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2.
J Environ Manage ; 270: 110868, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32721313

RESUMO

Acai seed was used herein as an Amazon biomass waste for the synthesis of activated and modified carbon in order to find a possible use for the large volume of residues generated during the processing of this fruit and to add value to this residue. Activated carbon materials were used to remove Pb2+, Fe2+, and Mg2+ metal ions from water. The efficiency of removal of these ions by the acai seed activated carbon was compared with that by commercial activated carbon. Activated carbon materials were prepared by carbonization and chemical activation using two KOH impregnation ratios, namely 1:1 (ACK1) and 5:1 (ACK5), by mass. These samples were modified by treatment with nitric acid under microwave heating (ACK1-M) and (ACK5-M), respectively. The result of the elemental analysis indicated that this biomass has carbon and sulfur contents of 43.29% and 0.10% wt, respectively. The textural parameters showed that the obtained activated carbon samples presented high surface areas between 1462 and 2774 m2 g-1. Raman analysis revealed the different degrees of graphitization of the activated carbon materials. Boehm titration identified the presence of phenolic, carboxylic, and lactonic groups in samples that were confirmed by Fourier transform infrared spectroscopy. In the metal adsorption tests, ACK5-M showed better removal efficiency, reaching 86% removal for Pb2+, 69% for Fe2+, and 8% for Mg2+in 1 h of contact time; these results were superior to those obtained for commercial carbon. The results indicated that acai seed can be used for the production of activated carbon and can also be used for metal removal.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água/análise , Adsorção , Biomassa , Íons , Cinética , Metais , Água
3.
Water Sci Technol ; 81(7): 1471-1478, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32616699

RESUMO

SiO2 gel was formed on the grain surface of silica sand by hydrolysis and condensation of tetraethyl orthosilicate in water with the addition of 1-butylamine. The resultant product was a composite consisting of sand grains with mesoporous silica coating containing alkylamine inside. This composite exhibited basicity in the wastewater from copper electroplating due to its release of amine. As a result, the strongly acidic wastewater was neutralized and the co-precipitation of complex metal ions occurred. It was shown that up to 12 major metal ions in the wastewater could be simultaneously removed under static condition at room temperature by using the sand composite. The Fe and Cu in the wastewater could be removed completely, while the concentrations of Al, Cd, Ti, V, and Zn in the wastewater were reduced by two to three orders of magnitude. After the removal of multiple metal ions from the electroplating wastewater, the used sand was further applied as a raw material for making a silicate glass. The glass was chemically stable and thus the heavy metal ions from the wastewater were immobilized.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Cobre , Galvanoplastia , Íons , Areia , Dióxido de Silício , Águas Residuárias
4.
Environ Monit Assess ; 192(8): 484, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32617676

RESUMO

As the application of nanoparticles (NPs) and their release to the environment has increased, it is important to verify their toxicity, with a special emphasis on particle solubilization and the interaction of NP mixtures. In the current study, a model luminescent bacteria, Vibrio fischeri, was employed to test the acute toxicity of individual NPs and their binary mixtures, including metal NPs (ZnNPs, CuNPs) and metal oxide NPs (ZnONPs, CuONPs). The independent action model was used to reflect the synergistic, additive, or antagonistic interactions of binary mixtures of these NPs. The results showed that the median effective concentration (EC50) inhibited the luminescence of V. fischeri were 20.5, 4.1, 11.6, and 118.7 mg L-1 for ZnNPs, CuNPs, ZnONPs, and CuONPs, respectively, suggesting that the toxicity of these NPs to V. fischeri were as the following order: CuNPs > ZnONPs > ZnNPs > CuONPs. The combined effect of NPs were found to be antagonistic for CuNPs-ZnONPs and CuNPs-CuONPs, synergistic for CuONPs-ZnNPs, CuNPs-ZnNPs, and ZnONPs-CuONPs, and additive for ZnNPs-ZnONPs, revealing a complex pattern of possible interactions. The differences of dissolved metal ions partly accounted for the different combined toxicity of binary mixtures of NPs. The findings have important implications for better understanding the true environmental risk of NP mixtures.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Aliivibrio fischeri , Monitoramento Ambiental , Íons , Luminescência
5.
Bone Joint J ; 102-B(7): 832-837, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32600130

RESUMO

AIMS: We have previously demonstrated raised cobalt and chromium levels in patients with larger diameter femoral heads, following metal-on-polyethylene uncemented total hip arthroplasty. Further data have been collected, to see whether these associations have altered with time and to determine the long-term implications for these patients and our practice. METHODS: Patients from our previous study who underwent Trident-Accolade primary total hip arthroplasties using a metal-on-polyethylene bearing in 2009 were reviewed. Patients were invited to have their cobalt and chromium levels retested, and were provided an Oxford Hip Score. Serum ion levels were then compared between groups (28 mm, 36 mm, and 40 mm heads) and over time. RESULTS: Metal ion levels were repeated in 33 patients. When comparing the results of serum metal ion levels over time, regardless of head size, there was a significant increase in both cobalt and chromium levels (p < 0.001). Two patients with larger head sizes had undergone revision arthroplasty with evidence of trunnion damage at surgery. Two patients within the 40 mm subgroup had metal ion levels above the MHRA (Medicines and Healthcare Products Regulatory Agency) threshold for detailed investigation. The increase in cobalt and chromium, when comparing the 36 mm and 40 mm groups with those of the 28 mm group, was not significant (36 mm vs 28 mm; p = 0.092/p = 0.191; 40 mm vs 28 mm; p = 0.200/p = 0.091, respectively). There was no difference, between femoral head sizes, when comparing outcome as measured by the Oxford Hip Score. CONCLUSION: This study shows an increase in cobalt and chromium levels over time for all modular femoral head sizes in patients with metal-on-polyethylene bearings, with two patients demonstrating ion levels above the MHRA threshold for failure, and a further two patients requiring revision surgery. These results may have clinical implications regarding longer term follow-up of patients and future implant choice, particularly among younger patients. Cite this article: Bone Joint J 2020;102-B(7):832-837.


Assuntos
Artroplastia de Quadril/métodos , Cromo/sangue , Cobalto/sangue , Prótese de Quadril , Adulto , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/instrumentação , Feminino , Humanos , Íons , Masculino , Pessoa de Meia-Idade , Polietileno , Desenho de Prótese
6.
Bone Joint J ; 102-B(7_Supple_B): 116-121, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32600200

RESUMO

AIMS: This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. METHODS: Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. RESULTS: On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant increase in aluminum (p < 0.001) among all groups compared with medium only. CONCLUSION: These results indicated that macrophages were able to attach to and affect the oxide surface of stainless steel and titanium alloy discs. Cite this article: Bone Joint J 2020;102-B(7 Supple B):116-121.


Assuntos
Prótese Articular , Macrófagos/química , Aço Inoxidável , Titânio , Vitálio , Ligas , Animais , Sobrevivência Celular , Cromo/análise , Meios de Cultura , Íons , Ferro/análise , Camundongos , Microscopia Eletrônica de Varredura , Níquel/análise , Óxido Nítrico/análise
7.
Chemosphere ; 257: 127145, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32497836

RESUMO

Sources of airborne particulates (PM10) were investigated in two contrasting sites over central Indo-Gangetic Plain (IGP), one representing a rural background (Mirzapur) and another as an urban pollution hotspot (Varanasi). Very high PM10 concentration was noted both in Varanasi (178 ± 105 µgm-3; N:435) and Mirzapur (131 ± 56 µgm-3; N:169) with 72% and 62% of monitoring days exceeded the national air quality standard, respectively. Particulate-bound elements contribute significant proportion of PM10 mass (15%-18%), with highest contribution from Ca (7%-10%) and Fe (2%-3%). Besides, presence of Zn (1%-3%), K (1%-2%) and Na (1%-2%) was also noted. Water-soluble ionic species contributed 15%-19% of particulate mass, primarily by the secondary inorganic aerosols (SIA). Among the SIA, sulphate (5%-7%) and nitrate (4%) were prominent, contributing 59%-62% of the total ionic load, especially in winter. Particulate-bound metallic species and ions were selectively used as signatory molecules and source apportionment of PM10 was done by multivariate factor analysis. UNMIX was able to extract particulate sources in both the locations and crustal resuspensions (dust/-soil) were identified as the dominant source contributing 57%-63% of PM10 mass. Secondary aerosols were the second important source (17%-23%), followed by emissions from biomass/-refuse burning (10-19%). Transport of airborne particulates from upper IGP by prevailing westerly were identified as the important contributor of particulates, especially during high particulate loading days. Health risks associated to particulate-bound toxic metal exposure were also assessed. Non-carcinogenic health risk was within the permissible limit while there is possibility of elevated risk for PM10-bound Cr and Cd, if adequate control measures are not in place.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Aerossóis/análise , Poluição do Ar/análise , Biomassa , Carvão Mineral/análise , Poeira/análise , Íons/análise , Metais/análise , Medição de Risco , Estações do Ano , Emissões de Veículos/análise
8.
PLoS Biol ; 18(6): e3000722, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569301

RESUMO

Inflammation and infection can trigger local tissue Na+ accumulation. This Na+-rich environment boosts proinflammatory activation of monocyte/macrophage-like cells (MΦs) and their antimicrobial activity. Enhanced Na+-driven MΦ function requires the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5), which augments nitric oxide (NO) production and contributes to increased autophagy. However, the mechanism of Na+ sensing in MΦs remained unclear. High extracellular Na+ levels (high salt [HS]) trigger a substantial Na+ influx and Ca2+ loss. Here, we show that the Na+/Ca2+ exchanger 1 (NCX1, also known as solute carrier family 8 member A1 [SLC8A1]) plays a critical role in HS-triggered Na+ influx, concomitant Ca2+ efflux, and subsequent augmented NFAT5 accumulation. Moreover, interfering with NCX1 activity impairs HS-boosted inflammatory signaling, infection-triggered autolysosome formation, and subsequent antibacterial activity. Taken together, this demonstrates that NCX1 is able to sense Na+ and is required for amplifying inflammatory and antimicrobial MΦ responses upon HS exposure. Manipulating NCX1 offers a new strategy to regulate MΦ function.


Assuntos
Macrófagos/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Sódio/metabolismo , Processamento Alternativo/genética , Animais , Cálcio/metabolismo , Espaço Extracelular/metabolismo , Inativação Gênica/efeitos dos fármacos , Ativação do Canal Iônico/efeitos dos fármacos , Íons , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Camundongos , Óxido Nítrico/biossíntese , Células RAW 264.7 , Cloreto de Sódio/farmacologia
9.
Water Sci Technol ; 81(5): 1063-1070, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32541122

RESUMO

A cross-linked chitosan-PVA spherical hydrogel (CSH) was synthesized and its structure was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The physical and chemical properties of CSH, such as acid resistance and swelling, were determined. Finally, Cu(II) ion removal by the CSH was investigated, and the effects of experimental parameters, including pH, adsorption time, and regeneration performance were examined. Results revealed that CSH has outstanding stability in strong acid solution, thus extending the useful pH range as an adsorbent material. The maximum capacity of CSH for Cu(II) was obtained to be 62.1 mg/g at 25 °C for 24 h. The adsorption process was best described by a pseudo-second-order kinetic model, while isotherm modeling revealed that the Langmuir equation better described the adsorption of Cu(II) on CSH. Moreover, the loaded CSH can be easily regenerated by the HCl-washing method and reused repeatedly for Cu(II) adsorption for up to five cycles.


Assuntos
Quitosana , Poluentes Químicos da Água , Adsorção , Cobre , Hidrogéis , Concentração de Íons de Hidrogênio , Íons , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 899-907, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567273

RESUMO

Stearoyl-CoAdesaturase-1 (SCD-1) is a key regulator of monounsaturated fatty acid synthesis. It plays a vital role in lipid synthesis and metabolism. Ca²âº is an important cation in the body and plays an important role in the organism. The aims of this study were to investigate the correlation of SCD-1 gene overexpression with lipid indexes and calcium ion level. The pcDNA3.1 (+) + SCD-1 +Flag eukaryotic expression vector and cultured duck uterine epithelial cells were co-transfected. The overexpression of SCD-1 gene was measured using the Flag Label Detection Kit. Ca ions and lipid contents were detected through Fluo-3/AM Calcium Ion Fluorescence Labeling method and Lipid Measuring Kit, respectively. SCD-1 gene overexpression was negatively correlated with triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C), and positively correlated with Ca ion, total cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C) and low density lipoprotein cholesterol (LDL-C) levels. Meanwhile, Ca ion was positively correlated with TG, LDL-C and HDL-C contents, and negatively correlated with TC and VLDL-C levels. Overexpression of SCD-1 gene could regulate Ca ion secretion, as well as lipid synthesis and transport in duck uterine epithelial cells.


Assuntos
Cálcio , Coenzima A Ligases , Células Epiteliais , Expressão Gênica , Lipídeos , Animais , Cálcio/metabolismo , Coenzima A Ligases/genética , Patos , Células Epiteliais/química , Células Epiteliais/enzimologia , Íons , Lipídeos/genética , Triglicerídeos/metabolismo
11.
Environ Monit Assess ; 192(7): 452, 2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32577995

RESUMO

This study presented the research work carried out for the investigation of chemical composition of bulk precipitation in two geographically and economically distinct areas, namely Gampaha and Kandy Districts. This study was conducted from 2013 to 2014 at three sampling stations in each District. The bulk precipitation was analyzed for pH, conductivity, Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, SO42-, Pb, Cu, Mn, Al, Zn and Fe for a total of 375 samples. Only 8% events of acidic precipitation were recorded in Gampaha District when compared with 3% in Kandy District. The volume weighted average concentrations of the major ionic species present in precipitation samples were in the order of Na+ > Ca2+ > Cl- > NH4+ > SO42- > Mg2+ > NO3- > K+ > F- in the Gampaha stations, while the order was NH4+ > Ca2+ > Na+ > Cl- > SO42- > Mg2+ > NO3- > K+ > F- in Kandy District. Neutralization of acidity of precipitation is much more related to CaCO3 than NH3, and high content of Ca2+ ions present in both Districts strongly supports this fact. When considering marine contribution, SO42-/Na+, Ca2+/Na+ and Mg2+/Na+ ratios are higher than the reference value suggesting contribution of sources other than marine. Depositions of both Districts show that the concentration of Al is the highest while that of Mn is the lowest. Principal component analysis suggests that influencing human activities on chemical composition of rain water depends on thermal power plant, oil refinery, heavy traffic and waste incineration in the study area.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Íons/análise , Chuva , Sri Lanka , Água
12.
Bull Environ Contam Toxicol ; 105(1): 62-66, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32556375

RESUMO

The various uses of copper or copper compounds in industrial, biocidal or pesticidal products lead to inputs of the metal into aquatic environments. To assess effects of copper ions on non-target organisms, the freshwater snail Theodoxus fluviatilis was used as test organism for a three-week laboratory experiment. Snails were exposed to four copper concentrations ranging from 4 to 39 µg Cu2+/L, and besides mortality, several sublethal parameters were evaluated. Concerning survival, an aqueous copper concentration of 6 µg/L was determined as NOEC, and 16 (± 0.1) µg/L as LC50. Negative sublethal effects on reproduction, activity and pathological modifications in the snails were detected in the treatment with an aqueous copper concentration of 15 µg/L. Our results using T. fluviatilis as a mere grazer exclusively feeding on biofilms contribute to findings that field relevant copper concentrations have a significant effect on non-target organisms in aquatic environments.


Assuntos
Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Água Doce , Íons , Reprodução/efeitos dos fármacos , Caramujos/efeitos dos fármacos
13.
Waste Manag ; 113: 32-40, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505109

RESUMO

To recycle the sharply growing spent lithium-ion batteries and alleviate concerns over shortages of resources, particularly Li, is still an urgent issue. In this work, an organic acids based leaching approach at room temperature is proposed to recover Li and FePO4 from spent LiFePO4 cathode powder. The coexistent metal ions, Cu and Al, have also been investigated. Citrus fruit juices, rich in organic acids, such as citric acid and malic acid, have been used as leaching agents in this work. Among lemon, orange and apple, lemon juice shows the best leaching effect based on its suitable pH of the reaction system. Under the optimized conditions, the leaching rates of Li, Cu and Al can reach up to 94.83%, 96.92% and 47.24%, while Fe and P remain as low as 4.05% and 0.84%, respectively. Li2CO3 and FePO4 can be recovered from the leachate and the leaching residue, respectively. The recovered FePO4 was used to prepare new cathode material LiFePO4. The crystalline carbon, present in the spent LiFePO4 cathode scraps, has a significant effect on the electrochemical performances of the regenerated LiFePO4. The regenerated LiFePO4 cathode material delivered a comparable discharge capacity of 155.3 mAh g-1 at 0.1C and rate capacity to the fresh LiFePO4. For the cycling stability, it displays capacity retention of 98.30% over 100 cycles at 1 C with a fading rate of 0.017% per cycle. The proposed organic acids-based recycling strategy is much benign for recycling the spent LiFePO4 cathode materials.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Íons , Reciclagem
14.
Shanghai Kou Qiang Yi Xue ; 29(1): 40-45, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32524119

RESUMO

PURPOSE: To study the change of ion precipitation and surface roughness of three dental alloys'coexisting in standard electrolyte solution, in order to provide a reference for the selection of clinical alloy materials. METHODS: Standard samples of Ni-Cr alloy, Co-Cr alloy and Au-Ag-Pd alloy were prepared and divided into 5 groups: Ni-Cr alloy(group N), Co-Cr alloy(group C), Au-Ag-Pd alloy(Group A), Ni-Cr alloy contact with Au-Ag-Pd alloy(group NA), Ni-Cr alloy contact with Co-Cr alloy(group NC). All groups of alloys were soaked in standard electrolyte solution (T=37 ℃, pH=2.31) for 7 days. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the amount of ions released from each group. The surface morphology of each group was observed and the surface roughness(Ra) was measured using atomic force microscope(AFM). SPSS 18.0 software package was used for statistical analysis. RESULTS: The amount of nickel ions released from group N, NA, NC was (1.32±0.03) µg/cm2, (2.13±0.07) µg/cm2, (1.53±0.08) µg/cm2, respectively. Nickel ions of group NA and NC was significantly more than that of group N(P<0.05), nickel ions of group NA was significantly more than that of group NC(P<0.05). The amount of chromium ions released from group N, NA, NC was (0.06±0.01) µg/cm2, (0.08±0.01) µg/cm2, (0.05±0.01) µg/cm2, respectively, the amount of chromium ions of group NA was significantly more than that of group NC(P<0.05). The surface roughness of Ni-Cr alloy in group N, NA, NC was (4.60±0.16) nm, (5.37±0.08) nm, (5.04±0.15) nm, respectively. The surface roughness of Ni-Cr alloy in group NA and group NC was significantly larger than that in group N (P<0.05). When contact with Au-Ag-Pd alloy or Co-Cr alloy, the amount of nickel ions released and the surface roughness of Ni-Cr alloy both significantly increased. Compared with Co-Cr alloy, Au-Ag-Pd alloy caused Ni-Cr alloy to release more nickel, chromium ions and formed a rougher surface.


Assuntos
Ligas de Cromo , Ligas Dentárias , Íons , Teste de Materiais , Níquel , Propriedades de Superfície
15.
Chemosphere ; 256: 127043, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32445999

RESUMO

Electrolytic manganese residue (EMR) is characterized by high silicon content, and thus, is an important silicon source. While considerable research has been conducted on bioleaching EMR for silicon recovery, sufficient information is not available on the impact of specific silicate mineral structures in EMR on silicon bioleaching. In the present study, the mineral composition of EMR was determined firstly, and then the leaching effect of Paenibacillus mucilaginosus on these different silicate minerals were investigated by shake flask experiments. Results showed that the silicon in EMR was mainly composed of quartz, sericite, muscovite, biotite, olivine and rhodonite; Paenibacillus mucilaginosus had a significantly different weathering and decomposition effects on different silicate minerals. Among them, sericite, muscovite and biotite with layered structure had the most obvious silicon leaching effect, followed by rhodonite with island structure, while silicon leaching from olivine with chained structure and quartz with frame structure was much more difficult. One can roughly judge the adaptability of bioleaching of silicon in EMR using Paenibacillus mucilaginosus if the main form of silicate minerals in EMR is determined.


Assuntos
Manganês/metabolismo , Paenibacillus/metabolismo , Silício/química , Silicatos de Alumínio , Eletrólitos , Compostos Ferrosos , Íons , Compostos de Ferro , Compostos de Magnésio , Minerais , Silicatos/química , Dióxido de Silício
16.
J Chromatogr A ; 1622: 461122, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376021

RESUMO

To understand the overall processes behind the decomposition of state-of-the-art organic liquid electrolytes in lithium ion batteries (LIBs), it is necessary to investigate and quantify the permanent gases and light hydrocarbons evolving during electrolyte decomposition. In this work a convenient way of sampling gas from pouch cells without any previous preparation of the cell as well as a comprehensive gas chromatographic (GC) investigation of the gas phase is shown. A barrier discharge ionization detector (BID) was utilized for gas quantification and a multi component gas standard in combination with a gas mixing device was implemented to prepare calibration standards for validation. Therefore, sensitivity, linearity and reproducibility as well as the limits of detection (LOD) and limits of quantification (LOQ) were determined. Gas samples from pouch cells using LiNi0.6Mn0.2Co0.2O2 as cathode material and natural graphite (NMC622 ∣∣ NG) as anode material were analysed after formation. Gas volume and gas composition are key factors for a sufficient formation of LIBs and of interest for research with respect to the development of new materials and additives.


Assuntos
Cromatografia Gasosa/métodos , Fontes de Energia Elétrica , Gases/análise , Lítio , Cobalto , Eletrodos , Eletrólitos/química , Grafite , Íons , Limite de Detecção , Lítio/química , Manganês , Níquel , Reprodutibilidade dos Testes
17.
Chemosphere ; 256: 127124, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32450354

RESUMO

In the present work, talc (a low-cost clay) encapsulated salts alginate (TAL) beads were synthesized by cross-linking with lanthanum ion and tested for phosphate adsorption. Multiple methods were applied for the characterization of composites. The combined effect of talc and lanthanum improved phosphate removal performance of TAL beads. Factors such as talc content, La3+ concentration, adsorbent dosage, pH, co-existing ions (Cl-, NO3- and SO42-) were studied in batch experiments. The optimized TAL-7 beads exhibited satisfactory selectivity towards phosphate in the coexistence of competing anions and could remain efficient phosphate removal in the pH range of 4-6. The phosphate removal efficiency reached to 95% with a maximum uptake of 16.4 mg P/g obtained at the optimal pH 4. Further experiments suggested that Langmuir isotherm model and the pseudo-second-order kinetic model could well describe the phosphate adsorption process of TAL-7 beads. Moreover, TAL-7 beads exhibited superior phosphate fixation performance in the long-term experiment. The results from adsorption experiment and characterization analysis demonstrated that TAL-7 beads could be a cost-effective and promising biosorbent for phosphate adsorption and fixation in the aqueous environment.


Assuntos
Alginatos/química , Hidrogéis/química , Lantânio/química , Fosfatos/análise , Talco/química , Poluentes Químicos da Água/análise , Adsorção , Ânions , Concentração de Íons de Hidrogênio , Íons/química , Cinética , Fosfatos/química , Água/química , Poluentes Químicos da Água/química , Purificação da Água/métodos
18.
Chemosphere ; 256: 127110, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32464361

RESUMO

Organic matter plays many roles in the soil ecosystem. One property of the substance concerns the metal complexation and interaction with organic contaminants. In this sense, the humic substances (HS), a heterogeneous mixture of compounds, naturally derived from degradation of biomass, have been widely studied in environmental sciences. Recent advances showed a new way to produce humic-like substances (HLS) through hydrothermal carbonization of biomass. Thus, this study aimed to evaluate the HLS of hydrochars, produced by using a mixture of sugarcane bagasse and vinasse with sulfuric acid added (1 and 4% v/v), and to assess their interactions with metal ions, (Fe(III), Al(III), Cu(II) and Co(II)) using EEM-PARAFAC and a two-dimensional FTIR correlation analysis. The results were compared to the humic substances extracted from the Amazonian Anthrosol, as a model of anthropogenic organic matter. NMR analysis showed that humic-like extracts from hydrochar are mainly hydrophobic, while the soil has a greater contribution of polar moieties. The HLS and HS showed similar complexation capacities for Fe(III), Al(III) and Cu(II) assays. For Co(II) HLS exhibited larger affinities than HS. Two-dimensional correlation analysis FTIR showed that chemical groups may undergo conformational alteration with metal additions to achieve more stable arrangements (higher stability constant). Therefore, these results contribute more knowledge about the mechanism of HS and metal ion interaction, as well as showing that HTC can be an interesting option for HLS production, to be used as humic based materials.


Assuntos
Carvão Vegetal/química , Substâncias Húmicas/análise , Metais Pesados/química , Solo/química , Sítios de Ligação , Brasil , Ecossistema , Interações Hidrofóbicas e Hidrofílicas , Íons , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Chemosphere ; 256: 127163, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470742

RESUMO

Seasonal changes in chemical compositions and source apportionment of PM2.5 during clear and hazy days help to develop effective control policy, but limited information is available in megacity Nanjing. In this study, 102 PM2.5 samples were collected during clear and hazy days from 4 seasons in 2014-2015. Their chemical compositions (organic and elemental carbon, 8 water-soluble ions, and 22 inorganic elements) were determined, which were used for PM2.5 source apportionment using the PMF model. The mean PM2.5 concentration was lower during clear days than hazy days (42 vs. 122 µg m-3), so were mean concentrations of metals (0.48 vs. 0.82 ng m-3 for Co and 2.0 vs. 2.4 µg m-3 for Na), water soluble ions (0.10 vs. 0.16 µg m-3 for Mg2+ and 12 vs. 23 µg m-3 for SO42-), and carbon species (3.2 vs. 5.4 µg m-3 for elemetal C and 20 vs. 35 µg m-3 for organic C). Based on the PMF model, five main sources of PM2.5 were identified including secondary aerosols (31%), coal combustion (27%), road & construction dust (26%), oil combustion (8.5%), and iron & steel industry (5.1%) for all samples. The PM2.5 concentrations from the 5 sources were 0.01-46.5, averaging 9.8 µg m-3 during clear days (PM2.5 < 75 µg m-3), which increased to 1.83-60.1, averaging 18 µg m-3 during hazy days. However, based on their contributions to PM2.5, only secondary aerosols increased during hazy days compared to clear days in all seasons (11 vs. 42%), indicating its dominant contribution to haze in Nanjing. For different seasons, road & construction dust was a major contributor to PM2.5 in the summer, while oil combustion (4.86 vs.16.8%) contributed more in spring. However, coal combustion became the main source of PM2.5 during the summer (44-85%) due to the pollution controls for the Youth Olympic Games. Our results suggest that secondary aerosols play an important role in haze formation and season-dependent pollution measures should be implemented for effective control of air pollution.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Carbono/análise , China , Carvão Mineral/análise , Poeira/análise , Indústrias , Íons/análise , Estações do Ano , Aço , Emissões de Veículos/análise , Água/química , Tempo (Meteorologia)
20.
Environ Sci Pollut Res Int ; 27(21): 26750-26762, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32382903

RESUMO

The aerosol samples of water-soluble inorganic ions (WSIs), including SO42-, NO3-, NH4+, Cl-, K+, Na+, Ca2+, and Mg2+ in size-segregated particulate matter (PM), were collected by an Anderson sampler (with 8 nominal cut-sizes ranged from 0.43 to 9.0 µm) in urban Tianjin during 2013-2014. The results showed that particulate matters in the fine mode (PM2.1, Dp < 2.1 µm) comprised large part of mass concentrations of aerosols, and the water-soluble ionic species in the fine mode were 47.07 ± 14.29 µg m-3 (spring), 67.87 ± 28.74 µg m-3 (summer), 86.60 ± 48.53 µg m-3 (autumn), and 104.16 ± 51.76 µg m-3 (winter), respectively, which accounted for 59.5%, 63.3%, 71.9%, and 71.4% of the PM2.1 mass concentrations. Secondary pollutants of SO42-, NO3-, and NH4+ (SNA) were the dominant contributors of WSIs, which showed a bimodal size distribution in each season, with the larger peak appeared in the size fraction of 0.65-1.1 µm and the smaller one in 3.3-5.8 µm fraction. SNA concentrations in lightly polluted days (LPD) and heavily polluted days (HPD) were observably higher than non-polluted days (NPD), especially in the fine mode, with the peak diameter moving from 0.43-0.65 µm on NPD to 0.65-1.1 µm on LPD and HPD. The correlation analysis between NH4+, NO3-, and SO42- suggested that almost all SO42- and NO3- for fine particles had been completely neutralized by NH4+, and primarily existed in the forms of (NH4)2SO4 and NH4NO3. The sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) on LPD and HPD in fine mode were observably higher than those on NPD, especially in the range of 0.65-1.1 µm and 1.1-2.1 µm. Furthermore, SOR and NOR values in the size fraction of 0.43-3.3 µm increase as the RH elevated, especially in 0.43-2.1 µm, where RH was significantly positive correlated with SOR and NOR, indicating the significant contributions of heterogeneous processes to the secondary formation of SO42- and NO3-. These results suggested an enhanced formation ability of secondary pollutants under high RH in the coast city. Therefore, controlling the precursors of SNA, such as SO2 and NOx, would be more effective to reduce the fine particulate pollution in the coast megacity of Tianjin.


Assuntos
Poluentes Atmosféricos/análise , Água , Aerossóis/análise , China , Monitoramento Ambiental , Íons/análise , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Solubilidade
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