A direct oxidative esterification of aldehydes with alcohols mediated by photochemical C-H bromination

The photochemical direct esterification of aldehydes with alcohols via in situ-generated acyl-bromides presented in this report is an attractive complementary addition to hitherto reported methods, as these are usually carried out in a two-step, one-pot procedure in order to avoid side reactions such as the oxidation of alcohols by halogen sources.

Co/Cd-MOF-Derived Porous Carbon Materials for Moxifloxacin Adsorption from Aqueous Solutions

In this study, Co/Cd-MOFs were synthesized via a solvothermal method. The resulting material was subjected to calcination at 900 °C for 2 h and characterized using FT-IR, XRD, and SEM techniques to assess its efficacy in moxifloxacin removal. The experimental findings revealed that the maximum adsorption capacity of Co/Cd-MOFs for moxifloxacin was observed at 350.4 mg/g within a 5 h timeframe. Furthermore, the analysis based on the pseudo-second-order kinetic model demonstrated that the adsorption process adhered to this specific model. Additionally, the adsorption isotherm analysis indicated that Freundlich multilayer adsorption provided the best description of the interaction between moxifloxacin and the Co/Cd-MOF material. These experimental and theoretical results collectively suggest that employing Co/Cd-MOFs as adsorbents holds promise for wastewater treatment applications.

Porous carbon nanoarchitectonics for the environment: detection and adsorption

As a post-nanotechnology concept, nanoarchitectonics has emerged from the 20th century to the 21st century. This review summarizes the recent progress in the field of metal-free porous carbon nanoarchitectonics.

Aqueous Nd3+ capture using a carboxyl-functionalized porous carbon derived from ZIF-8

A porous graphitic carbon was obtained via the pyrolysis of a zeolite imidazolate framework (ZIF-8) under Ar atmosphere. Then, the carbon was functionalized with carboxylic groups and applied for separation of neodymium ions (Nd³⁺) from water. The adsorbent (denoted as C-ZDC) was characterized by X-ray diffraction, N₂ adsorption-desorption isotherms, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning and transition electron microscopies, thermogravimetric analysis, and Boehm titration. A practical adsorption equilibrium was attained within 4 h, and the adsorption isotherm at 25 °C revealed a maximum adsorption capacity of 175 mg/g, which is one of the highest values reported for different kinds of adsorbents. The adsorption kinetics and equilibrium isotherms were modeled, and the selectivity for Nd³⁺ over other metal ions was examined. From the effect of solution pH on the adsorption and material characterization results before and after adsorption, the high adsorption capacity of C-ZDC was ascribed to the formation of coordination bonds between Nd³⁺ ions and the -COOH groups. Further, the material was reusable for at least four adsorption-desorption cycles after a simple step of acid washing.

Direct synthesis of nitrogen-doped mesoporous carbons from triazine-functionalized resol for CO2 uptake and highly efficient removal of dyes

In this study we synthesized a triazine-formaldehyde phenolic resin as a nitrogen-containing resol (N-resol) through the condensation of 2,4,6-tris(4-hydroxyphenyl)triazine and formaldehyde. We then used this N-resol as a carbon and nitrogen atom source, mixing it with a diblock copolymer of PEO-b-PCL as the soft template, for the direct synthesis of N-doped mesoporous carbons. Interestingly, the self-assembled N-resol/PEO-b-PCL blends underwent a mesophase transition from cylinder to gyroid and back again to cylinder structures upon increasing the N-resol concentration (i.e., cylinder at 50/50; gyroid at 60/40; cylinder at 70/30). After removing the soft template at 700 °C, the resultant N-doped mesoporous carbons possessed high N atom contents (up to 13 wt%) and displayed gyroid and cylinder nanostructures. The synthesized N-doped mesoporous carbons exhibited excellent CO₂ uptake capacities (up to 72 and 150 mg g^-1 at 298 and 273 K, respectively). Furthermore, the N-doped mesoporous gyroid carbon structure displayed high adsorption capacities toward organic dyes in water. The maximum adsorption capacities of rhodamine B and methylene blue in water reached as high as 204.08 and 308.64 mg g^-1, respectively; furthermore, these N-doped mesoporous carbons also maintained up to 98 % of their maximum adsorption capacities within 45 min.

From metal-organic frameworks to porous carbon materials: recent progress and prospects from energy and environmental perspectives

Metal-organic frameworks (MOFs) have emerged as promising materials in the areas of gas storage, magnetism, luminescence, and catalysis owing to their superior property of having highly crystalline structures. However, MOF stability toward heat or humidity is considerably less as compared to carbons because they are constructed from the assembly of ligands with metal ions or clusters via coordination bonds. Transforming MOFs into carbons is bringing the novel potential for MOFs to achieve industrialization, and carbons with controlled pore sizes and surface doping are one of the most important porous materials. By selecting MOFs as a precursor or template, carbons with heteroatom doping and well-developed pores can be achieved. In this review, we discussed the state-of-art study progress made in the new development of MOF-derived metal-free porous carbons. In particular, the potential use of metal-free carbons from environmental and energy perspectives, such as adsorption, supercapacitors, and catalysts, were analyzed in detail. Moreover, an outlook for the sustainable development of MOF-derived porous carbons in the future was also presented.

Carbonization and Preparation of Nitrogen-Doped Porous Carbon Materials from Zn-MOF and Its Applications

Nitrogen-doped porous carbon (NPC) materials were successfully synthesized via a Zn-containing metal-organic framework (Zn-MOF). The resulting NPC materials are characterized using various physicochemical techniques which indicated that the NPC materials obtained at different carbonization temperatures exhibited different properties. Pristine MOF morphology and pore size are retained after carbonization at particular temperatures (600 °C-NPC600 and 800 °C-NPC800). NPC800 material shows an excellent surface area 1192 m2/g, total pore volume 0.92 cm3/g and displays a higher CO2 uptake 4.71 mmol/g at 273 k and 1 bar. Furthermore, NPC600 material displays good electrochemical sensing towards H2O2. Under optimized conditions, our sensor exhibited a wide linearity range between 100 µM and 10 mM with a detection limit of 27.5 µM.

Photocatalytic and Ferric Ion Sensing Properties of a New Three-Dimensional Metal-Organic Framework Based on Cuboctahedral Secondary Building Units

A new three-dimensional microporous metal-organic framework based on Zn(II) clusters with the formula {[Zn₇(NDC)_5.5(μ₄-OH)₃]·7DMF} _n (1) (H₂NDC = 1,4-naphthalenedicarboxylic acid) had been synthesized and characterized. The MOF 1 displays an uncommon bsn topology, which is based on a unique heptanuclear Zn₇(OH)₃(CO₂)₁₁ cluster as a secondary building unit. The MOF had been employed as a photocatalyst for the photodegradation of model organic dyes rhodamine B and methyl violet in light. The results of photocatalytic experiments showed that 1 can successfully be employed as the photocatalyst for the benign decomposition of these dyes. A mechanism for the photcatalysis exhibited by 1 had been proposed using the results of density of states (DOS) and partial DOS calculations. The fluorescence properties of the MOF have been investigated, which revealed that 1 could be exploited as the luminescent sensor to recognize Fe³⁺ ions with perceptible quenching (K _sv = 6.55 × 10⁴ M-¹) and a limit of detection of 1.16 ppm.

MOF-templated self-polymerization of p-phenylenediamine to a polymer with a hollow box-assembled spherical structure

Cu–pPD acts as both a structural template and reactant to realize direct conversion from MOFs to polymers in one step.

Significance, evolution and recent advances in adsorption technology, materials and processes for desalination, water softening and salt removal

Desalination and softening of sea, brackish, and ground water are becoming increasingly important solutions to overcome water shortage challenges. Various technologies have been developed for salt removal from water resources including multi-stage flash, multi-effect distillation, ion exchange, reverse osmosis, nanofiltration, electrodialysis, as well as adsorption. Recently, removal of solutes by adsorption onto selective adsorbents has shown promising perspectives. Different types of adsorbents such as zeolites, carbon nanotubes (CNTs), activated carbons, graphenes, magnetic adsorbents, and low-cost adsorbents (natural materials, industrial by-products and wastes, bio-sorbents, and biopolymer) have been synthesized and examined for salt removal from aqueous solutions. It is obvious from literature that the existing adsorbents have good potentials for desalination and water softening. Besides, nano-adsorbents have desirable surface area and adsorption capacity, though are not found at economically viable prices and still have challenges in recovery and reuse. On the other hand, natural and modified adsorbents seem to be efficient alternatives for this application compared to other types of adsorbents due to their availability and low cost. Some novel adsorbents are also emerging. Generally, there are a few issues such as low selectivity and adsorption capacity, process efficiency, complexity in preparation or synthesis, and problems associated to recovery and reuse that require considerable improvements in research and process development. Moreover, large-scale applications of sorbents and their practical utility need to be evaluated for possible commercialization and scale up.

Enhanced Capacity and Rate Capability of Nitrogen/Oxygen Dual-Doped Hard Carbon in Capacitive Potassium-Ion Storage

The intercalation of potassium ions into graphite is demonstrated to be feasible, while the electrochemical performance of potassium-ion batteries (KIBs) remains unsatisfying. More effort is needed to improve the specific capacity while maintaining a superior rate capability. As an attempt, nitrogen/oxygen dual-doped hierarchical porous hard carbon (NOHPHC) is introduced as the anode in KIBs by carbonizing and acidizing the NH₂ -MIL-101(Al) precursor. Specifically, the NOHPHC electrode delivers high reversible capacities of 365 and 118 mA h g^-1 at 25 and 3000 mA g^-1 , respectively. The capacity retention reaches 69.5% at 1050 mA g^-1 for 1100 cycles. The reasons for the enhanced electrochemical performance, such as the high capacity, good cycling stability, and superior rate capability, are analyzed qualitatively and quantitatively. Quantitative analysis reveals that mixed mechanisms, including capacitance and diffusion, account for the K-ion storage, in which the capacitance plays a more important role. Specifically, the enhanced interlayer spacing (0.39 nm) enables the intercalation of large K ions, while the high specific surface area of ≈1030 m² g^-1 and the dual-heteroatom doping (N and O) are conducive to the reversible adsorption of K ions.

A boronate-decorated porous carbon material derived from a zinc-based metal–organic framework for enrichment of cis-diol-containing nucleosides

A new boronate-decorated carbon material derived from Zn-MOF was synthesized and used to selectively enrich cis-diol nucleosides.

Nitrogen-Doped Porous Carbons from Ionic Liquids@MOF: Remarkable Adsorbents for Both Aqueous and Nonaqueous Media

Porous carbons were prepared from a metal-organic framework (MOF, named ZIF-8), with or without modification, via high-temperature pyrolysis. Porous carbons with high nitrogen content were obtained from the calcination of MOF after introducing an ionic liquid (IL) (IL@MOF) via the ship-in-bottle method. The MOF-derived carbons (MDCs) and IL@MOF-derived carbons (IMDCs) were characterized using various techniques and used for liquid-phase adsorptions in both water and hydrocarbon to understand the possible applications in purification of water and fuel, respectively. Adsorptive performances for the removal of organic contaminants, atrazine (ATZ), diuron, and diclofenac, were remarkably enhanced with the modification/conversion of MOFs to MDC and IMDC. For example, in the case of ATZ adsorption, the maximum adsorption capacity of IMDC (Q₀ = 208 m²/g) was much higher than that of activated carbon (AC, Q₀ = 60 m²/g) and MDC (Q₀ = 168 m²/g) and was found to be the highest among the reported results so far. The results of adsorptive denitrogenation and desulfurization of fuel were similar to that of water purification. The IMDCs are very useful in the adsorptions since these new carbons showed remarkable performances in both the aqueous and nonaqueous phases. These results are very meaningful because hydrophobic and hydrophilic adsorbents are usually required for the adsorptions in the water and fuel phases, respectively. Moreover, a plausible mechanism, H-bonding, was also suggested to explain the remarkable performance of the IMDCs in the adsorptions. Therefore, the IMDCs derived from IL@MOF might have various applications, especially in adsorptions, based on high porosity, mesoporosity, doped nitrogen, and functional groups.

Structural diversity, luminescence and photocatalytic properties of six coordination polymers based on designed bifunctional 2-(imidazol-1-yl)terephthalic acid

Six CPs, based on 2-(imidazol-1-yl)terephthalic acid, have been prepared and characterized.

Coligand syntheses, crystal structures, luminescence and photocatalytic properties of five coordination polymers based on rigid tetracarboxylic acids and imidazole linkers

Coligand syntheses, crystal structures, luminescence and photocatalytic properties of five coordination polymers based on rigid tetracarboxylic acids and imidazole linkers.