Please remember when reading this, that the understanding of participles in the community is unfortunately limited and unlikely to clear up soon, this is just one of the more readily applicable interpretations of participle grammar.
Adûnaic participles exist, but behave differently compared to your standard participles. They appear to be formed via the agental suffix -ân, leading to possible confusion with its definite role in forming nouns from verbs. Despite using the same suffix however, participle formation differs from noun formation in that no syncope is used with the suffix, instead opting to leave the verb stem intact (due note that biconsonantal verb stems are identical to their syncoped version, so context is required to unmistakably recognize them). Adûnaic participles are also placed after the word modified.
Examples:
*Zigûrun zabathân: “The humbled Wizard.”
*Anadûnê zîrân hikalba: “Númenor the beloved she fell.”