(use-modules (srfi srfi-1)
             (srfi srfi-11)
             (srfi srfi-26))

(define vowels '(#\a #\e #\i #\o #\u))
(define text "helloworld")

(let-values (((vowels consonants)
              (partition (cut member <> vowels)
                         (string->list text))))
  (format #t "~a\n" vowels)
  (format #t "~a\n" consonants))