Dear friend Federica Quacquarelli

Thank you for sharing the details of your recent challenge with collecting silica nanoparticles via centrifugation at 10,000 g. It’s certainly an intriguing situation, and I appreciate the opportunity to discuss potential avenues for troubleshooting and optimization.

Given the absence of a visible pellet, it may be worthwhile to first assess the stability and density of your nanoparticles in suspension. Factors such as particle size distribution and the ionic strength of your solution can significantly influence sedimentation efficiency. Even minor variations in these parameters may affect whether the particles aggregate sufficiently to form a pellet during centrifugation.

Filtration could also be a promising alternative, especially using membrane-based methods tailored to your particle size. The zeta potential of your nanoparticles, as well as their propensity to clog filters, are important considerations that could impact filtration success. Additionally, have you considered ultrasonic or magnetic-assisted separation techniques? These methods can sometimes promote aggregation or alignment, potentially improving subsequent collection by more conventional means.

Lastly, the washing process itself can play a critical role. Ensuring complete removal of the washing medium before collection may enhance recovery, so reviewing your current protocol for any steps that might inadvertently disperse or lose particles could be beneficial.

I’d be interested to hear your thoughts on experimenting with these variables or any other approaches you’re considering. Please let me know if you’d like to discuss further or if there’s any way I can assist as you refine your methodology.

Article to read/cite:

Chapter Synthesis Of Manganese Oxide Nanoparticles Using Similar Pro...

Best regards,

Kaushik

Hello,

It is unusual to have nanoparticles that well dispersed but if it is compatible with your process you can try to use flocculants. Those are basically the opposite of surfactant, they favorize the aggregation of the nanoparticles. Both organic and inorganic flocculants exist some of which can be removed chemically after you collect your particles. However it still forms a type of contamination that you need to account for.

Federica Quacquarelli Try temperature-assisted centrifugation by slightly cooling the suspension (e.g., 4 °C); lower temperatures can reduce Brownian motion and promote nanoparticle sedimentation.