What is the difference between hemoperfusion and hemofiltration?

Here are some...: Hemoperfusion is to let blood circulate outside the body through a machine filled with absortent material like carbon so to remove toxins or unwanted wastes; mechanically, it like artificial heart. Hemofiltration is a process of circulating blood outside the body through a machine so to remove water and metabolic waste for acute kidney injury, which is usually used in ICU, but hoping to recover.