How does an artificial kidney separate waste products from
theblood?

Reverse Osmosis

Explanation: Reverse Osmosis is the use of a partially permeable membranes( semi-permeable membranes)to filter fluids such as Blood. It helps to trap ions,wastes and other solutes from fluids, Blood and other liquids. Artificial kidneys are machines which applies the reverse Osmosis to separate wastes and other solutes from fluids in our body,it has a pipe attached to the Vein,the pipe collects blood and pass it through series of pipes containing semi-permeable filters which separates the wastes and other solutes from the blood through reverse Osmosis and returns the filtered blood to the blood stream through the Vein. The wastes are removed accordingly.

that's what i got you can count the number of atoms