Using a Session Variable in a MySQL Update statement

Hello, so as the title says, I'm looking to include a Session Variable into a MySQL Update statement. I'm not exactly sure what I'm doing wrong, but I certainly know I am. I'm also fairly new to this, so that may explain it lol! Thanks in advance for your help.

Code:
In the original PHP:

$email = $conn->query("SELECT email FROM memberapplications WHERE ID = " . $_GET["appid"]);
$_SESSION["email"] = $email;

In a redirect PHP:
//There is also connections and stuff above and below, but I don't wanna bore you with that.

$sql = "UPDATE users SET appstatus='2' WHERE email='$email'";