try this :
$times->item($i)->nodeValue = str_replace(" ","",$times->item($i)->nodeValue);
it should delete every
EDIT
your line :
$item['datetime'][] = $dates->item($i)->nodeValue . $times->item($i)->nodeValue;
become :
$item['datetime'][] = $dates->item($i)->nodeValue
. str_replace(" ","",$times->item($i)->nodeValue);
EDIT 2
if str_replace
does not work, try with str_ireplace
as suggested in comment.
If it still doesn't work, you can also try with :
preg_replace("# #","",$times->item($i)->nodeValue);
EDIT 3
you may have an encoding problem. see uft8_encode
Or piggy solution :
str_replace("Â","",$times->item($i)->nodeValue);
Apolo