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1.
Bull Environ Contam Toxicol ; 105(2): 283-290, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32734360

RESUMO

The current study investigated the efficiency of sepiolite (SE), sodium humate (HS), microbial fertilizer (JF) and SE combined with JF/HS in a ratio of 2:1 (w/w) (JF-2SE and HS-2SE) on Cd, Pb and As bioavailability in field trials with rice (Oryza sativa L.). The results showed that all the amendments remarkably decreased (p < 0.05) the contents of available Cd and available Pb in soil. Only JF-2SE treatment reduced available As concentration in soil. All the amendments were found to effectively reduce (p < 0.05) the contents of As in brown rice. Both JF-2SE and HS-2SE co-applications reduced the concentrations of Cd in brown rice to 0.108 and 0.135 mg kg-1, and that of Pb reduced to 0.2 and 0.175 mg kg-1, which met the national standard limit of China. Thus, the co-application of JF/HS-2SE can be a promising remediation strategy in Cd, Pb and As co-contaminated paddy soil.


Assuntos
Cádmio/química , Recuperação e Remediação Ambiental/métodos , Chumbo/química , Poluentes do Solo/química , Disponibilidade Biológica , Cádmio/análise , China , Poluição Ambiental , Fertilizantes , Chumbo/análise , Silicatos de Magnésio , Oryza , Solo/química , Poluentes do Solo/análise
2.
PLoS One ; 15(8): e0238105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853282

RESUMO

Biochar derived from straw is a potential low-cost adsorbent for metal ions and organic pollutants, but its practical application is still limited by the adsorption capacity. In this study, the correlation between the biochar's properties and pyrolysis temperature was explored. The adsorption mechanism was studied by monitoring the changes of biochar properties before and after adsorption using BET, SEM, XPS and FT-IR spectroscopy. The adsorption mechanism was revealed following the adsorption kinetics and the changes in biochar's properties before and after adsorption. The methylene blue (MB) and Pb2+ adsorption removal efficiency reached 95% at the initial concentration of 125 and 500 mg/L, respectively. Physisorption, chemisorption, and pore filling mechanisms determined the adsorption process of MB and Pb2+ on biochar. The Pb2+ adsorption process was highly affected by chemical co-precipitation at higher pyrolysis temperatures. The appearance of tar particles increased the adsorption rate of Pb2+. The biochar obtained at the pyrolysis temperature at 500, 800 and 900°C proved to be applicable for Pb2+ removal. Chemisorption and porosity dominated the MB adsorption, and biochars produced at pyrolysis temperatures of 200, 800 and 900°C are potential materials for MB removal. This study provides optimal pyrolysis conditions for transforming maize straw into valuable, low-cost materials for the removal of different pollutants.


Assuntos
Carvão Vegetal/química , Chumbo/química , Azul de Metileno/química , Zea mays/química , Adsorção , Cinética , Chumbo/isolamento & purificação , Azul de Metileno/isolamento & purificação , Pirólise , Propriedades de Superfície , Resíduos
3.
Chemosphere ; 260: 127683, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758774

RESUMO

This study represents the first ever work on a novel oxone treated hydrochar as an adsorbent for the efficient removal of different contaminants from aqueous solutions. Pine wood hydrochar (HC) was prepared by hydrothermal treatment at 300 °C and oxidized with oxone to produce oxidized pine wood hydrochar (OHC). Different analytical tools such as elemental analysis, FTIR, TGA, FE-SEM, and BET were used for the characterization of the OHC. Conductometric titration of OHC showed a substantial increase from 22 µmol/g to 600 µmol/g in the hydrochar carboxylic content. The OHC sorption performance was assessed by using Pb(II) ions and methylene blue (MB) dye as two models of contaminants. Sorption benchmarks were performed by varying the contaminant initial concentration, time, and temperatures. Sorption kinetic data was fitted well to the pseudo-second order kinetic model with high correlation coefficients (R2 > 0.99) and isothermal data was fitted to the Langmuir model. The highest adsorption capacities for MB and Pb(II) were 86.7 mg/g and 46.7 mg/g, respectively. This study proves that oxone treatment could be a potential sustainable oxidation method to tune the hydrochar surface to increase selectivity towards heavy metal ions and dye sorption.


Assuntos
Chumbo/química , Azul de Metileno/química , Poluentes Químicos da Água/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados , Azul de Metileno/análise , Soluções , Ácidos Sulfúricos , Temperatura , Água , Poluentes Químicos da Água/análise
4.
Int J Occup Environ Med ; 11(3): 140-147, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32683426

RESUMO

BACKGROUND: The major portion of lead in the body resides in skeletal system. The bone turnover affects the release of lead into the circulation from bones. The bone turnover biomarkers (BTM) in lead-battery workers with long-term exposure to lead have not been explored yet. OBJECTIVE: To evaluate the BTM (formation and resorption) in lead-battery workers with long-term exposure to lead in lead-battery manufacturing plant. METHODS: 176 male lead-exposed workers and 80 matched comparison group were studied. All participants were examined for blood lead levels (BLLs), bone formation biomarkers- serum osteocalcin (OC), alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP)-and bone resorption biomarkers-serum pyridinoline (PYD), deoxypyridinoline (DPYD), tartarate-resistant acid phosphatase-5b (TRACP-5b), and urinary hydroxyproline (UHYP). RESULTS: We found a significantly higher bone formation biomarkers such as BALP (p=0.007) and bone resorption biomarkers, eg, PYD (p=0.048), TRCAP-5b (p=0.001), and UHYP (p=0.001) in lead-exposed workers. A significant (p=0.041) negative correlation (ρ ­0.128) was noted between BLLs and OC. A significant positive correlation was noted between BLLs and TRACP-5b (ρ 0.176, p=0.005) and UHYP (ρ 0.258, p=0.004). Serum OC (p=0.040) and UHYP (p=0.015) levels changed significantly with BLL level. Bone resorption biomarkers levels- PYD, TRACP-5b, and BALP-were higher among those with higher BLLs levels. The duration of exposure was significantly associated with BALP (p=0.037), DPYD (p=0.016), TRACP-5b (p=0.001), and UHYP (p=0.002) levels. CONCLUSION: Long-term lead exposure affects the bone turnover.


Assuntos
Biomarcadores/sangue , Remodelação Óssea/fisiologia , Fontes de Energia Elétrica , Chumbo/toxicidade , Exposição Ocupacional/análise , Fosfatase Ácida/sangue , Fosfatase Ácida/metabolismo , Adulto , Fosfatase Alcalina/sangue , Biomarcadores/análise , Reabsorção Óssea/sangue , Estudos de Casos e Controles , Estudos Transversais , Fontes de Energia Elétrica/efeitos adversos , Humanos , Isoenzimas/sangue , Isoenzimas/metabolismo , Chumbo/química , Intoxicação por Chumbo/sangue , Intoxicação por Chumbo/diagnóstico , Masculino , Instalações Industriais e de Manufatura , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/estatística & dados numéricos , Osteocalcina/sangue , Local de Trabalho
5.
Chemosphere ; 260: 127574, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688316

RESUMO

Artisanal and small-scale gold mining (ASGM) operations are major contributors to the Philippines' annual gold (Au) output (at least 60%). Unfortunately, these ASGM activities lacked adequate tailings management strategies, so contamination of the environment is prevalent. In this study, soil contamination with copper (Cu), lead (Pb), zinc (Zn) and arsenic (As) due to ASGM activities in Nabunturan, Davao de Oro, Philippines was investigated. The results showed that ASGM-impacted soils had Cu, Pb, Zn and As up to 3.6, 83, 73 and 68 times higher than background levels, respectively and were classified as 'extremely' polluted (CD = 30-228; PLI = 5.5-34.8). Minerals typically found in porphyry copper-gold ores like pyrite, chalcopyrite, malachite, galena, sphalerite and goethite were identified by XRD and SEM-EDS analyses. Furthermore, sequential extraction results indicate substantial Cu (up to 90%), Pb (up to 50%), Zn (up to 65%) and As (up to 48%) partitioned with strongly adsorbed, weak acid soluble, reducible and oxidisable fractions, which are considered as 'geochemically mobile' phases in the environment. Although very high Pb and Zn were found in ASGM-impacted soils, they were relatively immobile under oxidising conditions around pH 8.5 because of their retention via adsorption to hydrous ferric oxides (HFOs), montmorillonite and kaolinite. In contrast, Cu and As release from the historic ASGM site samples exceeded the environmental limits for Class A and Class C effluents, which could be attributed to the removal of calcite and dolomite by weathering. The enhanced desorption of As at around pH 8.5 also likely contributed to its release from these soils.


Assuntos
Mineração , Poluentes do Solo/análise , Poluentes do Solo/química , Solo/química , Arsênico/análise , Arsênico/química , Cobre/análise , Cobre/química , Ouro/análise , Ferro/química , Compostos de Ferro/química , Chumbo/análise , Chumbo/química , Minerais/química , Filipinas , Sulfetos/química , Difração de Raios X , Zinco/análise , Zinco/química
6.
Chemosphere ; 260: 127587, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32663673

RESUMO

In this work, a three-dimension grapnene-PbO2 (3DG-PbO2) composite anode was prepared using coelectrodeposition technology for electrocatalytic oxidation of perfluorooctane sulfonate (PFOS). The effect of 3DG on the surface morphology, structure and electrocatalytic activity of PbO2 electrode was investigated. The results indicated that the 3DG-PbO2-0.08 anode (3DG concentration in electrodeposition solution was 0.08 g L-1) possessed the best electrocatalytic activity due to its stronger ·OH radicals generation capacity, more active sites and smaller charge-transfer resistance. The degradation rate constant of PFOS on 3DG-PbO2-0.08 anode was 2.33 times than that of pure PbO2 anode. Additionally, the by-products formed in electrocatalytic degradation of PFOS were identified and a PFOS degradation pathway was proposed accordingly, which was dominated by the dissociation of -CF2- groups via the attack of ·OH radicals. Finally, the toxicity evolution of degradation solution was examined to evaluate the ecological risk of electrocatalytic oxidation of PFOS by acute toxicity assays to zebrafish embryos.


Assuntos
Ácidos Alcanossulfônicos/análise , Técnicas Eletroquímicas/métodos , Fluorcarbonetos/análise , Grafite/química , Chumbo/química , Nanocompostos/química , Óxidos/química , Titânio/química , Poluentes Químicos da Água/análise , Ácidos Alcanossulfônicos/toxicidade , Animais , Eletrodos , Galvanoplastia , Embrião não Mamífero/efeitos dos fármacos , Fluorcarbonetos/toxicidade , Oxirredução , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
7.
Bull Environ Contam Toxicol ; 105(1): 146-154, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32488396

RESUMO

Biochar was for the first time produced from Suaeda glauca. The immobilization of Pb and Cd by this biochar and pig manure biochar was examined in two types of soils by diethylene triamine pentaacetic acid (DTPA) extraction. Addition of biochars decreased DTPA extractable Pb and Cd in Fluvo-aquic soil with reduction rates being 11.3%-48.4% and 0.74%-64.9% compared with the control treatment. The pig manure biochar favored the immobilization of Pb and S. glauca biochar favored the immobilization of Cd. Biochars can effectively immobilize heavy metals in Fluvo-aquic soil. However, the addition of biochars increased extractable Pb and Cd in red soil, with pig manure biochars showing greater rates. This is ascribed to that the competition effects of ions released from biochar enhanced the moving of heavy metals from iron and manganese oxides bound form to organic matter bound form, and hence enhanced the mobility and bioavailability of heavy metals.


Assuntos
Cádmio/química , Chumbo/química , Poluentes do Solo/química , Animais , Disponibilidade Biológica , Carvão Vegetal/química , Chenopodiaceae , Compostos de Manganês , Esterco , Metais Pesados/análise , Óxidos , Solo , Poluentes do Solo/análise , Suínos
8.
Bull Environ Contam Toxicol ; 105(1): 166-172, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32564099

RESUMO

The growth response, tolerance, and enrichment characteristics of six ornamental species, Chlorophytum comosum, Calendula officinalis, Iris lacteal, Belamcanda chinensis, Saponaria officinalis, and Polygonum lapathifolium were studied under hydroponic culture with lead (Pb) concentrations ranging from 0 to 1000 mg/L. The results showed that the growth of the tested ornamental species under Pb stress was inhibited. Belamcanda chinensis presented the largest tolerance index (0.75), and Calendula officinalis had the highest toxicity threshold (500 mg/L) under Pb stress. The highest Pb contents in the shoots were detected in Iris lacteal and Belamcanda chinensis. The enrichment coefficients in the shoots of Iris lacteal and Belamcanda chinensis were significantly higher than those in the other ornamental species. In conclusion, Iris lacteal and Belamcanda chinensis are the most tolerant and have the greatest Pb enrichment and translocation abilities under Pb stress, and thus, they have a strong potential to restore Pb-contaminated water bodies and soils.


Assuntos
Biodegradação Ambiental , Hidroponia , Chumbo/química , Iris (Planta) , Raízes de Plantas/crescimento & desenvolvimento , Solo , Poluentes do Solo
9.
Proc Natl Acad Sci U S A ; 117(25): 14299-14305, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513701

RESUMO

The Lower Cretaceous Huajiying Formation of the Sichakou Basin in northern Hebei Province, northern China contains key vertebrate taxa of the early Jehol Biota, e.g., Protopteryx fengningensis, Archaeornithura meemannae, Peipiaosteus fengningensis, and Eoconfuciusornis zhengi This formation arguably documents the second-oldest bird-bearing horizon, producing the oldest fossil records of the two major Mesozoic avian groups Enantiornithes and Ornithuromorpha. Hence, precisely determining the depositional ages of the Huajiying Formation would advance our understanding of the evolutionary history of the Jehol Biota. Here we present secondary ion mass spectrometry (SIMS) U-Pb zircon analysis results of eight interbedded tuff/tuffaceous sandstone samples from the Huajiying Formation. Our findings, combined with previous radiometric dates, suggest that the oldest enantiornithine and ornithuromorph birds in the Jehol Biota are ∼129-131 Ma, and that the Jehol Biota most likely first appeared at ∼135 Ma. This expands the biota's temporal distribution from late Valanginian to middle Aptian with a time span of about 15 My.


Assuntos
Biota , Aves/classificação , Chumbo/química , Silicatos/química , Zircônio/química , Animais , Evolução Biológica , China , Fósseis , Geologia , Filogenia , Espectrometria de Massa de Íon Secundário
10.
Food Chem ; 330: 127212, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526650

RESUMO

In this work, a facile solid phase extraction (SPE) method was developed for the analysis of trace Pb2+ and Cd2+ by using chitosan/thiol modified metal-organic frameworks (CS/MOF-SH) composite as adsorbent followed by graphite furnace atomic absorption spectrometer (GF-AAS) detection. The potential influencing factors, such as solution pH, adsorbent dosage, and extraction time, were fully estimated. Under the optimized extraction conditions, the detection limits of Pb2+ and Cd2+ were 0.033 µg L-1 and 0.008 µg L-1, respectively. Compared to other studies, CS/MOF-SH not only possessed superior adsorption performance, but also had the advantages of ease of handling and recyclability. Encouragingly, the developed method was of high accuracy and could monitor trace Pb2+ and Cd2+ in various certified reference materials (rice, wheat and tea) with complicated matrices, demonstrating its practical potential for regular monitoring of trace heavy metal ions in real food samples.


Assuntos
Cádmio/análise , Quitosana/química , Chumbo/análise , Estruturas Metalorgânicas/química , Compostos de Sulfidrila/química , Cádmio/química , Cátions Bivalentes , Análise de Alimentos , Chumbo/química , Oryza/química , Extração em Fase Sólida/métodos , Chá/química , Triticum/química
11.
Chemosphere ; 251: 126382, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443238

RESUMO

A single metal Pd/γ-Al2O3 catalyst and a bimetallic Pd-Ce/γ-Al2O3 catalyst were prepared by the equal-volume impregnation method to investigate the effect of CeO2 loading on the catalytic oxidation of toluene. The specific surface area, surface morphology, and redox performance of the catalyst were characterized by N2 desorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), H2-TPR, O2-TPD, and electron paramagnetic resonance (EPR). The results showed that bimetal catalysts loaded CeO2 had smaller nano-PdO particles than those of the Pd/γ-Al2O3 catalyst. Compared with the catalyst of 0.2Pd/γ-Al2O3 (percentage of mass, the same as below), the catalyst doped with 0.3CeO2 had a stronger reduction peak, which was shifted to the low-temperature zone by more than 80 °C. The results of XPS and O2-TPD showed that the introduction of CeO2 provided more surface oxygen vacancy for the catalyst and enhanced its catalytic oxidation ability, and the amount of desorbed O2 increased from 3.55 µmol/g to 8.54 µmol/g. The results of EPR were that the addition of CeO2 increased the content of active oxygen species and oxygen vacancies on the surface of the catalysts, which might be due to the supply of electrons to the O2 and PdO during the Ce3+toCe4+ conversion process. That could have accelerated the catalytic reaction process. Compared with the single precious metal catalyst, the T10 and T90 of the Pd-Ce/γ-Al2O3 catalyst were decreased by 22 °C and 40 °C, respectively.


Assuntos
Tolueno/química , Óxido de Alumínio/química , Catálise , Cério/química , Chumbo/química , Oxirredução , Oxigênio/química , Espectroscopia Fotoeletrônica
12.
Chemosphere ; 256: 127139, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470737

RESUMO

The existence of ß-naphthoxyacetic acid (BNOA) pesticide in water system has aroused serious environmental problem because of its potential toxicity for humans and organisms. Therefore, exploiting an efficient method without secondary pollution is extremely urgent. Herein, a promising Ti/PbO2-Co-Pr composite electrode has been successfully fabricated through simple one-step electrodeposition for efficiently electrocatalytic degradation of BNOA. Compared with Ti/PbO2, Ti/PbO2-Co and Ti/PbO2-Pr electrodes, Ti/PbO2-Co-Pr electrode with smaller pyramidal particles possesses higher oxygen evolution potential, excellent electrochemical stability and outstanding electrocatalytic activity. The optimal degradation condition is assessed by major parameters including temperature, initial pH, current density and Na2SO4 concentration. The degradation efficiency and chemical oxygen demand removal efficiency of BNOA reach up to 94.6% and 84.6%, respectively, under optimal condition (temperature 35 °C, initial pH 5, current density 12 mA cm-2, Na2SO4 concentration 8.0 g L-1 and electrolysis time 3 h). Furthermore, Ti/PbO2-Co-Pr electrode presents economic energy consumption and superior repeatability. Finally, the possible degradation mechanism of BNOA is put forward according to the main intermediate products identified by liquid chromatography-mass spectrometer. The present research paves a new path to degrade BNOA pesticide wastewater with Ti/PbO2-Co-Pr electrode.


Assuntos
Eletrólise/métodos , Glicolatos/química , Chumbo/química , Praguicidas/química , Titânio/química , Águas Residuárias/análise , Poluentes Químicos da Água/química , Análise da Demanda Biológica de Oxigênio , Eletrodos , Eletrólise/instrumentação , Galvanoplastia , Oxirredução , Óxidos/química , Sulfatos/química
13.
Nucleic Acids Res ; 48(12): e71, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32463449

RESUMO

The dynamic conformation of RNA molecules within living cells is key to their function. Recent advances in probing the RNA structurome in vivo, including the use of SHAPE (Selective 2'-Hydroxyl Acylation analyzed by Primer Extension) or kethoxal reagents or DMS (dimethyl sulfate), provided unprecedented insights into the architecture of RNA molecules in the living cell. Here, we report the establishment of lead probing in a global RNA structuromics approach. In order to elucidate the transcriptome-wide RNA landscape in the enteric pathogen Yersinia pseudotuberculosis, we combined lead(II) acetate-mediated cleavage of single-stranded RNA regions with high-throughput sequencing. This new approach, termed 'Lead-seq', provides structural information independent of base identity. We show that the method recapitulates secondary structures of tRNAs, RNase P RNA, tmRNA, 16S rRNA and the rpsT 5'-untranslated region, and that it reveals global structural features of mRNAs. The application of Lead-seq to Y. pseudotuberculosis cells grown at two different temperatures unveiled the first temperature-responsive in vivo RNA structurome of a bacterial pathogen. The translation of candidate genes derived from this approach was confirmed to be temperature regulated. Overall, this study establishes Lead-seq as complementary approach to interrogate intracellular RNA structures on a global scale.


Assuntos
Análise de Sequência de RNA/métodos , Transcriptoma , Acetatos/química , Chumbo/química , Conformação de Ácido Nucleico , RNA Bacteriano/química , Yersinia pseudotuberculosis/genética
14.
Chemosphere ; 253: 126661, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32278913

RESUMO

Nano-hydroxyapatite (nHAP) has an excellent effect on the remediation of Pb contaminated water and soil. In this study, an efficient modified nHAP was prepared assisted with two-stage ultrasonic irradiation. The effects of ultrasound modification on the nHAP were tested using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform InfraRed spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and combined batch Pb uptake experiments. The nHAP with ultrasound has a fine structure with the width and length of around 9 nm and 40 nm respectively. The ultrasound parameter of 1s/36s in stage 1 and 16s/18s in stage 2 was verified as the optimum under which the nHAP prepared performed the best with the maximum adsorption capacity of 1300.93 mg/g. The results of XRD and SEM indicated that the sorbent after uptake of Pb2+ was mainly Pb10(PO4)6OH2 (HPY) with insignificant Ca10Pb10-x(PO4)6OH2. Compared the results of Pb/Ca, pH and XRD with the metal fraction of Pb in adsorbents during the dynamic sorption process, this research proved that the effects of complexation, cation exchange and dissolution and precipitation coexisted in the initial stage, while the dissolution and precipitation gradually dominated the adsorption mechanism with contact time. The processes of Pb2+ uptake by nHAP sorbents prepared under different ultrasound parameter presented almost the same dynamic mechanism with a little difference in time node. The research of dynamic mechanism of Pb2+ uptake by a superior nHAP is essential for both contaminated water and soil remediation.


Assuntos
Durapatita/química , Poluentes Ambientais/química , Recuperação e Remediação Ambiental/métodos , Chumbo/química , Adsorção , Solo/química , Poluentes do Solo/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Ondas Ultrassônicas , Difração de Raios X
15.
Chemosphere ; 253: 126650, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32268252

RESUMO

This study firstly reported a novel nano humboldtine/almandine composite (NHLA composite) prepared directly from almandine through one-pot method based on the interaction of almandine and oxalic acid. The formation of humboldtine/almandine binary phase from natural almandine was determined by X-ray diffraction. Analysis of scanning & transmission electron microscope showed that large amount of nano humboldtine with uniform size (average size of 15.59 nm) were loaded on the almandine sheets. Compared with raw minerals, Pb(Ⅱ) removal capacity of synthesized composite was significantly increased, demonstrating that the main active ingredient for Pb(Ⅱ) removal was humboldtine phase rather than almandine itself. Pb(Ⅱ) adsorption capacity was increased with the increasing of initial pH value or temperature. Langmuir isotherm and Pseudo-second order kinetic equation were well fitted with experimental results and the maximum Pb(Ⅱ) adsorption capacity from Langmuir isotherm was 574.71 mg/g at temperature of 25 °C. In addition, heavy metal removal experiments in coexisting systems of multiple heavy metal ions manifested that the composite had a high selectivity for Pb(Ⅱ) adsorption. Ion exchange, surface complexation and electrostatic interaction have involved in the Pb(Ⅱ) adsorption. The synthesized composite was considered as a low cost, high efficiency, super selectivity and easy to mass production material for Pb(Ⅱ) adsorption from solution.


Assuntos
Chumbo/química , Modelos Químicos , Adsorção , Concentração de Íons de Hidrogênio , Íons , Cinética , Metais Pesados , Minerais/química , Difração de Raios X
16.
Ecotoxicol Environ Saf ; 196: 110539, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247959

RESUMO

Contamination of arable land with trace metals is a global environmental issue which has serious consequences on human health and food security. Present study evaluates the adsorption of cadmium (Cd) and lead (Pb) by using different quantities of composite of sepiolite, organic manure and lime (SOL) at field and laboratory scale (batch experiments). Characterization of SOL by SEM, EDS and FTIR spectroscopy revealed the presence of elemental and functional groups (hydroxyl, C⋯H and -COOH groups) on its surface. The field experiment was performed in a paddy field of gleysol having moderate contamination of Cd and Pb (0.64 mg kg-1 and 53.44 mg kg-1). Here, different rates of SOL (0.25, 0.5, 1, 1.5 and 2% w/w) were applied by growing low and high Cd accumulator rice cultivars. Application of SOL at 2% w/w showed considerable efficiency to increase soil pH (up to 19%) and to reduce available Cd (42-66%) and Pb (22-55%) as compared to the control. Moreover, its application reduced metal contents in roots, shoots and grains of rice by 31%, 36% and 72% (for Cd) and 41%, 81% and 84% (for Pb), respectively in low accumulator cultivar. Further, the batch sorption experiment was performed to evaluate the adsorption capacity of SOL in a wide range of contamination. Obtained sorption data was better fitted to the Langmuir equation. Our results highlight the strong efficiency of composite treatment for an enhanced in-situ metal immobilization under field and lab conditions. Further, applied treatments greatly reduced the metal contents in rice grains. In a nut shell, application of SOL in a contaminated gleysol should be considered for soil remediation and safe food production.


Assuntos
Cádmio/química , Compostos de Cálcio/química , Chumbo/química , Silicatos de Magnésio/química , Esterco , Óxidos/química , Adsorção , Disponibilidade Biológica , Cádmio/farmacocinética , Chumbo/farmacocinética , Oryza/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/química , Poluentes do Solo/farmacocinética
17.
Mol Pharmacol ; 97(6): 409-422, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32241960

RESUMO

The microtubule-binding taxanes, docetaxel and cabazitaxel, are administered intravenously for the treatment of castration-resistant prostate cancer (CRPC) as the oral administration of these drugs is largely hampered by their low and highly variable bioavailabilities. Using a simple, rapid, and environmentally friendly microwave-assisted protocol, we have synthesized a number of 3,5-bis(styryl)pyrazoles 2a-l, thus allowing for their screening for antiproliferative activity in the androgen-independent PC3 prostate cancer cell line. Surprisingly, two of these structurally simple 3,5-bis(styryl)pyrazoles (2a and 2l) had concentrations which gave 50% of the maximal inhibition of cell proliferation (GI50) in the low micromolar range in the PC3 cell line and were thus selected for extensive further biologic evaluation (apoptosis and cell cycle analysis, and effects on tubulin and microtubules). Our findings from these studies show that 3,5-bis[(1E)-2(2,6-dichlorophenyl)ethenyl]-1H-pyrazole 2l 1) caused significant effects on the cell cycle in PC3 cells, with the vast majority of treated cells in the G2/M phase (89%); 2) induces cell death in PC3 cells even after the removal of the compound; 3) binds to tubulin [dissociation constant (Kd) 0.4 ± 0.1 µM] and inhibits tubulin polymerization in vitro; 4) had no effect upon the polymerization of the bacterial cell division protein FtsZ (a homolog of tubulin); 5) is competitive with paclitaxel for binding to tubulin but not with vinblastine, crocin, or colchicine; and 6) leads to microtubule depolymerization in PC3 cells. Taken together, these results suggest that 3,5-bis(styryl)pyrazoles warrant further investigation as lead compounds for the treatment of CRPC. SIGNIFICANCE STATEMENT: The taxanes are important components of prostate cancer chemotherapy regimens, but their oral administration is hampered by very low and highly variable oral bioavailabilities resulting from their poor absorption, poor solubility, high first-pass metabolism, and efficient efflux by P-glycoprotein. New chemical entities for the treatment of prostate cancer are thus required, and we report here the synthesis and investigation of the mechanism of action of some bis(styryl)pyrazoles, demonstrating their potential as lead compounds for the treatment of prostate cancer.


Assuntos
Antineoplásicos/uso terapêutico , Chumbo/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Pirazóis/uso terapêutico , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Sítios de Ligação , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Estabilidade de Medicamentos , Humanos , Chumbo/química , Masculino , Microtúbulos/efeitos dos fármacos , Modelos Moleculares , Células PC-3 , Pirazóis/síntese química , Pirazóis/química
18.
Chemosphere ; 251: 126369, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32163779

RESUMO

Thermal modification was simply performed on molybdenite to enhance the adsorption of Pb(II) in aqueous solutions, and the root of this phenomenon was well studied in this work. Various thermal modification temperatures at 300 °C, 400 °C and 500 °C were applied to modify the surface property of molybdenite, producing different degrees of edge defect and surface wettability in molybdenite samples. Contact angle tests, atomic force microscopy (AFM) observations and adsorption tests illustrated that molybdenite thermally modified at 400 °C contained most edge defects and achieved a 147.846 mg/g Pb(II) adsorption, which was almost 10 times of that obtained by natural molybdenite. The adsorption experiment also indicated that the increase of surface hydrophilia of molybdenite would slightly benefit the Pb(II) adsorption. The X-ray photoelectron spectroscope (XPS) exhibited that a strong chemical adsorption existed between Pb(II) and S elements. AFM study further demonstrated that the interaction between Pb(II) and S atoms exposed at the triangular edges of molybdenite were the intrinsic reason for the great enhancement of Pb(II) adsorption. This work provides a new insight to absorb Pb(II) in aqueous solutions using natural molybdenite.


Assuntos
Chumbo/química , Poluentes Químicos da Água/química , Adsorção , Cinética , Espectroscopia Fotoeletrônica , Soluções , Propriedades de Superfície , Água/química
19.
Chemosphere ; 250: 126329, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32126334

RESUMO

The increasing contamination of lead ions (Pb(II)) in groundwater has become a serious environmental issue, which provides the impetus for intense research on Pb(II) removal. ε-MnO2 nanoflowers were successfully fabricated through a simple decomposition reaction. And the obtained ε-MnO2 nanoflowers were employed to remove Pb(II) from water. The detailed microstructure and surface properties of ε-MnO2 were systematically characterized. The results indicate that the pure ε-MnO2 phase was obtained and the specific surface area is 96.33 m2 g-1. Batch adsorption experiments of Pb(II) were carried out, and the ε-MnO2 nanoflowers exhibited outstanding adsorption performance. The maximum adsorption capacity for Pb(II) and Cd(II) achieved to 239.7 mg g-1 and 73.6 mg g-1 at the dosage of 0.2 g L-1. Besides, the prepared ε-MnO2 nanoflowers show much higher removal efficiency toward Pb(II) compared with commercial MnO2. The XRD results reveal the stability of ε-MnO2 nanoflowers, and the XPS results suggest that both the electrostatic interaction and structural tunnels are responsible for the removal mechanisms of Pb(II). This work finds a facile method to synthesize ε-MnO2 nanoflowers, showing great potential for Pb(II) removal.


Assuntos
Chumbo/química , Compostos de Manganês/química , Nanoestruturas/química , Óxidos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Água Subterrânea , Íons , Propriedades de Superfície , Águas Residuárias/química , Água , Poluentes Químicos da Água/análise
20.
Chemosphere ; 252: 126529, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32220718

RESUMO

Magnetic ferrite/biochar composites are a kind of promising adsorbents due to their high adsorption efficiency and facile magnetic separation; however, their synthesis is associated with high cost and secondary environmental impacts. In this study, a novel Mn-Zn ferrite/biochar composite (MZF-BC) is synthesized via a green two-step biocheaching and hydrothermal method using waste batteries and pine sawdust. Characterization results indicate that the introduced Mn-Zn ferrite particles are successfully embedded and coated on biochar (BC), and synthesized MZF-BC50 with 50% BC content exhibits best performance with a specific surface area of 138.5 m2 g-1, the saturation magnetization of 27.5 emu g-1 and CEC value of 53.2 mmol 100 g-1. The maximum adsorption capacity of Pb2+ is 99.5 mg g-1 based on the Langmuir sorption isotherm study at 298 K, and pseudo-second-order model accurately describes the adsorption process. Regeneration test suggests that MZF-BC50 can be efficiently reused for 6 cycles. In addition, it exhibits a good selective Pb2+ and Cd2+ removal performance in lead-acid battery wastewater. The results illustrate that this newly developed material has low cost and rapid remediation of Pb2+ as good application potential.


Assuntos
Fontes de Energia Elétrica , Chumbo/química , Eliminação de Resíduos/métodos , Adsorção , Carvão Vegetal/química , Compostos Férricos/química , Química Verde , Cinética , Magnetismo , Águas Residuárias , Poluentes Químicos da Água/análise , Madeira/química , Zinco
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