Chromium(VI) removal via reduction-sorption on bi-functional silica adsorbents

► SH-functionalized silica is able to reduce Cr(VI) into less toxic Cr(III) species. ► Cr(III) can bind to ethylenediaminetriacetate groups in bi-functionalized sorbent. ► The reduction-sorption process is very fast and pH dependent (optimum: pH 1-3). ► Cr(III) binding is stronger than with sulfonate groups (possible column sorption). ► Good chromium sorption performance was observed in the presence of interference.