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Experimental stability analysis of different water-based nanofluids.

Fedele L, Colla L, Bobbo S, Barison S, Agresti F - Nanoscale Res Lett (2011)

Bottom Line: Different dispersion techniques were considered in this study, including sonication, ball milling and high-pressure homogenization.Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration.The high-pressure homogenization was found to be the best method, and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively in SWCNHs-water and TiO2-water nanofluids, improved the nanofluid stability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche, Istituto per le Tecnologie della Costruzione, Corso Stati Uniti, I-35127 Padova, Italy. sergio.bobbo@itc.cnr.it.

ABSTRACT
In the recent years, great interest has been devoted to the unique properties of nanofluids. The dispersion process and the nanoparticle suspension stability have been found to be critical points in the development of these new fluids. For this reason, an experimental study on the stability of water-based dispersions containing different nanoparticles, i.e. single wall carbon nanohorns (SWCNHs), titanium dioxide (TiO2) and copper oxide (CuO), has been developed in this study. The aim of this study is to provide stable nanofluids for selecting suitable fluids with enhanced thermal characteristics. Different dispersion techniques were considered in this study, including sonication, ball milling and high-pressure homogenization. Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration. The high-pressure homogenization was found to be the best method, and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively in SWCNHs-water and TiO2-water nanofluids, improved the nanofluid stability.

No MeSH data available.


Nanoparticles size distribution for water containing 0.1 wt.% TiO2 dispersed by means of the sonication method. At (thick line) day 1, (dashed line) day 4 and (dashed-dotted line) day 15.
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Figure 2: Nanoparticles size distribution for water containing 0.1 wt.% TiO2 dispersed by means of the sonication method. At (thick line) day 1, (dashed line) day 4 and (dashed-dotted line) day 15.

Mentions: The mean diameter of CuO, TiO2 and SWCNH nanoparticles dispersed in water by sonication method are presented in Table 2, at days 1, 4 and 15. This method proved to be more effective than the ball milling method in reducing aggregates. However, in terms of stability, for CuO nanoparticles, the results are similar to those obtained by ball milling method, since they could not be measured after 15 days, because of particle precipitation, as highlighted by visual observation. Also in TiO2-water nanofluid, a precipitation occurred, even if being slower than with ball milling, as shown in Figure 2 which presents the nanoparticles' size distributions for water containing TiO2 at days 1, 4 and 15.


Experimental stability analysis of different water-based nanofluids.

Fedele L, Colla L, Bobbo S, Barison S, Agresti F - Nanoscale Res Lett (2011)

Nanoparticles size distribution for water containing 0.1 wt.% TiO2 dispersed by means of the sonication method. At (thick line) day 1, (dashed line) day 4 and (dashed-dotted line) day 15.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211367&req=5

Figure 2: Nanoparticles size distribution for water containing 0.1 wt.% TiO2 dispersed by means of the sonication method. At (thick line) day 1, (dashed line) day 4 and (dashed-dotted line) day 15.
Mentions: The mean diameter of CuO, TiO2 and SWCNH nanoparticles dispersed in water by sonication method are presented in Table 2, at days 1, 4 and 15. This method proved to be more effective than the ball milling method in reducing aggregates. However, in terms of stability, for CuO nanoparticles, the results are similar to those obtained by ball milling method, since they could not be measured after 15 days, because of particle precipitation, as highlighted by visual observation. Also in TiO2-water nanofluid, a precipitation occurred, even if being slower than with ball milling, as shown in Figure 2 which presents the nanoparticles' size distributions for water containing TiO2 at days 1, 4 and 15.

Bottom Line: Different dispersion techniques were considered in this study, including sonication, ball milling and high-pressure homogenization.Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration.The high-pressure homogenization was found to be the best method, and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively in SWCNHs-water and TiO2-water nanofluids, improved the nanofluid stability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche, Istituto per le Tecnologie della Costruzione, Corso Stati Uniti, I-35127 Padova, Italy. sergio.bobbo@itc.cnr.it.

ABSTRACT
In the recent years, great interest has been devoted to the unique properties of nanofluids. The dispersion process and the nanoparticle suspension stability have been found to be critical points in the development of these new fluids. For this reason, an experimental study on the stability of water-based dispersions containing different nanoparticles, i.e. single wall carbon nanohorns (SWCNHs), titanium dioxide (TiO2) and copper oxide (CuO), has been developed in this study. The aim of this study is to provide stable nanofluids for selecting suitable fluids with enhanced thermal characteristics. Different dispersion techniques were considered in this study, including sonication, ball milling and high-pressure homogenization. Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration. The high-pressure homogenization was found to be the best method, and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively in SWCNHs-water and TiO2-water nanofluids, improved the nanofluid stability.

No MeSH data available.