Swimming Pool Disinfection

Chlorine is a popular disinfectant used to kill harmful bacteria and viruses. It works by breaking down the molecules of these pathogens. One efficient method of using chlorine for sanitization is through a process called electrochlorination. This technique, which involves passing an electric current through salty water, can produce hypochlorous acid (HClO) and hypochlorite (NaClO) that effectively disinfect water.

Here’s how it works:

When electricity is passed through the salty water using special electrodes, two important reactions happen. At the anode (positive electrode), chloride ions (Cl–) from the saltwater turn into chlorine gas (Cl2) and electrons. At the cathode (negative electrode), water molecules (H2O) gain these electrons and convert into hydroxide ions (OH–) and hydrogen gas (H2).

The key reaction that creates the disinfectant occurs when the chlorine gas produced at the anode reacts with the hydroxide ions created at the cathode. This reaction results in the formation of hypochlorite (ClO–) and chloride ions (Cl–), which are effective in disinfecting water.

In practical applications, certain electrode materials like titanium with coatings of IrO2 or IrO2/RuO2 are preferred due to their superior efficiency in chlorine production compared to materials like boron-doped diamond or platinum. This method is widely used in ensuring clean water supplies, treating wastewater, and sanitizing swimming pools effectively.