Asenda prime, the hostile home of the serion, is devoid of spiritual energy. Since this is the case, serion who go to earth are in danger of being corroded by spiritual energy, except for the fact that they're protected by special shields to block it from touching them.
However what about what happens when the inhabitants of earth and its dimensions go to Asenda prime? well, in the case of living beings, they are stripped of all Spiritual energy and thus spiritual powers, for their stay. This is not permanent however, once they return to earth their powers return.
But if a spiritual being tries to enter asenda prime by any means, they are spat back out onto earth. Since shinigami and hollow consist entirely of spiritual energy, they simply cannot go there. Atleast not without a body of some kind, such as a gigai. In a gigai they are still powerless, but can go to Asenda prime at the very least.
on a side note, since Serion are sentient, on earth they count as having a soul. If a serion is completely destroyed on earth, its possible for their soul to manifest for a short while. During that time, they could be purified by a shinigami or attacked by a hollow, and end up becoming one or the other. However their soul is garanteed to take on a new human form, and they retain none of their former traits.