He can present an appeal, but it won’t be heard. It will just be dismissed. Impeachment and removal from office is deemed a “political question,” because the official only faces removal from office, not imprisonment, fine, or loss of any property. To the extent the Senate says “you are hereby removed from office,” he shrugs. ‘”Okay, fine. I left a month ago.”
What I think we do not know is, assuming he be convicted by the senate after, can he be elected again? We will say yes, others will say no, and I think the federal courts will have and will exercise the power to grant (or deny) a request for an injunction to bar him from running.