How to eliminate a value from for loop result that exist in database in codeigniter

I am writing a script to eliminate a value from for loop which already exist in my database. Here’s the code I tried:

    $capacity;
    $builder = $this->db->table('tblcapacity');
    $builder->select('Capacity');
    $builder->WHERE('vesselID',$vessel)->WHERE('Seat_Type',$seats);
    $cap = $builder->get();
    foreach($cap->getResult() as $row)
    {
        $capacity = $row->Capacity;
    }
    $list = array();
    for($x=1;$x<=$capacity;$x++)
    {
        $seat = str_pad($x, 3, '0', STR_PAD_LEFT);
        $list[] = $seat;
    }
    $seat_num;$result;
    $builder = $this->db->table('tbltransaction');
    $builder->select('SeatNumber');
    $builder->WHERE('Seat_Type',$seat)->WHERE('ID',$depart)->WHERE('TrxnDate',$date);
    $datas = $builder->get();
    foreach($datas->getResult() as $row)
    {
        $seat_num = $row->SeatNumber;
    }
    $Obj = json_decode(json_encode($list));
    foreach($Obj as $objects)
    {
        echo "<option>".$objects."</option>";
    }

The script able to generate seat number depends to the capacity but unable to remove the existing seat value. Hope you could help me. Thanks in advance