Board Thread:Questions and Answers/@comment-24499616-20140208162134/@comment-11051098-20140208193052

Ulquiorra got his organs destroyed by the Cero Ichigo's full Hollow form used, and couldn't regenerate them, and he turned to dust and faded away.

It's also been confirmed by Kubo himself that Grimmjow and Harribel are the only Espada that are still alive.