Químicos da Água/análise
7.
Sci Total Environ ; 821: 153181, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35051458

RESUMO

Microplastic (MP) pollution has attracted much attention. To understand the characteristics of atmospheric MP pollution in Shihezi, Northwest China, this study used pine needles from trees in Shihezi City as passive samplers. MP contamination was found in all pine needle samples, with an average concentration of 16.52 ± 3.76 items/g. MPs were mainly in the shape of fragments (<0.05 mm). Differences in MP pollution were observed in different functional areas. The abundance of MPs in pine needles was the highest on the main traffic road (19.02 ± 2.52 items/g). Spectral analysis showed that the main polymer of MPs was polyethylene (17.2%), followed by polystyrene (15.5%) and polypropylene (13.8%). By analyzing the principal components and spatial distribution, fragments and pellets were found to have similar sources (mainly industrial activities), whereas films and fibers were influenced by traffic flow. The source of films was related to the packaging industry. The purpose of this study was to provide a reference for the future use of pine needles as atmospheric MP passive samplers, for the traceability and prevention of urban atmospheric MP pollution and for the formulation of national atmospheric MP environmental standards.


Assuntos
Microplásticos , Poluentes Químicos da Água , China , Cidades , Monitoramento Ambiental , Plásticos , Poluentes Químicos da Água/análise
8.
Analyst ; 146(20): 6323-6332, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34554156

RESUMO

A nitrogen-doped Fe-MOF shows a high specific surface area and excellent electrical conductivity after high temperature carbonization. A novel electrochemical sensor based on a N@Fe-MOF@C loaded dual-template molecularly imprinted polymer (DTMIP) modified glassy carbon electrode (GCE) was proposed for the rapid and ultra-sensitive simultaneous detection of clenbuterol hydrochloride (CLB) and ractopamine (RAC). N@Fe-MOF@C combined with a MIP significantly enhanced the electrical signal. Cyclic voltammetry (CV) was used to detect CLB and RAC. The electrochemical polymerization was conducted with O-phenylenediamine as the functional monomer and CLB and RAC as template molecules. The factors affecting the sensor response were optimized. Under the optimal experimental conditions, the CV current response showed a linear range of 10-12-8 × 10-9 M for both CLB and RAC, and the detection limit (LOD) for both CLB and RAC was 3.03 × 10-13 M (S/N = 3). This electrochemical sensing system has high sensitivity, selectivity, excellent reproducibility, repeatability and stability. The recoveries of the actual samples (97.4%-101.2%) and reasonable relative standard deviations (RSDs) (1.06%-3.17%) indicate the practicability of the sensor system. The system has high application value in the rapid detection of CLB and RAC in clenbuterol hydrochloride tablets, human urine and raw pork.


Assuntos
Clembuterol , Impressão Molecular , Técnicas Eletroquímicas , Eletrodos , Humanos , Limite de Detecção , Polímeros Molecularmente Impressos , Fenetilaminas , Reprodutibilidade dos Testes
9.
Artigo em Inglês | MEDLINE | ID: mdl-34501593

RESUMO

Wulungu Lake is a vital fishery area in Xinjiang. However, the concentration, enrichment rules, and sources of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the aquatic organisms, have rarely been investigated. The results suggest that the concentrations of As, Ni, Pb, and Zn were higher than those recommended by the national standards for edible fish in some species. Hg, Ni, Cu, Pb, Cr, and Zn in the fish were dependent on the concentration of trace metals in the water environment (p < 0.05). The body weights of the fish were significantly negatively correlated with only Hg (p < 0.05); however, their body lengths were significantly positively correlated with As, Cu, Zn, and Hg contents. Values of δ13C ‰ (δ15N ‰) for the entire fish food web was found to range from -19.9‰ (7.37‰) to -27.7‰ (15.9‰), indicating a wide range of trophic positions and energy sources. Based on the linear correlation, As, Cu, Cd, and Zn contents were positively correlated with δ15N (p < 0.05), and bioaccumulation was observed in the fish. The target hazard quotient (THQ) of all fish species was less than 1, indicating the absence of potential risks to human health.


Assuntos
Mercúrio , Metais Pesados , Poluentes Químicos da Água , Animais , Cádmio , China , Monitoramento Ambiental , Humanos , Isótopos , Lagos , Chumbo , Mercúrio/análise , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise , Zinco
10.
Anal Chim Acta ; 1176: 338768, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34399892

RESUMO

N-doped nickel carbide spheres (N-NiCSs) were synthesised for the first time by controlling the type of surfactant, surfactant-to-Ni molar ratio, reaction temperature, and reaction time. The morphology, composition, and electrochemical behaviour of the synthesised spheres revealed that the spheres presented a large specific surface area, abundant pores, and good conductivity, with excellent electrocatalytic performance. A glassy carbon electrode-modified with N-NiCSs was used for the simultaneous identification of hydroquinone (HQ), catechol (CC), and resorcinol (RS) utilising differential pulse voltammetry. The oxidation peaks of HQ, CC, and RS were observed at 9.8, 119, and 470 mV, respectively (vs. SCE). Under optimal conditions, the oxidation peak currents of HQ, CC, and RS were linear in the concentration ranges of 0.005-100 µM, 0.05-200 µM, and 5-500 µM, respectively. The detection limits of HQ, CC, and RS were 0.00152 µM, 0.015 µM, and 0.24 µM (S/N = 3), respectively. The sensitivities of HQ, CC, and RS were 4.635, 2.069, and 0.985 µA µM-1 cm-2 (S/N = 3), respectively. The fabricated sensor was successfully used to detect HQ, CC, and RS in hair dye, whitening cream, and local tap water samples. Moreover, the sensor presented a good repeatability, reproducibility, and stability during cosmetic testing and a relatively wide linear range, an ultralow detection limit, and an ultrahigh sensitivity.


Assuntos
Cosméticos , Nitrogênio , Carbono , Níquel , Reprodutibilidade dos Testes
11.
Analyst ; 146(16): 5135-5142, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34282821

RESUMO

Nitrogen doped carbon dots were synthesized using the hydrothermal reaction of cellulose and urea, and then carbonized in a N2 atmosphere at a high temperature to prepare N-doped carbon dots decorated with manganese oxide nanospheres (N-CMOS) formed using cetyltrimethylammonium bromide (CTAB) and MnO. The introduction of N-CMOS resulted in a large specific surface area, abundant pores, favourable conductivity and an excellent electrocatalytic performance. A glassy carbon electrode modified with N-CMOS was used for the simultaneous identification of paracetamol (AP) and p-aminophenol (PAP) utilising differential pulse voltammetry. Under optimum conditions, the electrical sensor showed a wide linear range of 0.1-100 µM for PAP and 0.1-80 µM for AP, with detection limits of 0.0456 and 0.0303 µM (S/N = 3), respectively. The sensitivities for detecting PAP and AP were calculated as 1.615 and 1.971 µA µM-1 cm-2, respectively. The sensitivity and limit of detection (LOD) meet the requirements of detection of drug impurity limits in tablets. In addition, the sensor has been successfully applied to detect PAP and AP in paracetamol tablets. The constructed sensor not only possesses a superior repeatability, reproducibility and stability, but a relatively wide linear range, and a superior detection limit and sensitivity.


Assuntos
Carbono , Nanosferas , Acetaminofen , Aminofenóis , Técnicas Eletroquímicas , Eletrodos , Limite de Detecção , Compostos de Manganês , Óxidos , Reprodutibilidade dos Testes
12.
Sci Total Environ ; 781: 146635, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-33798885

RESUMO

In this study, polyacrylate-divinylbenzene (PADVB) microspheres were facilely prepared via the precipitation polymerization method, and the microspheres were used as an efficient adsorbent for the removal of trace level organic micropollutants (OMPs) from environmental waters. Preparation conditions of PADVB microspheres were optimized, and the characterizations of the microspheres were performed using a scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption/desorption isotherms. The microspheres had broad-spectrum adsorption ability for various organic micropollutants containing hydroxy, amidogen, aromatic or heteroaromatic ring in their chemical structure, such as atrazine, 2,4 dichlorophenol, 2,4 dibromophenol, 2,6 dichlorophenol, sulfamethoxazole, estradiol, and bisphenol A. Besides, the effects of initial concentration, initial pH value, adsorption time, and the type of adsorbates on the adsorption performance were investigated systematically. PADVB microspheres could be used for removing trace OMPs from environmental water. Monolayer and homogeneous sorption process occurred on the surface of PADVB microspheres through chemisorption mechanisms. The X-ray photoelectron spectroscopy (XPS) and FT-IR spectrum of PADVB microspheres before and after adsorption proved that the OMPs adsorption onto PADVB microspheres was mainly due to the formation of the hydrogen bond and π-π electron-donor-acceptor (EDA) interactions. Besides, PADVB microspheres can be recovered for reuse via (low-pressure) microfiltration and could be regenerated sufficiently by using 80% (v/v) ethanol.

13.
Talanta ; 225: 122042, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33592765

RESUMO

To overcome the problem of incorrect levodopa (LD) dosage in the treatment of Parkinson's disease, a new analytical tool is urgently needed for accurately determining the concentration of LD in human fluids. Herein, an effective and stable sensor based on a Co-single-atomic-site catalyst (Co-SASC)-modified glassy carbon electrode (Co-SASC/GCE) was developed for the determination of LD concentration. The physicochemical characterization of Co-SASC is systematically investigated. It has excellent thermal stability, graphitization degree, and a large specific surface area. Benefiting from its porous structure for kinetically fast catalysis and component advantages for fix a single cobalt atom to improve stability, Co-SASC/GCE exhibits a superior electrochemical response. Under optimal conditions (pH 2.0, coating amount is 10 µg), an ideal linear relationship is achieved between the logarithm of the peak current of the sensor and the logarithm of LD concentration. The linear range is 0.1-200 µM, and the limit of detection (LOD) is 0.033 µM. After a simple pretreatment, LD in human serum is detected by Co-SASC/GCE with excellent stability and selectivity. As such, this work enlarges the existing electrochemical sensor toolbox by offering a reasonable design and synthesis protocol for advanced materials to accurately determine LD in human fluids for the clinical treatment of Parkinson's disease.


Assuntos
Cobalto , Levodopa , Catálise , Técnicas Eletroquímicas , Eletrodos , Humanos , Limite de Detecção
14.
RSC Adv ; 11(46): 28476-28487, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35478594

RESUMO

Dissolved organic matter (DOM) is ubiquitous in natural water and reacts with disinfectants to form disinfection by-products (DBPs). The analysis of DOM in raw water is helpful in evaluating the formation potential of DBPs. However, there is relatively little research on the DOM identification of raw water in northern China. In this study, the sources and characteristics of DOM were investigated in the samples collected from the Manas River. Dissolved organic carbon (DOC), UV254, specific ultraviolet absorbance, and fluorescence indices (fluorescence index, humification index, and biological index) were measured to characterize the DOM, and trihalomethanes (THMs) were quantified following formation potential tests with free chlorine. The maximum amount of total trihalomethane formation potential (THMsFP) was 225.57 µg L-1. The DOM of the Manas River consisted of microorganisms and soil resources. The excitation-emission matrix combined with parallel factor analysis (EEM-PARAFAC) identified microbial humus (C1, 54%) and tryptophan-like protein (C2, 46%). PARAFAC components were evaluated as the precursor surrogate parameters of THMsFP. Additionally, the linear THMsFP correlation was stronger with C1 + C2 (r = 0.529, p < 0.01) than with C1 (r = 0.485, p < 0.01). Thus, C1 + C2 is an accurate THMsFP precursor surrogate parameter for the Manas River, and the use of fluorescence spectroscopy may be a robust alternative for predicting DOC removal.

15.
Ecotoxicol Environ Saf ; 208: 111477, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091771

RESUMO

The ubiquity of microplastics in the environment has caused great influence to ecosystems and seriously threatened human health. To better understand the variation in microplastics in different seasons in an inland freshwater environment and determine the sources of microplastic pollution and its migration features, this study investigated the characteristics of microplastic pollution during dry (April) and wet (July) seasons in surface water of the Manas River Basin, China. The size, color, shape, area distribution and compound composition of microplastics were studied. Moreover, the risk of microplastic contamination was explored based on risk assessment models. The results demonstrated that the degree of pollution caused by microplastic abundance was minor in this study area. The average abundance of microplastics in April (17 ± 4 items/L) was higher than that in July (14 ± 2 items/L). The range in the abundance of microplastics in April and July were 22 ± 5-14 ± 3 items/L and 19 ± 2-10 ± 1 items/L, respectively. Highly hazardous polymers such as Polyvinyl chloride (PVC) and Polycarbonate (PC) have a significant impact on the results of the evaluation of the presence of microplastics. This study is an important reference for understanding the characteristics of the seasonal variation in microplastics in inland freshwater environments and has practical significance, as it will allow relevant agencies to accurately assess the pollution level of microplastics in different seasons. It is of practical significance to understand the sources and sinks of microplastics in inland freshwater environment.


Assuntos
Monitoramento Ambiental , Microplásticos/análise , Poluentes Químicos da Água/análise , China , Clima , Ecossistema , Poluição Ambiental , Água Doce , Humanos , Plásticos , Medição de Risco/métodos , Rios , Estações do Ano , Água
16.
Environ Sci Pollut Res Int ; 27(32): 40262-40276, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32661967

RESUMO

PM2.5 induces pulmonary inflammation via oxidative stress, and this role in the lungs is widely accepted, but studies on whether oxidative stress and inflammation can self-recover and be fully restored are limited. In this study, the oxidative stress and inflammation in the lungs of rats, which were first exposed to different PM2.5 dosages (0, 0.5, 3.0, and 15.0 mg/kg body weight) and different recovery days (0, 15, and 30 days) and then were exposed to the same PM2.5 dosages (30 mg/kg b.w.) after 30 days of recovery, were investigated. Results showed that the activity of superoxide dismutase (SOD) was significantly inhibited, and the levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß) significantly increased. These changes were accompanied with damage to the pathological structure of the rat lungs. After stopping PM2.5 exposure, the difference between the PM2.5 group and the control group gradually decreased with the extension of recovery time. However, when the rats were again exposed to the same dose of PM2.5, the levels of IL-6, IL-1ß, TNF-α, MDA, and iNOS were significantly increased, and the activities of SOD and GSH-Px were significantly inhibited in the high-dose group. And the high-dose group was accompanied by more severe lung pathological structural damage. Results showed that PM2.5 could induce oxidative stress and inflammatory damage in the lungs of rats, and these damages gradually recovered as exposure ceased, but increased lung susceptibility in rats.


Assuntos
Estresse Oxidativo , Material Particulado , Animais , Inflamação/induzido quimicamente , Pulmão , Malondialdeído , Material Particulado/toxicidade , Ratos , Superóxido Dismutase , Fator de Necrose Tumoral alfa
17.
Sci Total Environ ; 710: 136099, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-31923655

RESUMO

Microplastics, as a new type of pollutant, are widely found in various environmental media, and their effects on organisms are of great concern to society. However, research on the characteristics of microplastic pollution in inland rivers in China is still rare. The Manas River, which is located in the interior of Northeast China, was selected as the research object. The occurrence and pollution characteristics of microplastics in the surface water of the river were explored. The range of abundance of microplastics in the Manas River Basin was 21 ± 3-49 ± 3 items/L. Fibrous microplastics were dominant in all sites (88.0%); their size was mainly distributed between 0.1 and 1.0 mm (82.6%), and white and black were the dominant colours (82.9%). In addition, the size range of flaky-type microplastics were investigated in this study, which was principally between 2.5 × 103-9.0 × 104 µm2 (84.5%). Infrared spectral analysis revealed that most of the selected particles were identified as microplastics, and polymer types of microplastics were dominated by polypropylene and polyethylene terephthalate (48.3%). This study can be used as a reference to better understand the contamination features of microplastics in inland rivers.

18.
RSC Adv ; 10(18): 10681-10688, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-35492926

RESUMO

Nano magnesium oxide has wide applications, and MgO with (111) facets has wider potential applications than MgO with (100) facets (e.g., in catalysis and adsorption). However, nano MgO with (111) polar faces has not been studied throughly, so the preparation of nano-octahedral MgO (N-O-MgO) with eight exposed (111) facets remains a great challenge. Herein, we successfully synthesised N-O-MgO via an effective solvothermal-solid-decomposition method and studied its adsorption performance. The obtained N-O-MgO showed excellent performance (229.36 mg g-1) for methyl orange (MO). The adsorption follows the pseudo-second-order kinetic equation and the Langmuir isotherm model. The dimensionless parameter R L (0.042) and Gibbs free energy ΔG (-6.538 kJ mol-1) revealed that the adsorption of MO on N-O-MgO was a spontaneous and feasible process. The adsorption of MO and methyl blue (MB) on N-O-MgO were studied to determine the adsorption sites. Based on these experiments and analysis, it was determined that the adsorption sites were magnesium ions and the adsorption mechanism was proposed to describe the adsorption process.

19.
ACS Synth Biol ; 8(10): 2295-2302, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31525958

RESUMO

Whole-cell biosensors have attracted considerable interests because they are robust, eco-friendly, and cost-effective. However, most of the biosensors harness the naturally occurring wild-type promoter, which often suffers from high background noise and low sensitivity. In this study, we demonstrate how to design the core elements (i.e., RNA polymerase binding site and transcription factor binding site) of the promoters to obtain a significant gain in the signal-to-noise output ratio of the whole-cell biosensor circuits. As a proof of concept, we modified the arsenite-regulated promoter from Escherichia coli K-12 genome, such that it has a lower background and higher expression. This was achieved by balancing the relationship between the number of ArsR binding sites (ABS) and the activity of the promoter and adjusting the location of the auxiliary ABS. A promoter variant ParsD-ABS-8 was obtained with an induction ratio of 179 (11-fold increase over the wild-type promoter) when induced with 1 µM arsenite. Importantly, the developed biosensor exhibited good dose-response in the range of 0.1 to 4 µM (R2 = 0.9928) of arsenite with a detection limit of ca. 10 nM. These results indicated that the engineered promoter modification approach could be used to improve the performance of whole-cell biosensors, thereby facilitating their practical application.


Assuntos
Arsenitos/metabolismo , Técnicas Biossensoriais/métodos , Regiões Promotoras Genéticas/genética , Sítios de Ligação/genética , Escherichia coli K12/genética , Escherichia coli K12/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Genes Reporter/genética
20.
Environ Sci Pollut Res Int ; 26(27): 28062-28070, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31359316

RESUMO

Drinking water is a main pathway of human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). These two compounds have been identified in environmental waters worldwide, but little is known about their occurrence in Xinjiang. In this study, 155 water samples were obtained from 37 locations across Ulungur River, Manasi River, and Tarim River in Xinjiang, and were assessed by using liquid chromatography tandem-mass spectrometry. PFOS and PFOA were detected in over 50% of the samples with mean concentrations of 3.194 ng/L for PFOS and 3.460 ng/L for PFOA. Spatial and regional distribution differences do exist among the three analyzed rivers. PFOS and PFOA in Manasi River were observed at the highest levels (especially in M10 and M11), but no aggravation occurred from 2014 to 2017. Seasonal variations of PFOS and PFOA concentrations showed that water samples collected during summer were higher than those in other three seasons. The occurrence, levels, and distribution patterns of PFOS and PFOA were investigated in the present study, which provides useful theory and data support for human health risk assessment. The findings of the present study can be considered for controlling these water pollutants in environmental waters.


Assuntos
Ácidos Alcanossulfônicos/análise , Caprilatos/análise , Monitoramento Ambiental , Fluorocarbonos/análise , Poluentes Químicos da Água/análise , China , Cromatografia Líquida , Humanos , Rios/química
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