:- use_module(library(rdf_write)).(can be autoloaded)
utf8. Characters that cannot be represented in the encoding are represented as XML entities. Using ASCII is a good idea for documents that can be represented almost completely in ASCII. For more international documents using UTF-8 creates a more compact document that is easier to read.
rdf_write(File, Triples) :- open(File, write, Out, [encoding(utf8)]), call_cleanup(rdf_write_xml(Out, Triples), close(Out)).