Did someone use the filtration centrifuge Hermle Sieva-2 www.hermle-labortechnik.de/en/our-products/filtration-centrifuges/sieva-2.html Is it useful for the separation of nano-particles (when used with non-perforated basket)? I read in the description that it is mainly used for the separation of relatively coarse particles, which makes me confused, I wonder if I can use it for graphene oxide washing.
Noting also that the supernatant maybe relatively an acidic solution, I wonder if the basket will be corroded after several uses.
Actually I want to buy in this filtration centrifuge because it can work in batch and in continuous mode (adding the solution to be centrifuged during the run, separating the supernatant automatically), which maybe very practical. So do you advise me to buy it?
Thank you very much in advance.
This kind of centriguge is a centrifuge filter and can work very well with large particles.
When dealing with nano particles, unless they are agglomerated, they can pass trough any barrier material with pore size greater then them or the particles can flood the filter element and process stop.
It is very difficult to separate nanoparticles but you can try to centrifuge in tube centrifuges to get a particles concentrate. It is better to contact manufacturer to get a practical support for your system. The same manufacturer have other models to work
Thank you very much for your answer. Actually I sent several emails to the manufacturer but they didn't answer.
By the way, to avoid the leak of the nanoparticles through the filter, I thought of buying the centrifuge with a non-perforated basket. I wonder if this can be a good solution or not
Zineb
Even with a non-perforated basket, the question is whether the particles can reach the wall in a reasonable amount of time (if ever). This depends on the particle size, particle shape, liquid viscosity, the density difference between the particles and the liquid, the bowl diameter and the rotational speed. If you can assume you have spherical particles, a dilute slurry (no interactions between particles), and a Newtonian liquid, you can estimate the terminal settling velocity (under gravity) using Stokes Law. To obtain the velocity in the centrifuge, multiply this by the G force, which is the bowl radius times the square of the angular velocity, divided by the gravitational acceleration constant. You can use this to estimate the required centrifugation time, which can inform your decision whether to buy this centrifuge. Looking at the specs, I suspect this centrifuge is not a good option for you. I don't know what your budget is, but you may need an ultracentrifuge like one of these: http://www.thermofisher.com/us/en/home/life-science/lab-equipment/lab-centrifuges/floor-model-centrifuges/ultracentrifuges.html?gclid=EAIaIQobChMI39He2piW1wIVxB6GCh2YtAu8EAAYASAAEgINYPD_BwE&cid=lpd_gps_cfg_ultra_ultra_adwords&wt.mc_id=led_ultracentrifuges_adwords&wt.srch=1&adwordskeyword=ultracentrifuge&s_kwcid=AL!3652!3!199806605703!e!!g!!ultracentrifuge&ef_id=WeAvVgAAAQqOfCt8:20171029155703:s
Good luck
Alan
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