Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives

► Two EDTA derivatives were synthesized to extract anionic and cationic heavy metals. ► Decreased surface tension and enhanced solubility of humic acid were the mechanisms for Cr(VI) extraction. ► Extraction of Cu(II) was attributed to both chelation of Cu(II) by C12HEDTA and to enhanced solubility of humic acid. ► C12HEDTA enable the simultaneous extraction of both Cr(VI) and Cu(II).