Purify

To remove harmful or unwanted material so something becomes clean or safe.

Reach for it when describing a process that eliminates contaminants from a substance

Layers of sand and charcoal purify the collected rainwater.

• everyday

  sanitize

  for reducing microorganisms to an accepted hygiene level

  not when Sanitize does not mean removing every impurity or all microbes.

• warm

  cleanse

  when unwanted material is washed or cleared away

  not when Cleanse can sound ceremonial or wellness-oriented and may not guarantee purity.

• professional

  decontaminate

  when dangerous biological, chemical, or radioactive matter is removed

  not when Decontaminate addresses safety and can leave harmless impurities behind.

• professional

  filter

  if contaminants are physically separated by a barrier or medium

  not when Filtering removes selected particles but may leave dissolved hazards.

• professional

  sterilize

  if all viable microorganisms must be destroyed or removed

  not when Sterilize is a narrower and much stronger microbiological claim.

• formal

  refine

  when processing removes rough components to improve material quality

  not when Refining may prioritize performance or taste rather than safety.

• literary

  clarify

  when suspended matter is removed from a liquid to make it clear

  not when Clarify concerns appearance and does not establish that the liquid is safe.

• contaminate
• pollute
• taint

• purify water

  The portable unit can purify water for thirty people each day.

• purify the air

  Dense plantings helped purify the air beside the school entrance.

• purify a substance

  The chemist repeated the wash to purify a substance needed for testing.