Is it permissible to donate the usurious bank interest while keeping the bank account as is, or must the type of account be changed?

It is not permissible to open a bank account that includes interest-based (ribawi) gains, even if the intention is to dispose of these gains by giving them to the needy. Engaging in an interest-based contract is impermissible. The obligation is to close this account and open an account free from interest-based transactions.