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1.
Molecules ; 27(10)2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35630715

RESUMO

This work aimed to use abietic acid (AA), as a widely available natural product, as a precursor for the synthesis of two new amphiphilic ionic liquids (AILs) and apply them as effective demulsifiers for water-in-crude oil (W/O) emulsions. AA was esterified using tetraethylene glycol (TEG) in the presence of p-toluene sulfonic acid (PTSA) as a catalyst obtaining the corresponding ester (AATG). AATG was reacted with 1-vinylimidazole (VIM) throughout the Diels-Alder reaction, forming the corresponding adduct (ATI). Following this, ATI was quaternized using alkyl iodides, ethyl iodide (EI), and hexyl iodide (HI) to obtain the corresponding AILs, ATEI-IL, and ATHI-IL, respectively. The chemical structure, surface activity, thermal stability, and relative solubility number (RSN) were investigated using different techniques. The efficiency of ATEI-IL and ATHI-IL to demulsify W/O emulsions in different crude oil: brine volumetric ratios were evaluated. ATEI-IL and ATHI-IL achieved promising results as demulsifiers. Their demulsification efficiency increased as the brine ratios decreased where their efficiency reached 100% at the crude oil: brine ratio (90:10), even at low concentrations.


Assuntos
Líquidos Iônicos , Petróleo , Emulsões/química , Iodetos , Líquidos Iônicos/química , Petróleo/análise , Água/química
2.
Luminescence ; 36(4): 1078-1088, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33629466

RESUMO

Smart textiles with a multifunctional surface, such as with photoluminescence, antimicrobial, and superhydrophobic properties, are highly desirable. Silver nanoparticles (Ag NPs) were prepared and immobilized onto a cotton surface using a facile pad-dry-curing technique to introduce long-lasting antimicrobial properties. The morphology of the silver immobilized cotton fibres was explored using scanning electron microscopic images and energy-dispersive X-ray spectra. The morphology of the formed Ag NPs was determined using a transmission electron microscope. Ag NPs exhibited uniform spreading and a high deposition density with a particle diameter in the range 25-55 nm. Both photoluminescence and superhydrophobic properties were explored by studying the cotton samples treated with hexadecyltrimethoxysilane nanocomposite containing lanthanide-doped strontium oxide aluminate NPs. Ultraviolet-visible light absorption, phosphorescence, and lifetime spectra were measured. The produced transparent superhydrophobic and photoluminescent film showed two absorbance bands at 273 and 367 nm and emission bands at 415 and 437 nm, as recognized by both absorption and emission spectra. Excellent antibacterial activities towards E. coli and S. aureus were monitored for the coated samples. Both fastness and colorimetric properties of Ag NPs-coated fabrics were explored.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Escherichia coli , Luminescência , Óxidos , Prata/farmacologia , Staphylococcus aureus , Estrôncio , Têxteis
3.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499293

RESUMO

Applications of metal oxide nanoparticles in the agriculture sector are being extensively included as the materials are considered superior. In the present work, zinc oxide nanoparticle (ZnO NPs), with a developing fertilizer, is applied in the fortification of rice grain yield and nutrient uptake enhancement. To evaluate the role of ZnO NP, two field experiments were conducted during the 2018 and 2019 seasons. ZnO NPs were small, nearly spherical, and their sizes equal to 31.4 nm, as proved via the dynamic light scattering technique. ZnO NPs were applied as a fertilizer in different concentrations, varying between 20 and 60 mg/L as a foliar spray. The mixture of ZnSO4 and ZnO NP40 ameliorated yield component and nutrients (N, K, and Zn) uptake was enhanced compared to traditional ZnSO4 treatment. Nevertheless, the uptake of the phosphorous element (P) was adversely affected by the treatment of ZnO NPs. Thus, treatment via utilizing ZnO NPs as a foliar with a very small amount (40 ppm) with of basal ZnSO4 led to a good improvement in agronomic and physiological features; eventually, higher yield and nutrient-enriched rice grain were obtained.


Assuntos
Nanopartículas Metálicas/química , Oryza/crescimento & desenvolvimento , Óxido de Zinco/síntese química , Transporte Biológico Ativo , Grão Comestível/química , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Fertilizantes , Alimentos Fortificados/análise , Química Verde/métodos , Humanos , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica , Nanotecnologia , Valor Nutritivo , Oryza/química , Oryza/metabolismo , Difração de Raios X , Óxido de Zinco/administração & dosagem , Óxido de Zinco/farmacocinética
4.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499387

RESUMO

Two novel amphiphilic polyethylene amine terephthalate have been prepared via the glycolsis of polyethylene terephthalate (PET). The product, bis (2-hydroxyethyl terephthalate) (BHET), was converted to the corresponding dialkyl halide, bis(2-chloroethyl) terephthalate (BCET), using thionyl chloride (TC). This dialkyl compound was used for alkylation of dodecyl amine (DOA) and tetraethylenepentamine (TEPA) or pentaethylenehexamine (PEHA) to form the corresponding polyethylene amine terephthalate, i.e., DOAT and DOAP, respectively. Their chemical structure, surface tension, interfacial tension (IFT), and dynamic light scattering (DLS) were determined using different techniques. The efficiency of the prepared polyethylene amine terephthalate to demulsify water in heavy crude (W/O) emulsions was also determined and found to increase as their concentrations increased. Moreover, DOAT showed faster and higher efficiency, and cleaner separation than DOAP.


Assuntos
Petróleo/análise , Polietilenotereftalatos/química , Aminas/síntese química , Aminas/química , Difusão Dinâmica da Luz , Emulsões/química , Espectroscopia de Ressonância Magnética , Micelas , Estrutura Molecular , Polietilenotereftalatos/síntese química , Eliminação de Resíduos/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Tensão Superficial , Tensoativos/síntese química , Tensoativos/química , Águas Residuárias/química
5.
Molecules ; 26(4)2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33671351

RESUMO

The strong demand for rare-earth elements (REEs) is driven by their wide use in high-tech devices. New processes have to be developed for valorizing low-grade ores or alternative metal sources (such as wastes and spent materials). The present work contributed to the development of new sorbents for the recovery of rare earth ions from aqueous solutions. Functionalized mesoporous silica composite was synthesized by grafting diethylenetriamine onto composite support. The physical and chemical properties of the new sorbent are characterized using BET, TGA, elemental analysis, titration, FTIR, and XPS spectroscopies to identify the reactive groups (amine groups: 3.25 mmol N g-1 and 3.41 by EA and titration, respectively) and their mode of interaction with Nd(III) and Gd(III). The sorption capacity at the optimum pH (i.e., 4) reaches 0.9 mmol Nd g-1 and 1 mmol Gd g-1. Uptake kinetics are modeled by the pseudo-first-order rate equation (equilibrium time: 30-40 min). At pH close to 4-5, the sorbent shows high selectivity for rare-earth elements against alkali-earth elements. This selectivity is confirmed by the efficient recovery of REEs from acidic leachates of gibbsite ore. After elution (using 0.5 M HCl solutions), selective precipitation (using oxalate solutions), and calcination, pure rare earth oxides were obtained. The sorbent shows promising perspective due to its high and fast sorption properties for REEs, good recycling, and high selectivity.


Assuntos
Aminas/química , Gadolínio/química , Neodímio/química , Polímeros/química , Dióxido de Silício/química , Adsorção , Concentração de Íons de Hidrogênio , Resíduos Industriais/análise , Cinética , Espectroscopia Fotoeletrônica , Porosidade , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Molecules ; 24(21)2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31717813

RESUMO

The ionic crosslinked 2-acrylamido-2-methylpropane sulfonic acid-co-acrylic acid hydrogel, AMPS/AA and its Ag and Fe3O4 composites were synthesized using an in situ technique. The surface charge, particle sizes, morphology, and thermal stability of the prepared AMPS/AA-Ag and AMPS/AA-Fe3O4 composites were evaluated using different analytical techniques and their adsorption characteristics were evaluated to remove the methylene blue cationic dye, MB, from their aqueous solutions at optimum conditions. Also, the same monomers were used to synthesize AMPS/AA microgel and its Ag and Fe3O4 nanocomposites, which were synthesized using the same technique. The AMPS/AA-Fe3O4 nanocomposite was selected as conventional iron-supported catalyst due to the presence of both Fe(II) and Fe(III) species besides its magnetic properties that allow their easy, fast, and inexpensive separation from the aqueous solution. It was then evaluated as a heterogeneous catalyst for complete MB degradation from aqueous solution by heterogeneous Fenton oxidation. It achieved a high rate of degradation, degrading 100 mg L-1 of MB during a short time of 35 min as compared with the reported literature.


Assuntos
Azul de Metileno/química , Nanocompostos/química , Prata/química , Catálise , Óxido Ferroso-Férrico/química , Microgéis/química , Purificação da Água/métodos
7.
Molecules ; 22(6)2017 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-28574451

RESUMO

Montmorillonite (MMT) clay mineral is widely used as filler for several organic coatings. Its activity is increased by exfoliation via chemical modification to produce nanomaterials. In the present work, the modification of MMT to form nanogel composites is proposed to increase the dispersion of MMT into epoxy matrices used to fill cracks and holes produced by the curing exotherms of epoxy resins. The dispersion of MMT in epoxy improved both the mechanical and anti-corrosion performance of epoxy coatings in aggressive marine environments. In this respect, the MMT surfaces were chemically modified with different types of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) nanogels using a surfactant-free dispersion polymerization technique. The effect of the chemical structure, nanogel content and the interaction with MMT surfaces on the surface morphology, surface charges and dispersion in the epoxy matrix were investigated for use as nano-filler for epoxy coatings. The modified MMT nanogel epoxy composites showed excellent resistance to mechanical damage and salt spray resistance up to 1000 h. The interaction of MMT nanogel composites with the epoxy matrix and good response of AMPS nanogel to sea water improve their ability to act as self-healing materials for epoxy coatings for steel.


Assuntos
Bentonita/química , Resinas Epóxi , Polietilenoglicóis/química , Polietilenoimina/química , Aço , Nanocompostos/química , Nanogéis , Polímeros , Propriedades de Superfície
8.
Molecules ; 21(10)2016 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-27775576

RESUMO

This work first reports the preparation of super-amphiphilic silica-nanogel composites to reduce the contact angle of water to increase the diffusion of pollutant into adsorbents. In this respect, the silica nanoparticles were encapsulated into nanogels based on ionic and nonionic polyacrylamides by dispersion polymerization technique. The morphologies and the dispersion stability of nanogel composites were investigated to clarify the ability of silica-nanogel composites to adsorb at different interfaces. The feasibility of silica polyacrylamide nanogel composites to act as a high-performance adsorbent for removal of methylene blue (MB) dye and heavy metals (Co2+ and Ni2+) from aqueous solution was investigated. The surface tension, contact angle, average pore size, and zeta potential of the silica-nanogel composites have been evaluated. The MB dye and heavy metal adsorption capacity achieved Qmax = 438-387 mg/g which is considerably high. The adsorption capacity results are explained from the changes in the morphology of the silica surfaces as recorded from scanning electron microscopy (SEM).


Assuntos
Polietilenoglicóis/química , Polietilenoimina/química , Dióxido de Silício/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Resinas Acrílicas/química , Adsorção , Metais Pesados/química , Azul de Metileno/química , Microscopia Eletrônica de Varredura , Nanogéis
9.
Int J Mol Sci ; 16(4): 6911-31, 2015 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-25822876

RESUMO

In the present study, a new magnetic powder based on magnetite can be used as a petroleum crude oil collector. Amidoximes based on rosin as a natural product can be prepared from a reaction between hydroxylamine and rosin/acrylonitrile adducts. The produced rosin amidoximes were used as capping agents for magnetite nanoparticles to prepare hydrophobic coated magnetic powders. A new class of monodisperse hydrophobic magnetite nanoparticles was prepared by a simple and inexpensive co-precipitation method. Iron ions and iodine were prepared by the reaction between ferric chloride and potassium iodide. The structure and morphology of magnetite capped with rosin amidoxime were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), zeta potential, thermogravimetric analysis (TGA) and dynamic light scattering (DLS). The magnetic properties were determined from vibrating sample magnetometer (VSM) analyses. These prepared magnetite nanoparticles were tested as bioactive nanosystems and their antimicrobial effects were investigated. The prepared nanomaterials were examined as a crude oil collector using magnetic fields. The results show promising data for the separation of the petroleum crude oil from aqueous solution in environmental pollution cleanup.


Assuntos
Antibacterianos/síntese química , Hidroxilaminas/síntese química , Nanopartículas de Magnetita/química , Poluição por Petróleo/prevenção & controle , Resinas Vegetais/química , Antibacterianos/química , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hidroxilaminas/química , Hidroxilaminas/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Difração de Raios X
10.
Molecules ; 20(1): 1244-61, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25594340

RESUMO

This work presents a new method to prepare poly(sodium acrylate) magnetite composite nanoparticles. Core/shell type magnetite nanocomposites were synthesized using sodium acrylate as monomer and N,N-methylenebisacrylamide (MBA) as crosslinker. Microemulsion polymerization was used for constructing core/shell structures with magnetite nanoparticles as core and poly(sodium acrylate) as shell. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanocomposite chemical structure. Transmittance electron microscopy (TEM) was used to examine the morphology of the modified poly(sodium acrylate) magnetite composite nanoparticles. These particle will be evaluated for effective anticorrosion behavior as a hydrophobic surface on stainless steel. The composite nanoparticles has been designed by dispersing nanocomposites which act as a corrosion inhibitor. The inhibition effect of AA-Na/magnetite composites on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Polarization measurements indicated that the studied inhibitor acts as mixed type corrosion inhibitor. EIS spectra exhibit one capacitive loop. The different techniques confirmed that the inhibition efficiency reaches 99% at 50 ppm concentration. This study has led to a better understanding of active anticorrosive magnetite nanoparticles with embedded nanocomposites and the factors influencing their anticorrosion performance.


Assuntos
Ligas , Corrosão , Óxido Ferroso-Férrico/química , Nanopartículas/química , Aço , Adsorção , Espectroscopia Dielétrica , Microscopia Eletrônica de Transmissão , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
11.
Molecules ; 20(6): 11131-53, 2015 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-26091073

RESUMO

This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS) and oleylammonium tosylate (OA-TS) for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements, scanning electron microscope (SEM), Energy dispersive X-rays (EDX) analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface.


Assuntos
Corrosão , Meio Ambiente , Líquidos Iônicos/química , Aço/química , Adsorção , Espectroscopia de Ressonância Magnética , Propriedades de Superfície
12.
Int J Mol Sci ; 15(4): 6974-89, 2014 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-24758936

RESUMO

This work presents a new method to prepare monodisperse magnetite nanoparticles capping with new cationic surfactants based on rosin. Core/shell type magnetite nanoparticles were synthesized using bis-N-(3-levopimaric maleic acid adduct-2-hydroxy) propyl-triethyl ammonium chloride (LPMQA) as capping agent. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanoparticles chemical structure. Transmittance electron microscopies (TEM) and X-ray powder diffraction (XRD) were used to examine the morphology of the modified magnetite nanoparticles. The magnetite dispersed aqueous acid solution was evaluated as an effective anticorrosion behavior of a hydrophobic surface on steel. The inhibition effect of magnetite nanoparticles on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Results obtained from both potentiodynamic polarisation and EIS measurements reveal that the magnetite nanoparticle is an effective inhibitor for the corrosion of steel in 1.0 M HCl solution. Polarization data show that magnetite nanoparticles behave as a mixed type inhibitor. The inhibition efficiencies obtained from potentiodynamic polarization and EIS methods are in good agreement.


Assuntos
Nanopartículas de Magnetita/química , Resinas Vegetais/química , Aço/química , Tensoativos/química , Cátions/química , Óxido Ferroso-Férrico/química , Tamanho da Partícula
13.
Molecules ; 19(5): 6737-53, 2014 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-24858265

RESUMO

Silver nanoparticles (Ag NP) have been attracted much attention in recent years in biomedical applications due to their antimicrobial activity, but their drawbacks include toxicity and instability to aqueous hydrochloric acid solutions. Ag NPs have now been successfully prepared by a simple and "green" synthesis method by reducing Ag+ ions in the presence of modified poly(vinyl alcohol) thiol (PVA-SH) in aqueous acidic solution. In this respect, Ag NPs were stabilized by coating different types of citrate-reduced Ag NPs with different weight ratios (1-3 Wt. %) of PVSH derivatives. The as-prepared Ag NPs were characterized using UV-Visible, high resolution transmission electron microscopy/ energy dispersive X-ray spectroscopy (TEM/EDS), dynamic light scattering (DLS) and X-ray powder diffraction (XRD) combined with Rietveld analysis. The changes in size, shape, and hydrodynamic diameter of Ag NPs after different duration exposure to synthetic stomach fluid (SSF) and1 M HCl were determined using TEM, XRD and UV-Visible analyses. The data indicated that these Ag NPs possessed high stability to SSF for more than 90 days, which was not previously reported in the literature.


Assuntos
Suco Gástrico , Nanopartículas Metálicas/química , Humanos , Microscopia Eletrônica de Transmissão , Nanotecnologia/métodos , Álcool de Polivinil/química , Prata/química , Soluções , Espectrometria por Raios X , Difração de Raios X
14.
Molecules ; 19(2): 1713-31, 2014 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-24487568

RESUMO

Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.


Assuntos
Nanopartículas de Magnetita/química , Polímeros/química , Estireno/química , Estirenos/química , Adsorção , Corrosão , Interações Hidrofóbicas e Hidrofílicas , Polimerização , Polímeros/síntese química , Sódio/química , Aço/química
15.
Molecules ; 19(8): 11263-78, 2014 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-25090117

RESUMO

Herein we report a new method for synthesizing stabilized magnetic nanoparticle (MNP) colloids. A new class of monodisperse water-soluble magnetite nano-particles was prepared by a simple and inexpensive co-precipitation method. Iron ions and iodine were prepared by the reaction between ferric chloride and potassium iodide. The ferrous and ferric ions were hydrolyzed at low temperature at pH 9 in the presence of iodine to produce iron oxide nanoparticles. The natural product myrrh gum was used as capping agent to produce highly dispersed coated magnetite nanoparticles. The structure and morphology of the magnetic nanogel was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), and X-ray diffraction (XRD) was used to examine the crystal structure of the produced magnetite nanoparticles.


Assuntos
Nanopartículas de Magnetita/química , Resinas Vegetais/química , Terpenos/química , Coloides , Commiphora , Compostos Férricos/química , Nanopartículas de Magnetita/ultraestrutura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
Molecules ; 19(5): 6246-62, 2014 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-24840897

RESUMO

A facile method was developed to synthesize in high yield dispersed silver nanoparticles (AgNPs) with small particle sizes of less than 10 nm. Silver nitrate was reduced to silver nanoparticles by p-chloroaniline in the presence of polyoxyethylene maleate 4-nonyl-2-propylene-phenol (NMA) as a stabilizer. The produced AgNPs were used to prepare hybrid polymer based on N-isopropylacrylamide (NIPAm), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N,N-methylenebisacrylamide (MBA) and potassium persulfate (KPS) using a semi-batch solution polymerization method. The prepared AgNPs and hybrid polymer were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The corrosion inhibition activity of the AgNPs and hybrid polymer towards steel corrosion in the presence of hydrochloric acid has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that the AgNPs and hybrid polymer acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.


Assuntos
Polimerização , Polímeros/síntese química , Prata/química , Corrosão , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Aço/química , Difração de Raios X
17.
Molecules ; 19(7): 10410-26, 2014 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-25036152

RESUMO

Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA) and potassium peroxydisulfate (KPS) were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.


Assuntos
Nanopartículas/química , Compostos de Prata/química , Aço/química , Tensoativos/química , Corrosão , Nanopartículas/ultraestrutura , Propriedades de Superfície
18.
ACS Omega ; 9(19): 21545-21556, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38764647

RESUMO

Functionalization of room temperature liquids based on disubstituted imidazolium ionic liquids represents a promising avenue for tailoring their tunable physicochemical properties and expanding their potential application as green solvents to capture carbon dioxide as a greenhouse gas. In this work, new hydroxyl functionalized imidazolium ionic liquids were prepared from condensation of ethanolamine with glyoxal and formalin in the presence of acetic acid as catalyst. The chemical modification of the hydroxyl groups with epichlorohydrine added new hydroxylpropanoxychloride groups on the imidazolium cation that were quaternized with N-methylimidazolium chloride to produce new imidazolium acetate ionic liquids. The chemical structures, thermal stability, and thermal characteristics of the prepared imidazolium ionic liquids were evaluated. The incorporation of functionalized 1-chloro-2-hydroxypropanoxy and N-methylimidazolium chloride groups into the chemical structure of the imidazolium cations improved the thermal properties of the prepared ionic liquids. The application of the prepared ionic liquids as pure or mixed solvents with saline water to capture CO2 under atmospheric and 55.2 bar pressures was evaluated at room temperature. The data indicate that the prepared ionic liquids have superior CO2 adsorption/desorption rate in short time during 30 and 15 min and that their CO2 capture efficiency increased from 6.2 to 16.8 molCO2/kgIIL and from 9.1 to 20.0 molCO2/kgIIL at atmospheric and 55.2 bar pressures, respectively.

19.
ACS Omega ; 8(18): 16315-16326, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37179644

RESUMO

The large sizes of cations and anions of organic salts are the driving force for the application of ionic liquids (organic salts) in harsh salty conditions. Moreover, the formation of crosslinked ionic liquid networks as anti-rust and anticorrosion protective films on the substrate surfaces repels seawater salt and water vapor from their surface to prevent corrosion. In this respect, an imidazolium epoxy resin and polyamine hardener as ionic liquids were prepared by the condensation of either pentaethylenehexamine or ethanolamine with glyoxal and p-hydroxybenzaldehyde or formalin in acetic acid as a catalyst. The hydroxyl and phenol groups of the imidazolium ionic liquid were reacted with epichlorohydrine in the presence of NaOH as a catalyst to prepare polyfunctional epoxy resins. The chemical structure, nitrogen content, amine value, epoxy equivalent weight, thermal characteristics, and stability of the imidazolium epoxy resin and polyamine hardener were evaluated. Moreover, their curing and thermomechanical properties were investigated to confirm the formation of homogeneous, elastic, and thermally stable cured epoxy networks. The corrosion inhibition and salt spray resistance of the uncured and cured imidazolium epoxy resin and polyamine as coatings for steel in seawater were evaluated.

20.
Gels ; 8(11)2022 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-36354609

RESUMO

The present study develops on insulin-release studies from the chitosan-amide-modified stimuli-responsive polymers formed from various fatty acids including stearic acid, oleic acid, linoleic acid, and linolenic acid. This is the continuation of an earlier reported study that investigates the insulin-release profiles of chitosan-modified fatty acid amides (without stimuli responsive polymers). Following the synthesis and characterization of many different fatty acid amides with a varying amount of unsaturation, the insulin drug loading and release effects were compared among N-isopropylacrylamide (NIPAm), a thermo-responsive polymer, and 2-acrylamide-2-methylpropane sulfonic acid (AMPS), a pH-responsive polymer-modified hydrogel that is expected to enhance environmental response and the controllability of release. Finally, drug release effects were studied to investigate the drug release mechanisms with the help of five different pharmacokinetic models including the zero-order, first-order, Higuchi, Korsmeyers-Peppas, and Hixson models. The results indicate that the Higuchi and Hixson models are valid in terms of the operation of the NIPAm and AMPS matrices during the delivery of insulin.

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