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1.
Chemistry ; 26(2): 543-547, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31691389

RESUMO

Herein, a visible-light photochemical approach for practical helicene functionalization at very mild reaction conditions is described. The photochemical reactions allow for the regiospecific and innate late-stage functionalization of helicenes and are easily executed either through the activation of C(sp2 )-Br bonds in helicenes using K2 CO3 as inorganic base or direct C(sp2 )-H helicene bond functionalization under oxidative photoredox reaction conditions. Overall, using these transformations six different functional groups are introduced to the helicene scaffold through C-C and four different C-heteroatom bond-forming reactions.


Assuntos
Luz , Compostos Policíclicos/química , Carbonatos/química , Catálise , Oxirredução , Potássio/química , Teoria Quântica
2.
Chemosphere ; 239: 124823, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726520

RESUMO

Several studies have demonstrated that gypsum (CaSO4·2H2O) and calcite (CaCO3) can be important hosts of arsenic in contaminated hydrogeological systems. However, the extent to which microbial reducing processes contribute to the dissolution and transformation of carbonate and sulfate minerals and, thereby, to arsenic mobilization is poorly understood. These processes are likely to have a strong impact on arsenic mobility in iron-poor environments and in reducing aquifers where iron oxyhydroxides become unstable. Anoxic batch bioassays with arsenate (As(V)) coprecipitated with calcite, gypsum, or ferrihydrite (Fe(OH)3) were conducted in the presence of sulfate or molybdate to examine the impact of bioprocesses (i.e. As(V), sulfate, and Fe(III)-reduction) on arsenic dissolution, speciation, and eventual remineralization. Microbial reduction of As(V)-bearing calcite caused an important dissolution of arsenite, As(III), which remained in solution up to the end of the experiment (30 days). The reduction of As(V) from gypsum-As(V) also led to the release of As(III), which was subsequently remineralized, possibly as arsenic sulfides. The presence of sulfate triggered arsenic dissolution in the bioassays with ferrihydrite-As(V). This study showed that although gypsum and calcite have a lower capacity to bind arsenic, compared to iron oxides, they can play a critical role in the biogeochemical cycle of arsenic in natural calcareous and gypsiferous systems depleted of iron since they can be a source of electron acceptors for reducing bioprocesses.


Assuntos
Arsênico/química , Bactérias/metabolismo , Carbonato de Cálcio/química , Sulfato de Cálcio/química , Compostos Férricos/química , Arseniatos/química , Arsenicais/química , Arsenitos/química , Carbonatos/química , Água Subterrânea/química , Ferro/química , Molibdênio/química , Oxirredução , Solubilidade , Sulfatos/química , Sulfetos/química
3.
J Environ Sci (China) ; 87: 250-259, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791498

RESUMO

Water-uptakes of pure sodium carbonate (Na2CO3), pure ß-alanine and internally mixed ß-alanine/Na2CO3 aerosol particles with different mole ratios are first monitored using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) technique. For pure Na2CO3 aerosol particles, combining the absorptions at 877 and 1422 cm-1 with abrupt water loss shows the efflorescence relative humidity (ERH) of 62.9%-51.9%. Upon humidifying, solid Na2CO3 firstly absorbs water to from Na2CO3·H2O crystal at 72.0% RH and then deliquesces at 84.5% RH (DRH). As for pure ß-alanine particles, the crystallization takes place in the range of 42.4%-33.2% RH and becomes droplets at ~88.2% RH. When ß-alanine is mixed with Na2CO3 at various mole ratios, it shows no efflorescence of Na2CO3 when ß-alanine to Na2CO3 mole ratio (OIR) is 2:1. For 1:1 and 1:2 ß-alanine/Na2CO3 aerosols, the ERHs of Na2CO3 are 51.8%-42.3% and 57.1%-42.3%, respectively. While ß-alanine crystal appears from 62.7% RH for 2:1 and 59.4% RH for both 1:1 and 1:2 particles and lasts to driest state. On hydration, the DRH is 44.7%-75.2% for Na2CO3 with the OIR of 1:1 and 44.7%-69.0% for 1:2 mixture, and those of ß-alanine are 74.8% for 2:1 mixture and 68.9% for two others. After the first dehumidification-humidification, all the water contents decrease despite of constituent fraction. And at ~92% RH, the remaining water contents are 92%, 89% and 82% at ~92% RH, corresponding to OIR of 2:1, 1:1 and 1:2 mixed system, respectively.


Assuntos
Alanina/química , Carbonatos/química , Modelos Químicos , Espectroscopia de Infravermelho com Transformada de Fourier , Molhabilidade
4.
Chemosphere ; 238: 124466, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31425866

RESUMO

Arsenite is a highly toxic compound present in many water sources around the world. The removal of arsenite from water requires its oxidation to arsenate which is much more amenable to treatment using well attested technologies. Prior research has shown that the oxidation of arsenite by hydroxyl radicals is significantly accelerated in the presence of carbonate ions but the intrinsic mechanisms of the acceleration have not yet been established. The main goal of the present work was to examine the oxidation of arsenite in the framework of the density functional theory, to establish a detailed microscopic level mechanism of interactions between arsenite and hydroxyl radicals and to elucidate the nature of the catalytic effect of carbonate ions. Results of this study demonstrate that the [As(OH)2CO3]- complex is the thermodynamically most stable species formed in the system H3AsO3-CO32-/HCO3--H2O. Interactions of the hydroxyl radical with the [As(OH)2CO3]- complex yield the pre-reaction complex [As(OH)3CO3]-∗ in the reaction of subsequent oxidation of arsenite. The structures of the reactants, products and transition states, as well as pre- and post-reaction complexes corresponding to several possible mechanisms of the first stage of As(III) oxidation to As(IV) intermediate using hydroxyl radicals in the absence and in the presence of [As(OH)2CO3]-, were determined in this study. The data demonstrate that the arsenite-carbonate complexes [As(OH)2CO3]- are characterized by a significantly lower activation energy of the first oxidation stage under the action of a hydroxyl radical (2.8 kcal/mol) compared to that for the free arsenite H3AsO3 (13.6 kcal/mol).


Assuntos
Arsenitos/química , Carbonatos/química , Radical Hidroxila/química , Teoria Quântica , Água/química , Catálise , Modelos Moleculares , Conformação Molecular , Oxirredução , Termodinâmica
5.
Mater Sci Eng C Mater Biol Appl ; 104: 109966, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499942

RESUMO

In this study we present the first crystal structure model for bone apatite based on the analysis of individual nanocrystals by high resolution transmission electron microscopy (HRTEM). Crystallographic image processing of the obtained HRTEM images from different projections indicates symmetry reduction with respect to P63/m stoichiometric apatites and the presence of threefold symmetry along the c axis. Based on HRTEM observations and the measured Ca/P = 2 ratio we propose a structural model with phosphate-to-carbonate substitution and O vacancies localized along c axis, which explains the observed loss of 63 screw axis parallel, and the shift of mirror plane perpendicular to the c axis. Also, the presence of non-equivalent (010) surfaces has been proven. These results on the atomic structure of bone apatite nanocrystals contribute to the understanding of their biochemically controlled nucleation processes.


Assuntos
Apatitas/química , Osso e Ossos/química , Nanopartículas/química , Carbonatos/química , Cristalografia/métodos , Microscopia Eletrônica de Transmissão/métodos
6.
Artigo em Inglês | MEDLINE | ID: mdl-31397623

RESUMO

The kinetic, isotherm and thermodynamic modeling of the adsorption of arsenite by layered double hydroxide have been performed to analyze the feasibility, efficacy and mechanism of the system. The fast uptake was observed during the initial phase of the process, which reached equilibrium at 240 min following Elovich model. The diffusion kinetic model exhibited that the rate-limiting step of adsorption was controlled by film diffusion as well as intraparticle diffusion. The isotherm modeling revealed the applicability of the Freundlich equation with the Kf values as 8.19-13.99 (mg g-1)(L mg-1)1/n at 283-323 K showing the increasing trend of adsorption capacity, which was further confirmed by the positive value of ΔH0 (9.49 kJ mol-1) demonstrating the endothermic nature of the adsorption process. The spontaneous nature of the adsorption reaction was established by the negative values of ΔG0. Application of the calcined Mg-Fe-LDH adsorbent for the removal of arsenic from real arsenic contaminated groundwater was also successfully performed. The effect of process parameters of the adsorption system was modeled by an artificial neural network (ANN) for adsorption capacity and removal efficiency. The optimized model exhibited high R2, F-value and low values of error functions, establishing the significant applicability of the ANN model.


Assuntos
Arsenitos/química , Carbonatos/química , Água Subterrânea/química , Hidróxidos/química , Ferro/química , Magnésio/química , Adsorção , Arsênico/química , Difusão , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Termodinâmica , Poluentes Químicos da Água/química , Purificação da Água
7.
Int J Nanomedicine ; 14: 4559-4571, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31417258

RESUMO

Background and objective: Tetracycline and its derivatives, combined with calcium phosphates, have been proposed as a delivery system to control inflammatory processes and chronic infections. The objective of this study was to evaluate the microspheres of alginate encapsulated minocycline-loaded nanocrystalline carbonated hydroxyapatite (CHAMINO) as a biomimetic device to carry out target-controlled drug delivery for alveolar bone repair. Methods: CHAMINO microspheres were implanted in a rat central incisor socket after 7 and 42 days. New bone was formed in both groups between 7 and 42 days of implantation. However, the bone growth was significantly higher for the CHAMINO microspheres. Results: The minocycline (MINO) loading capacity of the nanocrystaline carbonated hydroxyapatite (CHA) nanoparticles was 25.1±2.2 µg MINO/mg CHA for adsorption over 24 hrs. The alginate microspheres containing minocycline-loaded CHA were biologically active and inhibited the Enterococcus faecalis culture growth for up to seven days of the MINO release. An osteoblastic cell viability assay based on the resazurin reduction was conducted after the cells were exposed to the CHAMINO powder and CHAMINO microspheres. Thus, it was found that the alginate extracts encapsulated the minocycline-loaded CHA microspheres and did not affect the osteoblastic cell viability, while the minocycline-doped CHA powder reduced the cell viability by 90%. Conclusion: This study concluded that the alginate microspheres encapsulating the minocycline-loaded nanocrystalline carbonated hydroxyapatite exhibited combined antibacterial activity against Enterococcus faecalis with cytocompatibility and osteoconduction properties. The significant improvement in the new bone formation after 42 days of implantation suggests that the CHAMINO microsphere has potential in clinical applications of bone regeneration.


Assuntos
Alginatos/química , Regeneração Óssea/efeitos dos fármacos , Carbonatos/química , Durapatita/química , Microesferas , Minociclina/farmacologia , Nanopartículas/química , Animais , Antibacterianos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Enterococcus/efeitos dos fármacos , Humanos , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Osteoblastos/efeitos dos fármacos , Ratos Wistar , Difração de Raios X
8.
Arch Environ Contam Toxicol ; 77(4): 605-618, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31428818

RESUMO

The concentrations of six metals (Zn, Cu, Pb, Ni, Cr, and Cd) were investigated in bottom sediments of Straszyn Lake (North Poland). This study was designed to determine a total content of metals and to assess their mobility and bioavailability. The sequential extraction was used to fractionate metals into five fractions: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual. The evaluation of sediments contamination degree by metals was performed by applying the geochemical quality guidelines, the pollution load index, and the geo-accumulation index (Igeo). The assessment based on these methods demonstrated that sediments were polluted with Cr and the sediments quality guidelines confirmed these results. Moreover, the average concentrations of Cu, Ni, and Cr were respectively 3.4, 3.9, and 21.2 times higher than their background values. According to ecological risk index and risk assessment code Cd was the most important factor affecting the ecological environment of the Straszyn Lake. The metal speciation analysis demonstrated that the mean percentage of metals in the exchangeable and carbonate fractions decreased in the following order: Cd (59.1%) > Zn (19.8%) = Ni (19.8%) > Pb (16.6%) > Cu (3.3%) > Cr (2.7%). The very strong correlation calculated between all the metals indicated their common origin.


Assuntos
Sedimentos Geológicos/análise , Lagos/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , Disponibilidade Biológica , Carbonatos/química , Fracionamento Químico , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Metais Pesados/farmacocinética , Polônia , Medição de Risco , Poluentes Químicos da Água/farmacocinética
9.
Sci Total Environ ; 686: 888-892, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412526

RESUMO

Fiber cement composites (FCCs) containing natural cellulosic fibres are emerging materials in the building industry. At the end of life, FCCs are often disposed of as part of the C&DW in a landfill. The production of landfill gasses in landfills needs to be kept as low as possible. Generally, leaching of total dissolved organic carbon (DOC) is used as a proxy for the biodegradability of a waste material and the subsequent production of landfill gasses, and is, therefore, used to evaluate biodegradability of waste. In this study, FCC samples with varying average diameter and varying age were subjected to both a batch leaching test (determine DOC leaching) and to a standardized biodegradability test. The batch leaching showed that the DOC leaching ranged between 520 and 1300 mg kg-1 for the tested samples, and that leaching of DOC decreases with increasing particle diameter and with increasing effects of ageing. Yet, the biodegradability results indicated that the leaching of DOC from FCCs does not result in the release of landfill gasses. This study hypothises that the DOC that leaches from the FCCs is being degraded to CO2, but that the formed CO2 is immediately captured by the material itself through the process of carbonation. An inpermeable layer is formed around the material that stops further leaching of DOC. The results of this study therefore suggest that leaching of DOC is a poor indicator for the biodegradability of FCCs.


Assuntos
Poluentes Atmosféricos/análise , Carbonatos/química , Materiais de Construção/análise , Monitoramento Ambiental , Gases/análise , Resíduos Sólidos/análise , Biodegradação Ambiental , Resíduos Industriais/análise , Instalações de Eliminação de Resíduos
10.
Environ Sci Pollut Res Int ; 26(27): 28243-28255, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31368067

RESUMO

The Tibetan Plateau is known as the "Asian water tower," and the Yarlung Tsangpo (YT) River is the largest river that originates in and flows across the southern Tibetan Plateau. Although the solute source of YT River has been extensively and qualitatively analyzed, there is a lack of the quantitative analysis for the whole basin and seasonal variation of hydrochemical characteristics. Here, 212 samples obtained in the mainstream and tributary of YT River in different (wet, normal, and dry) periods were used for the solute apportionment using the mass balance model. The results showed that the solutes in YT River water were mainly derived from the carbonate and silicate rock weathering that accounts 42.2% and 26.9% in the total solute source, respectively, as the complex geological conditions in the basin. A part of the ions (7.5%) was also originated from the atmospheric precipitation as the abundant rainfall in the wet period. Meanwhile, the contribution of solute sources had no significantly seasonal variation in the upstream, whereas it had significantly seasonal variation in the downstream with the tropical climate and heavy rainfall. Importantly, the rock weathering of the basin could consume so much atmospheric CO2 (0.54% of the consumption at global with the only 0.16% of the global surface area) that could mitigate the global warming, which followed an increasing trend from upstream to downstream. The quantitative analysis of the solute source for YT River fills in the gaps in the chemically characteristic cognition of the basin. It is beneficial for the water resource management for the Asian. The proportion of solute sources in the YT River and its tributaries for wet (W), normal (N), and dry (D) periods.


Assuntos
Dióxido de Carbono/análise , Carbonatos/análise , Água Doce/análise , Água/análise , Dióxido de Carbono/química , Carbonatos/química , China , Clima , Água Doce/química , Rios , Estações do Ano , Soluções , Tibet , Tempo (Meteorologia)
11.
Chem Pharm Bull (Tokyo) ; 67(10): 1046-1049, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31341115

RESUMO

A new catalytic system comprising chiral Ag complex and Li aryloxide/bisphosphine oxide is developed for the synthesis of ß2,2-amino acids via direct asymmetric Mannich-type reaction of 4-subsituted isoxazolidin-5-ones. The Mannich adduct is a direct precursor of ß-peptidic compounds otherwise difficult to obtain.


Assuntos
Aminoácidos/síntese química , Carbonatos/química , Complexos de Coordenação/química , Bases de Lewis/química , Lítio/química , Aminoácidos/química , Catálise , Complexos de Coordenação/síntese química , Isoxazóis/química , Estrutura Molecular , Prata/química
12.
Analyst ; 144(16): 5003-5009, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31332403

RESUMO

By employment of an aptamer-initiated hybridization chain reaction (HCR) to enhance the enzyme biomineralization of cupric subcarbonate, this work develops a novel colorimetric biosensing method for protein analysis. The HCR product was used to specifically attach a large amount of urease-functionalized gold nanoparticles (Au NPs) for the preparation of a gold nanoprobe. After the sandwich biorecognition reactions, this nanoprobe could be quantitatively captured onto the antibody-functionalized magnetic bead (MB) platform. Then, numerous copper ions would be enriched onto the MB surface through the urease-induced biomineralization of cupric subcarbonate. Based on the complete release of Cu2+ ions for the sensitive copper chromogenic reaction, convenient colorimetric signal transduction was thus achieved for the quantitative analysis of the target analyte of the carcinoembryonic antigen. The HCR product provides a large number of biotin sites for the attachment of Au NP nanotags. The biomineralization reaction of high-content urease loaded onto Au NPs leads to highly efficient Cu2+ enrichment for signal amplification. So this method features excellent performance including a very wide linear range and a low detection limit down to 0.071 pg mL-1. In addition, the satisfactory results of real sample experiments reveal that this method possesses huge potential for practical applications.


Assuntos
Biomarcadores Tumorais/sangue , Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Animais , Anticorpos Imobilizados/imunologia , Anticorpos Monoclonais/imunologia , Aptâmeros de Nucleotídeos/química , Biomarcadores Tumorais/imunologia , Biomineralização , Carbonatos/química , Antígeno Carcinoembrionário/imunologia , Colorimetria/métodos , Cobre/química , Ouro/química , Humanos , Imunoensaio/métodos , Separação Imunomagnética , Limite de Detecção , Nanopartículas Metálicas/química , Coelhos , Urease/química
13.
Appl Microbiol Biotechnol ; 103(17): 7217-7230, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31289902

RESUMO

The ureolytic activity of Neurospora crassa results in an alkaline carbonate-rich culture medium which can precipitate soluble metals as insoluble carbonates. Such carbonates are smaller, often of nanoscale dimensions, than metal carbonates synthesized abiotically which infers that fungal excreted products can markedly affect particle size. In this work, it was found that amino acid excretion was a significant factor in affecting the particle size of copper carbonate. Eleven different amino acids were found to be secreted by Neurospora crassa, and L-glutamic acid, L-aspartic acid and L-cysteine were chosen to examine the impact of amino acids on the morphology and chemical composition of copper carbonate minerals. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the obtained copper carbonate samples. Copper carbonate nanoparticles with a diameter of 100-200 nm were produced with L-glutamic acid, and the presence of L-glutamic acid was found to stabilize these particles in the early phase of crystal growth and prevent them from aggregation. FTIR and TG analysis revealed that the amino acid moieties were intimately associated with the copper mineral particles. Component analysis of the final products of TG analysis of the copper minerals synthesized under various conditions showed the ultimate formation of Cu, Cu2O and Cu2S, suggesting a novel synthesis method for producing these useful Cu-containing materials.


Assuntos
Aminoácidos/química , Carbonatos/química , Cobre/química , Fungos/metabolismo , Nanopartículas Metálicas/química , Aminoácidos/análise , Aminoácidos/metabolismo , Biomineralização , Meios de Cultivo Condicionados/química , Neurospora crassa/metabolismo , Tamanho da Partícula
14.
Int J Biol Macromol ; 137: 697-702, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31276727

RESUMO

The physicochemical and cooking properties of wheat starch isolated from alkaline yellow dough treated with sodium carbonate (Na2CO3; 0-3.2 g/100 g) were investigated. With increasing Na2CO3 addition, swelling power increased from 7.28 to 10.70 g/g. X-ray diffraction showed no changes in crystalline patterns while the relative crystallinity decreased from 30.11% to 23.13%. Differential scanning calorimetry results suggested that alkaline salt shifted the gelatinization peak of starch to higher temperatures. The values of pasting viscosity and pasting temperature in alkali-treated starch increased and decreased, respectively. Farinograph results revealed the strengthened structure of dough with alkali-treated starch that was manifested by an increase in the dough development time and dough stability time. Cooking loss and rehydration values of noodles prepared from alkali-treated starch increased by 42% and 36%, respectively. The results suggested that Na2CO3 affected starch crystalline structure, swelling power, gelatinization, pasting properties, starch-gluten interactions and cooking characteristics of noodle products.


Assuntos
Carbonatos/química , Fenômenos Químicos , Culinária , Farinha/análise , Qualidade dos Alimentos , Amido/química , Concentração de Íons de Hidrogênio
15.
Food Chem ; 298: 125081, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260952

RESUMO

The impact of kansui on the dough rheology and quality characteristics of chickpea-wheat composite flour-based noodles was investigated. For noodle dough, both the relative crystallinity and degree of order obtained from X-ray diffraction and Fourier transform infrared spectroscopy increased with the low level of kansui addition (0.5-1.5%), followed by a decreased trend at higher levels of alkali concentration (2.0-3.0%). Such variation was in accordance with the trend observed for G' and G″. Based on the confocal laser scanning microscopic observation for cooked noodle samples, the low concentration of kansui addition (0.5-1.5%) protected the well-embedded starch granules being disassociate from the gluten network, whereas with the increased alkali addition (2.0-3.0%), the protein network was impaired with a greater amount of ruptured starch granules being disassociated from the gluten network. The observation corresponded well with the electrophoretic profile, and the results of cooking properties, -SH content, and textural properties of cooked noodles.


Assuntos
Cicer/química , Farinha , Triticum/química , Carbonatos/química , Culinária , Qualidade dos Alimentos , Glutens/química , Microscopia Confocal , Potássio/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Difração de Raios X
16.
Environ Pollut ; 252(Pt B): 1464-1475, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265957

RESUMO

In this study, a proposed integrated high-gravity technology for air pollution control, CO2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO2), nitrogen oxides (NOx), total suspended particulates (TSP)) and CO2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO2, SO2, NOx, and TSP removal efficiencies of 96.3 ±â€¯2.1%, 99.4 ±â€¯0.3%, 95.9 ±â€¯2.1%, and 83.4 ±â€¯2.6% were respectively achieved. Moreover, a 112 kWh/t-CO2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO2 and 0.468 kg NOx per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO2 capture, and waste utilization.


Assuntos
Poluentes Atmosféricos/química , Poluição do Ar/prevenção & controle , Compostos de Cálcio/química , Dióxido de Carbono/química , Recuperação e Remediação Ambiental/métodos , Gravitação , Óxidos/química , Carbonatos/química , Carvão Mineral/análise , Cinza de Carvão/química , Óxidos de Nitrogênio
17.
Int J Nanomedicine ; 14: 3471-3490, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190805

RESUMO

Background: Zinc-doped hydroxyapatite has been proposed as a graft biomaterial for bone regeneration. However, the effect of zinc on osteoconductivity is still controversial, since the release and resorption of calcium, phosphorus, and zinc in graft-implanted defects have rarely been studied. Methods: Microspheres containing alginate and either non-doped carbonated hydroxyapatite (cHA) or nanocrystalline 3.2 wt% zinc-doped cHA (Zn-cHA) were implanted in critical-sized calvarial defects in Wistar rats for 1, 3, and 6 months. Histological and histomorphometric analyses were performed to evaluate the volume density of newly formed bone, residual biomaterial, and connective tissue formation. Biomaterial degradation was characterized by transmission electron microscopy (TEM) and synchrotron radiation-based X-ray microfluorescence (SR-µXRF), which enabled the elemental mapping of calcium, phosphorus, and zinc on the microsphere-implanted defects at 6 months post-implantation. Results: The bone repair was limited to regions close to the preexistent bone, whereas connective tissue occupied the major part of the defect. Moreover, no significant difference in the amount of new bone formed was found between the two microsphere groups. TEM analysis revealed the degradation of the outer microsphere surface with detachment of the nanoparticle aggregates. According to SR-µXRF, both types of microspheres released high amounts of calcium, phosphorus, and zinc, distributed throughout the defective region. The cHA microsphere surface strongly adsorbed the zinc from organic constituents of the biological fluid, and phosphorus was resorbed more quickly than calcium. In the Zn-cHA group, zinc and calcium had similar release profiles, indicating a stoichiometric dissolution of these elements and non-preferential zinc resorption. Conclusions: The nanometric size of cHA and Zn-cHA was a decisive factor in accelerating the in vivo availability of calcium and zinc. The high calcium and zinc accumulation in the defect, which was not cleared by the biological medium, played a critical role in inhibiting osteoconduction and thus impairing bone repair.


Assuntos
Alginatos/química , Regeneração Óssea , Cálcio/metabolismo , Durapatita/química , Microesferas , Nanopartículas/química , Zinco/química , Zinco/metabolismo , Animais , Materiais Biocompatíveis/química , Disponibilidade Biológica , Regeneração Óssea/efeitos dos fármacos , Carbonatos/química , Morte Celular , Linhagem Celular , Sobrevivência Celular , Feminino , Camundongos , Nanopartículas/ultraestrutura , Ratos Wistar , Crânio/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Artigo em Inglês | MEDLINE | ID: mdl-31248060

RESUMO

Rare earth elements (REE) are known to be emerging contaminants in hydrosphere, but roles of hydrous manganese oxyhydroxides (HMO) in REE transport in groundwater remains unknown. In this study, groundwater was sampled along a flow path in the North China Plain to determine the behavior of REE surface complexation to HMO by a modeling and field study approach. Results show that the proportion of neodymium (Nd) complexed by HMO ranges from 0.2% to 95.8%, and from 0.3% to 99.6% in shallow groundwater and deep groundwater, respectively. The amount of complexed REE increases along the flow path. REE bound to HMO exhibit decreasing trends with increasing atomic number. The process was determined to be independent of pH, HMO content, and metal loading. This finding further demonstrates HMO-REE complexation plays a key role in transport of REE in groundwater through preferential scavenging of light REE (LREE) over heavy REE (HREE). Nevertheless, carbonate ligands appear to be robust competitors in reducing the amount of REE sorbed to HMO when solution pH rises above 8.0. Assuming that 50% of Mn concentration occurs as HMO, the amount of complexed REE was predicted to show a more marked decrease in LREE compared to that of HREE.


Assuntos
Água Subterrânea/química , Manganês/química , Metais Terras Raras/química , Carbonatos/química , China , Fenômenos Físicos
19.
Environ Sci Pollut Res Int ; 26(23): 23899-23922, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31222648

RESUMO

The Jialing River is the second largest headwater tributary of the Yangtze River in China, therefore, the river water has been contaminated and water quality is deteriorated. Hence, this study aims to find the main controling factors of riverine chemistry. 52 water samples were collected for the determination of major ions and environmental isotopes of δ18O and δ2H. Stoichiometry of geochemical data with mixing end members and multivariate statistical analysis were employed with integrated GIS approach for data interpretations. The δ18O and δ2H of the Jialing River Basin (JRB) were used to define the origin of river water from meteoric water and water in the spring season is affected by high evaporation and evaporates dissolution. The average TDS 301 mg/L that is higher than the Yangtze River. In the JRB, 80% of the anion in water samples represented HCO3- (207 mg/L) and SO42- (80 mg/L) while 80% of the cations were accounted by Ca2+ (59.8 mg/L) and Mg2+ (17.9 mg/L). The water chemistry mainly derived from the water rock interaction. Piper plot indicated that Ca-Mg-HCO3- was the most dominant water type and most ions derived from carbonate weathering by H2SO4 and H2CO3. The stoichiometry results further confirmed carbonate weathering is dominant than silicate weathering. Evaporate ions were modified by anthropogenic sources. Agricultural inputs are higher than the industry and atmospheric inputs. Redundancy analysis showed that most contributive land-use type in explaining riverine chemistry was the cultivate land (62.6, 66.4, and 67.9%) at all buffer scales of 30, 20, and 10 km, respectively. Forest and grasslands mostly correlate with Ca2+, Mg2+, Cl-, SO42-, EC, pH, and HCO3- while anthropogenic land-use types such as cultivated and construction lands correlate with Na+, K+, Cl-, and NO3-. These results revealed that the lithology of the basin mainly controlled the upstream water chemistry while downstream riverine chemistry was controlled by both lithology and anthropogenic inputs. Nevertheless, this study suggested that explicitly determining the controlling factors of riverine chemistry involves a complex process and combination of different chemical constituents and factors on river water. However, this study managed to provide useful information to further understanding of the geochemical process in JRB.


Assuntos
Carbonatos/análise , Poluentes Químicos da Água/análise , Água/análise , Agricultura , Carbonatos/química , China , Isótopos/análise , Isótopos/química , Rios , Estações do Ano , Água/química , Poluentes Químicos da Água/química , Qualidade da Água , Tempo (Meteorologia)
20.
Meat Sci ; 156: 222-230, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31226650

RESUMO

Meat enhancement strategies like sodium tripolyphosphate (STP) are used to improve fresh meat quality attributes like color, water-holding capacity, and tenderness. However, alternatives are necessary because of reduced consumer acceptance of STP. One alternative is potassium carbonate (K2CO3). A study was conducted to evaluate K2CO3's impact on fresh, boneless, center-cut pork loins enhanced with one of five treatments: a negative control, positive control (0.3% STP), and three concentrations of K2CO3 (0.1, 0.3, and 0.5%). Loins were cut into chops, stored under simulated retail display, and analyzed for color (L*, a*, b*), pH, cook loss, and tenderness. For each quality characteristic measured, the 0.3% and 0.5% K2CO3 maintained redness (a*), decreased yellowness (b*), reduced cooking loss, and maintained tenderness compared to STP. SDS-PAGE analysis further determined that both K2CO3 and STP extracted myosin heavy chain. Combined, these data suggest that K2CO3 may function as an alternative to STP in the fresh pork industry provided microbial safety and shelf-life are appropriately controlled.


Assuntos
Carbonatos/química , Polifosfatos/química , Potássio/química , Carne Vermelha/análise , Animais , Cor , Comportamento do Consumidor , Culinária , Armazenamento de Alimentos , Humanos , Concentração de Íons de Hidrogênio , Odorantes , Resistência ao Cisalhamento , Suínos
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