scholarly journals Natural Nanoparticles, Anthropogenic Nanoparticles, Where Is the Frontier?

Author(s):  
Gaëtane Lespes ◽  
Stéphane Faucher ◽  
Vera I. Slaveykova
Author(s):  
Jorge Silva-Yumi ◽  
Telmo Moreno Romero ◽  
Gabriela Chango Lescano

Nanofluids constitute an alternative for the most efficient use of energy as they allow generating or improving thermal properties among others of traditional fluids, they are defined as so-called base fluids, such as: water, ethylene glycol, oils, etc., which contain nanoparticles in suspension , such as: aluminum oxide, silicon oxide, titanium oxide, metal nanoparticles, carbon nanotubes, graphene, carbides, etc. Nanofluids can be synthesized by two methods, the nanoparticles can be obtained separately and then the nanofluid is prepared or both nanoparticles and the nanofluid can be prepared simultaneously, an important factor to consider in obtaining nanofluids is their stability. Stability can be achieved by physical treatment or chemical treatment using surfactants. There are many studies about nanofluids, however, most are obtained with synthetic nanoparticles, leaving the use of natural nanoparticles as a field to be explored, as well as other surfactants to improve their stability. Keywords: nanofluids, hybrid nanofluids, nanoparticles, nano refrigerant. Resumen Los nanofluidos constituyen una alternativa para el uso más eficiente de energía pues permiten generar o mejorar las propiedades térmicas entre otras de los fluidos tradicionales, son definidos como fluidos denominados base, como: agua, etilenglicol, aceites, etc., que contienen nanopartículas en suspensión, como: óxido de aluminio, óxido de silicio, óxido de titanio, nanopartículas metálicas, nanotubos de carbono, grafeno, carburos, etc. Los nanofluidos se pueden sintetizar por dos métodos, se pueden obtener las nanopartículas por separado y luego preparar el nanofluido o se puede preparar simultáneamente las nanopartículas y el nanofluido, un factor importante a considerar en la obtención de nanofluidos es su estabilidad. La estabilidad se puede lograr mediante tratamiento físico o tratamiento químico mediante la utilización de surfactantes. Existen muchos estudios acerca de nanofluidos sin embargo, la mayoría se obtienen con nanopartículas sintéticas, quedando el uso de nanopartículas naturales como un campo por explorar al igual que otros surfactantes para mejorar su estabilidad. Palabras Clave: nanofluidos, nonofluidos híbridos, nanoparticulas, nanorefrigerantes.


2018 ◽  
Vol 14 (5) ◽  
pp. 1782
Author(s):  
Keon Wook Kang ◽  
Myung Geun Song ◽  
Ji-Yong Park ◽  
Yun-Sang Lee ◽  
Hyewon Youn ◽  
...  

2008 ◽  
Vol 72 (1) ◽  
pp. 373-376
Author(s):  
Z. Balogh ◽  
S. L. S. Stipp ◽  
K. Bechgaard ◽  
E. Johnson

AbstractWater supplies from chalk aquifers in northern Europe can be contaminated by semi-metals such as As and metals such as Cr, Ni and many more, as a result of leaks from landfills, industrial sites and from natural oxidation of pyrite in the chalk, releasing trace elements. Chalk, which is predominantly calcite (CaCO3), has the ability to immobilize Ni, but its uptake by chalk is sometimes greater than expected. In an attempt to identify the controls on metal uptake, chalk samples from Klintholm I/S (Fyn, Denmark) were decalcified in EDTA solution and the residue was examined with transmission electron microscopy (TEM) for morphology and composition. Energy dispersive X-ray spectrometry (EDXS) revealed minor Si and Al (probably clay) and major Mn and Fe as (hydr)oxides. These natural nanoparticles have very large surface areas contributing to chalk’s uptake capacity for Ni and other metals from groundwater.


Author(s):  
Luiz Gustavo Hiroki Komatsu ◽  
Angelica Tamiao Zafalon ◽  
Vinicius Juvino Santos ◽  
Nilton Lincopan ◽  
Vijaya Kumar Rangari ◽  
...  

2018 ◽  
Vol 5 (2) ◽  
pp. 313-326 ◽  
Author(s):  
Andreas Gondikas ◽  
Frank von der Kammer ◽  
Ralf Kaegi ◽  
Olga Borovinskaya ◽  
Elisabeth Neubauer ◽  
...  

Detecting and quantifying engineered nanoparticles (ENPs) in complex environmental matrices requires the distinction between natural nanoparticles (NNPs) and ENPs.


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