Systems and methods are provided for filtering a fluid containing nanoparticles. The systems and methods generally include introducing a stream of the nanoparticle-containing fluid into a holding vessel, and extracting at least a part of a nanoparticle-containing fluid accumulated in the holding vessel. The extracted nanoparticle-containing fluid is passed through a filtration module to separate a nanoparticle-containing retentate from a permeate, and the retentate is returned to the vessel. The filtration cycle can be repeated until a desired concentration of the nanoparticles is achieved in the holding vessel. In many embodiments, the generation of the nanoparticle-containing fluid and its filtration are performed concurrently.