Hi
I have slurries of silica nano particles with low wt% which I want to concentrate. I tried different methods which didn't work out.Now I have nano particle size anywhere from 15 to 100 nm which I want to disperse in water to high wt% (70). Does any body can help me find a procedure which can be done in a lab?
Hi Eshan, I do not fully understand your question.
Silica NPs should settle out of solution due to gravity. Centrifugation should speed up the process of concentrating the NPs.
If you already have a pellet of silica NPs, then a sonicating waterbath should easily disperse them in any volume of your choosing..
Hi Steingrimur
Thanks for your response.
Actually I have fine nano particles of spherical silica in nm size. I want to disperse them in DI water using conventional methods such as sonication and centrifugation. My goal is to get to high wt% of silica in water close to 70% (Which is 0.5 in Volume Fraction). I have tried sonication but the uniformity and stability of the resulted slurry is an issue.
when I do DLS test on the slurry, I see that the particle size has changed from 100 to 300 for example as a result of agglomeration.
That is what I am looking for exactly. Dispersing silica nano particles in DI water and make high concentrations slurry which are stable and uniform.
Hi Eshan, my feeling is that since silica has exposed -OH groups, the H2O is forming hydrogen bonds between the silica particles.
The smaller the silica particles are, the stronger the hydrogen bonds to water will become.
Can you try dissolving the Si NPs in DMSO to se if that results in more uniform size?
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