I say, and with God's help: it does not become pure, and distillation is not considered a transformation; the steam of impure water remains impure. Refer to: Al-Binayah 1: 755, Risā'il Al-Arkān p. 48, Al-Fatāwā Al-Tatārkhāniyyah q. 65/b, Naf' Al-Mufti p. 143, and God knows best.