Which type of filtration involves the removal of free residual chlorine?

The process that best relates to the removal of free residual chlorine is reduction. This is because reduction involves a chemical reaction in which chlorine is converted into chloride ions, effectively removing its oxidative properties. In water treatment processes, reducing agents, such as sodium bisulfite or sulfur dioxide, are commonly used to eliminate free chlorine from the water. This is essential for improving water quality and ensuring that chlorine does not negatively affect human health or interfere with subsequent treatment processes.

The other options do not accurately describe the process of removing free residual chlorine. Occlusion refers to the trapping of substances within another material and is not relevant in the context of chlorine removal. Adsorption is a physical process where molecules adhere to surfaces, which doesn’t specifically address the chemical transformation required for chlorine removal. Oxidation, conversely, involves the addition of oxygen or the removal of electrons, which would not help in the context of chlorine removal, as free chlorine is already in an oxidized state. Thus, the process of reduction directly aligns with the chemical conversion necessary for removing free residual chlorine from water.