Synthesis of heavy metal chelating agent with four chelating groups of N1,N2,N4,N5-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide (TMBTCA) and its application for Cu-containing wastewater

► A new heavy metal chelating agent of TMBTCA with four chelating groups was prepared and characterized. ► The effects of mole ratio of reactants, reaction temperature, reaction time on the yield of TMBTCA were illustrated. ► The effects of mole ratio of TMBTCA/Cu2+, reaction time and pH on its application properties were researched. ► This new chelating agent could effectively remove Cu2+ and CuEDTA to much lower than 0.5 mg/L.