Of course that won't happen, but it's possible.
There is about a 0.00000000000000000001% chance that 2/3rds of the Senate would actually vote to remove Trump, but in the event that hypothetically occurred, he wouldn't be able to return as President at a later date unless the Articles of Impeachment didn't bar him from future office.
The Articles of Impeachment explicitly banned Clinton from ever holding any future office in the United States. So if Slick Willie had hypothetically been removed from office, the ONLY way he'd ever be a "public servant" again would be by getting citizenship in another country and conning them into electing him.
Of course, its also possible the RATS forgot or didn't bother to include a clause barring Trump from holding office in the future. The Nixon impeachment (which never passed because Nixon resigned before they could vote on it) oddly enough didn't ban him from future office, though the RATS are so vindictive they'd probably sentence Trump to being flogged for the rest of his life except the Constitution doesn't allow corporal punishment for impeachment.