TY JOUR TI ACCOUNTING FOR THE HARD-SOFT PROPERTIES OF CHALCOGEN ATOMS IN THE DEVELOPMENT OF NEW EXTRACTANTS AND SORBENTS FOR HEAVY METAL COMPOUNDS KW heavy metal ions KW extraction from solutions KW Pearson's theory JO Modern Technologies and Scientific and Technological Progress AU Nalibaeva, A.M. AU Abdikalykov, E.N. AU Ilyassova, O.S. PY 2026 IS 2026 PB Federal State Funded Educational Establishment of Higher Education «Angarsk State Technical University»