How to remove special characters in php

I want to remove some special characters from a result of this query, this is the query:

$permiso = DB::table('personal_access_tokens')->select('abilities')->where('tokenable_id',$id)->get();

The result of this query is in json format:

[
  {
    "abilities": "[\"rol:user\"]"
  }
]

And I thought that the str_replace() function might be my solution, to remove everything else and just leave 'role:user', so I applied it.

$resultado = str_replace('{["\"/:abilities','',$permiso);

This was my result:

"[{\"abilities\":\"[\\\"rol:user\\\"]\"}]"

What I want is that it only remains: role: user

Additional Information:

Result of:

$permission = json_decode($permission,true);

$result = var_dump($permission);

   array(1){
  [
    0
  ]=>array(1){
    [
      "abilities"
    ]=>string(12)"["rol: user"]"
  }
}{}