please help me to find the error in codeigniter : from my side every thing is ok but it is not working, email or password is not fetching from db for verification. (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)

model: 

    class Login_model extends CI_Model
{

		public function login_valid($email,$password)
		{
			$q = $this->db-> select('*')
							->where(['email'=>'$email','password'=>'$password'])
							->get('admin');  
		}
}

controller: 

    class Adminlogin extends CI_controller
{

	public function login_form()
	{
		$this->load->view('common/login_form');
	}

	public function login_check()
	{

	$this->form_validation->set_rules('email','email','required|valid_email');
	$this->form_validation->set_rules('password','password','required|min_length[8]|max_length[15]');

		if ($this->form_validation->run())
		{

			$email	 = $this->input->post('email');
			$password = $this->input->post('password');

			$this->load->model('Login_model');
			$admin_id = $this->Login_model->login_valid($email,$password);

			if($this->load->model('Login_model')){
			$this->load->library('session');
			$this->session->set_userdata('Id',$admin_id);
			$this->load->view('admin/admin_dashboard');
			}
			else {
				echo "model not loaded";
			}
		}
		else
		{
			$this->load->view('common/login_form');
		}
	}