The miracle of osmosis unknown at the time of the revelation of the Koran 25:53
25:53 It was He (Allah) who let forth the two seas, this one is palatably sweet and this salt, a bitter taste, and He set a barrier between them, and a refuge which is forbidden.
25:55 Yet they (the unbelievers) worship, other than Allah, that which can neither benefit nor harm them. Surely, the unbeliever is ever a partisan against his Lord.