Trying to make a work around for the mysqli_real_escape_string

So currently I have my code in procedural format so inorder to prevent myself from adding the "link" in the mysqli_real_escape_string function I've made a method that looks like this:

    // Used to create a legal SQL string that you can use in an SQL statement in place of mysqli_real_escape_string
    public function escape_string($string) {
    $newstring = mysqli_real_escape_string($this->dbconn, $string);
    return $newstring;
}

When I use this though I don't get any results though let me know if you have any recommendations.

Here are some examples where I use the function:

function email_exists($email,$dblayer){

$sql            =   "SELECT `id` FROM `users` WHERE `email` = '" . $dblayer->escape_string($email) . "'";

$results        =   $dblayer->select_query($sql);

if($results){

    return true;

}else{

    return false;

}

And this:

public function pass_reset($email){

    $newpass        =   substr(md5(mt_rand(1,99999)),0,8);

    $newpasshash    =   md5($newpass . '************');

    $sql            =   "UPDATE `admin_users` SET `password` = '" . $newpasshash . "' WHERE `username` = '" . $this->dblayer->escape_string($email) . "'";

    $this->dblayer->modify_query($sql);

    return $newpass;

}

And this which is created around another dblayer which is called dbobject:

                case $range:

                $dates          =   explode(',',$_GET['search-string']);

                $sql            =   "SELECT SQL_CALC_FOUND_ROWS * FROM `user_profile` WHERE `created` BETWEEN '" . $dates[0] . "' AND '" . $dates[1] . "'";

                break;

            default:

                $sql            =   "SELECT SQL_CALC_FOUND_ROWS * FROM `user_profile` WHERE `" . $_GET['search-field'] . "` LIKE '%" . $dbobject->escape_string($_GET['search-string']) . "%'";



                break;

This is what I did differently to my original code to fix my problem. It might look a little ambiguous out of context.

// Used to create a legal SQL string that you can use in an SQL statement in place of mysqli_real_escape_string
public function escape_string($string) {
    $newstring = '';

    if ($this->dbconn) {

        switch ($this->dbtype) {

            case 'mysql' :

                $newstring = mysqli_real_escape_string ( $this->dbconn, $string );
                break;
        }
    }
    return $newstring;
}