Facile Approach To Prepare Sulfur-Functionalized Magnetic Amide-Linked Organic Polymers for Enhanced Hg(II) Removal from Water

Construction of adsorbents with specific porous structure and heteroatom doping is significant for enhancing adsorption performance toward the contaminants. However, it is still a crucial task for selective adsorption with high affinity and fast uptake kinetics. Herein, we present a facile and cost-effective postsynthesis modification approach to fabricate a novel effective sulfur-doped magnetic amide-linked organic polymer (S-MAOP), where AOP is chemically anchored on the surface of NH2-functionalized magnetic nanoparticles. The thionation process, e.g., transforming the amide group (-C=O-NH-) into the thioamide group (-C=S-NH-), was illustrated by treating the MAOP with Lawesson's reagent. The resultant S-MAOP exhibited much higher adsorption selectivity and affinity for Hg(II) uptake from water solution than the initial MAOP due to introduction of thioamide groups in the network. In addition, by covalently anchoring polymer networks onto magnetic nanoparticles, recovery and regeneration of S-MAOP were greatly facilitated due to its good superparamagnetism. Furthermore, it also showed superior stability, of which the adsorption capacity was well maintained even after 5 cycles. The remarkable adsorption performance, good cycling stability, and cost-efficient synthesis make S-MAOP a desirable adsorbent for contaminant removal.