Tetracycline removal from aqueous solution using zirconium-based metal-organic frameworks (Zr-MOFs) with different pore size and topology: Adsorption isotherm, kinetic and mechanism studies

Room-temperature synthesis of bimetallic ZnCu-MOF-74 as an adsorbent for tetracycline removal from an aqueous solution

The novel bimetallic MOF, ZnCu-MOF-74, has been evaluated for the remediation of tetracycline-contaminated water. ZnCu-MOF-74 was obtained at room temperature, avoiding high pressure and temperature. ZnCu-MOF-74 exhibited chemical stability in the 4-8 pH range. The adsorption result analysis was described using the Elovich kinetic model and the Langmuir adsorption isotherm, suggesting a physicochemical process. The maximum adsorption capacity was estimated at 775.66 mg g-1. The pH of the solution and the presence of ions such as NO3-, SO42-, Na+, Mg2+, Cl-, and Ca2+ had no influence on the removal of tetracycline. In addition, π-interactions and metal complexation were proposed as possible adsorption mechanisms through FT-IR and XPS. ZnCu-MOF-74 showed outstanding cyclability performance, preserving its adsorption capacity after 4 adsorption-desorption cycles, besides exhibiting chemical stability, proving the benefits of applying ZnCu-MOF-74 in the water treatment process.

Polydopamine coating for enhanced electrostatic adsorption of methylene blue by multiwalled carbon nanotubes in alkaline environments

The removal of dye molecules in alkaline environments is an issue that should receive increased attention. In this study, the interaction mechanism between polydopamine-modified multiwalled carbon nanotubes (P-MWCNTs) and multiwalled carbon nanotubes (MWCNTs) with the cationic dye methylene blue (MB) in alkaline environments was explained in depth by adsorption, spectroscopy, and density functional theory (DFT). The mechanism of action and dominant forces between the adsorbent and adsorbate were analyzed graphically by introducing energy decomposition analysis (EDA) and an independent gradient model (IGM) into the DFT calculations. In addition, the force distribution was investigated through an isosurface. Moreover, batch adsorption studies were conducted to evaluate the performance of MWCNTs and P-MWCNTs for MB removal in alkaline environments. The maximum MB adsorption capacities of the MWCNTs and P-MWCNTs in solution were 113.3 mg‧g-1 and 230.4 mg‧g-1, respectively, at pH 9. The IGM and EDA showed that the better adsorption capacity of the P-MWCNTs originated from the enhancement of the electrostatic effect by the proton dissociation of polydopamine. Moreover, the adsorption of MB by MWCNTs and P-MWCNTs in alkaline environments was governed by dispersion and electrostatic effects, respectively. Through this study, it is hoped that progress will be made in the use of DFT to explore the mechanism of adsorbent-adsorbate interactions.

Magnetic sporopollenin supported magnesium nanoparticles for removal of tetracycline as an emerging contaminant from water

Since the release of antibiotics as emerging contaminants into the environmental water can cause severe difficulties for human health, their removal from the water is necessary. In this regard, a novel environmentally friendly adsorbent was developed based on green sporopollenin, which was magnetized and modified with magnesium oxide nanoparticles to produce MSP@MgO nanocomposite. The newly developed adsorbent was applied to remove tetracycline antibiotic (TC) from aqueous media. The surface morphology of the MSP@MgO nanocomposite was characterized using FTIR, XRD, EDX, and SEM techniques. The effective parameters of the removal process were studied, and it was confirmed that the chemical structure of TC was highly affected by changes in pH solution due to different pKa; therefore, the results showed that pH 5 was the optimum. Also, the maximum sorption capacity of MSP@MgO for TC for adsorption was obtained at 109.89 mg.g-1. In addition, the adsorption models were investigated, and the process was fitted with the Langmuir model. Thermodynamic parameters showed that the process was spontaneous (ΔG < 0), endothermic (ΔH > 0) and the adsorption mechanism was following the physisorption mechanism at room temperature.

Cobalt metal replaces Co-ZIF-8 mesoporous material for effective adsorption of arsenic from wastewater

The high cost and low adsorption capacity of primary metal-organic frameworks (ZIF-8) limit their application in heavy metal removal. In this paper, Co/Zn bimetallic MOF materials were synthesized with excellent adsorption performance for As5+. The adsorption reached equilibrium after 180 min and the maximum adsorption was 250.088 mg/g. In addition, Co-ZIF-8 showed strong selective adsorption of As5+. The adsorption process model of Co-ZIF-8 fits well with the pseudo-second-order kinetic model (R2=0.997) and Langmuir isotherm model (R2=0.994), and it is demonstrated that the adsorption behavior of the adsorbent is a single layer of chemical adsorption. In addition, when the adsorbent enters the arsenic-containing solution, the surface of Co-ZIF-8 is hydrolyzed to produce a large number of Co-OH active sites, and As5+ arrives at the surface of Co-ZIF-8 by electrostatic adsorption and combines with the active sites to generate the arsenic-containing complex As-O-Co. After four cycles, Co-ZIF-8 showed 80% adsorption of As5+. This study not only provides a new method to capture As5+ in water by preparing MOF with partial replacement of the central metal, but also has great significance for the harmless disposal of polluted water.

Construction of SU-102 for adsorption and photocatalytic synergistic removal of tetracycline

Tetracycline (TC) is a significant group of broad-spectrum antibiotics that are frequently employed in medical health and animal husbandry. However, the problem of TC residues has been increasing globally with the large-scale production and widespread use, posing a serious threat to the human health and ecological environment. In this paper, a green plant-based MOF SU-102 was prepared, and the adsorption characteristics of SU-102 on TC were investigated. SU-102 was columnar crystal with considerable specific surface area and pore structure, and it could adsorb TC quickly and effectively. And compared to SU-102-a, the adsorption rate of TC by SU-102-b has increased by nearly four times. The adsorption reaction was a spontaneous, entropy-gaining, heat-absorbing process. The adsorption mechanisms between SU-102 and TC were π-π interaction and hydrogen bonding. In addition, SU-102 also had considerable photocatalytic properties, and its application in adsorbent desorption treatment effectively solved the problem of secondary pollution.

Design and Advanced Manufacturing of NU-1000 Metal-Organic Frameworks with Future Perspectives for Environmental and Renewable Energy Applications

Metal-organic frameworks (MOFs) represent a relatively new family of materials that attract lots of attention thanks to their unique features such as hierarchical porosity, active metal centers, versatility of linkers/metal nodes, and large surface area. Among the extended list of MOFs, Zr-based-MOFs demonstrate comparably superior chemical and thermal stabilities, making them ideal candidates for energy and environmental applications. As a Zr-MOF, NU-1000 is first synthesized at Northwestern University. A comprehensive review of various approaches to the synthesis of NU-1000 MOFs for obtaining unique surface properties (e.g., diverse surface morphologies, large surface area, and particular pore size distribution) and their applications in the catalysis (electro-, and photo-catalysis), CO2 reduction, batteries, hydrogen storage, gas storage/separation, and other environmental fields are presented. The review further outlines the current challenges in the development of NU-1000 MOFs and their derivatives in practical applications, revealing areas for future investigation.

Remarkable water-mediated proton conductivity of two porous zirconium(IV)/hafnium(IV) metal-organic frameworks bearing porphyrinlcarboxylate ligands

Obtaining crystalline materials with high structural stability as well as super proton conductivity is a challenging task in the field of energy and material chemistry. Therefore, two highly stable metal-organic frameworks (MOFs) with macro-ring structures and carboxylate groups, Zr-TCPP (1) and Hf-TCPP (2) assembled from low-toxicity as well as highly coordination-capable Zr(IV)/Hf(IV) cations and the multifunctional linkage, meso-tetra(4-carboxyphenyl)porphine (TCPP) have attracted our strong interest. Note that TCPP as a large-size rigid ligand with high symmetry and multiple coordination sites contributes to the formation of the two stable MOFs. Moreover, the pores with large sizes in the two MOFs favor the entry of more guest water molecules and thus result in high H2O-assisted proton conductivity. First, their distinguished structural stabilities covering water, thermal and chemical stabilities were verified by various determination approaches. Second, the dependence of the proton conductivity of the two MOFs on temperature and relative humidity (RH) is explored in depth. Impressively, MOFs 1 and 2 demonstrated the optimal proton conductivities of 4.5 × 10-4 and 0.78 × 10-3 S·cm-1 at 100 °C/98 % RH, respectively. Logically, based on the structural information, gas adsorption/desorption features, and activation energy values, their proton conduction mechanism was deduced and highlighted.

Development of hybrid MIL-53(Al)@CBS for ternary adsorption of tetracyclines antibiotics in water: Physical interpretation of the adsorption mechanism

In this study, a hybrid material, MIL-53(Al)@CBS, was synthesized via the solvothermal method, involving the growth of MIL-53(Al) crystals on cocoa bean shell residues (CBS). Physicochemical characterization techniques, including TGA, BET, FTIR, XRD, and SEM, confirmed successful hybridization. MIL-53(Al)@CBS was employed as an adsorbent for antibiotics (oxytetracycline, tetracycline, chlortetracycline) separation from aqueous solutions. Parameters like pH, adsorbent dose, concentration, time, and temperature were systematically evaluated. FTIR revealed π-π interactions and hydrogen bonds between tetracyclines and the adsorbent. MIL-53(Al)@CBS exhibited adsorption, with removal rates up to 98.92%, 99.04%, and 98.24% for OTC, TC, and CTC, respectively. Kinetics suggested adsorption depends on active site availability, with TC adsorbing fastest. Microscopic models showed adsorption on three distinct active site types with different affinities without competition or adherence to the Langmuir hypothesis. Importantly, MIL-53(Al)@CBS maintained high adsorption capacity even after ten washing cycles, highlighting its potential for water treatment.

Highly efficient removal of tetracyclines from water by a superelastic MOF-based aerogel: Mechanism quantitative analysis and dynamic adsorption

Metal-organic frameworks (MOFs) were promising adsorbents for removing antibiotics, but the inherent poor recyclability of MOF powders limits further application. Moreover, the dominant adsorption mechanisms and their quantitative assessment are less studied. Here, ultrahigh adsorption capacities of 821.51 and 931.87 mg g-1 for tetracycline (TC) and oxytetracycline (OTC), respectively, were realised by a novel adsorbents (biochar loaded with MIL-88B(Fe), denoted as BC@MIL-88B(Fe)), which were further immobilised in a 3D porous gelatin (GA) substrate. The obtained BCM/GA200 showed superior adsorption performance under wide pH ranges and under the interference of humic acid. Moreover, it can survive >8 cycles and even maintain high adsorption efficiency in different actual water samples. Notably, BCM/GA200 can selectively remove tetracyclines in a multivariate system containing other kinds of antibiotics and from a dynamic adsorption system. Most importantly, the results of X-ray photoelectron spectroscopy, 2D Fourier transform infrared correlation spectroscopy (2D-FTIR-COS) and density functional theory techniques revealed that (1) for TC adsorption, at pH < 4.0, the contribution of complexation was 25 %-45 %, whereas pore filling and hydrogen bonding accounted for 39 %-72 % of the total uptake. At 4.0 < pH < 10.0, the contribution of complexation increased to 60 %-82 %, whereas electrostatic attraction and π-π interaction were 4 %-13 % and 2 %-10 %, respectively. (2) For OTC adsorption, complexation was dominant at 3.0 < pH < 10.0, accounting for 55 %-86 % of the total uptake, and electrostatic attraction and π-π interactions caused 3 %-10 % and 3 %-15 %, respectively. (3) At pH > 10.0, pore filling dominated TC and OTC adsorption. Finally, the reaction sequences of the main adsorption mechanisms were also probed by 2D-FTIR-COS. This work solves the poor recyclability of MOF powders and provides a mechanistic insight into antibiotic removal by MOFs.

Advances in metal-organic frameworks for water remediation applications

Rapid industrialization and agricultural development have resulted in the accumulation of a variety of harmful contaminants in water resources. Thus, various approaches such as adsorption, photocatalytic degradation and methods for sensing water contaminants have been developed to solve the problem of water pollution. Metal-organic frameworks (MOFs) are a class of coordination networks comprising organic-inorganic hybrid porous materials having organic ligands attached to inorganic metal ions/clusters via coordination bonds. MOFs represent an emerging class of materials for application in water remediation owing to their versatile structural and chemical characteristics, such as well-ordered porous structures, large specific surface area, structural diversity, and tunable sites. The present review is focused on recent advances in various MOFs for application in water remediation via the adsorption and photocatalytic degradation of water contaminants. The sensing of water pollutants using MOFs via different approaches, such as luminescence, electrochemical, colorimetric, and surface-enhanced Raman spectroscopic techniques, is also discussed. The high porosity and chemical tunability of MOFs are the main driving forces for their widespread applications, which have huge potential for their commercial use.

Removal of fluorouracil from aqueous environment using magnetite graphene oxide modified with γ-cyclodextrin

Fluorouracil (FU) is a widely utilized antineoplastic medication in the pharmaceutical industry for combating gastrointestinal cancers. However, its presence in wastewater originating from pharmaceutical facilities and hospital effluents has a potential effect on DNA, and cannot be efficiently eliminated through conventional treatment methods. Consequently, the adoption of advanced technologies becomes crucial for effectively treating such wastewater. Accordingly, this study investigated the efficiency of magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin for removing fluorouracil from aqueous solutions. The magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin was synthesized via the hydrothermal method. Next, the effect of pH, temperature, adsorbent content, and contact time on the fluorouracil removal efficiency was explored. Ultimately, the experimental data were matched against Langmuir, Freundlich, and Temkin isotherms and Kinetic models. Accordingly, the efficiency of the absorbent used was dependent on the pH, contact time, temperature, and initial concentration of the adsorbent. The results indicated that the maximum removal efficiency for fluorouracil was achieved within the contact time of 45 min and adsorbent content of 0.020 g. In addition, the optimal pH for removing the medicine was 7. The conditions of the adsorption process followed Langmuir isotherm with correlation coefficients of 0.992 and a quasi-second kinetic model with a correlation coefficient of 0.999, with the maximum adsorption capacity of the adsorbent synthesized for the evaluated medicine estimated as 190.9 mg/g. The results showed that the magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin could be used as an effective and available adsorbent for removing fluorouracil from pharmaceutical wastewater.

High-efficient removal of anionic dye from aqueous solution using metal-organic frameworks@chitosan aerogel rich in benzene structure

With the exponentially increase of dye pollutants, the purification of dye wastewater has been an urgent ecological problem. As a novel type of porous adsorbent, metal-organic frameworks still face challenges in recyclability, agglomeration, and environmentally unfriendly synthesis. Herein, MOF-525 was in-situ growth onto the surface of the chitosan (CS) beads to fabricate MOF-525@CS aerogel. CS was utilized as substrate to uniformly disperse MOF-525, thereby significantly mitigating agglomeration and improving recyclability of MOF-525. The characterization results shown that MOF-525@CS aerogel had a high specific surface area of 103.0 m2·g-1, and MOF-525 was uniformly distributed in the 3D porous structure of CS, and the presence of benzoic acid was detected. The MOF-525@CS aerogel had a remarkable adsorption capacity of 1947 mg·g-1 for Congo red, which is greater than the sum of its parts. MOF-525@CS aerogel also inherited the rapid adsorption ability of MOF-525, removing 80 % of Congo red within 600 min. Such excellent adsorption performance can be attributed to the benzoic acid trapped by CS via CN band to enhance the π-π stacking interactions. Additionally, the utilization of benzoic acid makes the synthesis process of MOF-525@CS aerogel more environmentally friendly. The high-efficient MOF-525@CS aerogel is a competitive candidate for dye pollution adsorption.

Porous metal-organic framework-acrylamide-chitosan composite aerogels: Preparation, characterization and adsorption mechanism of azo anionic dyes adsorbed from water

Micro- and nano-metal-organic frameworks with different adsorption properties were prepared by a time-modulation hydrothermal method. By comparing the adsorption properties, the most effective MIL-68(Fe)-12 was selected to be mixed with chitosan (CS), and porous metal-organic framework-acrylamide-chitosan composite aerogel (PMACA) was prepared by introducing acrylamide prior to glutaraldehyde crosslinking. The adsorption capacity of PMACA doped with acrylamide was as high as 2086.44 mg·g-1. The adsorption performance of PMACA was 1.48 times higher compared to the porous metal-organic framework-chitosan composite aerogel (PMCA) undoped with acrylamide. With the introduction of acrylamide, the stability of PMACA was improved, making it less prone to dispersion and decomposition. Structural characterization and adsorption properties were analyzed using methods such as XRD, FTIR, TGA, SEM, BET, and Zeta potential. The adsorption performance of PMACA was investigated further through batch tests with variables such as adsorbent dosage, pH, contact time, initial CR solution concentration, and temperature. The model fitting of PMACA was consistent with the pseudo-second-order model and the Sips model. The adsorption thermodynamics showed that high temperature promoted spontaneous adsorption behavior. PMACA showed a recovery rate of approximately 86 % after six cyclic adsorption tests. PMACA maintained a recovery rate of roughly 86 % after six cyclic adsorption tests. The combined effects of electrostatic attraction, hydrogen bonding, and π-π conjugation resulted in excellent adsorption performance, while pore filling also contributed to the efficient adsorption of Congo red (CR).

The L-proline modified Zr-based MOF (Basu-proline) catalyst for the one-pot synthesis of dihydropyrano[3,2-c]chromenes

A novel, reusable, and efficient L-proline-modified Zr-based metal-organic framework (Basu-proline) was designed, synthesized, and characterized by Fourier Transform-Infrared spectroscopy (FT-IR), Energy-Dispersive X-ray spectroscopy (EDX), elemental mapping, Field Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction analysis (XRD), Thermo-Gravimetric-Differential Thermal Analysis (TGA-DTA), and N2 adsorption-desorption isotherms. Then, its catalytic performance was assessed in the synthesis of dihydropyrano[3,2-c]chromenes via the one-pot, three-component tandem condensation reaction of 4-hydroxycoumarin, aromatic aldehydes and malononitrile. The Basu-proline catalyst exhibited a better efficiency than some reported protocols regarding higher yields, lower reaction times, and simple separation.

Preparation of a Multifunctional and Multipurpose Chitosan/Cyclodextrin/MIL-68(Al) Foam Column and Examining Its Adsorption Properties for Anionic and Cationic Dyes and Sulfonamides

A multifunctional cylindrical hybrid foam column, referred to as the chitosan/cyclodextrin/MIL-68(Al) (CS/CD/MIL-68(Al)) foam column, was prepared for the first time. The prepared foam column could be used for the adsorption/removal of hydrophilic and hydrophobic contaminants by different forms. Here, it was placed in hydrophilic dye solutions to investigate the adsorption behavior of methylene blue and trypan blue. The adsorption process followed the pseudo-second-order kinetic model with R2 ranging from 0.9983 to 0.9998 for methylene blue and from 0.9993 to 1.0000 for trypan blue, and the adsorption process was consistent with the Langmuir isothermal model with R2 greater than 0.96. The RL values for methylene blue and trypan blue were 0.8871 and 0.5366, respectively, which were present between 0 and 1, indicating that the adsorption behaviors of the two dyes onto the CS/CD/MIL-68(Al) foam column were favorable. The maximum adsorption capacities (Qm) of methylene blue and trypan blue were 60.61 and 454.55 mg/g at 298 K, respectively. Also, the CS/CD/MIL-68(Al) foam column was spun into a syringe and used to adsorb trace hydrophobic sulfonamides from water in the form of filtration. The porous structure impeded the need for any external force and equipment, allowing the water sample to pass through the foam column smoothly. The conditions of the CS/CD/MIL-68(Al) foam column were optimized. The adsorption was carried out under the condition of pH = 4, the amount of the adsorbent was two foam columns, and no salt was added. It was found that the removal rate of the CS/CD/MIL-68(Al) foam column for six sulfonamides was 100%, and it could be reused at least five times. Therefore, this CS/CD/MIL-68(Al) foam column had a simple preparation method, offered a flexible and diverse form of use, was nonpolluting, biodegradable, and reusable, and could have a wider application in the field of environmental pollutant removal and adsorption.

Functional MOF-Based Materials for Environmental and Biomedical Applications: A Critical Review

Over the last ten years, there has been a growing interest in metal-organic frameworks (MOFs), which are a unique category of porous materials that combine organic and inorganic components. MOFs have garnered significant attention due to their highly favorable characteristics, such as environmentally friendly nature, enhanced surface area and pore volume, hierarchical arrangements, and adjustable properties, as well as their versatile applications in fields such as chemical engineering, materials science, and the environmental and biomedical sectors. This article centers on examining the advancements in using MOFs for environmental remediation purposes. Additionally, it discusses the latest developments in employing MOFs as potential tools for disease diagnosis and drug delivery across various ailments, including cancer, diabetes, neurological disorders, and ocular diseases. Firstly, a concise overview of MOF evolution and the synthetic techniques employed for creating MOFs are provided, presenting their advantages and limitations. Subsequently, the challenges, potential avenues, and perspectives for future advancements in the utilization of MOFs in the respective application domains are addressed. Lastly, a comprehensive comparison of the materials presently employed in these applications is conducted.

Porous biochar derived from walnut shell as an efficient adsorbent for tetracycline removal

In this study, a high-performance porous adsorbent was prepared from biochar through a simple one-step alkali-activated pyrolysis treatment of walnut shells, and it was effective in removing tetracycline (TC). The specific surface area (SSA) of potassium hydroxide-pretreated walnut shell-derived biochar pyrolyzed at 900°C (KWS900) increased remarkably compared to that of the pristine walnut shell and reached 1713.87±37.05 m²·g^-1. The maximum adsorption capacity of KWS900 toward TC was 607.00±31.87 mg·g^-1. The pseudo-second-order kinetic and Langmuir isotherm models were well suited to describe the TC adsorption process onto KWS900. The KWS900 exhibited high stability and reusability for TC adsorption in the presence of co-existing anions or cations over a wide pH range of 1.0-11.0. Further investigations demonstrated that the proposed adsorption mechanism involved pore filling, hydrogen bonding, π-π stacking, and electrostatic interaction. These findings provide a valuable reference for developing biochar-based adsorbents for pollutant removal.

Construction of ZnIn2S4/MOF-525 heterojunction system to enhance photocatalytic degradation of tetracycline

Zirconium-based porphyrin metal organic frameworks (Zr-PMOFs) had attracted attention in the field of photocatalysis in recent years. However, the recombination of photogenerated carriers of monomer PMOF limits its performance of photocatalytic organic pollutants degradation. Metal sulfide has a suitable visible band gap, which can form a heterojunction with MOF materials to enhance the photocatalytic efficiency of MOF. Therefore, a typical metal sulfide semiconductor ZnIn₂S₄ (ZIS) was introduced into a Zr-MOF (MOF-525) by solvothermal method to prepare a series of ZIS/MOF-525 (ZIS/MOF-525-1, ZIS/MOF-525-2, ZIS/MOF-525-3 and ZIS/MOF-525-4) composite photocatalysts in this work. The results of characterization analysis, optical analysis and electrochemical analysis showed that the interface of ZIS/MOF-525 formed a typical type-II heterojunction, which accelerated the electron transport rate and effectively inhibited the recombination of photogenerated e^- and h⁺ in MOF-525. The optimal removal efficiency of tetracycline (TC) by ZIS/MOF-525-3 (the mass of MOF-525 is 30 mg) reached 93.8% under 60 min visible light illumination, which was greater than that of pure MOF-525 (37.2%) and ZnIn₂S₄ (70.0%), and it still maintained good stability after five cycles reusing experiment. This work provides feasible insight for the preparation of novel and efficient PMOF-based photocatalysts in the future.

Metal-Organic Framework-Based Materials for Wastewater Treatment: Superior Adsorbent Materials for the Removal of Hazardous Pollutants

In previous years, different pollutants, for example, organic dyes, antibiotics, heavy metals, pharmaceuticals, and agricultural pollutants, have been of note to the water enterprise due to their insufficient reduction during standard water and wastewater processing methods. MOFs have been found to have potential toward wastewater management. This Review focused on the synthesis process (such as traditional, electrochemical, microwave, sonochemical, mechanochemical, and continuous-flow spray-drying method) of MOF materials. Moreover, the properties of the MOF materials have been discussed in detail. Further, MOF materials' applications for wastewater treatment (such as the removal of antibiotics, organic dyes, heavy metal ions, and agricultural waste) have been discussed. Additionally, we have compared the performances of some typical MOFs-based materials with those of other commonly used materials. Finally, the study's current challenges, future prospects, and outlook have been highlighted.

The effects of UiO-66 ultrafine particles on the rapid detection of sulfonamides in milk: Adsorption performance and mechanism

Nanoscale MOFs particles possess both excellent adsorption and dispersion properties. In this study, ultrafine particles UiO-66 (UP/UiO-66) with a particle size below 50 nm were synthesised by a template-controlled method. UP/UiO-66 was able to achieve a maximum adsorption capacity of 139.64 mg/g for 5 methoxylated sulfonamides. Adsorption studies showed that UP/UiO-66 adsorption of sulfonamides can be classified as a pseudo-secondary kinetic adsorption model for single molecular layer adsorption. ELISA (validated by Raman and molecular docking) showed that the sulfonamide molecule was still immunoreactive with antibodies after adsorption by UP/UiO-66. In 15 min, UP/UiO-66 could be used directly in the ELISA test for sulfonamides in milk without elution and separation. The LOQ (IC₂₀) of UP/UiO-66-ELISA for sulfonamides in milk was 0.21-2.05 ng/mL. The ultrafine particle strategy of UiO-66 is expected to be applied to other MOFs and used as a general pretreatment material for residue monitoring in complex matrices.

Metal-organic frameworks for food contaminant adsorption and detection

Metal-organic framework materials (MOFs) have been widely used in food contamination adsorption and detection due to their large specific surface area, specific pore structure and flexible post-modification. MOFs with specific pore size can be targeted for selective adsorption of some contaminants and can be used as pretreatment and pre-concentration steps to purify samples and enrich target analytes for food contamination detection to improve the detection efficiency. In addition, MOFs, as a new functional material, play an important role in developing new rapid detection methods that are simple, portable, inexpensive and with high sensitivity and accuracy. The aim of this paper is to summarize the latest and insightful research results on MOFs for the adsorption and detection of food contaminants. By summarizing Zn-based, Cu-based and Zr-based MOFs with low cost, easily available raw materials and convenient synthesis conditions, we describe their principles and discuss their applications in chemical and biological contaminant adsorption and sensing detection in terms of stability, adsorption capacity and sensitivity. Finally, we present the limitations and challenges of MOFs in food detection, hoping to provide some ideas for future development.

Adsorption performance and optimization by response surface methodology on tetracycline using Fe-doped ZIF-8-loaded multi-walled carbon nanotubes

Herein, an iron-doped ZIF-8-loaded multi-walled carbon nanotube (FZM) was synthesized and its adsorption performance on tetracycline (TC) was investigated. The experimental conditions (solution pH, temperature, adsorbent dose) were optimized by Box-Behnken design (BBD) in response surface methodology (RSM). The results show that the adsorption effect of TC by FZM is optimal under the conditions of temperature = 298 K, pH = 6, and contact time = 360 min. The adsorption processes of TC by FZM follow the pseudo-second-order (PSO) kinetic and Freundlich isotherm models, indicating that chemisorption is the dominant factor and the adsorption reaction is multi-layer, with a theoretical maximum saturation capacity of 1111.11 mg/g at 298 K. The adsorption thermodynamic results indicate that the adsorption of TC by FZM is a spontaneous and endothermic process. The mechanism of TC adsorption by FZM possibly occurs through hydrogen bonding, surface complexation, π-π interaction, and electrostatic interaction. From the statistical results, the optimal adsorption capacity of TC by FZM is 599.78 mg/g at a pH of 7.1, a temperature of 312.5 K, and an adsorbent dose of 64.43 mg/L, with a deviation of 1.73% from the actual value. Furthermore, regeneration experiments demonstrate that FZM has excellent reusability with a 15% loss of adsorption capacity after four cycles. This study provides some insights to study the adsorption behavior of TC by MOFs and the optimization of the adsorption experimental conditions, and also shows the potential of FZM for TC removal.

Adsorption of 2,4-dichlorophenoxyacetic acid by UiO-66-NH2 obtained in a green way

In this study, a zirconium elemental organic framework (UiO-66-NH₂) was prepared by a green synthesis method and showed a good adsorption performance for removing 2,4-dichlorophenoxyacetic acid (2,4-D) from water. UiO-66-NH₂ was analyzed by a variety of characterization methods and the adsorption properties of 2,4-D on UiO-66-NH₂ were investigated by static adsorption experiments. The results showed that the adsorption of 2,4-D had a wide pH range (2-10) and good salt tolerance with the adsorption equilibrium time about 2 h. The maximum adsorption capacity from Langmuir was up to 652 mg g^-1 at 303 K. The isotherms can be described by Langmuir model and the adsorption kinetics was consistent with pseudo-second-order kinetic model and Elovich model. The regeneration efficiency was still 95% after 5 cycles with 0.01 mol L^-1 NaOH as desorption solution. The feasibility of practical application of UiO-66-NH₂ was explored by simulating actual wastewater at different pH. UiO-66-NH₂ is promising to remove 2,4-D from water.

Coupling humic acid in Fe-bearing montmorillonite for enhanced adsorption and catalytic degradation of tetracycline

Clay-based materials have attracted attention owing to their dual effects of adsorption and advanced oxidation degradation in removing organic pollutants. In this study, the introduction of humic acid (HA) in the Fe-bearing montmorillonite (Fe-Mt) nano platform enhanced its tetracycline (TC) adsorption and degradation were investigated. The result showed that the adsorption and degradation efficiency of humic acid/poly-hydroxyl-iron/montmorillonite (HA-Fe-Mt) was greater than those of Fe-Mt. The adsorption performance and characterization confirmed that HA-Fe-Mt had more functional groups, stronger hydrophobic character, and higher specific surface area. The introduction of HA onto the Fe-Mt platform enhanced its specific surface area, electrostatic interaction, and hydrophobic character, therefore providing more active sites to interact with the carbonyl and amide groups of TC. Moreover, the catalytic performance and characterization results revealed that HA-Fe-Mt had greater persulfate (PS) activation, the coupled HA would speed up the transmission of electrons between Fe (III) and PS in the Fe (III) / Fe (II) cycle when PS was captured by the HA-Fe-Mt system, and the in situ generated Fe accelerates the generation of reactive oxygen species (ROS) to further degrade TC. Consequently, HA can not only promote the adsorption of TC but also promote the degradation of TC in the Fe-Mt nano platform. HA-Fe-Mt provided a feasible and promising platform with PS activation for TC adsorption and degradation.

Polydopamine-mediated modification of ZIF-8 onto magnetic nanoparticles for enhanced tetracycline adsorption from wastewater

Magnetic nanoparticle materials which could be used to remove tetracycline were confined seriously due to their poor stability and unsatisfactory reusability. Here, we facilely prepared novel zeolitic imidazolate framework-8 (ZIF-8) functionalized magnetic nanoparticles (Fe₃O₄@PDA-ZIF-8) adsorbent utilizing polydopamine as a bond to establish a connection between zeolitic imidazolate framework-8 and Fe₃O₄, which could improve the stability of magnetic nanoparticles and enhance the tetracycline adsorption capacity simultaneously. The prepared nanocomposites were characterized and their TC adsorption abilities under various experiment conditions (contact time, TC initial concentration and pH values) were also investigated. Experimental results proved that the prepared adsorbent showed superior TC adsorption capacities (92.01 mg/g at pH = 7). Further, the adsorption mechanisms were comprehensively studied and the prepared adsorbent showed satisfactory stability and reusability during the cycle experiment. Altogether, our findings provided a feasible way to design and construct functional magnetic MOF materials for enhancing tetracycline adsorption from wastewater.

Methylene Blue Removed from Aqueous Solution by Encapsulation of Bentonite Aerogel Beads with Cobalt Alginate

It can be difficult to remove dark methylene blue (MB) from water effectively. The use of sodium alginate and bentonite (Ben) as the matrix produced a displacement reaction that occurred in cobalt chloride, which allowed Ben to be successfully encapsulated in cobalt alginate (CA). Finally, a vacuum freeze-drying method was used to prepare a low-cost composite of CA/Ben aerogel for adsorbing MB in aqueous solutions. In addition to scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy, the composites were also characterized and analyzed. Different adsorption experiments were conducted in order to determine the effects of dosage, pH, adsorption time, and temperature on the adsorption performance of the adsorbent. According to the results of the experiment, the adsorption capacity of CA/Ben aerogel was 258.92 mg·g^-1, and the pseudo-first-order kinetic model and Freundlich isotherm model can fully explain the adsorption process of MB on this aerogel. The composite material reported in this paper is easily recycled, and the removal rate reaches 65% after four times of recycling. Moreover, compared with other adsorbents, the composite material of the invention is highly environmentally friendly and has a simple preparation process. A large-scale application of this technology is the removal of dyes from water on a large scale.

Enhanced adsorption of tetracycline using modified second pyrolysis oil-based drill cutting ash

In this work, second pyrolysis oil-based drill cutting ash (OBDCA-sp) was modified using NaOH and cetyltrimethylammonium bromide (CTAB), respectively. The modified OBDCA-sp was used as the novel adsorbent for adsorption of tetracycline (TC) in aqueous solutions. The original and modified OBDCA-sp were characterized by SEM, XRD, FTIR, zeta potential analysis, contact angle, and BET. The maximum theoretical adsorption quantity (45 ℃) for TC was calculated as 1.7 mg/g using CTAB-OBDCA-sp as the adsorbent. The adsorption isotherm of TC on OBDCA-sp was fitted well with Freundlich model and the adsorption kinetic was illustrated by pseudo-second-order model. Neutral condition was favorable for the adsorption of TC. The result of regeneration experiment indicated the reusability of OBDCA-sp. The hydrogen bonding was the possible mechanism for TC adsorption. This paper developed the novel surface modification methods of OBDCA-sp and provided an approach for the resource utilization of OBDCA-sp as an environmental functional material.

Modular Construction of an MIL-101(Fe)@MIL-100(Fe) Dual-Compartment Nanoreactor and Its Boosted Photocatalytic Activity toward Tetracycline

Iron-based metal-organic frameworks (MOFs) have aroused extensive concern as prospective photocatalysts for antibiotic (e.g., tetracycline, TC) degradation. However, efficiencies of single and simple Fe-based MOFs still undergo restricted light absorption and weak charge separation. Assembly of different iron-based MOF building blocks into a hybrid MOF@MOF heterostructure reactor could be an encouraging strategy for the effective capture of antibiotics from the aqueous phase. This paper reports a new-style MIL-101(Fe)@MIL-100(Fe) photocatalyst, which was groundbreakingly constructed to realize a double win for boosting the performances of adsorption and photocatalysis. The optical response range, surface open sites, and charge separation efficiency of MIL-101(Fe)@MIL-100(Fe) can be regulated through accurate design and alteration. Attributed to the synergistic effects of double iron-based MOFs, MIL-101(Fe)@MIL-100(Fe) exhibits an excellent photocatalytic activity toward TC degradability compared to MIL-101(Fe) and MIL-100(Fe), which is even superior to those reported previously in the literature. Furthermore, the main active species of •O₂^- and h⁺ were proved through trapping tests of the photocatalytic process. Additionally, MIL-101(Fe)@MIL-100(Fe) possesses remarkable stability, maintaining more than 90% initial photocatalytic activity after the fifth cycle. In brief, MIL-101(Fe)@MIL-100(Fe) was highly efficient for TC degradation. Our work offers a new strategy for visible-light photodegradation of TC by exploring the double Fe-based MOF composite.

Metal-organic framework-based materials for the abatement of air pollution and decontamination of wastewater

Developing new and efficient technologies for environmental remediation is becoming significant due to the increase in global concerns such as climate change, severe epidemics, and energy crises. Air pollution, primarily due to increased levels of H₂S, SO_x, NH₃, NO_x, CO, volatile organic compounds (VOC), and particulate matter (PM) in the atmosphere, has a significant impact on public health, and exhaust gases harm the natural sulfur, nitrogen, and carbon cycles. Similarly, wastewater discharged to the environment with metal ions, herbicides, pharmaceuticals, personal care products, dyes, and aromatics/organic compounds is a risk for health since it may lead to an outbreak of waterborne pathogens and increase the exposure to endocrine-disrupting agents. Therefore, developing new and efficient air and water quality management systems is critical. Metal-organic frameworks (MOFs) are novel materials for which the main application areas include gas storage and separation, water harvesting from the atmosphere, chemical sensing, power storage, drug delivery, and food preservation. Due to their versatile structural motifs that can be modified during synthesis, MOFs also have a great promise for green applications including air and water pollution remediation. The motivation to use MOFs for environmental applications prompted the modification of their structures via the addition of metal and functional groups, as well as the creation of heterostructures by mixing MOFs with other nanomaterials, to effectively remove hazardous contaminants from wastewater and the atmosphere. In this review, we focus on the state-of-the-art environmental applications of MOFs, particularly for water treatment and air pollution, by highlighting the groundbreaking studies in which MOFs have been used as adsorbents, membranes, and photocatalysts for the abatement of air and water pollution. We finally address the opportunities and challenges for the environmental applications of MOFs.

Effective Removal of Tetracycline from Water Using Copper Alginate @ Graphene Oxide with In-Situ Grown MOF-525 Composite: Synthesis, Characterization and Adsorption Mechanisms

For nanomaterials, such as GO and MOF-525, aggregation is the main reason limiting their adsorption performance. In this research, Alg-Cu@GO@MOF-525 was successfully synthesized by in-situ growth of MOF-525 on Alg-Cu@GO. By dispersing graphene oxide (GO) with copper alginate (Alg-Cu) with three-dimensional structure, MOF-525 was in-situ grown to reduce aggregation. The measured specific surface area of Alg-Cu@GO@MOF-525 was as high as 807.30 m²·g^-1, which is very favorable for adsorption. The synthesized material has affinity for a variety of pollutants, and its adsorption performance is significantly enhanced. In particular, tetracycline (TC) was selected as the target pollutant to study the adsorption behavior. The strong acid environment inhibited the adsorption, and the removal percentage reached 96.6% when pH was neutral. Temperature promoted the adsorption process, and 318 K adsorption performance was the best under experimental conditions. Meanwhile, 54.6% of TC could be removed in 38 min, and the maximum adsorption capacity reached 533 mg·g^-1, far higher than that of conventional adsorption materials. Kinetics and isotherms analysis show that the adsorption process accords with Sips model and pseudo-second-order model. Thermodynamic study further shows that the chemisorption is spontaneous and exothermic. In addition, pore-filling, complexation, π-π stack, hydrogen bond and chemisorption are considered to be the causes of adsorption.

A high-performance electrochemical sensor for sensitive detection of tetracycline based on a Zr-UiO-66/MWCNTs/AuNPs composite electrode

Herein, a high-performance electrochemical sensor was constructed based on a metal-organic framework (Zr-UiO-66)/multi-carbon nanotubes/gold nanoparticles (Zr-UiO-66/MWCNTs/AuNPs) composite modified glassy carbon electrode for sensitive determination of tetracycline. The morphology, structure, and performance of Zr-UiO-66/MWCNTs/AuNPs were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and electrochemical techniques. The Zr-UiO-66/MWCNTs/AuNPs nanohybrids exhibited excellent electrocatalytic activity towards the oxidation of tetracycline, mainly because of the synergistic effect of the MOFs, MWCNTs, and gold nanoparticles. The electrochemical kinetics and catalytical mechanism of tetracycline were demonstrated, proving that tetracycline's electrocatalytic oxidation reaction was an absorption-controlled two-step process involving the transfer of two protons and two electrons, respectively. Furthermore, a simple and facile method was used to achieve the regeneration of the absorbed saturated electrode. A low concentration of tetracycline was detected by amperometry with the linear ranges of 5 × 10^-7 to 2.25 × 10^-4 mol L^-1 (R² = 0.9941), the sensitivity was 45.4 mA L mol^-1, and the limit of detection was as low as 1.67 × 10^-7 mol L^-1 (S/N = 3). In addition, the composite electrode demonstrated high selectivity (interference deviation of ± 5%), satisfactory reproductivity (RSD of 5.31%), and long-term stability (easy regeneration) and was successfully applied in the analysis of tetracycline antibiotics in actual samples. Thus, the proposed electrode provides a promising and prospective MOFs-based sensing platform for the detection of tetracyclines in the environment.

Adsorption and removal of direct red 31 by Cu-MOF: optimization by response surface

Cu(PABA) is a Cu-based MOF material assembled from Cu²⁺ and the organic ligand p-aminobenzoic acid (PABA). Cu (PABA) was synthesized by a solvothermal method, characterized and applied to the adsorption of direct red 31 dye (DR-31). The effects of pH, DR-31 concentration and temperature on the adsorption performance of Cu(PABA) were investigated. The adsorption kinetics were analyzed by pseudo-first-order, pseudo-second-order and intra-particle diffusion models, and the adsorption equilibrium data was fitted by Langmuir and Freundlich isotherm models. The pseudo-first-order kinetics and Langmuir model satisfactorily described the adsorption kinetics and adsorption equilibrium, respectively. The maximum adsorption capacity of Cu(PABA) for DR-31 dye at room temperature was 1,244.8 mg/g, as calculated using the Langmuir adsorption isotherm model. By response surface methodology (RSM), the optimal adsorption was found at pH value of 10.9, DR-31 dye concentration of 216.6 mg/L, and temperature of 27 °C, and the removal rate was as high as 99.4%. Therefore, Cu(PABA) can be used as an efficient adsorbent for removing DR-31 dye from aqueous solution.

Immobilization mechanism of antimony by applying zirconium-manganese oxide in soil

Antimony (Sb) accumulation in soil poses great potential risk to ecological environment, and its mobilization, transformation and bioavailability are controlled by its fractions and species. Hence, it is important to develop functional materials with both adsorption and oxidation that achieve detoxification and control the mobilization of Sb. In this study, the synthesized zirconium‑manganese oxide (ZrMn) could extremely promoted the transformation of antimonite [Sb(III)] to antimonate [Sb(V)], induced the bioavailable Sb shift to well-crystallized (hydr)oxides of Mn and residual fractions, and further reduced mobility and bioavailability Sb in soil. The sorption of ZrMn to Sb(III) and antimonate Sb(V) were affected by interfering ions, and to Sb(III) was a heterogeneous adsorption process. Spectroscopic characterization of XPS and FTIR suggested exchange between the hydroxyl groups and Sb was crucial in its retain and forming an electronegative inner-sphere mononuclear or binuclear bridging compound. The oxidation induced the transformation of Mn species in ZrMn, generated Mn(II) and Mn(III) exposing more reactive sites conducive to oxidation and adsorption, thus Mn oxides has a higher adsorption capacity for Sb(III). However, the Zr oxides of ZrMn presented adsorption rather than oxidation. The application of ZrMn could realize the dual effect of Sb oxidation detoxification and adsorption immobilization in soil, which provided references for Sb contaminated soil remediation.

Metal-organic frameworks with peroxidase-like activity for efficient removal of aflatoxin B1

Aflatoxin B₁ (AFB₁), a naturally produced toxin existing in major food crops, is highly toxic and carcinogenic to human and animals. In this study, a reusable material, Pd@PCN-222 with great adsorption performance and peroxidase-like activity was synthesized for the removal of AFB₁. Pd@PCN-222 exhibited great adsorption performance owing to hierarchical porous structure. Pd@PCN-222 also could catalyze the AFB₁ in the presence of H₂O₂ due to the Fe-tetrakis (4-carboxyphenyl) porphyrin and Pd as effective peroxidase active site, which improved the removal efficiency of AFB₁. Pd@PCN-222 was applied for the removal of AFB₁ with a removal rate of 96.52% in 2 h. Owing to the advantages of high removal efficiency and reusability, Pd@PCN-222 had great application potential in AFB₁ removal.

Magnetite graphene oxide modified with β-cyclodextrin as an effective adsorbent for the removal of methotrexate and doxorubicin hydrochloride from water

The purpose of this investigation was to analyze the performance of magnetite graphene oxide modified with β-cyclodextrin (GO@Fe₃O₄@β-CD) for adsorption of methotrexate (MTX) and doxorubicin (DOX) from aqueous solutions. Characterization of GO@Fe₃O₄@β-CD was carried out using some methods. The perfect conditions for the adsorption of MTX and DOX were 7.0, 45 min, 20 mg, and 25 °C for solution pH, contact time, adsorbent dose, and temperature, respectively, with removal efficiency values of 97.8% and 98.5% for MTX and DOX, respectively. The adsorption kinetic of MTX and DOX via GO@Fe₃O₄@β-CD followed pseudo second-order (PSO) model, while the adsorption isotherm obeyed Langmuir model by monolayer adsorption with maximum adsorption capacities of 198.5 and 204.5 mg g^-1 for MTX and DOX, respectively. Therefore, it could be argued that HCl and 0.1 mol L^-1 NaOH would reflect adequate elution properties for GO@Fe₃O₄@β-CD recovery.

Template-directed synthesis of pomegranate-shaped zinc oxide@zeolitic imidazolate framework for visible light photocatalytic degradation of tetracycline

The development of photocatalysts for efficient tetracycline (TC) degradation under visible light is urgently needed yet remains a great challenge. Most semiconductor photocatalysts with low specific surface area are easy to agglomerate in solution and unfavorable for enriching pollutants. Herein, we present the preparation of pomegranate-shaped zinc oxide@zeolitic imidazolate framework (ZnO@ZIF-8) by in situ growth of ZIF-8 on a petal-shaped ZnO template that enhances the adsorption and photocatalytic degradation of TC. ZnO@ZIF-8 exhibits an excellent photostability and a TC photodegradation efficiency of 91% under visible light (λ > 420 nm) in 50 min at room temperature, which can be recycled over five times without any loss of activity. Moreover, the plausible photocatalysis reaction mechanism and the degradation intermediates are elucidated with the aid of three-dimensional excitation-emission matrix spectra and liquid chromatography-mass spectrometry system. This study offers new insights into the design of antibiotic degradation photocatalysts and the development of photocatalysts with broad-spectrum responses for efficient TC elimination.

Integration of Phosphotungstic Acid into Zeolitic Imidazole Framework-67 for Efficient Methylene Blue Adsorption

To enhance the dye adsorption capacity of zeolitic imidazolate framework-67 (ZIF-67), phosphotungstic acid (HPW) was integrated into ZIF-67 to prepare composite adsorbents. Characterization results demonstrated that the electronegative HPW was uniformly and tightly deposited on the electropositive ZIF-67. Methylene blue (MB) was selected as a model contaminant to evaluate the adsorption performance of hybrid adsorbents. Results showed that HPW@ZIF-67 had excellent adsorption capacity toward cationic MB. The optimal ZIF-67-0.2 HPW sample with a HPW dosage of 9.9 wt % presented an adsorption capacity of 446.4 mg g^-1. ZIF-67-0.2 HPW displayed good reusability, and the adsorption data can be well described by pseudo-second order and Langmuir isotherm models. The adsorption mechanism was ascribed to the preferred electrostatic attraction and π-π stacking between MB and composite adsorbents. This work provides a route to enhance organic dye removal efficiency of ZIF materials through regulation of surface charge property and sheds light on the development of ZIF-based adsorbents.

Biomass-derived porous material synthesized by one-step calcination method for the magnetic solid phase extraction of polychlorinated biphenyls in water

Recent findings unfold that biomass materials with the micro/mesoporous structure were often treated as adsorbents for organic substances. In this work, one-step calcination method was adopted in the preparation of magnetic porous green bean biomass material. It has the properties of magnetism and porosity after the addition of Co(NO₃ )₂ and high temperature calcination. A variety of characterizations have been operated, including energy dispersive X-ray detector, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis and so on. It has the specific surface area 168.1611 m² ∙g^-1 and the pore volumes 0.1764 cm³ ∙g^-1 . The material was used in magnetic solid phase extraction of three polychlorinated biphenyls including 2-chlorobiphenyl, 4-chlorobiphenyl and 2,2,5-trichlorobiphenyl. Several factors were investigated, such as material amount, eluents, adsorption time, solution pH, salinity and the reusability. Under optimized conditions, good recoveries (90.24-93.34%) were achieved with the relative standard deviation in a range from 2.30 % to 4.83 %. Three real water samples (tap, river and lake water) were tested to verify the accuracy of the method. This method can be successfully used in the analysis of some polychlorinated biphenyls congeners in water. This article is protected by copyright. All rights reserved.

High-performance and selective adsorption of ZIF-8/MIL-100 hybrids towards organic pollutants

Environmental contamination by organic pollutants has become a pressing concern. In this study, metal-organic framework composites with a core-shell structure of MIL-100 wrapped around ZIF-8 (ZIF-MIL hybrids) were synthesized and characterized for their effectiveness to remove organic pollutants. First, a sequence of routine characterizations will examine the ZIF-MIL series samples' physicochemical properties and morphological characteristics. Then, the adsorption capacities of ZIF-MIL towards organic pollutants, including cationic dyes (methylene blue (MB), and rhodamine B (RHB)), anionic dyes (methyl orange (MO)), neutral pollutants (Sudan III (SD-III), tetracycline (TC) and amoxicillin (AMX)), were investigated. Among the ZIF-MIL series, ZIF-MIL-4 has an excellent specific surface area with high uptake of TC (1288 mg g^-1) and RHB (1181 mg g^-1). Based on the adsorption data from kinetic and dynamic studies, the adsorption process was closest to the pseudo-second-order kinetic model and Freundlich isotherm. In terms of thermodynamic parameter values, the adsorption of TC is an endothermic and spontaneous process, while the adsorption of RHB is an exothermic and spontaneous process. Furthermore, the reusability and selectivity studies of ZIF-MIL-4 towards TC and RHB exhibited significant regeneration ability and high selectivity. The effects of ionic strength and pH on pollutant removal efficiency were also tested. The experimental results showed that the main interactions between ZIF-MIL-4 and RHB or TC were weak coordination, electrostatic, hydrogen bonding, and π-π stacking interactions. Thus, the proposed MOF hybrid, by forming mixtures with other MOFs, can be a potential purifier with improved adsorption capacity and selectivity for organic pollutants as well as self-reusability.