Replace some Special Characters in a String

I have a special character that I want to replace from a string.
The character is Å¡ and i want to replace with s but I didn't managed to do this with this particular php file. It is actually encoded utf-8 .

Please help me this is becoming a nightmare.

 

$string = $content; //or some other variable
$content = str_replace("Å¡", "s", $content);
echo $content;

PHP:

 

yes the problem is that id doesn't work!!

 

EDIT: IT WORKS ! I CAN't BELIEVE BEFORE I USED $content = str_replace('Å¡', 's', $content); instead of " " and it didn't work, why?