Circular economy and “green technologies” Nadezhda Avramchikova, Ivan Rozhnov, Tatyana Zelenskaya, Olga Maslova and Vyacheslav Avramchikov E3S Web Conf., 291 (2021) 02014 Published online: 19 July 2021 DOI: 10.1051/e3sconf/202129102014