Highly Efficient and Selective Removal of Lead Ions from Aqueous Solutions by Conjugated Microporous Polymers with Functionalized Heterogeneous Pores

Abstract

The development of viable absorbents for highly efficient and selective removal of lead (Pb) ions, which might exist in various waste discharges related to human activities, is considered a long-standing challenge. Current scientific interests reside in achieving material absorbents with high porosity and desired functionality that respectively relate to generally higher Pb­(II) uptake and selectivity. In this work, two-dimensional conjugated microporous polymers (CMP-2 and CMP-3) were rationally designed in which the heterogeneous (large and narrow) pores of these materials were chemically functionalized with cyano and pyridyl groups, respectively. As expected, the activated CMP-2a and CMP-3a displayed a high Pb­(II) adsorption capacity of 62.7 and 93.2 mg g–1, respectively. Of note is that the CMP-3a could selectively uptake Pb­(II) (84%) over Cu­(II) (40%) and Ni­(II) (18.6%) in simulated wastewater. It was demonstrated that the formation of functionalized and heterogeneous pore structures in CMP-3a accounted for its highly efficient and selective adsorption property toward Pb2+. In addition, CMP-2a and CMP-3a could be easily recovered and regenerated for Pb2+ removal from aqueous solutions and exhibited nondetectable cytotoxicity, which were favorable for their applications as viable and safe absorbents for Pb­(II) removal in aqueous phases.

Porosity Design on Conjugated Microporous Poly(Aniline)S for Exceptional Mercury(II) Removal

“…To meet formidable requirements from the mercury removal of real industrial wastewater and to overcome the drawbacks of the recent pore structure for mercury adsorption in the CMPs, we, for the first time, proposed a rational design approach for CMP synthesis through the interval introduction of various linkers with differential molecular lengths for polymerization to attend both diffusion channel and storage space for mercury (as described in Scheme ), while Buchwald–Hartwig (BH) coupling chemistry was exploited to couple these building blocks for the construction of novel C–N bonds and poly­(aniline) (PANi) units in the three-dimensional (3D) conjugated frameworks. The newly produced CMPs [or more detailed, conjugated microporous poly­(aniline)-mix (CMPA-M)] inherit the rich adsorption sites for the mercury-ion storage and densely populated N binding sites that would trigger the selective adsorption of mercury and newly acquire novel diffusion channels that enable faster and more efficient kinetics for mercury adsorption compared to their ancestors. , The design strategy we proposed herein could not only well address the current challenges in the mercury removal of CMPs, producing adsorbents with new benchmarks in the adsorption capacity, efficiency, and selectivity but also, more importantly, could be extended to produce other high-quality CMP materials that would impact on environmental science and technology.…”

“…The newly produced CMPs [or more detailed, conjugated microporous poly(aniline)-mix (CMPA-M)] inherit the rich adsorption sites for the mercury-ion storage and densely populated N binding sites that would trigger the selective adsorption of mercury and newly acquire novel diffusion channels that enable faster and more efficient kinetics for mercury adsorption compared to their ancestors. 25,26 The design strategy we proposed herein could not only well address the current challenges in the mercury removal of CMPs, producing adsorbents with new benchmarks in the adsorption capacity, efficiency, and selectivity but also, more importantly, could be extended to produce other highquality CMP materials that would impact on environmental science and technology.…”

Synthesis of functional conjugated microporous polymer/TiO2 nanocomposites and the mechanism of the photocatalytic degradation of organic pollutants

“…However, obtaining sufficient visible light absorption and large-scale production of highly stable TiO 2 -based composite materials is still challenging. To solve the above problems, we have set our sights on conjugated microporous polymers (CMPs) [25][26][27][28][29][30]. CMPs are considered as a valuable material in a variety of organic porous polymers, which were first synthesized by the Cooper's group in 2007.…”

Structure–Activity Relationship of Lanthanide-Incorporated Nano-Hydroxyapatite for the Adsorption of Fluoride and Lead

“…Toxic elements even with low concentrations in drinking water can be considered as silent killers for both terrestrial and aquatic organisms. Their sources vary, and these can be simple leaching from minerals or due to anthropogenic activities . Of these elements, lead is of major concern as water can get exposed to it frequently. − On the other hand, nonmetals like fluoride have also been the topic in many issues as it is being identified in connection to chronic kidney disease of unknown etiology (CKDu), dental fluorosis, arthritis, and brittle bone disease …”