Ketone-based conjugated microporous poly(aniline)s for the ultradeep separation of heavy metal ions

Abstract

The heavy-metal contamination of aquatic environments presents imminent threat. Herein, we report a class of dual-heteroatomic conjugated microporous poly(aniline)s showing high-affinity separation performance toward heavy metals. The prepared keto-CMPA shows monolayer adsorption capacity for Hg (II) as high as 980 mg g⁻¹ according to the Langmuir model, and ultra-rapid kinetic with h reaching 30.41 mg g⁻¹ that could be described by the pseudo-second-order model. It maintains excellent stability across six reuses under harsh conditions, and furthermore demonstrates ultradeep separation efficiency that could adsorb almost all of heavy metals to ppb level with low usage. For further industrialization, a competent adsorption device was developed to remove heavy metals down to 1 ppb with a remarkable breakthrough over 20,000 BV. Characterizations and DFT calculation showed that the triangular synergistic region formed by the N-O-sites in the singular CMPA structure provided a feasible binding energy to enable the above impressive performance.