Novel Carbazole-Based Porous Organic Polymer for Efficient Iodine Capture and Rhodamine B Adsorption

84-Nuclearity Lanthanide-Aluminum Cyclic Clusters: Promising Materials for Iodine Capture and Storage

Developing high-performance adsorbents for iodine uptake and storage has become an urgent priority for safe disposal and long-term storage of nuclear waste. In this work, two cyclic lanthanide-aluminum clusters with the formula [Ln12Al72(hmp)60(C2H5O2)6(μ2-OH)120(μ3-OH)18(H2O)30]Cl24·(NO3)24·(H2O)x (Ln = Tb, x ≈ 80, Tb12Al72; Ln = Gd, x ≈ 100, Gd12Al72; Hhmp = 2-(hydroxymethyl)pyridine and C2H6O2 = ethylene glycol) are reported. Single-crystal analysis reveals that its inner diameter is approximately 1.1 nm, with an outer diameter of 4.1 nm and a thickness of 3.1 nm. The packing of cyclic clusters through intermolecular interactions generates a 3D supramolecular structure with one-dimensional channels. Investigation of the iodine adsorption performance of the cluster indicates an uptake capacity of 3.14 g g-1 for Tb12Al72 and 3.1 g g-1 for Gd12Al72. The effectiveness of iodine adsorption is largely due to the accessible micropore structure along with the high density of pyridine rings and abundant hydroxyl oxygen atoms. Consistently, DFT calculations indicate that the [Al(μ-OH)n] clusters and pyridine ring regions synergistically facilitate iodine adsorption, effectively promoting the dissociation of I2 into I- anions. This unique micropore environment enhances the electrostatic stabilization of polyiodide anions through a strong Coulombic attraction, significantly boosting the capture of iodine.

Fabricating Tetraphenylethylene-Based Ionic Porous Organic Polymers for Efficient Sequestration of Toxic Iodine and Oxoanions in Multiple Media

Water pollution, driven by rapid industrialization, has become a global issue, threatening human health and ecosystems. The contamination of water sources with radioactive waste, heavy metals, and toxic oxoanions has led to a scarcity of clean drinking water. Ionic porous organic polymers (iPOPs) offer a superior way for water purification due to their multiple binding sites and ion-exchange properties, which enable them to remove contaminants through electrostatic interactions efficiently. Moreover, iPOPs can be regenerated through simple desorption processes and reused over multiple cycles, making them cost-effective. Herein, we have synthesized chemically and thermally robust iPOPs (TPE-C1 and TPE-C4) using a one-step nucleophilic substitution reaction and utilized them for the removal of radioactive waste (iodine in vapor, aqueous, and organic phases) along with various hazardous oxoanions (Cr2O72-, MnO4-, and ReO4-) from water via an ion-exchange process with high uptake capacities. To the best of our knowledge, the adsorption capacity of TPE-C1 for I3- (4.3 g/g) is the highest in the field of iPOPs. Both the iPOPs showed ultrafast kinetics (>90% removal within 50-150 s), with a kinetic constant value as high as 0.14 mg g-1 min-1 (for permanganate ion), which enhances their efficiency and applicability. In the presence of a large excess (100 times) of competitive anions, the efficiency of TPE-C1 remained mostly unaffected, demonstrating its excellent selectivity. Further, density functional theory (DFT) studies confirmed the presence of electrostatic interactions between the iPOPs and the oxoanions, as well as determined the binding sites and binding energy for the iPOPs toward the pollutants. These iPOPs were recyclable for up to five cycles with no loss in efficiency and maintained consistent performance across various water sources (sea, river, and lake), reflecting their practical applicability. For real-time use, a column-based setup was prepared using TPE-C1, which could achieve >98% removal of these toxic pollutants. With high adsorption capacity, superfast kinetics, superior selectivity, and facile recyclability, these iPOPs offer an affordable and effective solution for removing a wide variety of pollutants and advancing water treatment technologies.

Cost-Effective Synthesis of Carbazole-Based Nanoporous Organic Polymers for SO2 Capture

Sulfur dioxide (SO2), a pervasive air pollutant, poses significant environmental and health risks, necessitating advanced materials for its efficient capture. Nanoporous organic polymers (NOPs) have emerged as promising candidates; however, their development is often hindered by high synthesis temperatures, complex precursors, and limited SO2 selectivity. Herein, we report a room-temperature, cost-effective synthesis of carbazole-based nanoporous organic polymers (CNOPs) using 1,3,5-trioxane and paraldehyde, offering a significant advancement over traditional Friedel-Crafts alkylation methods. The resulting CNOPs exhibit a high surface area of up to 842 m2·g-1 and feature ultramicroporous structures optimized for SO2 adsorption. At 298 K and 1 bar, the CNOPs demonstrated SO2 adsorption capacities of up to 9.39 mmol·g-1. Ideal adsorbed solution theory (IAST) calculations revealed outstanding selectivities of 105 for SO2/CO2 and 6139 for SO2/N2 mixtures, supported by breakthrough experiments demonstrating superior separation performance. This work not only provides a straightforward synthetic route for CNOPs but also offers valuable insights into the design and development of porous materials tailored for enhanced SO2 capture, addressing critical environmental and health challenges.

Carbazole-Bismaleimide Based Hyper-Cross-Linked Porous Organic Polymer for Efficient Iodine Capture

Radioactive iodine, a key waste product of nuclear energy, has been a significant concern among nuclear materials because of its high volatility and its ability to easily enter the human metabolism. Porous materials containing a large number of N-heterocyclic units such as carbazole in the skeletons use as effective adsorbents showing high iodine capture capacities. Herein, a new carbazole-bismaleimide-based hyper-cross-linked porous organic polymer (CzBMI-POP) was successfully prepared from a new tetra-armed carbazole-maleimide monomer (Bis-Cz(BMI)), which contains biscarbazole units and maleimide side groups. To produce CzBMI-POP, a free radical polymerization reaction was carried out via the unsaturated double bonds of Bis-Cz(BMI), enabling the construction of the N-rich porous skeleton in a simple and practical way. A high surface area carbazole-bismaleimide-based POP with polymer backbone having affinity for iodine uptake and sponge-like pore structures ranging from 2 to 20 nm showed iodine uptake capacity up to 215 wt %. The study highlights new opportunities to use POPs as iodine capture platform from nuclear waste, highlighting their potential for environmental remediation due to their easy synthesis and low cost.

Role of Charge Density and Surface Area of Tailored Ionic Porous Organic Polymers for Adsorption and Antibacterial Actions

The development of high-performance adsorbents for environmental remediation is a current need, and ionic porous organic polymers (iPOPs), due to their high physicochemical stability, high surface area, added electrostatic interaction, and easy reusability, have already established themselves as a better adsorbent. However, research on the structural design of high-performance iPOP-based adsorbents is still nascent. This study explored the building blocks' role in optimizing the polymers' charge density and surface area to develop better polymeric adsorbents. Among the three synthesized polymers, iPOP-ZN1, owing to its high surface area and high charge density in its active sites, proved to be the best adsorbent for adsorbing inorganic and organic pollutants in an aqueous medium. The polymers were efficient enough to capture and store iodine vapor in the solid state. Further, this study tried to address using iodine-loaded polymers in antibacterial action. Iodine-loaded iPOPs show impressive antibacterial behavior against E. coli, B. subtilis, and H. pylori.

Exploitation of porphyrin-based titanium-rich porous organic polymers for targeted phosphopeptide enrichment from the serum of colorectal cancer individuals

A porphyrin-based titanium-rich porous organic polymer (Th-PPOPs@Ti4+) was designed based on immobilized metal ion affinity chromatography technique and successfully applied to phosphopeptide enrichment with 5,10,15,20-tetrakis(4-carboxyphenyl) porphine tetramethyl ester (TCPTE), 2,3-dihydroxyterephthalaldehyde (DHTA), and 2,3,4-trihydroxybenzaldehyde (THBA) as raw materials. Th-PPOPs@Ti4+ exhibited remarkable sensitivity (0.5 fmol), high selectivity (β-casein: BSA = 1:2000, molar ratio), outstanding recovery (95.0 ± 1.9%), reusability (10 times), and superior loading capacity (143 mg·g-1). In addition, Th-PPOPs@Ti4+ exhibited excellent ability to specifically capture phosphopeptides from the serum of colorectal cancer (CRC) individuals and normal subjects. Sixty phosphopeptides assigned to 35 phosphoproteins were obtained from the serum of CRC individuals, and 43 phosphopeptides allocated to 28 phosphoproteins were extracted in the serum of healthy individuals via nano-LC-MS/MS. Gene ontology assays revealed that the detected phosphoproteins may be inextricably tied to CRC-associated events, including response to estrogen, inflammatory response, and heparin binding, suggesting that it is possible that these correlative pathways may be implicated in the pathogenesis of CRC.

Two Metal-Organic Frameworks with a Fused Cis-Decalin Conformation for Multimedia Iodine Capture

The extensive growth of nuclear power plants has a severe detrimental effect on human health and the surroundings due to the uncontrolled and unfiltered release of radioactive wastes into the environment. One such radioactive waste is 129I which has a fatal effect when released into the air or water bodies. Hence, molecular and ionic iodine capture from multimedia has become an important area of interest in the recent past. This work is aimed at introducing two 2D metal-organic frameworks with a fused cis-decalin conformation, {[Zn2(tpbn)(fdc)2]·6H2O}n (1) and {[Cd2(tpbn)(fdc)2(H2O)2]·2H2O}n (2), synthesized at room temperature utilizing a combination of M(OAc)2·2H2O (M: Zn/Cd), a neutral flexible ligand, tpbn, and a simple commercially available furan dicarboxylate, fdc2-, for the target application. The polarizing nature of the furan moieties and the oxygen rich pores in 1 and 2 facilitate the easy capture of molecular iodine from both the vapor phase and aqueous media with high uptake values. Furthermore, their efficiency was tested for the practical application under real-world conditions using river and seawater. In addition to confirming their recyclability with the retention of structural integrity, the interaction between 1 and 2 with iodine has also been established with experimental and theoretical calculations.

Harnessing the Chemical Functionality of Metal-Organic Frameworks Toward Removal of Aqueous Pollutants

Wastewater treatment has been bestowed with a plethora of materials; among them, metal-organic frameworks (MOFs) are one such kind with exceptional properties. Besides their application in gas adsorption and storage, they are applied in many fields. In orientation toward wastewater treatment, MOFs have been and are being successfully employed to capture a variety of aqueous pollutants, including both organic and inorganic ones. This review sheds light on the postsynthetic modifications (PSMs) performed over MOFs to adsorb and degrade recalcitrant. Modifications performed on the metal nodes and the linkers have been explained with reference to some widely used chemical modifications like alkylation, amination, thiol addition, tandem modifications, and coordinate modifications. The boost in pollutant removal efficacy, reaction rate, adsorption capacity, and selectivity for the modified MOFs is highlighted. The rationale and the robustness of micromotor MOFs, i.e., MOFs with motor activity, and their potential application in the capture of toxic pollutants are also presented for readers. This review also discusses the challenges and future recommendations to be considered in performing PSM over a MOF concerning wastewater treatment.

Construction of hydroxyl-functionalized hyper-crosslinked networks from polyimide for highly efficient iodine adsorption

The rapid development of nuclear energy posed a great threat to the environment and human health. Herein, two hydroxyl-functionalized hyper-crosslinked polymers (PIHCP-1 and PIHCP-2) containing different electron active sites have been synthesized via Friedel-Crafts alkylation reaction of the polyimides. The resulting polymers showed a micro/mesoporous morphology and good thermal and chemical stability. Rely on the high porosity and multi-active sites, the PIHCPs show an ultrahigh iodine uptake capacity reached 6.73 g g-1 and the iodine removal efficiency from aqueous solution also reaches 99.7%. Kinetic analysis demonstrates that the iodine adsorption on PIHCPs was happened on the heterogeneous surfaces in the form of multilayer chemisorption. Electrostatic potential (ESP) calculation proves the great contribution of hydroxyl groups on the iodine capture performance. In addition, the iodine capture efficiency of both adsorbents can be maintained over 91% after four cyclic experiments which ensures their good recyclability for further practical applications.

Capture of Volatile Iodine Gas and Identification of Adsorption Sites in the Pore Network of Unsubstituted Imidazole Linker-Incorporated Zeolitic Imidazolate Framework-8

The incorporation of unsubstituted imidazole (Im) in zeolitic imidazolate framework-8 (ZIF-8) crystallized in sodalite topology is proposed to improve gas capture and gas separation performance drastically. However, the incorporation of unsubstituted Im in ZIF-8 has remained challenging due to the thermodynamic instability of zinc and Im bonding in sodalite topology. We have incorporated up to 24.4 (mol %) Im linker in highly crystalline ZIF-8 with similar morphology and sodalite topology using a delayed linker addition strategy at room temperature. Im incorporation brings significant tuning to the pore architecture of ZIF-8, as confirmed by positron annihilation lifetime spectroscopy. The modifications in the pore architecture are primarily due to linker defects produced in the frameworks during crystallization and the elimination of steric hindrance due to the absence of a methyl group on Im. The Im-incorporated ZIF-8 shows significant enhancement in iodine capture as well as higher crystal structure stability under iodine vapor exposure as compared to pristine ZIF-8. Through ortho-positronium interaction with the adsorbed molecular iodine in the pore network of the frameworks, it is confirmed that iodine is preferentially adsorbed at cavity and intercrystalline voids, whereas aperture sites remain unoccupied by iodine molecules.

Unusual 3,4-Oxidative Coupling Polymerization on 1,2,5-Trisubstituted Pyrroles for Novel Porous Organic Polymers

Porous organic polymers (POPs) have demonstrated promising task-specific applications due to their structure designability and thus functionality. Herein, an unusual 3,4-polymerization on 1,2,5-trisubstituted pyrroles has been developed to give linear polypyrrole-3,4 in high efficiency, with Mn of 20000 and PDI of 1.7. This novel polymerization technique was applied to prepare a series of polypyrrole-based POPs (PY-POP-1-4), which exhibited high BET surface areas (up to 762 m2 g-1) with a meso-micro-supermicro hierarchically porous structure. Furthermore, PY-POPs were doped in the mixed matrix membranes based on the polysulfone matrix to enhance the gas permeability and gas pair selectivity, with H2/N2 selectivity up to 84.6 and CO2/CH4 and CO2/N2 selectivity up to 46.8 and 39.6.