Nitrogen-enriched porous carbons were prepared for the first time via pyrolysis (at different temperatures) of melamine-loaded polypyrrole. The melamine/polypyrrole-derived carbons (MPpDCs) and the carbon prepared from pure polypyrrole were characterized with various means; it was found that melamine increased the contents of nitrogen and total acidic or basic groups in the obtained carbon. The derived carbons were applied to the adsorptive removal of three herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), clofibric acid, and methylchlorophenoxypropanoic acid from water. The optimized adsorbent, MPpDC(800), showed the highest adsorption capacity (510 mg/g) for 2,4-D removal compared with other reported results. Hydrogen bonding and π-π stacking could be suggested as a plausible adsorption mechanism, based on the adsorption and surface charge under wide pH conditions, X-ray photoelectron spectroscopic analyses of MPpDC(800) with or without adsorption of 2,4-D, and calculations. The facile regeneration of MPpDC(800), via ethanol washing, was also confirmed. Therefore, MPpDC(800) could be suggested as a potential adsorbent for the removal of herbicides from water.

Phenolic pollutants such as 4-chlorophenol (4-CPh), 4-chloro-3,5-dimethylphenol (PCMX), and 2,6-dimethylphenol (2,6-DMP) are toxic and persistent organic contaminants that pose serious environmental and health concerns due to their low biodegradability and high chemical stability. In this work, the roles of the functional groups and the framework flexibility of the MIL-53 derivative metal–organic frameworks (MOFs) in the adsorption-based removal of phenolic pollutants were systematically investigated. Structural characterization confirmed the flexible breathing nature of MIL-53(Al), whereas NH2-MIL-53(Al) and MIL-53(Al)-TDC had comparatively rigid frameworks. Adsorption analysis revealed remarkably high adsorption capacities for PCMX on MIL-53(Al) and 2,6-DMP on MIL-53(Al)-TDC. The adsorption process followed pseudo-second-order kinetics, indicating that host-guest interactions may be responsible for the high adsorption capacity. The conventional Langmuir and the Freundlich isotherms did not describe the adsorption behavior due to the sigmoidal nature of the adsorption profiles. The sigmoidal adsorption behavior is consistent with multiple host–guest interactions, as supported by PXRD, FTIR, XPS, and DFT analyses. Temperature-dependent adsorption analysis revealed a predominantly exothermic adsorption process, with 4-CPh exhibiting more stable adsorption than PCMX and 2,6-DMP due to stronger hydrogen-bonding interactions. This work highlights the importance of framework functionality and structural adaptability in designing efficient MOF adsorbents for the removal of phenolic pollutants.

Metal nitride (MeN) catalysts have recently emerged as promising materials for oxidative desulfurization (ODS) and denitrogenation (ODN). However, systematic comparisons of different MeN species remain limited due to variations in synthesis routes and reaction conditions. In this study, we employed both computational and experimental methods to evaluate three MeNs, such as TiN, VN, and CrN, which have an identical crystal structure (Fm-3 m). Density functional theory calculations predicted the catalytic activity trends by examining three key parameters: the adsorption energy (Delta Ead) of oxidant H2O2on MeNs, the intrinsic HOMO-LUMO energy gap of MeNs, and the intermolecular HOMO(MeN)-LUMO(H2O2) energy gap. VN exhibited the highest predicted reactivity due to its strongest Delta Ead, narrowest intrinsic energy gap, and smallest intermolecular energy gap. To validate the predictions, TiN-, VN-, and CrN-doped polyaniline-derived carbons (MeN@PDCs) were synthesized and applied to the oxidation reactions. VN@PDC demonstrated superior catalytic performance, achieving complete dibenzothiophene removal in 120 min at 45 degrees C and complete indole removal within 30 min, whereas TiN@PDC showed significantly lower efficiencies (and CrN@PDC had the lowest reactivities). Radical scavenger tests and ESR spectroscopy revealed that all MeN@PDCs promoted oxidation through nonradical pathways. This work represents the first integrated computational-experimental comparison of MeNs under a unified catalyst support system and identical reaction conditions, providing a practical guideline for the rational design of MeNbased oxidation catalysts.

A Cr2O3-melamine@MAF-6 derived carbon nanozyme composite (CrN@MDC) was developed and integrated into a lateral flow assay (LFA) for the sensitive and specific quantification of transglutaminase 2 (TGM2), a potential biomarker for liver cancer, in clinical plasma samples. CrN(x)@MDC nanozymes with varying Cr2O3 contents (x = 0, 0.05, 0.10, and 0.15 g) were synthesized, and their peroxidase-like activities were evaluated using a 3,3',5,5'-tetramethylbenzidine (TMB)/H2O2 colorimetric reaction, which identified CrN(0.10)@MDC as the most catalytically active composition. The CrN(0.10)@MDC-based LFA generated a distinct black-to-blue colorimetric signal through nanozyme-catalyzed TMB oxidation, enabling detection of TGM2 concentrations as low as 0.025 nM in both buffer and plasma. This corresponded to an approximately 40-fold improvement in visual detection sensitivity compared with a conventional gold nanoparticle-based LFA. In addition to a low limit of detection (0.0095 nM) in a plasma matrix, the assay exhibited high selectivity against abundant plasma proteins, relevant biomarkers, and liver disease-associated interferents, likely attributable to effective nanozyme surface blocking using bovine serum albumin. Direct analysis of undiluted clinical plasma samples from healthy individuals and liver cancer patients showed that TGM2 concentrations measured using the proposed LFA were consistent with those obtained by a commercial enzyme-linked immunosorbent assay. These results support the applicability of the nanozyme-amplified LFA as a proof-of-concept platform for clinically relevant TGM2 detection.

Carbon‐supported sulfated titania (S‐TiO2/C) was prepared for the first time by synthesizing the S‐TiO2 nanoparticles within the pores of carbon derived from polyaniline. After comprehensive characterization of the catalyst including relevant materials, via X‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), the material was utilized for the oxidative denitrogenation of model fuel with H2O2 oxidant. A remarkable performance of S‐TiO2/C in indole oxidation was confirmed. For example, a low activation energy of 33.6 kJ mol−1 and complete conversion of 1000 ppm of indole within 60 min at 45°C (while 97% conversion was achieved after 60 min at 35°C) were observed. Quinoline might be fully oxidized with the developed catalyst under comparable conditions, with a slight optimization. This performance might be because of the well‐dispersed S‐TiO2 within the carbon matrix, which facilitates H2O2 activation, after effective adsorption on the catalyst. Radical scavenger and electron spin resonance spectrometry experiments suggested the generation of hydroxyl radicals as reactive oxygen species. Based on the oxidation of methylindole isomers, a mechanism of nucleophilic attack from N of N‐containing compounds on hydroxyl radicals could be suggested. The S‐TiO2/C catalyst demonstrated excellent reusability, maintaining performance over five cycles, indicating its suitability for oxidative denitrogenation.

Carbonaceous materials, especially oxidized ones, have been frequently used as adsorbents. Oxidation of carbons has usually been carried out using ammonium persulfate/H2SO4 solution under electric heating. In this work, polyaniline-derived carbons were oxidized with both the conventional method and HNO3 under microwaves. The obtained carbons, after thorough characterization, were applied to the adsorptive purification of water polluted with emerging contaminants, especially basic pharmaceuticals with amino groups (like atenolol (ATNL) and diphenhydramine (DPHA)). The carbon oxidized under microwave was much more effective in the adsorption than the carbon oxidized by the conventional method using electric heating. Both the adsorbed quantities and adsorption kinetic constants increased with increasing oxidation (by microwaves) temperatures up to 100 °C. The best performing MPDC(100) was recyclable and highly competitive in the adsorption of ATNL and DPHA. The mechanism of ATNL and DPHA adsorptions over MPDC(100) was investigated by checking surface charge and adsorbed quantities under wide pH conditions. Electrostatic interaction with π-π interaction and hydrogen bonding (adsorbent: hydrogen-acceptor) was the major mechanism for the effective adsorption over MPDC(100). Finally, porous carbon with a high concentration of anionic sites like carboxylates can be suggested as an effective adsorbent to remove basic pharmaceuticals with amino groups.

Organonitrogen compounds (ONs) in fuels cause harmful emissions and reduce the efficiency of refinery catalysts, creating a need for effective removal methods. Sulfonated polyaniline (SPAN) supported on porous carbon offers a promising metal-free catalyst for efficient oxidative denitrogenation under mild conditions. SPAN was synthesized under ambient conditions via the co-polymerization of aniline and sulfonated aniline within a highly porous polyaniline-derived carbon (pDC) support, demonstrating an efficient metal-free sulfonated catalyst for the oxidative removal of various ONs from liquid fuels. The -SO3H functionalities in the SPAN/pDC catalyst played a crucial role in enhancing oxidation performance, enabling high activity even at room temperature (25 °C) and without the use of polar extractants during the reaction. The catalyst exhibited high conversion efficiencies along with rapid reaction kinetics, characterized by a very low activation energy (25.4 kJ/mol), and showed excellent reusability. For example, SPAN(4)/pDC achieved complete indole conversion within 90 min at 25 °C, with a rate constant of 3.9 × 10−2 min−1. The combined benefits of the sulfonated polyaniline component and the porous pDC support were assessed by evaluating the catalytic activity and reaction kinetics in comparison with a conventional W-based oxidation catalyst. Furthermore, a potential oxidation mechanism/pathway was suggested based on experiments conducted in the presence of radical scavengers and analysis of the catalytic systems using electron spin resonance (ESR) spectroscopy. Overall, this study offers a sustainable and efficient route for deep denitrogenation of liquid fuels under ambient conditions and advances the design of high-performance/metal-free oxidation catalysts.

Efficient CO2 capture using amine-functionalized metal-organic frameworks (MOFs) requires a rational design strategy that considers the interplay between amine configuration and pore geometry. In this study, a series of Zrbased MOFs (UiO-67, MOF-808, and NU-1000) were post-synthetically functionalized by grafting diaminoalkanes of varying chain lengths onto their metal sites. The structure-function relationship between the host MOFs and the grafted amines, which governs CO2 adsorption performance, was systematically investigated. The CO2 uptake, isosteric heat of adsorption, and ideal adsorbed solution theory (IAST) CO2/N2 selectivity all initially increased and then decreased with increasing the chain length of the grafted diamines, showing maximum performance when the diamine length was optimally matched to the MOF pore size. At the optimal combinations (U67-DAB, M808-DAPen, and N1000-DAO), the materials exhibited 1.3-2.7 times the CO2 uptake at 15 kPa and 3.3-17.8 times the CO2/N2 selectivity at 100 kPa compared with the pristine MOFs. Spectroscopic analyses (FTIR and XPS) confirmed that ammonium carbamate formation occurs only when the terminal amines are spatially proximate, enabling cooperative chemisorption. These results highlight that spatial compatibility between MOF pore size and diamine length is a critical factor in maximizing CO2 capture efficiency via ammonium carbamate formation. This study provides a generalizable guideline for tailoring amine-functionalized MOFs for efficient CO2 adsorption.

The development of efficient and sustainable catalysts for oxidative desulfurization (ODS) of refractory sulfur compounds remains a critical challenge for ultra-clean fuel production. Herein, we report a simple, green, and template-free strategy for the phase-selective synthesis of tungsten nitride nanoparticles supported on nitrogen-doped porous carbon (WxNy@C) using ethanol and urea as benign carbon and nitrogen sources. By controlling the pyrolysis temperature, distinct tungsten nitride phases (W2N3, beta-W2N, and delta-W2N) with tunable nitrogen stoichiometry and electronic structures were selectively obtained. Among them, nitrogen-rich W2N3@C500 exhibits outstanding catalytic activity toward the oxidative desulfurization of thiophene-one of the most chemically stable and difficult-to-oxidize sulfur compounds-achieving 91% conversion at a relatively low temperature of 60 degrees C within 30 min, with an apparent kinetic constant (k) of 8.7 & times; 10-2 min-1. The developed catalyst exhibited a relatively low apparent activation energy (Ea: 23.4 kJ & sdot;mol-1), which is comparable to values reported for diffusion-influenced processes in liquid media and is consistent with its high catalytic efficiency. Radical scavenging experiments, ESR analysis, and DFT calculations demonstrate that the superior performance of W2N3@C500 originates from its narrowed band gap and enhanced electron density at W-N sites, which facilitate efficient H2O2 activation to generate superoxide radicals and W-peroxo species. The catalyst shows excellent stability and recyclability without structural degradation. This work highlights the critical role of nitride phase engineering in regulating electronic structure and catalytic functionality, offering a scalable and environmentally benign platform for designing advanced nitride-based hybrid catalysts for fuel purification.

Abstract Six new Zn–siloxane‐based 0D clusters were synthesized using silanes bearing methyl, phenyl, cyclohexyl, and bicyclo[2.2.1]hept‐5‐en‐2‐yl substituents in combination with acetate or propionate ligands. Single‐crystal X‐ray diffraction analysis revealed a substituent‐dependent structural transition: Me‐ and Ph‐substituted systems formed conventional T 8 siloxane frameworks, whereas Hex‐ and Hep‐substituted systems selectively generated rare, metal‐containing T 6 architectures, regardless of the carboxylate ligand employed. Structural analyses suggest that conformationally induced steric effects associated with the non‐planar cyclic substituents play a crucial role in directing framework selectivity. The synthesized clusters exhibited characteristic deep‐ultraviolet (DUV) absorption behavior and were readily processed into transparent PMMA composite films through solution‐based fabrication. These findings reveal a substituent‐shape‐dependent pathway for accessing rare T 6 Zn–siloxane architectures and establish substituent engineering as an effective strategy for directing siloxane framework assembly.

Metal-Organic Frameworks (MOFs) are highly versatile porous materials with applications spanning gas storage, catalysis, and sensing. Among the MOFs, zirconium-based ones (Zr-MOFs) stand out due to their exceptional chemical, mechanical, and thermal stability, which is crucial for practical applications in harsh conditions. The choice of organic linker is paramount in MOF design; tetradentate linkers, with their four coordination points, significantly enhance framework connectivity, leading to superior stability, large pore volumes, and intricate architectures. This review firstly provides a comprehensive overview of Zr-MOFs constructed with tetratopic organic linkers, focusing on their structural features, synthesis strategies, and diverse applications in environmental remediation, including gas capture (e.g., CO2) and catalysis. This review highlights the unique advantages and promising future of tetratopic Zr-MOFs.

A microporous covalent-organic polymer (triazine polymer, referred to as MCTP), was synthesized and subsequently carbonized, after loading urea and KOH (serving as an additional nitrogen source and activator, respectively), through high-temperature pyrolysis. This process resulted in materials named KUCDCs, which exhibited high porosity and a broader range of pore sizes compared to carbon materials produced without the addition of urea and KOH, referred to as CDC. KUCDCs, CDC, and commercially available activated carbon (AC) were evaluated for their ability to remove sulfonamide drugs, sulfamethoxazole (SMX) and sulfachlorpyridazine (SCP), from aqueous solution. Among these materials, KUCDC-800, which was carbonized at a temperature of 800 degrees C, demonstrated superior adsorption performances for sulfonamides, attributed to its high porosity, nitrogen content, and presence of surface oxygen groups. The adsorption capacities for SMX and SCP on KUCDC were notably higher than those on AC and MDC, with maximum capacities (Q0) of 619 and 554 mg/g for SMX and SCP, respectively. Notably, KUCDC-800 stands out as a recyclable adsorbent with the highest reported Q0 for SMX to date under near-neutral conditions. The exceptional performance of KUCDC in adsorbing SMX could be explained by its high porosity and surface functionalities for hydrogen bonding interactions with the adsorbate.

A homogeneously dispersed and immobilized tungsten oxide (WO3) catalyst supported on a metal-organic framework (MOF) NU-1000 was prepared for the first time and applied for the oxidation of organic sulfur compounds (OSCs) from liquid fuels. The composite was prepared at room temperature; therefore, cost-effective and environmentally friendly. The defective sites of NU-1000 helped the firm immobilization of WO3 species within the NU-1000 pores. The composite material denoted as W@NU-1000 was prepared from ammonium tungstate para pentahydrate in the presence of NU-1000 using nitric acid as a precipitating agent. The material was characterized by several techniques including XRD, FTIR, TGA, N2 adsorption-desorption, XPS, SEM, and TEM. The material showed remarkable performances in the oxidative conversion of dibenzothiophene (DBT, a typical OSC) using H2O2 as an oxidant. For example, almost complete conversion of DBT (1000 ppm) was achieved at room temperature within 120 min of the reaction, and the activation energy was very low of 25.9 kJmol- 1. The remarkable performance of the catalyst might be due to the well-dispersed WO3 (that can effectively activate H2O2) and relatively high porosity. The radical scavenger experiments and electron spin resonance analyses confirmed a non-radical pathway for the oxidation of DBT probably by the formation of a W6+-peroxo complex during the oxidation process. The material W@NU-1000 could be used for five cycles without any loss in performance, suggesting that it can be utilized as a potential oxidation catalyst.

This review discusses the various preparation methods and physicochemical properties of highly porous carbons derived from metal-organic frameworks (MDCs) or covalent organic frameworks (CDCs). It also explains the roles of physical and chemical activation processes in the preparation of MDCs/CDCs with tailored physicochemical characteristics. The carbonization and activation parameters that control (i) the formation of pores (micropores, mesopores, or macropores), (ii) carbon yield, (iii) the incorporation of heteroatoms (N, S, O, P, metal, etc.), (iii) morphology, and (iv) the hydrophobicity of MDCs/CDCs are explained systematically. Importantly, the physicochemical properties of MDCs/CDCs are compared with those of conventional carbons to highlight the advantages of these materials. Additionally, the applications of MDCs/CDCs in the adsorptive removal of typical hazardous organics, such as pharmaceuticals, personal care products, phenolics, pesticides, dyes, and aromatics from water, are reviewed. The adsorption results are also compared with those of conventional carbons to demonstrate the superior performance of MDCs/CDCs in liquid-phase adsorption. These results are explained in terms of maximum adsorption capacities, adsorption mechanisms, and reusability. Finally, this review provides research outlooks for readers in the relevant fields.

Tungstic acid (TA, WO3 center dot H2O) was synthesized for the first time on the porous polypyrrole-derived carbon (PpyrlDC) under mild hydrothermal conditions. The TA particles were uniformly distributed within the porous PpyrlDC support and the composite was used for the oxidative denitrogenation of several organonitrogen compounds (ONCs) from liquid fuel. The TA/PpyrlDC catalysts demonstrated remarkable efficiency in the oxidation of indole (one of the typical ONCs) with H2O2, even at room temperature and in the absence of any extractant or solvent. For example, one invented catalyst, TA(5)/PpyrlDC, had the lowest activation energy (22.6 kJ mol(-1) which is not far from the Ea of diffusion in the liquid phase), the highest turnover frequency, and the fastest kinetic constant, reported for W-based catalysts, in indole oxidation. Moreover, the catalyst can fully oxidize indole even at 25 degrees C and can be recyclable for several runs via simple soaking and washing with solvents. The oxidation mechanism could be suggested by analyzing the catalytic systems with the electron spin resonance and indole oxidation in the presence of radical scavengers.

Removal of pharmaceuticals from water is crucial for our health and clean environment. In this work, porous carbon, which is suitable for carbamazepine (CBMZ) adsorption, is produced via two-step-pyrolysis of a Zn-based metal-organic framework (MOF), MAF-6(Zn), especially in the presence of KOH activator in various quantities in the second step. After comprehensive characterizations of the derived carbon, adsorption of CBMZ was carried out under wide conditions. One carbon, named MDC-4, prepared from carbonization of MAF-6(Zn)-pyrolyzed product (obtained in the first step), with 4 times the weight of KOH, showed a large adsorption capacity for CBMZ (1295 mg/g). This capacity is higher than that of any reported adsorbent; moreover, this is around 2 times that of the most efficient adsorbent reported so far. MDC-4 was readily recyclable with acetone washing. Based on CBMZ adsorption and surface charge of MDC-4 under wide pH conditions and XPS analysis of MDC-4 (with or without CBMZ adsorption), a plausible adsorption mechanism like u03C0u2013u03C0 and hydrophobic interactions could be suggested. Pyrolyzing Zn-based MOFs like MAF-6(Zn) in the existence of much KOH activator will be effective in preparing an adsorbent like MDC-4 to remove hydrophobic organics with ample u03C0-electrons (like polycyclic aromatic hydrocarbons) from water.

Polypyrrole-derived carbons (PpDCs) were obtained via pyrolysis of polypyrrole under various preparation conditions. After characterization, PpDCs were used for the adsorptive purification of water contaminated with organic dyes. One PpDC (PpDC-800) exhibited the highest adsorption capacity (Qo) for cationic dyes (e.g., methylene blue and crystal violet) compared to other adsorbents. The adsorption capacity of PpDC-800 for methylene blue and crystal violet was approximately seven times higher than that of activated carbon. The effective adsorption of cationic dyes (200 mg/L) over PpDC-800 was also observed in water with very low concentrations of methylene blue or crystal violet (1 mg/L), which causes toxicity and affects aesthetics. PpDC800 showed high selectivity for methylene blue adsorption from an equivalent-weight mixture of anionic methyl orange and cationic methylene blue. Plausible adsorption mechanisms of methylene blue removal, such as electrostatic and pi-pi interactions, have been suggested. Structural characterization and adsorption mechanism were confirmed using XRD, N2 adsorption, Raman spectroscopy, SEM, XPS, zeta potential analysis, and other techniques. The facile regeneration of PpDC-800 was confirmed through successive adsorption/reactivation cycles using FT-IR, N2 adsorption, Raman, and SEM analyses. PpDC-800 is one of the most promising adsorbents for the effective and selective removal of cationic dyes from water.

Esterified bio-oil, derived from microalgae, serves as a promising substitute for diminishing fossil fuel resources although improving quality and reducing its high nitrogen content remain key challenges. Here, metal-free B and N co-doped carbon catalysts were used for oxidative denitrogenation of a model esterified bio-oil. The catalysts were prepared by pyrolysis, in two steps, of composites of boric acid (with various contents) and urea-loaded polypyrroles (Ppy). Nearly complete conversion of indole and quinoline could be obtained even at 25 degrees C in 50 min with a selected metal-free catalyst, B(40%)-PpyDC. An extremely low activation energy (26.9 kJ mol-1), which is not far from the energy of a physical process or diffusion, was observed in the indole oxidation. The remarkable performance of the catalyst in oxidative denitrogenation might be due to the ready formation of hydroxyl radicals that was confirmed by electron spin resonance spectroscopy and radical trapping experiments. DFT calculations supported the large charge separations (N delta-and B delta+) on the carbonaceous catalyst where oxidant H2O2 can be effectively adsorbed and activated to produce center dot OH radicals. A potential reaction mechanism could be suggested to follow the experimental and calculation results. B(40%)-PpyDC was recyclable for the oxidative denitrogenation, by simple acetonitrile and ethanol soaking, with comparable performance to the fresh catalyst.

Solketal is one of the most promising additives improving the properties of motor fuels. Investigations related to process intensification of synthesis of solketal from glycerol and acetone is gaining importance. The present work illustrates the use of the microwave mode for intensification of this process in the presence of silicoaluminophosphates (SAPO) as catalysts. The main focus of the study was placed on tuning the textural, acidic, and catalytic properties of SAPO-34 and SAPO-5 via variation of the synthesis parameters, such as the nature of Al and Si sources and the structure-directing agent. The catalytic properties of SAPO materials were investigated in the synthesis of solketal from glycerol and acetone under microwave assistance at the acetone/glycerol molar ratio of 2.4 in a methanol solution (glycerol/methanol: 1 g/1 mL) and 56 degrees C. It was demonstrated that the selectivity towards solketal was 91.1-98.6 % in the presence of the studied materials. The activities of mesoporous SAPO-34 and SAPO-5 prepared in the presence of triethylamine were higher as compared with micro- porous SAPO-34 prepared in the presence of tetraethylammonium hydroxide due to the high mesoporosity and a larger content of acid sites. The 90.4 % conversion of glycerol and 98.6 % selectivity towards solketal were observed in the presence of mesoporous 7.6%SAPO-34 for 90 min. The advantage of using microwave technology is shown. The solketal yield in the reaction under microwave irradiation was 3 times higher than that in the process performed under thermal heating conditions.