Conjugated micro-mesoporous poly(aniline)s for ultrafast Hg (II) capture

Abstract

Attempts to develop adsorbents for toxic Hg (II) removal from wastewater in an all-round high-capacity, rapid-kinetic and super-selective manner remain interesting but unsolved. Here, we report a novel class of conjugated micro-mesoporous poly(aniline)s (CMMPAs) by an ingenious integrated porosity design and decoration over porous organic polymers (POPs). We pre-create unstable ZIF-7-NH2 and crosslink it into POPs but remove it subsequently through a time-saving acid wash to allow the formation of mesopores and the “in-situ” decoration of ZIF-7-NH2 ligands as adsorption sites on the pore wall. The resulting adsorbent exhibits an ultra-high capacity of 1032 mg g−1, extremely fast kinetic with h of 1425 mg g−1 min−1 that could reduce Hg (II) from 10 to 1 ppm in 2 s and further to 2 ppb in ca. 30 min, and nearly 100% exclusive adsorption towards Hg (II). The mesopore volume within 15–50 nm as created is responsive to the diffusion coefficient k2 (k2 = 0.0215 V-0.000079); the outstanding capture is also essentially trigged by the unique affinity from N sites, thus highlighting CMMPA as an appealing platform for drinking-water purification that would significantly serve for practical environmental application.