Search Results (265)

Direct air capture (DAC), as a complementary strategy to carbon capture and storage (CCS), offers a scalable and sustainable pathway to remove CO₂ directly from the ambient air. This study presents a detailed evaluation of the amine-functionalised metal-organic framework (MOF) sorbent, mmen-Mg₂(dobpdc), for DAC using a temperature–vacuum swing adsorption (TVSA) process. While this sorbent has demonstrated promising performance in point-source CO₂ capture, this is the first dynamic simulation-based study to rigorously assess its effectiveness for low-concentration atmospheric CO₂ removal. A transient one-dimensional TVSA model was developed in Aspen Adsorption and validated against experimental breakthrough data to ensure accuracy in capturing both the sharp and gradual adsorption kinetics. To enhance process efficiency and sustainability, this work provides a comprehensive parametric analysis of key operational factors, including air flow rate, temperature, adsorption/desorption durations, vacuum pressure, and heat exchanger temperature, on process performance, including CO₂ purity, recovery, productivity, and specific energy consumption. Under optimal conditions for this sorbent (vacuum pressure lower than 0.15 bar and feed temperature below 15 °C), the TVSA process achieved ~98% CO₂ purity, recovery over 70%, and specific energy consumption of about 3.5 MJ/KgCO₂. These findings demonstrate that mmen-Mg₂(dobpdc) can achieve performance comparable to benchmark DAC sorbents in terms of CO₂ purity and recovery, underscoring its potential for scalable DAC applications. This work advances the development of energy-efficient carbon removal technologies and highlights the value of step-shape isotherm adsorbents in supporting global carbon-neutrality goals. Full article

Plastic waste and water pollution demand circular economy-driven innovations. This review examines metal–organic framework (MOF) synthesis from polyethylene terephthalate (PET) waste for wastewater treatment. Depolymerized PET yields terephthalic acid and ethylene glycol—essential MOF precursors. We evaluate the following: (1) PET depolymerization (hydrolysis, glycolysis, ammonolysis) for monomer recovery efficiency; (2) MOF synthesis (solvothermal, microwave, mechanochemical) using PET-derived linkers; (3) performance in adsorbing heavy metals, dyes, and emerging contaminants. PET-based MOFs match or exceed commercial adsorbents in pollutant removal while lowering costs. Their tunable porosity and surface chemistry enhance selectivity and capacity. By converting waste plastics into functional materials, this strategy tackles dual challenges: diverting PET from landfills and purifying water. The review underscores the environmental and economic benefits of waste-sourced MOFs, proposing scalable routes for sustainable water remediation aligned with zero-waste goals. Full article

Phosphate and fluoride ions are common water pollutants whose presence and excessive discharge cause potential hazards to the environment and human health. MOF materials commonly used to remove phosphate and fluoride ions are usually in powder form, with low recovery during regeneration. Herein, to address these issues, Fe₃O₄@La-Zr-MOFs magnetic composites for phosphate and fluoride removal were fabricated by means of the hydrothermal method. The adsorption properties of the adsorbent were systematically assessed by means of adsorption experiments. The magnetic Fe₃O₄@La-Zr-MOFs exhibited a magnetic recovery efficiency of 93%, and they could maintain outstanding adsorption performance at a broad range of pH values and superior selectivity for phosphate and fluoride ions. The adsorption process conformed to the Langmuir isotherm and pseudo-second-order models, indicating that it was dominated by monomolecular chemisorption. Further characterization of the Fe₃O₄@La-Zr-MOFs before and after adsorption and kinetic thermodynamic investigation revealed that the elimination mechanism of phosphate and fluoride ions by Fe₃O₄@La-Zr-MOFs includes ion exchange, electrostatic interactions, and surface complexation. This study demonstrates that magnetic reusable Fe₃O₄@La-Zr-MOFs composites have great promise for phosphate and fluoride removal and recovery. Full article

Micropollutants (MPs), which include both natural and manmade substances, are becoming more prevalent in aquatic habitats as a result of the insufficient removal of these compounds in wastewater treatment plants (WWTPs). Advanced remediation techniques are required due to their persistence and potential ecotoxicological hazards. Although adsorption and photo(electro)catalysis exhibit potential in laboratory-scale investigations, the effects of their use in actual WWTP systems are still poorly understood. However, before large-scale application can be implemented, a number of issues need to be resolved, including material limitations, reactor design and optimization, and actual wastewater complexities. This study critically evaluates the application of adsorption and photo(electro)catalysis to actual wastewater, as well as recent advancements in adsorption and photo(electro)catalytic systems for the removal of micropollutants. We also explore the particular difficulties and strategies involved in the large-scale use of adsorption and photo(electro)catalysis in the treatment of wastewater. Emerging trends such as nanocomposites, metal–organic frameworks (MOFs), heterojunctions, and single-atom catalysts (SACs) are highlighted by the bibliometric analysis. We also evaluate MPs’ ecological effects in aquatic environments and the incorporation of artificial intelligence (AI) for process optimization. A strategy for transferring nanotechnologies from laboratory-scale research to wastewater treatment implementation is presented in this paper. In this strategy, implementation is proposed based on actual wastewater conditions, focusing on the development of adsorbents and catalysts, reactor design and optimization, synergy between adsorption and catalysis, life cycle analysis, and cost–benefit studies. Full article

An outstanding adsorbent, such as the metal–organic framework (MOF) MIL-101 (Cr), was employed to study the adsorption of two dyes, namely reactive red 2 (RR2) and reactive blue 19 (RB19). Experimental adsorption data were retrieved at T = 25, 35 and 45 °C and analyzed to define the adsorption mechanism of these dyes. A modeling approach based on a double-layer model derived from statistical physics was used. The maximum adsorption capacity (MAC) was found to be 875, 954 and 1002 mg/g for RR2 and 971, 1093 and 1148 mg/g for RB19, at T = 25, 35 and 45 °C, respectively. These values indicate that MIL-101 (Cr) exhibits outstanding performance in removing potential water pollutants such as the RR2 and RB19 dyes. The possible orientations of the RR2 and RB19 dyes upon adsorption were determined by analyzing the number of dye molecules bound per MIL-101 (Cr) active sites during the adsorption process. It was found that the RR2 dye was removed via a mixed parallel and non-parallel orientation on MIL-101 (Cr), while RB19 was removed via an inclined orientation at higher temperatures. The adsorption mechanism suggested that MIL-101 (Cr) site density was reduced due to an exothermic effect, which decreases the number of active sites participating in dye adsorption, even though the reduction in water adsorption may be attributed to the overall endothermic behavior. From the adsorption energy (AE) and the chemical structure of MIL-101 (Cr) and both dyes, it was concluded that hydrogen bonds, Van der Waals forces and π-π stacking are involved in the dye removal process. This research provides new physical insights into the adsorption mechanism of two relevant dyes on an outstanding adsorbent such as the MIL-101 (Cr) MOF. Full article

UiO-66-NH₂ is a metal–organic framework (MOF) with open metal sites, making it a promising candidate for adsorption and catalysis. However, the powdery texture of MOFs and the use of toxic solvents during synthesis limit their application. A novel solution to this issue is to create a layered porous composite by encasing the MOF within a flexible and structurally robust aerogel substrate using safe, eco-friendly, and green solvents such as ethanol. The fibrous MOF aerogels, characterized by a desirable macroscopic shape of cylindrical block and hierarchical porosity, were synthesized by two approaches: in situ growth of amine-functionalized UiO-66-NH₂ crystals on a TEMPO-oxidized cellulose nanofiber (TOCNF) and ex situ crosslinking of UiO-66-NH₂ crystals onto a TOCNF network to form UiO-66-NH₂/TOCNF. The incorporation of MOF into the cellulose nanofibrils via the in situ method reduces their aggregation potential, alters the nucleation/growth balance to produce smaller MOF crystals, and enhances mechanical flexibility, as evidenced by SEM images. The three adsorbents, including UiO-66-NH₂, ex situ UiO-66-NH₂/TOCNF, and in situ UiO-66-NH₂/TOCNF, were synthesized and used in this study. The effects of pH, time, temperature, and initial concentration were studied. A maximum adsorption capacity (Qmax) of 549.45 mg/g for Congo Red (CR) and 171.23 mg/g for Orange II (ORII) was observed at pH 6, using 10 mg of in situ UiO-66-NH₂/TOCNF at 40 °C with a contact time of 75 min for CR and 2 h for ORII. The adsorption of both dyes primarily occurs through monolayer chemisorption on the in situ UiO-66-NH₂/TOCNF. The main removal mechanisms were hydrogen bonding and surface complexation. The noteworthy adsorption capacity of in situ UiO-66-NH₂/TOCNF coupled with environment-friendly fabrication techniques indicates its potential applications on a large scale in real wastewater systems. Full article

To address the limitations of low CuO loading and poor dispersion in conventional supported adsorbents, in this study, MOF (metal–organic framework)-derived CuO with Ce doping (Cu_xCe_yO) was synthesized and used for the adsorption–oxidation of PH₃ under low-temperature and low-oxygen conditions. The results demonstrated that Ce doping increased the PH₃ capacity of the adsorbent from 75.54 mg·g⁻¹ (MOF-derived CuO) to 226.87 mg·g⁻¹ (Cu₁Ce_0.2O). The characterization results indicated that Ce doping significantly altered the physicochemical properties of CuO. Specifically, Cu₁Ce_0.2O exhibited optimal CuO dispersion, the highest adsorbed oxygen concentration, superior redox performance, an increased number of basic sites, and a larger specific surface area and pore volume, all contributing to its improved performance. Analysis of the exhausted adsorbent revealed the formation of Cu₃P and phosphoric acid. And the deactivation of the adsorbent can be attributed to the consumption of CuO and the blockage of pore structure. Surprisingly, the exhausted adsorbent demonstrated considerable photocatalytic performance due to the formation of Cu₃P, enabling the resource utilization of the waste adsorbent, making it a promising material for the adsorption–oxidation of PH₃. This waste-to-resource conversion reduces hazardous solid waste while creating value-added photocatalysts, establishing a sustainable lifecycle from pollutant removal to functional material regeneration. Full article

In this work, hollow dodecahedral carbon structures with abundant N-doping sites and metal nanoparticles (NC-Co-CNTs) based on MOF-derivative materials were designed and prepared as host materials for lithium metal to ensure uniform lithium deposition on a Cu current collector. NC-Co-CNTs have good electrical conductivity, which ensures fast electron transport and Li⁺ transfer. The carbon nanotubes catalytically derived by Co can promote the uniform distribution of Li⁺ along the hollow dodecahedral carbon surface and deposition inside the cavity, and the larger electronegativity of N-doped sites and lithophilic sites such as Co nanoparticles can effectively adsorb lithium, inducing the Li⁺ to be deposited in the form of spherical lithium in a dendrite-free state, inhibiting the growth of dendritic lithium and improving the electrochemical performance of the lithium metal battery. Based on the above advantages, the electrodes of NC-Co-CNT-based symmetric cells present superior cycling performance for more than 1100 h with low overpotential at 1 mAh cm⁻²/1 mAh·cm⁻². Even cycling at high current density of 5 mA cm⁻² and high deposition parameters of 5 mAh cm⁻², it still cycles for up to 800 h at a relatively low overpotential. Full article

Arsenic is a highly toxic element, and excessive levels can affect human health. Composites possess a larger specific surface area and better adsorption performance than single-MOF materials. In this paper, a simple novel nanocomposite (MnFe₂O₄@Fe-UiO-67) was synthesized by the one-pot method for the removal of arsenic from industrial wastewater. The synthesis and adsorption mechanism of the adsorbent were analyzed by a series of characterizations. The results showed that the adsorption behavior of MnFe₂O₄@Fe-UiO-67 was consistent with the pseudo-secondary kinetics and Langmuir isotherm model, i.e., it is a monomolecular layer chemisorption. Characterization by Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) showed that the active site formed a strong coordination bond (As-O bond) with As ions to achieve efficient adsorption. At 298 K and pH = 10, the arsenic removal rate can reach 98.43%, and the adsorption capacity is 600.25 mg/g, which is more than most of the existing reported adsorbents. Through thermodynamic analysis, it is found that the adsorption of As ions by the adsorbent is a spontaneous exothermic process. It can exhibit excellent adsorption performance at room temperature without the need for additional energy consumption. This adsorbent has great development prospects in the treatment of wastewater. Full article

Heterocyclic aromatic amines (HAAs), known for their mutagenic and carcinogenic potential, are formed during the heating of protein-rich food items. Detecting HAAs swiftly and accurately poses challenges due to complex food matrices and low HAA concentrations. In this study, a simple and efficient magnetic solid-phase extraction (MSPE) strategy was developed for the simultaneous isolation and enrichment of three HAAs such as 2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx), and 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) in processed meats, employing the magnetic covalent organic framework Fe₃O₄@MOF-545-AMSA as an adsorbent. It was synthesized via a solvothermal method, with Fe₃O₄ as the magnetic core. Its building blocks are as follows: zirconium (Zr) as the coordination metal ion, tetrakis(4-carboxyphenyl)porphyrin and benzoic acid as organic ligands, and aminomethanesulfonic acid (AMSA). This composite captures targeted HAAs efficiently by exploiting the unique porous MOF-545-AMSA structure, specific metal–ligand coordination, and AMSA’s amino and sulfonic acid groups. The quantification of HAAs was achieved through the combination of Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) and MSPE, demonstrating satisfactory linearity (R² ≥ 0.9917), high recovery rates (83.7–111.0%), and low detection limits (0.1–1.0 μg/kg). Moreover, an automated high-throughput detection system was developed using MSPE to assess the presence of HAAs in meat products. Full article

Sodium alginate is a polysaccharide compound extracted from natural plants that has been successfully prepared as a hydrogel for adsorbing and removing pollutants. However, the selectivity of alginate-based hydrogels to malachite green (MG) dyes and the stability of alginate-based hydrogels in air cannot meet requirements. Herein, metal–organic frameworks (MOFs) are embedded into a magnetic hydrogel to create magnetic MOF hydrogel (MMOF hydrogel) microspheres with high adsorption capacity. The morphology and physical properties of the MMOF hydrogel microspheres were characterized by scanning electron microscopy and optical microscopy. Under optimized adsorption conditions, the adsorption rate of MG reached 96.5%. The maximum adsorption capacity of the MMOF hydrogel for MG was determined to be 315 mg·g⁻¹. This highly efficient magnetic adsorbent for dye removal has considerable potential for rapidly removing toxic contaminants from aquatic food matrices for high-throughput sampling pretreatment, which has the potential for rapid, green, large-scale environmental remediation in the future. Full article

Removing arsenic from industrial wastewater remains a crucial task. To protect public health and safety and address environmental pollution, there is an urgent need for a material that can efficiently remove arsenic from wastewater. In this study, a simple and highly efficient adsorbent, namely, a Co/Mn bimetallic-based organic framework (CoMn-MOF-74) adsorbent, was prepared by a hydrothermal synthesis method. Experimental results demonstrate that CoMn-MOF-74 exhibits excellent adsorption capacity for arsenic ions in wastewater. It was found that the optimal Co/Mn molar ratio of the adsorbent is 1:1. The CoMn-MOF-74 adsorbent compensates for the deficiencies in the adsorption performance of Co-MOF-74 and Mn-MOF-74, increasing the adsorption rate and the highest adsorption capacity. The maximum adsorption rate of CoMn-MOF-74 is 93.4%, and the highest adsorption capacity is 531 mg/g. Fitting CoMn-MOF-74 according to two categories of models, specifically, the adsorption isotherm and adsorption kinetics models, indicated that CoMn-MOF-74 adheres to the Langmuir model and pseudo-second-order kinetic model. The adsorption process is mainly chemical adsorption and monolayer adsorption. Analysis by XPS revealed that metal–oxygen groups and hydroxyl groups play important roles in the adsorption process. In conclusion, the CoMn-MOF-74 adsorbent shows excellent prospects in the field of arsenic adsorption from wastewater and is a promising arsenic-removing adsorbent. Full article

In this review article the synthesis and solid state structure of squaramide/squarate based metal–organic frameworks (MOFs) are analyzed and discussed. In detail, a thorough search in the literature revealed the successful utilization of these two organic molecules as MOF building blocks capable of catalyzing (i) water splitting reactions, (ii) electrocatalytic oxygen evolution reactions, and (iii) Michael addition reactions. Additionally, some of the highlighted examples also utilized these two molecular synthons to compose MOFs exhibiting gas adsorbent properties, concretely for capturing propadiene and propylene. In each of the selected examples a theoretical study of the noncovalent interactions (NCIs) established between the squaramide/squarate-based MOF and the guest molecules trapped inside was carried out, providing additional information regarding the strength of the MOF–guest interactions, which certainly influence the catalytic/adsorbent capabilities of these materials. We believe that the examples collected herein will be useful for those scientists working in the fields of supramolecular chemistry, crystal engineering, catalysis, and materials science by providing a retrospective guide on the role of squaramide and squarate in the formation of MOFs. Full article

The continuous increase in global energy consumption has caused a considerable increase in CO₂ emissions and environmental problems. To address these challenges, adsorbents and catalytic materials that can effectively reduce the CO₂ levels in the atmosphere should be developed. Metal–organic frameworks (MOFs) have emerged as promising materials for CO₂ capture owing to their high surface areas and tunable structures. Herein, the CO₂ adsorption properties of MIL-100(Fe) and UiO-66(Zr) were investigated. Both MOFs exhibited excellent thermal stability and high CO₂ adsorption capacities at 300 K, and they maintained good adsorption properties at 500 K compared to those of activated carbon fiber owing to their high adsorption potentials. A slight change in the UiO-66(Zr) structure and no change in the MIL-100(Fe) structure were observed under the CO₂ atmosphere at 500 K. At that time, CO emissions and changes in the carboxyl and OCO functional groups were observed on MIL-100(Fe), suggesting a mechanism of CO₂ reduction to CO on the bare Fe(II) sites. These findings confirm the potential of MOFs for the thermo-catalytic reduction of CO₂ to achieve effective CO₂ capture and conversion. Full article

Arsenic is a well-known, highly toxic carcinogen element that is widely found in nature, with numerous studies highlighting its hazardous impact on human health and the environment. Therefore, considering its toxicity and adverse health effects on mammals and the environment, rapid, sensitive, and effective methods for the recognition of arsenic are necessary. Over the past decade, a variety of fluorescent probes, such as small molecules, nanomaterials, gold nanoparticles (AuNPs), carbon dots (CDs), quantum dots (QDs), and more, have been designed and successfully employed for the recognition of lethal arsenic. Compared to other conventional sensor materials, sensors based on metal-organic frameworks (MOFs) are advantageous due to their simple preparation, easy functional group modulation, large specific surface area, and excellent chemical stability. In recent years, MOFs have been utilized as dual-functional materials for the detection and adsorptive removal of arsenic from water. This unique functionality distinguishes MOF-based materials from conventional sensors and arsenic adsorbents. Herein, we provide an overview of the state-of-the-art knowledge on the current development of MOFs for the fluorogenic detection of arsenic in aqueous media. Furthermore, the underlying detection mechanisms are also summarized in this review. The existing challenges in this field and potential remedial strategies for improving detection are elaborated upon in the relevant sections. Full article