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1.
Environ Monit Assess ; 192(4): 240, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185514

RESUMO

Metal ion contamination in wastewater is an issue of global concern. The conventional methods of heavy metal removal from wastewater have some drawbacks, ranging from generation of sludge to high cost of removal. Adsorption technique for copper(II), zinc(II), and chromium(VI) using activated carbon has been found efficient. However, it is not economical on a large scale. This, therefore, necessitates the search for economical and readily available plant biomass-based activated carbons for the sequestration of the metal ions. This review presents the state of the art on the adsorption of copper(II), zinc(II), and chromium(VI) from industrial wastewater. Based on the literature review presented, the groundnut husk and corncob based activated carbons were found to possess the maximum adsorption capacities for copper(II), zinc(II), and chromium(VI) removal, when compared with the other plant biomass-based activated carbons. The high values of the adsorption capacities obtained were as a result of the isotherms and pH of the adsorbent as well as the initial concentration of the metal solutions. From the review, the equilibrium data fitted better with Langmuir and Freundlich isotherms than with other isotherms. Research gaps were identified which include a need to investigate the kinetic and the thermodynamic behaviors of the metal ions onto the studied adsorbents. Furthermore, a comparative analysis of the three types of activation of the adsorbents should be investigated using single and multi-metals. The optimization of particle size, contact time, temperature, initial concentration, and adsorbent dosage for adsorption of copper(II), zinc(II), and chromium(VI) onto the studied adsorbents using response surface methodology is equally required.


Assuntos
Cromo , Metais Pesados , Águas Residuárias , Purificação da Água , Adsorção , Biomassa , Carvão Vegetal , Cromo/isolamento & purificação , Cobre/isolamento & purificação , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/isolamento & purificação , Zinco/isolamento & purificação
2.
Chemosphere ; 243: 125439, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995887

RESUMO

This paper introduces a novel method for ethylenediaminetetraacetic acid (EDTA)-enhanced electrokinetic (EK) remediation by combining dual cation-exchange membranes and circulation methods for an aged electroplating soil contaminated by chrome (Cr), copper (Cu), and nickel (Ni). Three laboratory-scale EK experiments were carried out, including T1, the traditional EK process; T2, the traditional EDTA-enhanced EK process; and T3, the assisted EDTA-enhanced EK process. The results obtained show that removal of Cu and Ni in T3 was 3-10 times higher than after T1 and T2. However, the removal of Cr (total) was small in all experiments because of the high content of Cr(III). T3 eliminated the metal accumulation problem that existed for T1 and T2. Simultaneously, the highly acidified area (pH < 4) was reduced from 80% in T1 and T2 to only 20% in T3. The results obtained in T3 indicate that the chelating effect of EDTA has a greater ability to dissolve oxidizable Cu and Ni in the soil than the acidification effect. Toxicity evaluation confirmed that the soil treated by T3 presented a lower effect on a luminescent bacterium (Photobacterium phosphoreum T3) because soil pH tended to be more neutral after this treatment. This research provides a novel method for removing heavy metals from soil in a more environmentally friendly way and clarifies the cause of the existing problems of low removal efficiency and high accumulation in the traditional EK process.


Assuntos
Técnicas Eletroquímicas/métodos , Recuperação e Remediação Ambiental/métodos , Resinas de Troca de Cátion , Compostos de Cromo/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Ácido Edético/química , Galvanoplastia , Metais Pesados/isolamento & purificação , Níquel/isolamento & purificação , Solo/química , Poluentes do Solo/isolamento & purificação
3.
Chemosphere ; 240: 124884, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31542586

RESUMO

Antibiotics and heavy metals are frequently detected simultaneously in water environment. In this study, the competitive adsorption behavior of tylosin (TYL) and sulfamethoxazole (SMX) on nano-hydroxyapatite modified biochar (nHAP@biochar) in accordance with Cu(II) in single, binary and ternary systems was investigated. The specific surface area of nHAP@biochar was 566.056 m2/g. The adsorption of TYL on nHAP@biochar reduced by 13.36%-41.04% or 9.92%-38.69% with Cu(II) and SMX in the solution, respectively. The suppression of SMX was stronger than Cu(II) on the adsorption of TYL when the SMX or Cu(II) was constant. The adsorption of SMX increased by 2.01-3.56 times in the present of Cu(II), while suppressed by TYL up to 42.30%. Due to the bridging of TYL or SMX between the nHAP@biochar and Cu(II) and destroying of bound water surrounded, the adsorption of Cu(II) increased to a greater extent. Electrostatic interaction and H-bond were the two main interactions between TYL, SMX and Cu(II) and nHAP@biochar. π-π interactions was also interaction between the SMX and nHAP@biochar.


Assuntos
Carvão Vegetal/química , Cobre/metabolismo , Durapatita/química , Nanopartículas/química , Sulfametoxazol/metabolismo , Tilosina/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Cobre/isolamento & purificação , Sulfametoxazol/isolamento & purificação , Tilosina/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
4.
Chemosphere ; 240: 124860, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31542578

RESUMO

In order to increase the adsorption properties of sodium alginate gel beads, a series of SA@PF-beads (sodium alginate-based beads with different amount of pore-forming agent) were prepared with calcium carbonate as the pore forming agent. The experimental results showed that the adsorption capacity of Cu(Ⅱ) increased by at least two times (from 13.69 mg/g to 33.88 mg/g, treated with SA@PF-0 and SA@PF-2.0, respectively) with proper amount of calcium carbonate added, which is economical and effective. In the experiment, SEM was used to measure the morphology of gel beads with different amount of pore-forming agent. FTIR and XPS were used to analyze the variation of functional groups and bond energies in the adsorption process. Adsorption isotherms and kinetics were conducted and showed that the adsorption process was consistent with Langmuir model and Elovich kinetic model. The maximum Langmuir adsorption 229.746 mg/g. The effects of pH, temperature and solid-liquid ratio on adsorption capacity were also investigated. In brief, calcium carbonate is an efficient and convenient pore-forming agent, which can be used to improve the adsorption properties of alginate gel materials.


Assuntos
Alginatos/química , Cobre/isolamento & purificação , Microesferas , Adsorção , Carbonato de Cálcio/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Poluentes Químicos da Água/isolamento & purificação
5.
Int J Nanomedicine ; 14: 7781-7792, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576122

RESUMO

Purpose: Mesoporous silica (MS) have been considered as a biocompatible compound and found to have various pharmaceutical applications. Recently, novel approaches in applications of MS as antidote agents were introduced. In this study, the capacity of ethylenediaminetetraacetic acid modified mesoporous silica (MS-EDTA) was evaluated in in vitro and in vivo adsorption of copper (Cu). Methods: The MS-EDTA was characterized by fourier transform infrared (FT-IR) and X-ray diffraction, while surface area was determined by N2 adsorption-desorption technique. Morphological studies were observed by high resolution-transmission electron microscopy and field emission-scanning electron microscopy and the sizes were determined by dynamic light scattering. The capacity of these particles for copper adsorption was investigated in vitro in both 1.2 and 7.2 pH. In in vivo animal study, the Cu adsorption efficiency of MS-EDTA in Cu-overdosed mice was evaluated. In this case, an animal model of acute copper poisoning was prepared. Results: The MS-EDTA with surface area of 352.35 was synthesized. Scanning electron microscope showed spherical particle formation with less than 500 nm in size. Transmission electron microscope images showed porous and honeycomb structure. FT-IR spectroscopy showed an appropriate formation of functional groups. Particle efficiency was investigated for Cu adsorption. MS-EDTA in both media showed a high adsorption capability for Cu (II) adsorption in pH=1.2 and pH=7.2. In addition, the study of Langmuir, Freundlich, and Redlich-Peterson adsorption models showed that copper adsorption by MS-EDTA followed the Freundlich model with multi-layer adsorption. In vivo evaluation showed that MS-EDTA could alleviate the symptoms of acute copper poisoning by lowering Cu plasma levels. Conclusion: Structural evaluation showed successful formation of MS-EDTA. In vitro analysis demonstrated that supreme Cu adsorption occurs in both pH conditions (7.2 and 1.2), and was especially more favorable in simulated intestinal pH (7.2). The in vivo studies in animal models with acute Cu poisoning showed that MS-EDTA could be a potent antidote agent.


Assuntos
Antídotos/farmacologia , Cobre/isolamento & purificação , Cobre/toxicidade , Ácido Edético/química , Dióxido de Silício/química , Adsorção , Animais , Antídotos/administração & dosagem , Biomarcadores/sangue , Cobre/sangue , Difusão , Íons , Cinética , Camundongos , Modelos Animais , Tamanho da Partícula , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
Mar Pollut Bull ; 149: 110586, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31550572

RESUMO

The objective of this research was to evaluate the capacity of Enteromorpha derived biochar to adsorb heavy metals from seawater. The biochar characteristics were determined, and isothermal and kinetic data were obtained using batch experiments. Copper [Cu(II)] and lead [Pb(II)] adsorption by the biochar was favored by high pH conditions, while elevated salinity had a relatively weak negative effect on adsorption. The Langmuir isotherm and adsorption kinetics pattern enabled interpretation of the equilibrium and kinetics of Cu(II) and Pb(II) removal by the biochar. The maximum removal rates of Cu(II) and Pb(II) by the biochar in 60 min were estimated to be 91% and 54%, respectively. A model describing the adsorption processes was developed to predict the efficiency of heavy metal removal by the biochar. The outcomes of the present study indicate that Enteromorpha derived biochar could be an effective and environmentally friendly adsorbent for removing heavy metals from marine environments.


Assuntos
Carvão Vegetal/química , Cobre/isolamento & purificação , Chumbo/isolamento & purificação , Água do Mar/química , Ulva/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cobre/química , Concentração de Íons de Hidrogênio , Cinética , Chumbo/química , Modelos Químicos , Salinidade , Fatores de Tempo , Poluentes Químicos da Água/química
7.
Ecotoxicol Environ Saf ; 184: 109610, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31522058

RESUMO

Montmorillonite (G-Mt) modified by a gemini quaternary ammonium cationic surfactant (Propyl bis (hexadecyl dimethyl ammonium) chloride, 16-3-16) was used to remove emerging contaminants (ECs) (such as 1H-Benzotriazole (BTA), 5-Methyl-1H-benzotriazole (TTA) and 1-Hydroxybenzotriazole (HOBT)) and Cu2+ from wastewater. Based on the adsorption of the above three ECs in our previous studies, single adsorption of Cu2+ and the simultaneous adsorption of three ECs with Cu2+ on G-Mt were also investigated. G-Mt showed much lower adsorption amount on Cu2+ comparing with original montmorillonite (Ca-Mt) in single adsorption system due to the difficulty of ion-exchange property of G-Mt. In co-adsorption system, three organic pollutants and Cu2+ played a synergistic effect and the adsorption capacity of G-Mt on them increased, the influence sequence of Cu2+ on the adsorption of three ECs or the effect of ECs on the adsorption of Cu2+ both followed as: TTA > BTA > HOBT. The results of FT-IR, EDS and XPS revealed that the complex of Cu2+ and ECs were adsorbed onto G-Mt via forming complexes and hydrophobic interaction in co-adsorption system. The pH experiment showed that the optimum pH of the co-adsorption of ECs and Cu2+ on G-Mt was 5. Molecular dynamics (MD) simulations showed that three ECs or ECs combining with Cu2+ were dominantly adsorbed in the interlayer space of G-Mt, which resulted in the arrangement manner of 16-3-16 between the layer of G-Mt before and after adsorption of three organic pollutants was different. Furthermore, by quantitatively analyzing electrostatic potential (ESP) distribution, average local ionization energy (ALIE) distribution and their minimum points on three ECs molecules surfaces, Multiwfn program has been applied to probe the microscopic mechanism. The synergistic effect of co-adsorption will promote enrichment of copper ions and ECs to remove them more efficiently in polluted waters.


Assuntos
Bentonita/química , Cobre/química , Compostos de Amônio Quaternário/química , Tensoativos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Cobre/isolamento & purificação , Concentração de Íons de Hidrogênio , Íons/química , Íons/isolamento & purificação , Triazóis/química , Triazóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
8.
Molecules ; 24(17)2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31470528

RESUMO

This work presents a simple green synthesis of gold nanoparticles (AuNPs) by using an aqueous extract of Etlingera elatior (torch ginger). The metabolites present in E. elatior, including sugars, proteins, polyphenols, and flavonoids, were known to play important roles in reducing metal ions and supporting the subsequent stability of nanoparticles. The present work aimed to investigate the ability of the E. elatior extract to synthesise AuNPs via the reduction of gold (III) chloride hydrate and characterise the properties of the nanoparticles produced. The antioxidant properties of the E. elatior extract were evaluated by analysing the total phenolic and total flavonoid contents. To ascertain the formation of AuNPs, the synthesised particles were characterised using the ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) microscopy, and dynamic light scattering (DLS) measurement. The properties of the green synthesised AuNPs were shown to be comparable to the AuNPs produced using a conventional reducing agent, sodium citrate. The UV-Vis measured the surface plasmon resonance of the AuNPs, and a band centered at 529 nm was obtained. The FTIR results proved that the extract contained the O-H functional group that is responsible for capping the nanoparticles. The HRTEM images showed that the green synthesized AuNPs were of various shapes and the average of the nanoparticles' hydrodynamic diameter was 31.5 ± 0.5 nm. Meanwhile, the zeta potential of -32.0 ± 0.4 mV indicates the high stability and negative charge of the AuNPs. We further successfully demonstrated that using the green synthesised AuNPs as the nanocomposite to modify the working surface of screen-printed carbon electrode (SPCE/Cs/AuNPs) enhanced the rate of electron transfer and provided a sensitive platform for the detection of Cu(II) ions.


Assuntos
Técnicas Biossensoriais/instrumentação , Cobre/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Ouro/química , Nanopartículas Metálicas/química , Zingiberaceae/química , Antioxidantes/química , Antioxidantes/isolamento & purificação , Cátions Bivalentes , Flavonoides/química , Química Verde , Nanopartículas Metálicas/ultraestrutura , Oxirredução , Tamanho da Partícula , Extratos Vegetais/química , Proteínas de Plantas/química , Polifenóis/química , Citrato de Sódio/química , Eletricidade Estática , Açúcares/química
9.
Chemosphere ; 236: 124416, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545207

RESUMO

The objective of this study was to develop a novel graphene oxide (GO)-based adsorbent by loading the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA) to simultaneously scavenge copper ion, a charged species, and bisphenol A, an uncharged organic compound, from water. The HDTMA modification process was studied and the GO/HDTMA composites characterized using SEM (scanning electron microscopy), XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy) and FTIR (Fourier Transform Infrared) spectroscopy. Within the concentration range of 6.4-11.5%, HDTMA caused the 2D GO sheets to form into solid 3D networks by reducing the repulsive forces and increasing the hydrophobic interactions between the adjacent GO sheets. The unique feature of this material is the simultaneous uptake of charged heavy metal ions and uncharged organic contaminants. The negative charges on GO results in the retention of heavy metal ions, while the hydrophobic phase created by the alkyl chain in HDTMA enables the adsorption of organic contaminants. The adsorption capacity of Cu2+ and bisphenol A reached 59.7 mg/g and 141.0 mg/g, respectively. The adsorption processes for both Cu2+ and bisphenol A were rapid, attaining ∼100% removal in 1 h and 2 h, respectively. Increasing the pH favored the adsorption of the two solutes. The presence of NaCl reduced the retention of Cu2+, but was beneficial for the adsorption of bisphenol A. The results demonstrate that the 3D structure and the adsorption of the target species can be achieved by tailoring the surface coverage of HDTMA on GO.


Assuntos
Compostos Benzidrílicos/isolamento & purificação , Cobre/isolamento & purificação , Grafite/química , Fenóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Cobre/química , Interações Hidrofóbicas e Hidrofílicas , Íons , Metais Pesados/isolamento & purificação , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química , Poluentes Químicos da Água/análise
10.
Molecules ; 24(15)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370233

RESUMO

The chemical composition and daily mineral intake (DMI) of six macro (calcium, magnesium, sodium, potassium, phosphorous, and chloride) and four microminerals (copper, iron, manganese, and zinc) were determined in four types of Portuguese breads (white wheat, maize, wheat/maize, and maize/rye breads). Samples were processed with microwave assisted digestion and mineral composition was determined with a high-resolution continuum-source atomic absorption spectrometer with flame and graphite furnace. Bread contributes to an equilibrated diet since it is rich in several minerals (0.21 mg/100 g of copper in wheat bread to 537 mg/100 g of sodium in maize/rye bread). Maize/rye bread presented the highest content of all minerals (except phosphorous and chloride), while the lowest levels were mainly found in wheat bread. Median sodium concentrations (422-537 mg/100 g) represented more than 28% of the recommended daily allowance, being in close range of the maximum Portuguese limit (550 mg/100 g). Maize/rye bread exhibited the highest DMI of manganese (181%), sodium (36%), magnesium (32%), copper (32%), zinc (24%), iron (22%), potassium (20%), and calcium (3.0%). A Principal Component Analysis (PCA) model based on the mineral content allowed the differentiation among white wheat, maize, and maize/rye bread. Zinc, magnesium, manganese, iron, phosphorus, potassium, copper, and calcium proved to be good chemical markers to differentiate bread compositions.


Assuntos
Pão/análise , Farinha/análise , Minerais/química , Triticum/química , Pão/normas , Cobre/química , Cobre/isolamento & purificação , Fibras na Dieta/análise , Humanos , Ferro/isolamento & purificação , Magnésio/química , Magnésio/isolamento & purificação , Minerais/isolamento & purificação , Fósforo/química , Fósforo/isolamento & purificação , Portugal , Espectrofotometria Atômica , Zinco/química , Zinco/isolamento & purificação
11.
Biosens Bioelectron ; 143: 111597, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442755

RESUMO

Marine pollution and monitoring have received more and more concern in recent years. Herein, a fully automatic whole-algae biosensor was designed for low-cost and fast detection of toxic contaminants in seawater. It consists of a digital microfluidic (DMF) diluter chip, an actuation element, a detector element, and a microalgae bioreporter. A feedback-control protocol based on charging-time compensation was introduced. It ensures precise actuation of the droplet with diverse salty concentrations and contents in the marine environment. The two-mixer cross-split dilution engine increases the accuracy of droplet dispensing and concentration diluting. By selecting motility of P. subcordiformis as the sensor signal, the developed biosensor showed good sensitivity and robustness for a wide range of salinity (10-37‰), temperature (0-25 °C), light levels (0-325 µmol photons m-2 s-1), and cell density factor (1.0-4.0). The biosensor responses were examined in the presence of copper, lead, phenol, and nonylphenol (NP). In all cases, toxic responses (i.e. dose-related inhibition of algal motion) were detected with the detection limits of 0.65  µmol.L-1, 1.90  µmol.L-1, 2.85 mmol.L-1, and 5.22  µmol.L-1 respectively. These results were obtained in a much shorter time (2 h for our biosensor vs. 24 h-10 d for growth inhibition test) and the data are consistent with previous classical studies. We thus developed a simple, rapid, and adaptable system for marine routine monitoring and early-warning detection for lab and on-site applications.


Assuntos
Técnicas Biossensoriais , Monitoramento Ambiental , Poluentes Ambientais/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Poluentes Ambientais/química , Poluição Ambiental , Limite de Detecção , Microalgas/química , Microfluídica , Movimento (Física) , Água do Mar/química , Poluentes Químicos da Água/química
12.
Nutr. hosp ; 36(4): 764-768, jul.-ago. 2019. tab, ilus
Artigo em Inglês | IBECS | ID: ibc-184698

RESUMO

Objective: we found a black precipitate during the infusion of a parenteral nutrition without lipids. The objective of this study is to check the composition of the precipitate and the influence of the type of amino acids in its formation. Methods: four PN bags were prepared with the following composition: 1 l of amino acids solution, 150 g glucose, 60 mEq potassium, 217 mEq chloride, 105 mEq sodium, 15 mEq magnesium, 15 mEq calcium, 18.63 mmol phosphorus and trace elements (Addamel(R)). Each bag was prepared using a different type of amino acids solution with different amount of cysteine per litre: Tauramin(R) 10% (0.5 g/l), Primene(R) 10% (1.89 g/l), Tauramin(R) 12.6% (0.62 g/l) or Synthamin(R) 10% (0 g/l). Tauramin(R) 10% and Primene(R) 10% were packaged in glass containers whereas Tauramin(R) 12.6% and Synthamin(R) 10%, in plastic. The contents of each bag were filtered using Pall NEO96E 0.2 micron filters. A 2.25% area of each filter was observed by scanning electron microscopy at 100x magnification. The analysis by energy dispersive spectroscopy (EDS) was performed at 1,000x magnification. Results: in the Primene(R) 10% and Tauramin(R) 10% filters, a greater amount of precipitate was observed than with Tauramin(R) 12.6% and Synthamin(R) 10%. The percentage of copper and sulphur in each area of the filters studied was, respectively, 22.9% and 11.5% (Primene(R) 10%), 19.3% and 9.6% (Tauramin(R) 10%), 3.7% and 0% (Tauramin(R) 12.6%), 2.5% y 0% (Synthamin(R) 10%). Conclusions: the observed precipitate contains copper and sulphur. Precipitate formation occurs in high cysteine content amino acids solutions packaged in glass containers. It is important to use filters in the administration of PN to ensure that this type of precipitates are retained and do not pass to the patient. Key words


Objetivo: durante la infusión de una nutrición parenteral (NP) sin lípidos se observó un precipitado negro en el filtro. El objetivo del estudio es comprobar la composición del precipitado y la influencia del tipo de aminoácidos en su formación. Métodos: se prepararon cuatro bolsas de NP con 1.000 ml de solución de aminoácidos, 150 g glucosa, 60 mEq potasio, 217 mEq cloruro, 105 mEq sodio, 15 mEq magnesio, 15 mEq calcio, 18,63 mmol fósforo y oligoelementos (Addamel(R)). Se utilizaron distintos tipos de aminoácidos con concentraciones de cisteína diferentes: Tauramin(R) 10% (0,5 g/l), Primene(R) 10% (1,89 g/l), Tauramin(R) 12,6% (0,62 g/l) o Synthamin(R) 17 (0 g/l). Tauramin(R) 10% y Primene(R) 10% estaban envasados en vidrio y Tauramin(R) 12,6% y Synthamin(R) 17, en plástico. El contenido de cada bolsa se filtró utilizando filtros Pall NEO96E de 0,2 micras. Se estudió un área de 2,25% de cada filtro mediante microscopía electrónica de barrido a 100 aumentos. El análisis mediante espectroscopia de dispersión de energía (EDS) se realizó a 1.000 aumentos. Resultados: en los filtros con Primene(R) 10% y Tauramin(R) 10%, se observó mayor precipitación que con Tauramin(R) 12,6% y Synthamin(R) 10%. El porcentaje de cobre y azufre en cada área de los filtros estudiados fue 22,9% y 11,5% (Primene(R) 10%), 19,3% y 9,6% (Tauramin(R) 10%), 3,7% y 0% (Tauramin 12,6%), 2,5% y 0% (Synthamin 10%). Conclusiones: el precipitado observado contiene cobre y azufre. La formación de precipitados se produce con soluciones de aminoácidos envasadas en vidrio, con gran cantidad de cisteína. Es importante usar filtros en la administración de NP para garantizar que los precipitados se retengan y no se pasen al paciente


Assuntos
Humanos , Aminoácidos/análise , Aminoácidos/química , Precipitação Química , Cobre/química , Enxofre/química , Aminoácidos/classificação , Cobre/análise , Cobre/isolamento & purificação , Enxofre/análise , Espectrometria por Raios X
13.
Chemosphere ; 235: 239-247, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31260864

RESUMO

A modified cellulose acetate, modified chitosan, titanium dioxide membrane (MCA-MCS-TiO2) was prepared for oil-water emulsion separation and Cu(II) adsorption. This membrane shows excellent hydrophilicity and underwater oleophobicity. After being modified, the water contact angles of the membranes attain 13.7°, and the underwater oil contact angles reach 157.24°. The membrane exhibits high oil-water separation efficiency (99.4%) for cyclohexane, at the same time, the adsorption amount of Cu(II) on the membrane was measured. The variables include the ratio of modified cellulose to modified chitosan, the initial concentration of Cu(II), and the pH of Cu(II) solution. When pH = 7, the adsorption capacity of the membrane to Cu(II) reaches 220.67  mg g-1. When the concentration of Cu(II) solution is 1000 mg L-1, the adsorption efficiency is as high as 97.0%.


Assuntos
Celulose/análogos & derivados , Quitosana/química , Cobre/isolamento & purificação , Óleos/química , Titânio/química , Poluentes Químicos da Água/isolamento & purificação , Água/química , Adsorção , Celulose/química , Cobre/análise , Cobre/metabolismo , Emulsões , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos
14.
Int J Biol Macromol ; 138: 188-197, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31302131

RESUMO

Sodium lignosulfonate (Na-LS) was used to modified montmorillonite to form lignosulfonate-montmorillonite (LS-MMT). The as-prepared samples were characterized by various equipment to analyze the surface morphology and structure of the pure and reformed samples. The adsorption capability (qe, mg/g) of LS-MMT or Ca/Na-MMT for Pb(II) and Cu(II) at different reaction intervals, the concentration of metal ions, temperature, and pH were studied by batch adsorption experiments. The results revealed that LS-MMT displayed a higher adsorption capacity than Ca/Na-MMT. The pH of solutions had a great influence on the qe of the two adsorbents, and the qe was slightly enhanced with temperature increasing. The isotherm and kinetic experiments studies indicated that the adsorption of heavy metal on LS-MMT or Ca/Na-MMT fit well with the Langmuir model and pseudo-second-order kinetic model. The competitive adsorption showed that LS-MMT had a stronger affinity for Pb(II) than Cu(II), which was different from Ca/Na-MMT. Additionally, the desorption experiment showed that LS-MMT had a stronger ability to lock heavy metal ions than Ca/Na-MMT in an acidic environment with pH ranging from 3 to 5.


Assuntos
Bentonita/química , Cobre/química , Chumbo/química , Lignina/análogos & derivados , Poluentes Químicos da Água/química , Adsorção , Cobre/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Chumbo/isolamento & purificação , Lignina/química , Temperatura Ambiente , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação
15.
Int J Biol Macromol ; 136: 476-485, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31220490

RESUMO

In this work, we reported a novel "one-pot" strategy for preparation of chitosan-coated carbon nanotubes (CNTs) composites via a combination of Diels-Alder (DA) reaction and mercaptoacetic acid locking imine (MALI) reaction for the first time. To evaluate the adsorption characteristics, the as-prepared samples were applied to remove copper ions (Cu2+) from aqueous solution. The effects of contact time, solution pH, temperature and initial Cu2+ concentration on the adsorption of Cu2+ onto the as-prepared samples were investigated. The chitosan modified CNTs composites showed high affinity and fast kinetics for the adsorption of Cu2+ ions, and adsorption capacity of the composites was found to be 2 times that of pristine CNTs. Adsorption kinetics and thermodynamic indicated a spontaneous and endothermic nature of the adsorption of Cu2+ on the surface of chitosan-coated CNTs composites, kinetically obeyed the pseudo-second-order model. Equilibrium data could be best described by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 115.84 mg/g. In view of the extensive applicability of DA chemistry and MALI reaction, different carbon nanomaterials based composites with various functional groups could be fabricated and applicable to different fields such as environmental catalysis and biomedicine.


Assuntos
Quitosana/química , Cobre/química , Cobre/isolamento & purificação , Nanotubos de Carbono/química , Tioglicolatos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Conformação Molecular , Temperatura Ambiente
16.
Int J Biol Macromol ; 136: 1273-1281, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31201908

RESUMO

A series of polyampholyte nanocomposite biopolymers, poly(N,N-diallyldimethylammonium chloride-co-acrylamide) grafted on carboxymethylcellulose/iron(III) oxide [P(DADMAC-AAm)CMC/Fe2O3] and poly(N,N-diallyldimethylammonium chloride-co-sodium acrylate) grafted on carboxymethylcellulose/iron(III) oxide [P(DADMAC-SA)CMC/Fe2O3], was prepared with different molar ratios of anionic groups to cationic groups using gamma irradiation. The grafting properties and swelling behavior were investigated as a function of grafting conditions such as DADMAC, AAm, SA, and CMC concentrations and absorbed dose. Fourier transform infrared spectroscopic analysis (FTIR) confirmed the graft copolymerization. Scanning electron microscope (SEM) was employed to check the morphological structure of CMC, P(DADMAC-AAm)CMC/Fe2O3, and P(DADMAC-SA)CMC/Fe2O3. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) further characterized the grafted copolymers and showed their high thermal stability. Using batch sorption experiments and 60Co as a radiotracer, P(DADMAC-AAm)CMC/Fe2O3 and P(DADMAC-SA)CMC/Fe2O3 were evaluated for Co(II) removal from aqueous solutions. Experimentally, P(DADMAC-AAm)CMC/Fe2O3 and P(DADMAC-SA)CMC/Fe2O3 show high sorption capacity of Co(II), i.e. 69.67 mg g-1 and 75.17 mg g-1, respectively, which makes them potential sorbents for Co(II) removal from water/wastewater. Finally, the Co(II) sorption was examined using sorption isotherm and kinetic models. Cobalt sorption was best fitted to Langmuir model which suggests the sorption is of chemisorption type. On the other hand, the sorption kinetics was best represented by the pseudo-first-order kinetic model.


Assuntos
Cobre/química , Cobre/isolamento & purificação , Raios gama , Nanocompostos/química , Polímeros/química , Purificação da Água/métodos , Carboximetilcelulose Sódica/química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Tamanho da Partícula , Temperatura Ambiente , Água/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
17.
Int J Biol Macromol ; 136: 668-675, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31201912

RESUMO

In this study, crosslinked chitosan/Waste Active Sludge Char (WASC) beads were developed as a novel composite adsorbent for the removal of Cu(II) ions from aqueous solution. The surface morphology and elemental composition of chitosan/WASC beads were characterized using Scanning Electron Microscopy (SEM). Adsorption isotherms of Cu(II) ions on adsorbents were correlated with the Langmuir and Freundlich models, and the data fitted better to the Freundlich isotherm model. The kinetic data were evaluated to calculate the theoretical metal uptake as a function of time. The highest correlation coefficient (R2) was calculated with the pseudo-second order kinetic model for the adsorption. The successive adsorption studies (0.25 g/L adsorbent dosage, contact time 180 min, pH 5) indicated that the WASC beads were able to remove 81.7% of Cu(II) from the aqueous solution contained 300 mg/L Cu(II) ions, and the adsorption capacity was obtained as 980.80 mg Cu(II)/g beads. This value is a great significant as it is much higher than any reported paper. The thermodynamic parameters like ∆G°(298K), ∆H°, and ∆S° changes for the adsorption of Cu(II) ions have been calculated as - 7.122 kJ·mol-1, 19.25 kJ·mol-1, and 88.49 J·mol-1·K-1, respectively.


Assuntos
Quitosana/química , Cobre/química , Cobre/isolamento & purificação , Microesferas , Esgotos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cinética , Propriedades de Superfície , Temperatura Ambiente , Água/química , Purificação da Água
18.
Int J Biol Macromol ; 136: 189-198, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31201914

RESUMO

In this work, a simple method was developed for hydrogel preparation from 1,5-Diphenylcarbazide (DPC) and chitosan (CS) through Diazotization reaction of CS as a selective adsorbent (DPCCS) for Cu(II) ions. CS was treated with sodium nitrate and subsequent crosslinking reaction with DPC for the preparation of DPCCS. Different techniques were used for characterization of DPCCS. Various parameters such as, temperature, pH, and concentration of Cu(II) were used for adsorption studies. Kinetics of Cu(II) ion on DPCCS follows the Pseudo second order and equilibrium of adsorption occurs in short time. The equilibrium data was best fitted with the Langmuir isotherm and the maximum adsorption capacity of DPCCS was 185.505 mg g-1. Thermodynamic parameters ΔG°, ΔH° and ΔS° suggested that the adsorption of Cu(II) ion on the surfaces of DPCCS was spontaneous, endothermic and randomness of Cu(II) ion in the solution was enhanced respectively. Regeneration of DPCCS and Cu(II) ion recovery were studied up to five cycles without the lost of the adsorption capacity.


Assuntos
Técnicas de Química Sintética/métodos , Quitosana/química , Cobre/química , Cobre/isolamento & purificação , Difenilcarbazida/química , Hidrogéis/química , Hidrogéis/síntese química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Mecânicos , Temperatura Ambiente , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água
19.
Int J Biol Macromol ; 135: 691-697, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31154038

RESUMO

In this study, hordein and hordein/N,N'-methylene bisacrylamide (MBA) nanofiber membranes were prepared by electrospinning technique. Then the fabricated membranes were modified with ß-cyclodextrin (ß-CD) to remove heavy metal ions from aqueous solution. The prepared nanofiber membranes were characterized by ATR-FTIR, SEM and XRD. The diameters of the nanofibers were determined to be around 600-910 nm and ß-CD was successfully attached to the nanofiber membrane, which was confirmed by ATR-FTIR and XRD analysis. Cu(II) was selected as the model ion to investigate the heavy metal adsorption properties of the membranes. Adsorption capacities of the membranes increased with a higher initial pH, adsorption temperature and a longer adsorption time before reaching the saturation point. The adsorption isotherm results were described with the Langmuir model. It was found that additions of MBA and ß-CD at proper concentrations could significantly improve the adsorption capacities and the maximum adsorption of hordein, hordein/MBA, and hordein/MBA/ß-CD nanofiber membranes were 64.94, 81.97, and 88.50 mg/g, respectively. Furthermore, regeneration study showed that these hordein nanofiber membranes possessed reasonably good reusability. The novel functionalized hordein/MBA/ß-CD nanofiber membranes have great potential in the application of water treatment.


Assuntos
Cobre/química , Cobre/isolamento & purificação , Eletricidade , Glutens/química , Nanofibras/química , Purificação da Água/métodos , beta-Ciclodextrinas/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Membranas Artificiais , Temperatura Ambiente , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
20.
Int J Biol Macromol ; 133: 1051-1062, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31039375

RESUMO

A novel adsorbent material for removal of metal ion from aqueous solution was made by modification of chitosan. Schiff base prepared from reaction of chitosan with 3-methyl-1-phenyl-5-(piperidin-1-yl)-1H-pyrazole-4-carbaldehyde was crosslinked with epichlorohydrin to form a crosslinked gel. Fe3O4 nanoparticles were incorporated into the modified chitosan gel to obtain a magnetic adsorbent material. The magnetic nanocomposite thus obtained was characterized using FTIR, TGA, SEM, EDS and XRD techniques and evaluated for adsorptive removal of Cu(II) and Cr(VI) ions from aqueous solutions. The maximum adsorption capacity of the adsorbent for Cu(II) and Cr(VI) ions was found to be 90.90 and 83.33 mg g-1 respectively. The adsorption data fitted well with Langmuir isotherm model and the pseudo-second order kinetic model. Thermodynamic parameters indicated the adsorption to be spontaneous and endothermic. The desorption studies revealed the efficient recovery of adsorbate species and possible reusability of the adsorbent material.


Assuntos
Quitosana/química , Cromo/química , Cromo/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Nanopartículas de Magnetita/química , Água/química , Adsorção , Entropia , Géis , Cinética , Bases de Schiff/química , Soluções , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água
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