What substance is used as a method of purifying water alongside boiling?

Iodine tablets are commonly used as a method of purifying water, particularly in survival situations where access to clean water is limited. Iodine has antiseptic properties that effectively kill bacteria, viruses, and other pathogens present in contaminated water. When iodine tablets are added to water, they release iodine, which then works to sanitize the water, making it safer for drinking.

Boiling water is another reliable method of purification that kills microorganisms. By combining these two methods — boiling to eliminate pathogens and iodine tablets for additional disinfection — individuals can ensure that the water they consume is safe.

In contrast, while sand can be used in some filtration systems, it does not purify water on its own; it merely helps in physical filtration of larger particles. Sugar and salt do not have purifying properties and are not used for sanitizing water.