The main difference between simple diffusion and facilitated diffusion is that simple diffusion occurs without channel or carrier proteins' participation, while facilitated diffusion occurs through channel or carrier proteins. Simple distribution is a process that carries molecules from a region of high concentration to a region of low concentration.
It occurs along the concentration gradient. It does not utilize energy. This procedure can be explained by a simple task where you open a bottle of something, and the smell immediately spreads throughout the room by diffusion. If you placed an ink drop into a cup filled with water, the color will spread evenly in the water. Diffusion not only appears in those situations, but it also arises in the cells as well.
However, occasionally when larger molecules diffuse across the membrane, the membrane's proteins necessitate the diffusion progression. It is suggested to as facilitated diffusion, and it differs from simple diffusion because it involves the membrane proteins, which are channels or carrier proteins. A significant difference between simple diffusion and facilitated diffusion is that simple diffusion can transport only smaller molecules. In comparison, the facilitated diffusion can transport both the small and larger molecules across the cell membrane.