Are sponges echinoderms

No. Sponges belong to the phylum Porifera, which means 'pore bearing.' The have pores that are called incurrent vents, where water comes in, and excurrent vents, where water goes out. They are considered the most primitive of animals because they don't have any complex organs or tissues, so, for example, they don't have a circulatory system or a digestive system or a nervous system. Their cells are somewhat loosely structured in that some cells can move around from place to place in the sponge and there are some unspecialized cells that can become other kinds of cells. Also, they only have two layers of cells. There are some types of sponges that you can put through a sieve to separate all the cells but then the cells will go back together to recreate a sponge again.

Echinoderms are a completely different and more advanced phylum. They have organ systems and fixed (non-changing) cell types and more layers of cells. Also, if you put an echinoderm through a sieve, he's a gonner.