A student observed a patient undergoing heamodialysis

A student observed a patient undergoing heamodialysis. He has many doubts about heamodialysis. What might be his doubts ?
A. He got following doubts about heamodialysis.

  1. What is the use of dialysis ?
  2. How the impurities are separated from blood ?
  3. How much time needed to complete dialysis ? .
  4. How frequently, does a patient should undergo dialysis ?
  5. How to prevent blood coagulation during dialysis ?
  6. What is major difference between kidney and artificial kidney ?
  7. Can this process done at home ? .