How is money borrowed from an interest-based bank and designated for buying and selling land to be purified (given in zakat)?

Repentance from borrowing with usury is obligatory, as it incurs the curse and wrath of Allah. The one who consumes usury is at war with Allah and His Messenger. As for the Zakat (definition) on lands prepared for trade, it is obligatory. Their value should be calculated with the zakatable money at the end of each lunar year, and a quarter of one-tenth (2.5%) should be given out. Regarding deducting debt from Zakat, the majority of scholars hold the view that any debt can be deducted except for usurious debt, as it is not Islamically recognized.