Is it permissible to pay Zakat on wealth from bank profits, and what should be done in this case?

If the bank is usurious, its profit is unlawful (haram) and the usurer does not own it; he must dispose of it. As for paying zakat from lawful money using unlawful money, there is a difference of opinion regarding its validity. Our fatwa is that it is not valid, and this is the well-known view of Ibn Rajab al-Hanbali. However, it is mentioned in Radd al-Muhtar that some jurists consider it valid. If it is deemed invalid, then he must pay the zakat again.