A free nitrogen-containing Sm-MOF for selective detection and facile removal of mercury(II)

Mercury (Hg 2+ ) is a highly hazardous and widespread environmental pollutant with bioaccumulative properties, so highly sensitive detection and effective removal of mercury in water environment are very necessary. Considering “soft base” property of N atom, N-containing organic groups cannot coordinate effectively with “hard acid” rare earth ions . A [Sm(ATPA) 1.5 (DEF)] n (Sm-MOF) (H 2 ATPA = 2-aminoterephthalic acid) containing free amino groups is constructed for simultaneous detection and removal of Hg 2+ ions. Hg 2+ can quench effectively the charge transfer emission of Sm-MOF in aqueous solution, and simultaneously induce the Sm 3+ characteristic fluorescence emission of Sm-MOF. The results shows that the prepared Sm-MOF has an excellent selectivity and a high sensitivity for detecting Hg 2+ with a wide linear range of 0.6–300 μM and a low detection limit of 0.87 μM. At the same time, the MOF is also employed to adsorb and remove Hg 2+ in aqueous solution and it is found that over 97% of Hg 2+ can be removed in approximately 2 h.