Definitions of purification:

• noun:   the act of purging of sin or guilt; moral or spiritual cleansing

  Example: "Purification through repentance"

• noun:   a ceremonial cleansing from defilement or uncleanness by the performance of appropriate rites
• noun:   the act of cleaning by getting rid of impurities
• noun:   the process of removing impurities (as from oil or metals or sugar etc.)