Dialysis is the process by which a solute passes from one side of a semi-permeable membrane to the other. Any natural (e.g., peritoneal) or artificial semi-permeable membrane can move solutes from one side of the membrane to the other by dispersion and convection, as long as the membrane contains a pore size that allows the solute to pass through. The "poisons" in the body, including metabolites, drugs, and exogenous poisons, can be removed from the body by dialysis if they have the right atomic or molecular weight.
The basic principle is diffusion and convection. Diffusion is a semi-permeable membrane on both sides of the liquid contains a gradient of solute concentration and the formation of different osmotic concentration, solute from the concentration of the side of the semi-permeable membrane through the concentration of the side of the movement of the low concentration. Convection, also known as ultrafiltration, is the process by which solutes and solvents are transported across the membrane due to differences in hydrostatic and osmotic pressure gradients on both sides of the dialysis membrane.