gistfile1.php

function removeDuplicates($firstArray, $secondArray, $byTheKey)
{
    $collect = array();
    $walker = function($v, $k) use(& $collect, $byTheKey) { $collect[$v[$byTheKey]] = $v; };
    array_walk(array_merge($firstArray, $secondArray), $walker);
    return $collect;
}