The use of conjugated microporous polymers (CMPs) in practical wastewater treatment demands further design on the pore structure, otherwise their adsorption capacities toward heavy-metal ions were moderate. Here, we report a rational design approach, which produces hybrid molecular pores in conjugated microporous poly(aniline)s (CMPAs) for mercury removal. It is achieved through a delicate interval introduction of linkers with differential molecular lengths during polymerization, acquiring both diffusion channels and storage pores for radical enhancement of mass transfer and adsorption storage. The resulting CMPA-M featured a large adsorption capacity of 975 mg g-1 and rapid kinetics that could remove 94.8% of 50 mg g-1 of mercury(II) within a very short contact time of 48 s, with a promising initial adsorption rate h as high as 113 mg g-1 min-1, which was 2.54-fold larger in the adsorption capacity and 45.2-fold faster in the adsorption efficiency compared with the undeveloped CMPAs. More importantly, our CMPA-M-2, with robust stability and easy reusability, was able to scavenge over 99.9% of mercury(II) from the actual wastewater in a harsh condition with a very low pH of 0.77, extremely high salinity of 53,157 mg L-1, and complex impurities, featuring exceptional selectivity that allows us to extract and recycle a high purity of 99.1% of mercury from the wastewater. These outcomes demonstrate the unprecedented potential of CMPs for environmental remediation and real-world mercury extraction and present benchmarks for CMP-based mercury adsorbents.
Keywords: conjugated microporous poly(aniline)s; efficient adsorption; mercury removal; pore design; selectivity.