Those are temperature and particle size. Solution concentration, diffusion distance, and a membrane's surface area and permeability affect net diffusion without impacting the kinetic energy.
Diffusion occurs when molecules move randomly using thermal or kinetic energy. Molecules in a solution tend to achieve a state of equilibrium, becoming evenly distributed. In net diffusion, molecules move in a direction from higher to lower concentrations. If a membrane separates two areas of differing concentration of the substance, net diffusion occurs through the membrane.
The diffusion is a movement of atoms or molecules from a high concentration area to the lower concentration area. The process of diffusion is caused by a random motion of particles.
The rate of diffusion depends on factors like temperature, pressure, nature of the material and size of the molecules. It is evident from the physics perspective due to the kinetic molecular theory.
The kinetic energy of the molecules raises when the temperature increases. Thus, firstly, the collisions of particles are likely to be more frequent. Secondly, the particles are spread evenly throughout the material. These factors cause the higher diffusion rate.
Diffusion also depends on the nature of the material and on the size of molecules. The particles, when reaching a particular temperature, have equal average energy. Therefore, the lighter atoms, such as hydrogen, carbon or oxygen, are more bouncy than the heavier. So eventually, the lighter are the atoms in a compound, the faster they diffuse.