Functionalized Conjugated Microporous Polymers

A robust triphenylamine-based monolithic polymer network for selective sieving of CO2 and PM from flue gas

The increasingly urgent issue of climate change is driving the development of carbon dioxide (CO2) capture and separation technologies in flue gas after combustion. The monolithic adsorbent stands out in practical adsorption applications for its simplified powder compaction process while maintaining the inherent balance between energy consumption for regeneration and selectivity for adsorption. However, optimizing the adsorption capacity and selectivity of CO2 separation materials remains a significant challenge. Herein, we synthesized monolithic polymer networks (N-CMPs) with triphenylamine adsorption sites, acid-base environment tolerance, and precise narrow microchannel pore systems for the selective sieving of CO2 and particulate matter (PM) in flue gas. The inherent continuous covalent bonding of N-CMPs, along with their highly delocalized π-π conjugated porous framework, ensures the stability of the monolithic polymer network's adsorption and separation capabilities under wet and acid-base conditions. Specifically, under the conditions of 1 bar at 273 K, the CO2 adsorption capacity of N-CMP-1 is 3.35 mmol/g. Attributed to the highly polar environment generated by triphenylamine and the inherent high micropore/mesopore ratio, N-CMPs exhibit an excellent ideal adsorbed solution theory (IAST) selectivity for CO2/N2 under simulated flue gas conditions (CO2/N2 = 15:85). Dynamic breakthrough experiments further visualize the high separation efficiency of N-CMPs in practical adsorption applications. Moreover, under acid-base conditions, N-CMPs achieve a capture efficiency exceeding 99.76 % for PM0.3, enabling the selective separation of CO2 and PM in flue gas. In fact, the combined capture of hazardous PM and CO2 from the exhaust gases produced by the combustion of fossil fuels will play a pivotal role in mitigating climate change and environmental issues until low-carbon and alternative energy technologies are widely adopted.

Conjugated microporous polymer for solid-phase extraction of neonicotinoid insecticides from environmental water samples

Conjugated microporous polymers (CMPs) have unique characteristics and have been used in a range of fascinating applications in separation sciences. In this study, a CMP, designated as CMP-1, was synthesized via the Sonogashira-Hagihara coupling reaction using 1,3,5-triphenylbenzene and 1,4-dibromobenzene as building blocks. CMP-1 features a large surface area, abundant micropore structures, and excellent stability, making it a promising solid-phase extraction adsorbent for the efficient enrichment of neonicotinoid insecticides (NEOs). Under the optimized conditions, CMP-1 was combined with high-performance liquid chromatography and diode array detection to enable the detection of NEOs with a wide linear range (0.5-200 μg·L-1), a low detection limit (0.26-0.58 μg·L-1), and acceptable precision. The developed method was applied to determine spiked NEOs in three types of environmental water samples, with recoveries of 73.7%-112.0% and relative standard deviations of 0.6%-9.4%.

Facile Synthesis of Organically Synthesized Porous Carbon Using a Commercially Available Route with Exceptional Electrochemical Performance

Organically synthesized porous carbon (OSPC) is a subclass of conjugated microporous polymer materials that have shown potential applications as anodes in ion batteries. However, a challenging, low-yielding, multistep synthetic route (the A method) has hindered further exploration of this exciting family. Here, OSPC-1 has been synthesized via an alternative, efficient one-pot method from commercially available reagents (the B method), hereafter referred to as OSPC-1b in contrast to OSPC-1a, where it is synthesized via the A method. Characterization revealed the same polymer structure and the highest surface area to date of an OSPC (or OSPC analogue) family member for OSPC-1b with 909 m2 g-1. OSPC-1b was tested as an anode for Li-ion batteries, demonstrating the same high capacity, fast charging, resistance to degradation, and inhibition of the formation of dangerous lithium dendrites as OSPC-1a. Furthermore, the electrochemical properties of OSPC-0 were evaluated for the first time, agreeing with previously predicted values, giving scope for the design and targeting of specific properties.

Role of Nitrogenous Functional Group Identity in Accelerating 1,2,3-Trichloropropane Degradation by Pyrogenic Carbonaceous Matter (PCM) and Sulfide Using PCM-like Polymers

Groundwater contamination by 1,2,3-trichloropropane (TCP) poses a unique challenge due to its human toxicity and recalcitrance to degradation. Previous work suggests that nitrogenous functional groups of pyrogenic carbonaceous matter (PCM), such as biochar, are important in accelerating contaminant dechlorination by sulfide. However, the reaction mechanism is unclear due, in part, to PCM's structural complexity. Herein, PCM-like polymers (PLPs) with controlled placement of nitrogenous functional groups [i.e., quaternary ammonium (QA), pyridine, and pyridinium cations (py+)] were employed as model systems to investigate PCM-enhanced TCP degradation by sulfide. Our results suggest that both PLP-QA and PLP-py+ were highly effective in facilitating TCP dechlorination by sulfide with half-lives of 16.91 ± 1.17 and 0.98 ± 0.15 days, respectively, and the reactivity increased with surface nitrogenous group density. A two-step process was proposed for TCP dechlorination, which is initiated by reductive ß-elimination, followed by nucleophilic substitution by surface-bound sulfur nucleophiles. The TCP degradation kinetics were not significantly affected by cocontaminants (i.e., 1,1,1-trichloroethane or trichloroethylene), but were slowed by natural organic matter. Our results show that PLPs containing certain nitrogen functional groups can facilitate the rapid and complete degradation of TCP by sulfide, suggesting that similarly functionalized PCM might form the basis for a novel process for the remediation of TCP-contaminated groundwater.

Ultra-stable hollow nanotube conjugated microporous polymer incorporating fluorenyl moieties for Co-capture of PM and CO2

Conjugated microporous polymers have a highly delocalized π-π conjugated porous skeleton connected by covalent bonds, which can combine their excellent stability with high adsorption, in order to be applied to the study of co-capture of harmful particulate matter (PM) and carbon dioxide (CO2) under high temperature and high humidity conditions. In this paper, fluorene-based coupled conjugated microporous polymers (D-CMPs) with functionalized hollow nanotubes and abundant microporous structures were proposed. Through mechanism exploration and molecular electrostatic potential (MESP) calculation, the capture efficiency, adsorption capacity and selectivity of PM and CO2 in the waste gas stream of carbon-based combustion were analyzed. The results indicate that D-CMPs, with their rigid carbon-based π-conjugated framework, exhibit excellent tolerance under prolonged high-humidity conditions, with a capture efficiency exceeding 99.87% for PM0.3 and exceeding 99.99% for PM2.5. Meanwhile, based on its chemical/thermal stability, it can realize the recycling of adsorption-regeneration. On this basis, the "slip effect" induced by the open three-dimensional hierarchical porous structure of D-CMPs significantly enhances airflow dispersion and improves gas throughput (with a minimal permeation resistance of only 15 Pa). At a pressure of 1 bar and a temperature of 273.15 K, D-CMP-2 exhibited a CO2 adsorption capacity of up to 2.69 mmol g-1. The fitting results of three isothermal adsorption models demonstrate that D-CMPs exhibit an outstanding equilibrium selectivity towards CO2. Therefore, prior to the widespread adoption of low-carbon and clean energy technologies, porous solid materials exhibiting excellent structural stability, equilibrium selectivity, environmental tolerance, and high adsorption capacity emerge as optimal candidates for the treatment of industrial waste gases.

Porous organic polymers (POPs) for environmental remediation

Modern global industrialization along with the ever-increasing growth of the population has resulted in continuous enhancement in the discharge and accumulation of various toxic and hazardous chemicals in the environment. These harmful pollutants, including toxic gases, inorganic heavy metal ions, anthropogenic waste, persistent organic pollutants, toxic dyes, pharmaceuticals, volatile organic compounds, etc., are destroying the ecological balance of the environment. Therefore, systematic monitoring and effective remediation of these toxic pollutants either by adsorptive removal or by catalytic degradation are of great significance. From this viewpoint, porous organic polymers (POPs), being two- or three-dimensional polymeric materials, constructed from small organic molecules connected with rigid covalent bonds have come forth as a promising platform toward various leading applications, especially for efficient environmental remediation. Their unique chemical and structural features including high stability, tunable pore functionalization, and large surface area have boosted the transformation of POPs into various macro-physical forms such as thick and thin-film membranes, which led to a new direction in advanced level pollutant removal, separation and catalytic degradation. In this review, our focus is to highlight the recent progress and achievements in the strategic design, synthesis, architectural-engineering and applications of POPs and their composite materials toward environmental remediation. Several strategies to improve the adsorption efficiency and catalytic degradation performance along with the in-depth interaction mechanism of POP-based materials have been systematically summarized. In addition, evolution of POPs from regular powder form application to rapid and more efficient size and chemo-selective, "real-time" applicable membrane-based application has been further highlighted. Finally, we put forward our perspective on the challenges and opportunities of these materials toward real-world implementation and future prospects in next generation remediation technology.

Synergistic Regulation of Pt Clusters on Porous Support by Mo and P for Robust Bifunctional Hydrogen Electrocatalysis

Developing efficient electrocatalysts toward hydrogen oxidation and evolution reactions (HER/HOR) in alkaline electrolytes is essential for realizing renewable hydrogen technologies. Herein, we demonstrate that the introduction of dual-active species such as Mo and P (Pt/Mo,P@NC) can effectively regulate the surface electronic structure of platinum (Pt) and significantly improve the HOR/HER performance. The optimized Pt/Mo,P@NC exhibits remarkable catalytic activity, achieving a normalized exchange current density of 2.89 mA cm^-2 and a mass activity of 2.3 mA μg_Pt^-1, which are approximately 2.2 and 13.5 times higher than those of the state-of-the-art Pt/C catalyst, respectively. Moreover, it performs an impressive HER performance with an overpotential of 23.4 mV at 10 mA cm^-2, which is lower than most documented alkaline electrocatalysts. Experimental results reveal that the modifying effect of Mo and P optimizes the adsorption of H and OH on Pt/Mo,P@NC, resulting in an outstanding catalytic performance. This work has significant theoretical and practical significance for developing a novel and highly efficient catalyst for bifunctional hydrogen electrocatalysis.

Polarity and functionality tailored conjugated microporous polymer coatings on silica microspheres for enhanced pollutant adsorption

Many sources of pollution that are generated by modern society are not addressable by conventional methods. Especially organic compounds, like pharmaceutics, are particularly hard to remove from waterbodies. Herein, a new approach is presented using conjugated microporous polymers (CMPs) to coat silica microparticles yielding specifically tailored adsorbents. The CMPs are generated with three different monomers: 2,6-dibromonaphthalene (DBN), 2,5-dibromoaniline (DBA) and 2,5-dibromopyridine (DBPN) respectively coupled to 1,3,5-triethynylbenzene (TEB) via Sonogashira coupling. By optimizing the polarity of the silica surface, all three CMPs were converted into microparticle coatings. The resulting hybrid materials feature the advantages of being adjustable in polarity and functionality, as well as morphology. Sedimentation allows facile removal of the coated microparticles after the adsorption. Further, the expansion of the CMP to a thin coating increases the accessible surface area compared to the bulk material. These effects were demonstrated by the adsorption of the model drug diclofenac. Thereby, the aniline-based CMP proved to be most advantageous due to a secondary crosslinking mechanism of amino and alkyne functionalities. An outstanding adsorption capacity of 228 mg diclofenac per gram of the aniline CMP within the hybrid material was achieved. This represents a five-fold increase compared to the value obtained by the pure CMP material underlining the advantages of the hybrid material.

Combining Polymerization and Templating toward Hyper-Cross-Linked Poly(propargyl aldehyde)s and Poly(propargyl alcohol)s for Reversible H2O and CO2 Capture and Construction of Porous Chiral Networks

Two series of hyper-cross-linked microporous polyacetylene networks containing either -[CH=C(CH=O)]- or -[CH=C(CH₂OH)]- monomeric units are reported. Networks are prepared by chain-growth copolymerization of acetal-protected propargyl aldehyde and acetal-protected propargyl alcohol with a 1,3,5-triethynylbenzene cross-linker followed by hydrolytic deprotection/detemplating. Deprotection not only liberates reactive CH=O and CH₂OH groups in the networks but also modifies the texture of the networks towards higher microporosity and higher specific surface area. The final networks with CH=O and CH₂OH groups attached directly to the polyene main chains of the networks have a specific surface area from 400 to 800 m²/g and contain functional groups in a high amount, up to 9.6 mmol/g. The CH=O and CH₂OH groups in the networks serve as active centres for the reversible capture of CO₂ and water vapour. The water vapour capture capacities of the networks (up to 445 mg/g at 297 K) are among the highest values reported for porous polymers, making these materials promising for cyclic water harvesting from the air. Covalent modification of the networks with (R)-(+)-3-aminopyrrolidine and (S)-(+)-2-methylbutyric acid enables the preparation of porous chiral networks and shows networks with CH=O and CH₂OH groups as reactive supports suitable for the anchoring of various functional molecules.

Highly crystalline and water-wettable benzobisthiazole-based covalent organic frameworks for enhanced photocatalytic hydrogen production

Two-dimensional covalent organic frameworks are promising for photocatalysis by virtue of their structural and functional diversity, but generally suffer from low activities relative to their inorganic competitors. To fulfill their full potential requires a rational tailoring of their structures at different scales as well as their surface properties. Herein, we demonstrate benzobisthiazole-based covalent organic frameworks as a superior photocatalyst for hydrogen production. The product features high crystallinity with ordered 2.5-nm-wide cylindrical mesopores and great water wettability. These structural advantages afford our polymeric photocatalyst with fast charge carrier dynamics as evidenced by a range of spectroscopic characterizations and excellent catalytic performances when suspended in solution or supported on melamine foams. Under visible-light irradiation, it enables efficient and stable hydrogen evolution with a production rate of 487 μmol h^-1 (or a mass-specific rate of 48.7 mmol g^-1 h^-1)-far superior to the previous state of the art. We also demonstrate that hydrogen production can be stoichiometrically coupled with the oxidation conversion of biomass as exemplified by the conversion of furfuryl alcohol to 2-furaldehyde.

Surface-catalyzed hydrolysis by pyrogenic carbonaceous matter and model polymers: An experimental and computational study on functional group and pore characteristics

We employed a polymer network to understand what properties of pyrogenic carbonaceous matter (PCM; e.g., activated carbon) confer its reactivity, which we hereinafter referred to as PCM-like polymers (PLP). This approach allows us to delineate the role of functional groups and micropore characteristics using 2,4,6-trinitrotoluene (TNT) as a model contaminant. Six PLP were synthesized via cross-coupling chemistry with specific functionality (-OH, -NH2, -N(CH3)2, or -N ( CH 3 ) 3 + ) and pore characteristics (mesopore, micropore). Results suggest that PCM functionality catalyzed the reaction by: (1) serving as a weak base (-OH, -NH2) to attack TNT, or (2) accumulating OH- near PCM surfaces (-N ( CH 3 ) 3 + ). Additionally, TNT hydrolysis rates, pH and co-ion effects, and products were monitored. Microporous PLP accelerated TNT decay compared to its mesoporous counterpart, as further supported by molecular dynamics modeling results. We also demonstrated that quaternary ammonium-modified activated carbon enhanced TNT hydrolysis. These findings have broad implications for pollutant abatement and catalyst design.

Engineering Polymeric Nanofluidic Membranes for Efficient Ionic Transport: Biomimetic Design, Material Construction, and Advanced Functionalities

Design elements extracted from biological ion channels guide the engineering of artificial nanofluidic membranes for efficient ionic transport and spawn biomimetic devices with great potential in many cutting-edge areas. In this context, polymeric nanofluidic membranes can be especially attractive because of their inherent flexibility and benign processability, which facilitate massive fabrication and facile device integration for large-scale applications. Herein, the state-of-the-art achievements of polymeric nanofluidic membranes are systematically summarized. Theoretical fundamentals underlying both biological and synthetic ion channels are introduced. The advances of engineering polymeric nanofluidic membranes are then detailed from aspects of structural design, material construction, and chemical functionalization, emphasizing their broad chemical and reticular/topological variety as well as considerable property tunability. After that, this Review expands on examples of evolving these polymeric membranes into macroscopic devices and their potentials in addressing compelling issues in energy conversion and storage systems where efficient ion transport is highly desirable. Finally, a brief outlook on possible future developments in this field is provided.

In Situ Separator Modification with an N-Rich Conjugated Microporous Polymer for the Effective Suppression of Polysulfide Shuttle and Li Dendrite Growth

Lithium-sulfur (Li-S) batteries are very promising high-energy-density electrochemical energy storage devices, but suffer from serious Li polysulfide (LiPS) shuttle and uncontrollable Li dendrite growth. Here, we show in situ polyolefin separator modification with an N-rich conjugated microporous polymer (NCMP) for advanced Li-S battery. In situ polymerization generates an ultrathin NCMP coating on the whole external surface and the internal surface of the separator, which is substantially different from the conventional approaches with thick coatings only on the external surface. The NCMP coating with abundant N-containing groups (-NH₂ and -N═), uniform nanopores (12.294 Å), and π-conjugated structure can simultaneously inhibit LiPS shuttle and regulate uniform nucleation and growth of Li dendrites. Consequently, the NCMP-based separator endows the Li-S battery with significantly enhanced cycling stability at high S loading (5.4 mg cm^-2), lean electrolyte (E/S = 6.3 μL mg^-1), and limited Li excess (50 μm).

Hairy Conjugated Microporous Polymer Nanoparticles Facilitate Heterogeneous Photoredox Catalysis with Solvent-Specific Dispersibility

Substrate accessibility is a key limiting factor for the efficiency of heterogeneous photoredox catalysis. Recently, a high photoactive surface area of conjugated microporous polymer nanoparticles (CMP NPs) has made them promising candidates for overcoming the mass transfer limitation to achieve high photocatalytic efficiency. However, this potential has not been realized due to limited dispersibility of CMP NPs in many solvents, particularly in water. Here, we report a polymer grafting strategy that furnishes versatile hairy CMP NPs with enhanced solvent-specific dispersibility. The method associates hundreds of solvent-miscible repeating units with one chain end of the photocatalyst surface, allowing minimal modification to the CMP network that preserves its photocatalytic activity. Therefore, the enhanced dispersibility of hairy CMP NPs in organic solvents or aqueous solutions affords high efficiency in various photocatalytic organic transformations.

Processable Conjugated Microporous Polymer Gels and Monoliths: Fundamentals and Versatile Applications

Conjugated microporous polymers (CMPs) as a new type of conjugated polymers have attracted extensive attention in academia and industry because of the combination of microporous structure and π-electron conjugated structure. The construction and application of gels and monoliths based on CMPs constitute a fertile area of research, promising to provide solutions to complex environmental and energy issues. This review summarizes and objectively analyzes the latest advances in the construction and application of processable CMP gels and monoliths, linking the basic and enhanced properties to widespread applications. In this review, we open with a summary of the construction methods used to build CMP gels and monoliths and assess the feasibility of different preparation techniques and the advantages of the products. The CMP gels and monoliths with enhanced properties involving various special applications are then deliberated by highlighting relevant scientific literature and discussions. Finally, we present the issues and future of openness in the field, as well as come up with the major challenges hindering further development, to guide researchers in this field.

Turning Electronic Waste to Continuous-Flow Reactor Using Porous Aromatic Frameworks

Extraction of valuable metals such as gold from electronic wastes (e-waste) is regarded as a promising way of environmental remediation; however, this process is still confronted with the cost-ineffective product for normal usages like electronic devices or jewelry. Therefore, there would be merits in directly converting gold from e-waste to materials of higher value, for example, catalysts for pollutant treatment. Herein, a porous aromatic framework (PAF) with cationic sites, named iPAF-7, was synthesized and exhibited rapid extraction of gold from e-waste. Au@iPAF-7 completely converted nitroarenes to arylamines within 10 s at a rate constant of 7.8 × 10^-2 s^-1, which is much higher than that of any other gold nanoparticle (AuNP) catalysts with solid supports reported so far. Furthermore, considering the limitations and difficulties of operating powder materials, the aerogel monolith incorporating iPAF-7 was successfully fabricated, which retained the excellent gold extraction ability and catalytic activity of its powder form, thus exhibiting its potential application for continuous-flow catalysis of nitroarene reduction.

Design and preparation of functional azo linked polymers for the adsorptive removal of bisphenol A from water: Performance and analysis of the mechanism

In order to effectively remove refractory bisphenol A (BPA) from water, a novel nitrogen doped organic porous functional azo linked polymer (ALP-p) was designed and prepared according to the physicochemical characteristics of propane linked to two phenol hydroxyl groups. This ALP-p was synthesized with 98.5% yield, from pararosaniline and phloroglucinol, via the diazo coupling reaction to produce multiple adsorption functional groups of benzene ring, hydroxyl group and azo group. This functional material showed high adsorption capacity of 357.8 mg/g for 50 mg/L BPA, at 20 °C. The adsorption kinetics and isotherms were described by the pseudo-second-order and Langmuir model, respectively. The major adsorption mechanisms were attributed to the high specific surface area (259.8 m²/g) and pore volume (0.56 cm³/g) related surface adsorption and pore diffusion through porous stereoscopic stacking cavity anchorage. The functional group from the three-dimensional skeleton structures of ALP-p for BPA anchoring endowed chemisorption via π-π interaction between benzene rings and hydrogen-bonding (O-H⋯O, C-H⋯N, C-H⋯O and C-H⋯C) with the hydrogen atom of benzene ring, -OH from BPA and -OH, NN from ALP-p, respectively. The coexisting organic pollutants and alkali environment posed a negative effect on adsorption, while salinity had no significant effect on the process. The adsorption capacity and recovery of ALP-p were >93.5% and 81.6% after five cycles of operation.

Novel benzylphosphate-based covalent porous organic polymers for the effective capture of rare earth elements from aqueous solutions

It has been a major challenge to develop stable and cost-effective porous materials that efficiently recover heavy rare earth elements (HREEs) due to ever-increasing demand, low availability and high cost of HREEs. This study presents two novel benzylphosphate-based covalent porous organic polymers (BPOP-1 and BPOP-2) that were prepared by facile one-pot Friedel-Crafts reactions. Various analytical techniques are used to investigate the successful syntheses of BPOP materials and establish their material properties, which include an unusual crystalline nature, large surface area, hierarchical pore structure, and superior chemical stabilities. The BPOPs effectively adsorb, and thus remove HREEs from aqueous media. In particular, BPOP-1 had higher phosphate content and exhibits superior adsorption capacities (Eu³⁺: 289.5; Gd³⁺: 292.7; Tb³⁺: 294.4; Dy³⁺: 301.9 mg/g) than BPOP-2, while BPOP-2 had higher mesoporosity and correspondingly supports faster adsorption kinetics. Remarkably, both BPOP materials exhibit some of the highest HREE adsorption capacities reported to date, the selective capture of Dy³⁺ ions, and excellent cyclic adsorption/desorption properties. We provide a potential adsorption mechanism for Dy³⁺ capture by the BPOP adsorbent. These demonstrate that introducing phosphate functionality into a robust porous polymer backbone with high surface area is a promising strategy for selective HREEs capture from wastewater.

Pyrogenic carbon-promoted haloacetic acid decarboxylation to trihalomethanes in drinking water

Drinking water disinfection by chlorination or chloramination can result in the formation of disinfection byproducts (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs). Pyrogenic carbonaceous matter (PCM), such as activated carbon (AC), is commonly used as an ostensibly inert adsorbent to remove HAAs from water. HAA degradation has been mainly attributed to biological factors. This study, for the first time, revealed that abiotic HAA degradation in the presence of PCM could be important under water treatment conditions. Specifically, we observed complete destruction of Br3AA, a model HAA, in the presence of powder AC at pH 7 within 30 min. To understand the role of PCM and the reaction mechanism, we performed a systematic study using a suite of HAAs and various PCM types. We found that PCM significantly accelerated the transformation of three HAAs (Br3AA, BrCl2AA, Br2ClAA) at pH 7. Product characterization indicated an approximately 1:1 HAA molar transformation into their respective THMs following a decarboxylation pathway with PCM. The Br3AA activation energy (Ea) was measured by kinetic experiments at 15-45 °C with and without a model PCM, wherein a significant decrease in Ea from 25.7 ± 3.2 to 13.6 ± 2.2 kcal•mol-1 was observed. We further demonstrated that oxygenated functional groups on PCM (e.g., -COOH) can accelerate HAA decarboxylation using synthesized polymers to resemble PCM. Density functional theory simulations were performed to determine the enthalpy of activation (ΔH‡) for Br3AA decarboxylation with H3O+ and formic acid (HCOOH). The presence of HCOOH significantly lowered the overall ΔH‡ value for Br3AA decarboxylation, supporting the hypothesis that -COOH catalyzes the C-C bond breaking in Br3AA. Overall, our study demonstrated the importance of a previously overlooked abiotic reaction pathway, where HAAs can be quickly converted to THMs with PCM under water treatment relevant conditions. These findings have substantial implications for DBP mitigation in water quality control, particularly for potable water reuse or pre-chlorinated water that allow direct contact between HAAs and AC during filtration as well as PAC fines traveling with finished water in water distribution systems. As such, the volatilization and relative low toxicity of volatile THMs may be considered as a detoxification process to mitigate adverse DBP effects in drinking water, thereby lowering potential health risks to consumers.

Efficient capture of airborne PM by nanotubular conjugated microporous polymers based filters under harsh conditions

The exploitation of high-performance filters which can capture and remove airborne particulate matter (PM) in harsh conditions is greatly important to limit the serious effect of PM on human health. Herein, we demonstrate a simple approach for the creation of robust and hierarchically porous filters based on conjugated microporous polymers (CMPs) nanotubes for efficient PM capture. Taking advantage of their inherently superhydrophobic wettability, the CMPs-based filters possess high filtration efficiency of higher than 99.4% for PM_0.3 and 99.9% for PM_2.5 and PM₁₀, respectively, even in high humidity environment (RH ≥ 94%). The CMPs-based filters show highly physicochemical and thermal stability, e.g., by calcination at 500 °C for 2 h, the filtration efficiency of the samples still reaches as great as 99.4% for both PM_2.5 and PM₁₀ with a low-pressure drop of only 10 Pa. In addition, these CMPs-based filters can be easily regenerated and their high PM filtration efficiency remains nearly unchanged by a simple methanol washing. More interestingly, the CMPs-based filters also exhibit superior antibacterial performance, which enables them to sterilize or eliminate the bacteria possibly loaded on PM pollutions, thus showing great potential for various applications such as PM removal, air purification and so on.

Bifunctional conjugated microporous polymer based filters for highly efficient PM and gaseous iodine capture

Cross-linked conjugated microporous polymers (CMPs) based air filters obtained by a one-step cross-coupling reaction for effective capture of particulate matter and gaseous iodine from dusty air.

A sulfur-containing fluorescent hybrid porous polymer for selective detection and adsorption of Hg2+ ions

A dual-function material, that is, a sulfur-containing fluorescent hybrid porous polymer, has been simply prepared and utilized to simultaneously detect and capture Hg2+ with high efficiency and selectivity.

Potential applications of porous organic polymers as adsorbent for the adsorption of volatile organic compounds

Volatile organic compounds (VOCs) with high toxicity and carcinogenicity are emitted from kinds of industries, which endanger human health and the environment. Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency. In recent years, activated carbons, zeolites, and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity. However, the hydrophilic nature and low desorption rate of those materials limit their commercial application. Furthermore, the adsorption capacities of VOCs still need to be improved. Porous organic polymers (POPs) with extremely high porosity, structural diversity, and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption. This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs. Moreover, the mechanism of competitive adsorption between water and VOCs on the POPs was discussed. Finally, a concise outlook for utilizing POPs for VOCs adsorption was discussed, noting areas in which further work is needed to develop the next-generation POPs for practical applications.

Covalent Triazine Frameworks Based on the First Pseudo-Octahedral Hexanitrile Monomer via Nitrile Trimerization: Synthesis, Porosity, and CO2 Gas Sorption Properties

Herein, we report the first synthesis of covalent triazine-based frameworks (CTFs) based on a hexanitrile monomer, namely the novel pseudo-octahedral hexanitrile 1,4-bis(tris(4'-cyano-phenyl)methyl)benzene 1 using both ionothermal reaction conditions with ZnCl2 at 400 °C and the milder reaction conditions with the strong Brønsted acid trifluoromethanesulfonic acid (TFMS) at room temperature. Additionally, the hexanitrile was combined with different di-, tri-, and tetranitriles as a second linker based on recent work of mixed-linker CTFs, which showed enhanced carbon dioxide captures. The obtained framework structures were characterized via infrared (IR) spectroscopy, elemental analysis, scanning electron microscopy (SEM), and gas sorption measurements. Nitrogen adsorption measurements were performed at 77 K to determine the Brunauer-Emmett-Teller (BET) surface areas range from 493 m2/g to 1728 m2/g (p/p0 = 0.01-0.05). As expected, the framework CTF-hex6 synthesized from 1 with ZnCl2 possesses the highest surface area for nitrogen adsorption. On the other hand, the mixed framework structure CTF-hex4 formed from the hexanitrile 1 and 1,3,5 tricyanobenzene (4) shows the highest uptake of carbon dioxide and methane of 76.4 cm3/g and 26.6 cm3/g, respectively, at 273 K.

Microporous Hyper-Cross-Linked Polymers with High and Tuneable Content of Pyridine Units: Synthesis and Application for Reversible Sorption of Water and Carbon Dioxide

New hyper-cross-linked porous organic polymers (POPs) with a high content of pyridine segments (7.86 mmol pyridine g^-1 ), and a micro/mesoporous texture are reported. The networks are achieved by the chain-growth homopolymerization of 2,6- and 3,5-diethynylpyridines. The pyridine segments form links interconnecting the polyacetylene main chains in these networks. The content of pyridine segments in the networks can be tuned by copolymerizing diethynylpyridines with 1,3-diethynylbenzene. The pyridine rings in the networks serve as base and hydrophilic centers for the sorption of CO₂ and water. The homopolymer pyridine networks are highly efficient in the low-pressure adsorption/desorption of CO₂ . This sorption mode is promising for the postcombustion removal of CO₂ from the fuel gas. The poly(3,5-diethynylpyridine) network exhibits high efficiency in capturing and releasing water vapor (determined capacity 376 mg g^-1 at 298 K and relative humidity (RH) = 90% is one of the highest values reported for POPs) and is a promising material for the cyclic water harvesting from air. The reported networks are characterized by ¹³ C cross-polarization magic angle spinning NMR, thermogravimetric analysis, and N₂ adsorption/desorption and their efficiency in CO₂ and H₂ O capturing is discussed in relation to the content and type of incorporated pyridine segments.

Organic molecular sieve membranes for chemical separations

Molecular separations that enable selective transport of target molecules from gas and liquid molecular mixtures, such as CO2 capture, olefin/paraffin separations, and organic solvent nanofiltration, represent the most energy sensitive and significant demands. Membranes are favored for molecular separations owing to the advantages of energy efficiency, simplicity, scalability, and small environmental footprint. A number of emerging microporous organic materials have displayed great potential as building blocks of molecular separation membranes, which not only integrate the rigid, engineered pore structures and desirable stability of inorganic molecular sieve membranes, but also exhibit a high degree of freedom to create chemically rich combinations/sequences. To gain a deep insight into the intrinsic connections and characteristics of these microporous organic material-based membranes, in this review, for the first time, we propose the concept of organic molecular sieve membranes (OMSMs) with a focus on the precise construction of membrane structures and efficient intensification of membrane processes. The platform chemistries, designing principles, and assembly methods for the precise construction of OMSMs are elaborated. Conventional mass transport mechanisms are analyzed based on the interactions between OMSMs and penetrate(s). Particularly, the 'STEM' guidelines of OMSMs are highlighted to guide the precise construction of OMSM structures and efficient intensification of OMSM processes. Emerging mass transport mechanisms are elucidated inspired by the phenomena and principles of the mass transport processes in the biological realm. The representative applications of OMSMs in gas and liquid molecular mixture separations are highlighted. The major challenges and brief perspectives for the fundamental science and practical applications of OMSMs are tentatively identified.

Preparation and dye adsorption properties of an oxygen-rich porous organic polymer

Porous organic polymers (POPs), allowing fine synthetic control over their chemical structures, have shown great promise for addressing environmental issues. The high specific surface area and abundant porous structures of POPs can provide large storage space to adsorb dye molecules. Meanwhile, the introduction of polar groups, such as oxygen-containing functional groups in POPs, can not only improve the hydrophilicity, but also provide a strong interaction with dye molecules, thereby improving their adsorption performance. In this paper, an oxygen-rich porous polymer, POP-O, containing polar carbonyl and hydroxyl groups, was prepared by Sonogashira-Hagihara cross-coupling polycondensation. The characteristic results show that POP-O exhibits a hierarchical pore structure with a high specific surface area of 619 m² g^-1. The combination of abundant polar functional groups and high porosity endows POP-O with decent dye adsorption performance, and its theoretical maximum adsorption capacity for Rhodamine B (Rh B) is calculated to be 1012 mg g^-1.

Self-cleaning and flexible filters based on aminopyridine conjugated microporous polymers nanotubes for bacteria sterilization and efficient PM2.5 capture

The capture and elimination of harmful particulate matter (PM) both in air and water is of great importance for human health and environmental sustainability. Here, we demonstrate a novel strategy for the exploitation of conjugated microporous polymer bearing aminopyridine moiety (A-CMPs) as an advanced filter for bacteria sterilization and efficient PM capture. The A-CMPs network shows a hierarchically porous structure with mechanical robustness and flexibility, which facilitates to filtration especially for PM with different particle sizes. The capture efficiency of A-CMPs aerogels for PM_2.5 and PM₁₀ were respectively up to PM_2.5 ≥ 99.57 ± 0.19% and PM₁₀ ≥ 99.98 ± 0.01% in a long-term durability test and easy to be regenerated. Moreover, the A-CMPAs features excellent superhydrophobicity, which is difficult to saturate with water aerosols in humid air (RH: 89 ± 3%) and in turn shows superior stability and high-performance in terms to capture efficiency. More importantly, the A-CMP monolith exhibits excellent antimicrobial activity and high concentrations of bacterial suspension (e.g., using E. coli as probe bacterial) could be effectively captured and quickly killed during filtration, which endows the A-CMPs additional sterilization performance and thus is of great technological significance with remarkable potentials as a new kind of advanced filter for multifunctional filtration in both air and water.

Facile preparation of composite flame retardantbased on conjugated microporous polymer hollow spheres

The development of functional materials with better flame-retardant and thermal insulation properties has attracted considerable attention for energy storage applications in modern society. Here, we describe a facile approach for the preparation of conjugated microporous polymer hollow spheres (CMP-HSs) by using SiO₂ nanoparticles as a template via the Sonogashira-Hagihara cross-coupling reaction. The as-synthesized CMP-HSs have good thermal stability with a thermal decomposition temperature of up to 281 °C, high porosity (the BET specific surface area is measured to be approximately 666 m² g^-1) along with lipophilic and hydrophobic characteristics. To further improve their flame retardancy, CMP-HSs were treated with dimethyl phosphonate (DMMP) though an immersion method to prepare the CMP-HSs composite (CMP-HSs-DMMP) flame-retardants. By introducing CMP-HSs-DMMP into the epoxy resin (EP) matrix, the as-prepared EP composites showed excellent flame-retardant properties, e.g., the peak heat release rate (pHRR) and total heat release (THR) value of EP composites containing only 0.2% CMP-HSs-DMMP flame-retardant were 650.9 kW m^-2 and 79.4 MJ m^-2 respectively, in the range of 0 °C - 650 °C, which are 19.6 ± 2% and 19.1 ± 5% lower than that of pure EP within the same temperature range. Considering the significant enhancement of its flame retardancy with only a slight dosage of CMP-HSs-DMMP, such CMP hollow sphere-based flame-retardant composites may have great potential as functional bulk materials or coatings in a variety of fireproofing applications.

Synthesis methods of microporous organic polymeric adsorbents: a review

MOPs can be synthesized in a large variety of ways, which affect their pores and surface area. Variation in synthesis and porosity has a significant effect on their adsorption properties.

Superhydrophobic conjugated microporous polymers grafted silica microspheres for liquid chromatographic separation

Vigorously developing new high performance liquid chromatography (HPLC) stationary phases to meet the versatile separation requirements is still an important issue in the field of analytical chemistry. Conjugated microporous polymers (CMPs) are a new type of three-dimensional network porous material with high specific surface area, good chemical stability and superhydrophobicity. Herein, we firstly report the synthesis and applications of CMPs@SiO₂ material for HPLC stationary phase. The CMPs@SiO₂ material can be in situ fabricated via Sonogashira coupling of 1,3,5-triethynylbenzene and 1,4-diiodobenzene on the surface of spherical silica. The morphology and physicochemical properties of the synthesized stationary phase material were investigated by a series of characterization methods. Due to the superhydrophobic nature of the CMPs@SiO₂ material, the packed CMPs@SiO₂ HPLC column displays ultrastrong chromatographic retention and can be used for separation of both hydrophobic and hydrophilic compounds with good selectivity. Significantly, CMPs@SiO₂ column can be performed for separation with pure acetonitrile as the eluent. Thus, the new column was successfully exploited for monitor and analysis of the hydrolysis of silane coupling agents. Furthermore, based on its oleophilicity, this report firstly utilized the CMPs@SiO₂ material to identify and analyze the quality of cooking oils through one-step enrichment and subsequent HPLC separation. We will further exploit to fabricate versatile CMPs-based stationary phases, highlighting their potential applications in different separation scopes.

Artificial Synthesis of Conjugated Microporous Polymers via Sonogashira-Hagihara Coupling

Amorphous network materials are becoming increasingly important with applications, for example, as supercapacitors, battery anodes, and proton conduction membranes. The design of these materials is hampered by the amorphous nature of the structure and sensitivity to synthetic conditions. Here, we show that through artificial synthesis, fully mimicking the catalytic formation cycle, and full synthetic conditions, we can generate structural models that can fully describe the physical properties of these amorphous network materials. This opens up pathways for the rational design where complex structural influences, such as the solvent and catalyst choice, can be taken into account.

Advances in Conjugated Microporous Polymers

Conjugated microporous polymers (CMPs) are a unique class of materials that combine extended π-conjugation with a permanently microporous skeleton. Since their discovery in 2007, CMPs have become established as an important subclass of porous materials. A wide range of synthetic building blocks and network-forming reactions offers an enormous variety of CMPs with different properties and structures. This has allowed CMPs to be developed for gas adsorption and separations, chemical adsorption and encapsulation, heterogeneous catalysis, photoredox catalysis, light emittance, sensing, energy storage, biological applications, and solar fuels production. Here we review the progress of CMP research since its beginnings and offer an outlook for where these materials might be headed in the future. We also compare the prospect for CMPs against the growing range of conjugated crystalline covalent organic frameworks (COFs).

Skeleton Engineering of Homocoupled Conjugated Microporous Polymers for Highly Efficient Uranium Capture via Synergistic Coordination

Developing efficient adsorbents for uranium enrichment is of great significance for resource sustainability and environmental safety. This study presents a facile and adaptable post-synthetic strategy to prepare highly efficient uranium adsorbents via engineering the π-conjugated skeletons of homocoupled conjugated microporous polymers (HCMPs). Taking advantage of the diyne units in the π-conjugated skeletons, bis-amidoxime uranophiles, one of the state-of-the-art ligands of uranyl ions, were introduced to the frameworks of HCMPs. The functionalized HCMPs preserved the interconnected 3D microporous networks and rigid conjugated skeletons with abundant bis-amidoxime ligands uniformly distributed in the pore channels. Such structural advantages of the adsorbents afforded very fast adsorption kinetics within 15 min to reach the equilibrium and high capacity of uranium (450 mg/g). Moreover, DFT calculation suggests a synergistic coordination as the most energetically favored coordination mode of the uranyl/bis-amidoxime complexes. This study contributes new insights into the underlying mechanism responsible for the highly efficient adsorption ability of the bis-amidoxime-functionalized HCMPs toward uranium. Meanwhile, the synthetic methodology established here could be extended to task-specific design and skeleton engineering of more functional HCMPs for broadened applications.

Conjugated porous polymers: incredibly versatile materials with far-reaching applications

This review discusses conjugated porous polymers and focuses on relating design principles and synthetic methods to key properties and applications such as (photo)catalysis, gas storage, chemical sensing, energy storage and environmental remediation.

Facile synthesis of tetraphenylethene-based conjugated microporous polymers as adsorbents for CO2 and organic vapor uptake

We present three novel conjugated microporous polymers (CMP@1–3), which were formed by an imidization reaction between tetra-(4-aminophenyl)ethylene and anhydrides.

A porous fluorinated organic [4+4] imine cage showing CO2 and H2 adsorption

We report the first POC, containing perfluorinated aromatic panels forming quickly and in high purity, despite low preorganization encoded in the starting materials.