Rapid adsorption of cationic and anionic dyes from aqueous solution via metal-based coordination polymers nanoparticles

摘要

Two new amorphous infinite coordination polymers with M2L composition were spontaneously self-assembled from functionalized Schiff base and metal cations (Zn2+ and Pb2+). The Schiff base was obtained via step by step functionalization of salen (N,N'-Bis(salicylidene)ethylenediamine) with 2-mercaptobenzoic acid. Dyes adsorption performance of the prepared coordination polymers was investigated. The results revealed that the removal efficiency of methylene blue is high for both coordination polymers (97.2% for Pb coordination polymer and 99.9% for Zn coordination polymer). However, removal efficiency of methyl orange is much higher in the case of Pb coordination polymer (94.5%) with respect to the Zn coordination polymer (23.1%). The removal amount of 20 ppm dye solution reaches to <0.5 ppm for methylene blue which is much higher than most experimental values of the other materials reported so far, as we know. The reusability and stability of Pb based coordination polymer were also investigated.