Meaning of “purify” - Learner’s Dictionary

purify

verb [ T ] uk us /ˈpjʊərɪfaɪ/

to remove bad substances from something to make it pure:

Plants help to purify the air.
purified water
purification uk us /ˌpjʊərɪfɪˈkeɪʃən/ noun [ U ]

(Definition of “purify” from the Cambridge Learner’s Dictionary © Cambridge University Press)