The solvent volume surrounding the gelatin particles is calculated and is fitted in the equation given as under to determine the hydrodynamic size of particles. A new method has been developed to determine the acetic acid adsorption by charcoal. It is seen that the surface excess concentration of the surfactant in water is determined by using the surface energy of a continuous thin film of the water at the air-water interface. The hydrophobic-hydrophobic networking could hold some structured water with the maximum entropic changes. The interface is developed by the hydrogen bonding of the water. Once the surfactant gets saturated at the interface then the surface energy becomes constant. A similar method could be extended to acetic acid adsorption by activated charcoal since activated charcoal has also got a saturation point for acetic acid adsorption that shows a constant surface energy.