Efficient and selective removal of Pb2+ from aqueous solutions by modified metal-organic frame materials

The broad application of lead in various industries has caused it to accumulate in the environment, with severe implications for human health. There is an urgent need to develop efficient separation materials for treating lead-containing wastewater. In this study, a novel metal-organic framework material (UIO-66-TETA) was prepared using triethylenetetramine (TETA) as a modifier and applied to remove Pb2+ from water. The material was characterized by SEM, EDS, BET, XRD, FTIR, XPS, and other analytical methods. The results indicated that TETA was successfully introduced into the material surface, and the original crystal structure and morphology were maintained. The effects of pH, contact time, initial Pb2+ concentration, and temperature on Pb2+ removal were systematically investigated. Adsorption experimental data were consistent with the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. The adsorption thermodynamic analysis revealed that the adsorption process was endothermic and spontaneous. UIO-66-TETA had excellent adsorption selectivity for Pb2+ even in a mixed solution containing many other heavy metal ions. Regeneration experiments showed that UIO-66-TETA has good regeneration performance. Based on the results obtained in this work, it can be concluded that UIO-66-TETA can be used as an ideal adsorbent for the removal of Pb2+.