Superior selective removal of lead via sulfate doped flower like layered double oxide: An example of high value-added utilization of organic waste

Selective removal of metal ions , especially lead (Pb 2+ ), is of enormous importance for environmental protection. A major challenge is to rational design capture agent for Pb 2+ with high efficiency and excellent selectivity . Here we recycled the organic layered wastes to prepare a novel sulfate-loaded flower-like layered double oxide (S-FLDO) via precursor-calcination method, which exhibited preeminent selective ability toward Pb 2+ removal than the other coexisting metal ions (Cu 2+ , Ni 2+ , Co 2+ and Cd 2+ ). The isotherm and kinetic results unveiled that the immense capacity of Pb 2+ was up to 869.57 mg g −1 at 318 K, with the rapid decrease of the residue Pb 2+ concentration from mg·L −1 levels to trace levels (≤1 μg·L −1 ) limited in 30 min. More importantly, the exceptional removal of Pb 2+ could maintain in a wide pH range and even in the authentic water matrices. The mechanism for Pb 2+ removal was strongly associated with sulfate functional group via the formation of Pb-sulfate precipitation benefited by ion-exchange interaction. The alkaline environment resulted from LDO hydration further enhanced the removal process. In addition, the S-FLDO could maintain the high removal efficiency in real water as well as exhibited excellent recycle performance. This work provides a high value-added sulfate-loaded agent derived from organic layered wastes for superior selective lead removal.