A person or device that purifies (by removing impurities)(noun)
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Use "purifier" in a sentence
"I just take my purifier from the hunting closet and use it in my home to have a healthier living space for my family."
"Usually my water purifier is on, but about 5% of the time the ozone light has failed and I've only had my water go through the rather inefficient filter."
"A purifier is a cool thing to have, but it only works if you have fairly clean water to start with."