Delete data by a form field

I want to delete email addresses from my database via a form field. If the email address in the field equals to the email address in the database, it (the row) gets deleted. I'm a bit confused how to do it.

View:

Code:

<form action="Controller/delete" method="post" id="form" name="form">
   <input id="email" name="email" type="email">
   <input name="submit" id="submit" type="submit" value="Unsubscribe">
</form>

<?php

if (isset($_GET['submit'])) {
 $email=$_POST['email'];

foreach($select->result() as $row){
 $email=$row->email;

 if($email==$row){
   delete($row);
 }
}
}
?>

Model:

Code:

function select() {
 $this->db->select("email");
 $this->db->from("users");
 $query=$this->db->get();
 return $query;
}

function delete($email) {
 $this->db->where("email", $email);
 $this->db->delete("users");
}

Controller:

Code:

public function index()
{
   $this->load->model('users');

   $data["select"]=$this->users->select();
   $this->load->view("view", $data);
}

public function delete(){
  $this->load->model('users');
  $this->users->delete($email);
  redirect(Controller/index);  
}