Returning distinct values from foreach loop in PHP?

Try with:

$property_types = array();
foreach($search_results_unique as $filter_result){
    if ( in_array($filter_result['property_type'], $property_types) ) {
        continue;
    }
    $property_types[] = $filter_result['property_type'];
    echo $filter_result['property_type'];
}

http://php.net/manual/en/function.array-unique.php

Example:

$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input); 
print_r($result);

Array
(
    [a] => green
    [0] => red
    [1] => blue
)

You will need to alter it slightly to check using the property_type part of your array.