How to process the data which type is BLOB?
Pass it to unserialize(). That is the string obtained from serialize(), when the argument is the following array.

$array = array(
  'attributes' =&gt; array('title' =&gt; ''),
  'langcode' =&gt; 'zh-hans',
);


serialize() is the function used from Drupal when the data to save in the database is an array.