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[Display omitted] • Adsorption is one of the most promising methods to remove pollutants from water. • MOFs is considered as important adsorbent due to excellent structural performance. • Various modification methods on the structure of MOF and its derivatives are reviewed. • The adsorption mechanism and the factors that affect the performance are discussed. Emerging contaminants have widely existed in terrestrial and river and lake ecosystems, and gradually bioaccumulate and amplify along the food chain, seriously threatening the survival of animals and plants and human health. Adsorption has long been regarded as one of the most promising methods to remove pollutants from wastewater. Among various adsorbent materials, metal–organic frameworks (MOFs), a new class of porous materials, are considered as an excellent adsorbent due to its high specific surface area, high porosity, high crystallinity, tunable pore size and structure, and abundant active sites. In this review, we analyze the influences of different preparation and modification methods on the structure of MOFs and the improvement of adsorption properties of MOFs and its derivatives. In addition, we focus on the emerging contaminants that pose a great threat to human life and health, and further analyze the adsorption mechanism and the factors that affect the adsorption performance. This review emphasizes the application value of the materials, summarizes the challenges faced by the application of MOFs in adsorbing emerging contaminants, and provides insights for future large-scale applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • La-MOFs was prepared by adjusting ligands for fluoride removal from water. • La-BDC material exhibits a high fluoride adsorption capacity of 171.7 mg/g. • Adsorbents have excellent performance with high stability and renewability. • Adsorption mechanism is proposed as ligand exchange and coordination. • La-MOFs is a potential adsorbent for practical application. Excess fluoride in water poses a threat to ecology and human health, which has attracted global attention. In this study, a series of lanthanum-based metal–organic frameworks (La-MOFs) were synthesized by varying the organic ligands (i.e. , terephthalic acid (BDC), trimesic acid (BTC), biphenyl-4,4-dicarboxylic acid (BPDC), 2,5-dihydroxyterephthalic acid (BHTA), and 1,2,4,5-benzenetetracarboxylic acid (PMA)) to control the microscopic structure of the MOFs and subsequently apply them for the removal of fluoride in water. The maximum capture capacities of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC at 298 K are 105.2, 125.9, 145.5, 158.9, and 171.7 mg g−1, respectively. The adsorption capacity is greater than most reported adsorbents. The adsorption isotherms of La-MOFs for fluoride are well fit to the Langmuir isotherm model. In addition, the adsorption kinetics of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC follows the pseudo-second-order kinetic model, and the kinetic rate-limiting step of adsorption is chemical adsorption. Thermodynamics revealed that temperature is favorable for the adsorption of fluoride. Meanwhile, La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC are suitable for the removal of fluoride in a relatively wide pH range (4.0–9.0). Simultaneously, from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis, electrostatic attraction and ligand exchange are identified as the main action mechanisms for the adsorption of fluoride of La-MOFs. The prepared La-MOFs are used as efficient adsorbents for removal of fluoride in actual water, indicating that they have great potential in removing fluoride in real and complex environmental water. This work provides a new strategy for designing adsorbents with adjustable microstructure and expected function to effectively recover fluorosis in water. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are a class of organic–inorganic hybrid functional materials generally formed via self-assembly of metal ions or metal clusters and rigid organic ligands with nitrogen and oxygen atoms. The wide range of potential applications of MOF materials includes gas storage and separation, catalysis, sensing, and drug transportation and release, which can be attributed to their versatile designable structures, modifiable chemical functionality, low-density framework, large specific surface area, and functional and permanent pore space. MOF and its composite materials have also been employed to remove various contaminants from the environment in the recent decade. To present the remarkable research progress and outcomes of MOF materials in the removal of pollutants from the water environment, the related studies on the removal of heavy metals and organic pollutants from the water environment were reviewed in this paper. This was the second paper on the topic that mainly introduced the research progress of MOF materials in the removal of organic pollutants in aqueous solution. The previous studies have shown that MOF materials have open metal sites and Lewis acid–base sites; thus, they exhibit a high adsorption performance for dyes, antibiotics, pesticides, and persistent organic pollutants. Hydrogen bonding, π–π interaction, hydrophobic interaction, and electrostatic attraction are the main mechanisms for their adsorption of organic pollutants. In addition, the large pore structure of some MOF materials is conducive to the adsorption of macromolecular organic pollutants. Moreover, some MOF materials that can be used as catalysts for Fenton-like reactions, photocatalytic reactions, and persulfate activation to degrade organic pollutants, exhibit excellent catalytic performance. The degradation of pollutants in photocatalytic reactions can be mainly attributed to the contributions of ·O2−, ·OH, and h+. In the persulfate system, ·O2−, ·OH, SO4·−, and 1O2 are the main reactive oxide species that cause the decomposition of organic pollutants. Based on the review of previous studies, it is believed that future research will include but will not be limited to the following: (1) the improvement of the performance of MOF in removing organic pollutants and its recyclability; (2) the preparation of new MOF catalytic materials and investigation of catalytic reaction mechanisms; (3) the regulation of the defect structure of MOF to develop new MOF materials with high adsorption and catalytic efficiency; and (4) the analysis of new framework materials, e.g., covalent organic framework materials, and their applications in the field of pollutant purification.

One of the attractive iron-based metal organic framework (MOF) MIL-101(Fe) (Material Institute Lavoisier, MIL) and amine-functionalized NH2-MIL-101(Fe) materials were synthesized by conventional solvothermal method and characterized by TGA (Thermo Gravimetric Analysis), SEM (Scanning Electron Microscopy), XRD (X-Ray Diffractograms), BET (Braunner Emmet Teller) and FTIR (Fourier Transform Infrared Spectroscopy). Characterization results indicated that MIL-101(Fe) materials have well defined morphology, good thermal stability, high surface area and also high porosity. These MOF materials were used as photocatalysts for photodegradation of a pesticide, imidacloprid (IMC). The response surface methodology (RSM) was applied in designing the IMC photodegradation experiments for evaluating the interactive effects of independent variables and determining the optimum condition. Central composite design as five independent variables such as initial MIL-101(Fe) concentration, initial IMC concentration, H2O2 concentration, pH and time were coded with low and high level and IMC removal percent was obtained as a response. As for the RSM results on the optimum photocatalytic condition, maximum IMC removal values were determined as 100% for the both catalysts in the end of the 30 min. The adsorption efficiencies of catalysts were also investigated and obtained results showed that amine-functionalized MIL-101(Fe) was the more effective sorbent than MIL-101(Fe). [ABSTRACT FROM AUTHOR]

Background: Phosphate (PO43−) is the main etiological factor of eutrophication in surface waters. Metal organic frameworks (MOFs) are novel hybrid materials with amazing structural properties that make them a prominent material for adsorption. Methods: Zeolitic imidazolate framework 67 (ZIF-67), a water stable member of MOFs, with a truncated rhombic dodecahedron crystalline structure was synthesized in aqueous environment at room temperature and then characterized using XRD and SEM. PO43− adsorption from synthetic solutions using ZIF-67 in batch mode were evaluated and a polynomial model (R2: 0.99, R2adj: 0.98, LOF: 0.1433) developed using response surface methodology (RSM). Results: The highest PO43− removal (99.2%) after model optimization obtained when ZIF-67 dose, pH and mixing time adjusted to 6.82, 832.4 mg/L and 39.95 min, respectively. The optimum PO43− concentration in which highest PO43− removal and lowest adsorbent utilization occurs, observed at 30 mg/L. PO43− removal eclipsed significantly in the presence of carbonate. The equilibrium and kinetic models showed that PO43− adsorbed in monolayer (qmax: 92.43 mg/g) and the sorption process controlled in the sorption stage. Adsorption was also more favorable at higher PO43− concentration, according to the separation factor (KR) graph. Thermodynamic parameters (minus signs of ∆G°, ∆H° of 0.179 KJ/mol and ∆S° of 44.91 KJ/mol.K) demonstrate the spontaneous, endothermic and physisorption nature of the process. Conclusion: High adsorption capacity and adsorption rates, make ZIF-67 a promising adsorbent for PO43− removal from aqueous environment. [ABSTRACT FROM AUTHOR]

The removal of Methylene Blue (MB) from water samples was successfully achieved with high efficiency of 94.2% at 298 K after 60 min using Basolite C300 (or HKUST-1) as a new class of emerging adsorbent called metal organic frameworks. The effect of different experimental parameters, namely dye concentration (50, 150, 200, and 300 mg/L), adsorbent dosage (50, 100, and 150 mg), and temperature (298, 313, and 323 K) was investigated. The adsorption of MB onto HKUST-1 was confirmed using several characterization tests including X-ray diffraction, scanning electron microscope, energy dispersive X-Ray analyzer, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The Langmuir and Freundlich isotherm models were applied to correlate the adsorption isotherms. Although the experimental data fit both models, the Langmuir model is more suitable for higher adsorbent dosage while the Freundlich model is better for lower adsorbent dosage. Based on the Langmuir isotherm, the maximum adsorption capacity of MB onto HKUST-1 reached 250 mg/g. Furthermore, the adsorption kinetic studies showed that the pseudo-second-order kinetic model yields the best fit for the kinetic data with a regression constant, R², of (0.9916 to 0.9998). The thermodynamic studies revealed that the process is exothermic (ΔH° = –112.172 kJ/mol) and spontaneous (ΔG° negative) in nature. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are currently recognized as unique platforms for environmental studies. This study evaluated the potential of nine MOFs from ZIF-8, ZIF-67, and UIO-66 families for the removal of ciprofloxacin (CIP), a toxic, bio-accumulative, and persistent fluoroquinolone antibiotic. ZIF-67-SO4, with a rhombic crystalline morphology and 1375 m2/g BET surface area, has the highest CIP adsorption efficiency among the studied MOFs. The mathematical sorption model predicted that the highest CIP removal (99.2%) occurs when adsorbent dose, pH, and agitation time are adjusted to 6.82, 832.4 mg/L, and 39.95 min, respectively. Further studies revealed that the CIP adsorbed onto ZIF-67-SO4 in monolayer (qmax: 2537.5 mg/g) and chemisorption controlled the rate of the process. Mass transfer kinetic coefficients improved significantly by sonication at 35 KHz in comparison with mechanical agitation. Thermodynamic parameters (minus signs of ∆G° [7.8 to 14.2], positive signs of ∆H° (58.9 KJ/mol), and ∆S° (0.23 KJ/mol·K)) demonstrated the spontaneous, endothermic, and chemical sorption of CIP. The level of cobalt leached from ZIF-67-SO4 structure varied 1.2−4.5 mg/L, depending on pH, mixing time, and agitation type. In conclusion, the excellent adsorption properties of ZIF-67-SO4 for CIP, made it an outstanding candidate for environmental protection purposes.

We present the results of a thermodynamic and kinetics of adsorption study of CO 2 sorbed in ZIF-8. Adsorption isotherms were measured at ten temperatures between 133 K and 237 K. Consistent with what has been reported for this system at higher temperatures, there is only one step in the sorption isotherms up to reaching the saturated vapor pressure. We obtained the isosteric heat of adsorption as a function of loading from the isotherm data. The isosteric heat displays a non-monotonic dependence on loading: there is a maximum in the isosteric heat at high sorbent loadings. For all loadings below the maximum, the isosteric heat is an increasing function of loading. We also measured the time required to reach equilibrium after a dose of gas was added to the sorbent to establish the sorption kinetics for this system. While the general trend in the equilibration times is that equilibration times are shorter for increasing loading, we found a small local maximum in a region in the neighborhood of where the isosteric heat has its peak value. The thermodynamic and kinetic results obtained for CO 2 in ZIF-8 are compared with those obtained in prior studies of O 2 and Xe in ZIF-8. [ABSTRACT FROM AUTHOR]

The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based metal organic framework, MIL-101(Cr) and its application for hydrogen storage. MIL-101(Cr) has been synthesized hydrothermally using HF, acetic acid, perfluorobenzoic acid, and without acid. The characterization of the synthesized materials were carried out using powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and surface area (BET) by nitrogen adsorption isotherm at 77 K. The results demonstrated that acetic acid mediated synthesized MIL-101(Cr) exhibited higher surface area and pore volume than those synthesized with other organic acids. This may be due to the enhanced dissolution of terephthalic acid in the presence of acetic acid which facilitates the formation of MIL-101(Cr) nuclei during the synthesis. A comparison of conventional and HF free-synthesized MIL-101(Cr) for hydrogen adsorption capacity determined at 77 K up to 4500 kPa revealed that MIL-101(Cr) synthesized using acetic acid exhibited higher hydrogen adsorption capacity (5.6 wt %) than the MIL-101(Cr) synthesized with perfluorobenzoic acid (3.7 wt %) and without acid (4.8%). However, it is slightly less than the H2 adsorption capacity of MIL-101(Cr) synthesized using HF (6.1 wt %). The higher H2 adsorption capacity of MIL-101(Cr) synthesized using acetic acid can be attributed to the better terephthalate-chromium interaction which facilitates the formation of more crystalline product thereby creating more unsaturated metal centers in MIL-101(Cr). The present study suggested that acetic acid may be a suitable alternative for highly corrosive and hazardous HF which led to easier preparation of MIL-101(Cr) for the large-scale production and applications. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 461-468, 2016 [ABSTRACT FROM AUTHOR]

A novel metal organic frameworks (MOFs) material was fabricated by the solvothermal method and used as a high-efficiency adsorbent for the perchlorate removal from aqueous solution. The properties of material were characterized by SEM–EDS, FTIR and XRD. Various effects on adsorption process were systematically investigated, such as adsorbent dosage, pH, zeta potential, temperature, contact time and initial concentration of perchlorate. The results showed that the maximum sorption amount of perchlorate reached 133.5 mg/g at pH 7, and the perchlorate could be removed effectively over a broad range of pH value (from 2 to 11) at room temperature. The kinetics and equilibrium adsorption data could be fitted well by pseudo-first-order kinetic model and Langmuir model, respectively. Value of Δ G was found to be negative at all studied temperatures which confirmed the feasibility of process. The proposed adsorption mechanism was the co-effect of electrostatic force and ion-exchange between the perchlorate ions and MOFs material, which improved the adsorption capacity greatly. The results of the present study point to the possibility of developing a highly efficient adsorbent for removing perchlorate from aqueous solution under multi-adsorption forces. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel covalently connected core–shell NH 2 -UiO-66@Br-COFs hybrid materials was prepared. • Abundant ultramicropores were generated at the core–shell interface. • The hybrid materials had high S BET (966 m2·g−1), V total (0.655 cm3·g−1) and V ultra (0.157 cm3·g−1). • The hybrid materials exhibited much higher CO 2 uptake (169.5 mg·g−1) than NH 2 -UiO-66 and Br-COFs. • The hybrid materials exhibited good I 2 vapor adsorption capacity (3.73 g·g−1). Metal organic frameworks (MOFs)@covalent organic frameworks (COFs) (MOFs@COFs) hybrid materials not only combine the advantages of MOFs and COFs, but the possible synergistic effect at the MOFs-COFs interface can improve the performance of the hybrid materials greatly. Herein, the Br-COFs shell was in-situ grown on the surface of the NH 2 -UiO-66 core by Schiff-based reaction and a kind of novel covalently connected core–shell NH 2 -UiO-66@Br-COFs hybrid materials were prepared accordingly. Unique structure was generated at the core–shell interface which could be effectively adjusted by the coating amount of Br-COFs. In particular, abundant ultramicropores were generated at the interfacial layers as compared with NH 2 -UiO-66 and Br-COFs, and the maximum ultramicropore volume (V ultra) was up to 0.157 cm3·g−1. These produced ultramicropores at the core–shell interface made a great positive contribution to the CO 2 capacity and the maximum CO 2 capacity of the hybrid materials was measured to be 169.5 mg·g−1 at 273 K and 1.0 bar, outperformed the corresponding single MOF and COF. Additionally, the highest I 2 vapor uptake of the hybrid materials was determined to be 3.73 g·g−1 and it increased with the increase of the coating amount of Br-COFs. This work presents the successful regulation of the adsorption performance by the rational fabrication of novel hybrid MOFs@COFs interface. [ABSTRACT FROM AUTHOR]

Efficient and convenient methods for the removal of toxic heavy metal ions especially Cd(II) and Pb(II) from aqueous solutions is of great importance due to their serious threat to public health and the ecological system. In this study, two magnetic metal-organic frameworks (namely: Fe 3 O 4 @ZIF-8, and Fe 3 O 4 @UiO-66–NH 2) were synthesized, fully characterized, and applied for the adsorption of Cd(II) and Pb(II) from aqueous solutions. The adsorption efficiencies for the prepared nanocomposites are strongly dependent on the pH of the aqueous solution. The maximum adsorption capacities of Fe 3 O 4 @UiO-66–NH 2 , and Fe 3 O 4 @ZIF-8 at pH 6.0 were calculated to be 714.3 mg·g−, and 370 mg·g−1 for Cd(II), respectively, and 833.3 mg·g−1, and 666.7 mg·g−1 for Pb(II), respectively. The adsorption process follows a pseudo -second-order model and fit the Langmuir isotherm model. Moreover, the thermodynamic studies revealed that the adsorption process is endothermic, and spontaneous in nature. A plausible adsorption mechanism was discussed in detail. The magnetic adsorbents: Fe 3 O 4 @ZIF-8, and Fe 3 O 4 @UiO-66–NH 2 showed excellent reusability, maintaining the same efficiency for at least four consecutive cycles. These results reveal the potential use of magnetic Fe 3 O 4 @ZIF-8, and Fe 3 O 4 @UiO-66–NH 2 as efficient adsorbents in removing Cd(II) and Pb(II) from aqueous solutions. [Display omitted] • Two magnetic metal-organic frameworks were synthesized and characterized. • Adsorption of Cd(II) and Pb(II) from aqueous solutions were assessed. • Adsorption kinetics and mechanisms were analyzed. [ABSTRACT FROM AUTHOR]

CuBTC (Copper(II) benzene-1,3,5-tricarboxylate) is one of the most well characterized and widely studied metal organic framework (MOF) structures for potential use in industrial applications due to its relatively easy synthesis and excellent textural and physicochemical properties. In this comprehensive review, a different perspective on MOF materials for future sustainability is presented by critically examining the recent works that have considered the synthesis and adsorption/catalytic applications of CuBTC as a model case. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structure tunable bimetallic Fe-Al-based MOF was prepared for arsenic removal. • The second metal doping can significantly enhance the absorption of arsenic. • The adsorption mechanism of arsenic on bimetallic MOF was proposed. • The adsorbent with excellent performance has water stability and renewability. • Fe-Al-based MOF is efficient for arsenic treatment in contaminated spring water. Arsenic pollution of groundwater and surface water has come to the attention of the public. To explore economically affordable and efficient adsorbents for the treatment of arsenic, bimetallic MOFs based on trivalent iron and aluminum were synthesized and used to capture arsenic from wastewater. Characterization methods including SEM, EDX, XRD, and N 2 adsorption–desorption were applied to analyze the morphology and element content, crystal structure, porosity and specific surface area of the Fe/Al-BDC-NH 2 materials. The microstructures of bimetallic MOFs were tuned through changing the ratio of Al and Fe in the precursor material. Adsorption results show that introducing aluminum into the iron-based material formed bimetallic Fe/Al-BDC-NH 2 MOFs that had much better adsorption performance for arsenic than the monometallic Fe-BDC-NH 2 or Al-BDC-NH 2 MOF. The adsorption isotherm of bimetallic MOF materials for arsenic is in accordance with the Langmuir isotherm model, and the maximum adsorption capability of Fe/Al-BDC-NH 2 (1:1) at 298 K was 146.8 mg g−1. The kinetics of arsenic adsorption follow the pseudo-second-order model. Also, the thermodynamics indicate that arsenic adsorption is endothermic. Fe/Al-BDC-NH 2 (1:1) is suitable for removal of arsenic from wastewater in a relatively wide pH range (5.0–9.0). Within this pH range, Fe and Al are hardly dissolved in water after arsenic capture, and this indicates that Fe/Al-BDC-NH 2 (1:1) is very stable and suitable for arsenic capture from water without generating secondary pollution. Furthermore, through FTIR and XPS analysis, ligand exchange was identified as the main adsorption mechanism of Fe/Al-BDC-NH 2 (1:1) for arsenic. [ABSTRACT FROM AUTHOR]

A new type of Eu-based metal organic framework (Eu-MOF) characterized with ability of arsenate ion luminescence sensing and entrapping was constructed via solvothermal method based on the optimization of the organic ligand. The Eu-MOF aqueous dispersion sample displayed arsenate-triggered augment in luminescence emission intensity with appreciable contrast and detection sensitivity with limit of detection down to 17.8 nM toward arsenate ion, which is less than one-fourth of the upper limit concentration of arsenic in drinking water that the World Health Organization (WHO) set for public health, 72 nM. Additionally, the excellent recognition specificity Eu-MOF toward arsenate species over various potential interfering anions and cations was also confirmed. The rapid adsorption ability of Eu-MOF nanostructures toward arsenate in aqueous milieu that plausibly originated from its nature of chemical adsorption and the adsorption feature conforming to the Langmuir model was also verified. The advantages that Eu-MOF nanostructure displays in terms of high sensitivity and recognition specificity in luminescence sensing of arsenate ion and the desired arsenate entrapping ability in aqueous milieu is expected to impart it potential for sensing and entrapping trace amount of arsenate in water in practical applications. • The Eu-based MOFs characterized with ability of arsenate ion luminescence sensing and entrapping. • Arsenate ion sensing with detection limit down to 17.8 nM, much lower than the upper limit that WHO set for public health. • High recognition specificity in luminescence sensing and rate in adsorption of arsenate ions. [ABSTRACT FROM AUTHOR]

Adsorption is considered as one of the eco-friendly methods to effectively remove pollutants from water environment. 1 , namely ([Zn 3 (dpcp) 2 (1,4′-bmib) 2 ] n , dpcp ​= ​3-(3,5-dicarboxylphenoxy)-5-carboxylpyridine and 1,4′-bmib = 1,4-bis(2-methylimidazol-1-yl) butane), was synthesized under simple solvothermal method and characterized by XRD, PXRD, TGA, FTIR, BET and Zeta potential. The influence of temperature and pH of the solution and the dye initial concentration on the adsorption process of 1 was investigated using Congo red (CR) as the adsorption object. Pseudo second-order kinetics and Langmuir isotherms more accurately described the adsorption process of 1. The maximum adsorption capacity measured in the adsorption experiment was about 262.2 ​mg ​g-1. Thermodynamic studies showed that the entire adsorption process was spontaneous. In addition, 1 released the CR dye by a simple organic solvent (ethanol solution of NaOH) and exhibited stable and high adsorption performance over 5 cycles. The subtle hydrogen bond between 1 and the dye promotes its selective adsorption of CR. A Zn-based MOF, namely [Zn 3 (dpcp) 2 (1,4′-bmib) 2 ] n , highly selective and rapid adsorption of CR dyes through subtle hydrogen bonds, with an adsorption capacity of up to 262.2 ​mg ​L-1. Image 1 • A new Zn-based MOF synthesized by solvothermal method is reported. • The adsorption data is more accurately described by pseudo-second-order kinetics and Langmuir isotherms. • Zn-MOF has an adsorption capacity of 262.2 ​mg ​g-1 for Congo red (CR). • Highly efficient and selective adsorption of CR via hydrogen bonding. [ABSTRACT FROM AUTHOR]

Intense efforts have been made to eliminate toxic volatile organic compounds (VOCs) in indoor environments, especially formaldehyde (FA). In this study, the removal performances of gaseous FA using two metal-organic frameworks, MOF-5 and UiO-66-NH 2 , and two covalent-organic polymers, CBAP-1 (EDA) and CBAP-1 (DETA), along with activated carbon as a conventional reference material, were evaluated. To assess the removal capacity of FA under near-ambient conditions, a series of adsorption experiments were conducted at its concentrations/partial pressures of both low (0.1–0.5 ppm/0.01–0.05 Pa) and high ranges (5–25 ppm/0.5–2.5 Pa). Among all tested materials at the high-pressure region ㅐ (e.g., at 2.5 ppm FA), a maximum adsorption capacity of 69.7 mg g−1 was recorded by UiO-66-NH 2. Moreover, UiO-66-NH 2 also displayed the best 10% breakthrough volume (BTV10) of 534 L g−1 (0.5 ppm FA) to 2963 L g−1 (0.1 ppm FA). In contrast, at the high concentration test (at 5, 10, and 25 ppm FA), the maximum BTV10 values were observed as: 137 (UiO-66-NH 2), 144 (CBAP-1 (DETA)), and 36.8 L g−1 (CBAP-1 (EDA)), respectively. The Langmuir isotherm model was observed to be a better fit of the adsorption data than the Freundlich model under most of the tested conditions. The superiority of UiO-66-NH 2 was attributed to the van der Waals interactions between the linkers (framework) and the hydrocarbon "tail" (FA) coupled with interactions between its open metal sites and the FA carbonyl groups. This study demonstrated the good potential of these advanced functional materials toward the practical removal of gaseous FA in indoor environments. Image 1 • The adsorptive removal of gaseous formaldehyde is investigated using novel materials. • Two MOFs and two COPs were evaluated for the adsorptive removal of formaldehyde. • Sorption experiments were conducted in two partial pressure regions (0.01–0.05 and 0.5–2.5 Pa). • UiO-66-NH 2 displayed the best performance amongst all the tested adsorbents. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are currently recognized as unique platforms for environmental studies. This study evaluated the potential of nine MOFs from ZIF-8, ZIF-67, and UIO-66 families for the removal of ciprofloxacin (CIP), a toxic, bio-accumulative, and persistent fluoroquinolone antibiotic. ZIF-67-SO4, with a rhombic crystalline morphology and 1375 m2/g BET surface area, has the highest CIP adsorption efficiency among the studied MOFs. The mathematical sorption model predicted that the highest CIP removal (99.2%) occurs when adsorbent dose, pH, and agitation time are adjusted to 6.82, 832.4 mg/L, and 39.95 min, respectively. Further studies revealed that the CIP adsorbed onto ZIF-67-SO4 in monolayer (qmax: 2537.5 mg/g) and chemisorption controlled the rate of the process. Mass transfer kinetic coefficients improved significantly by sonication at 35 KHz in comparison with mechanical agitation. Thermodynamic parameters (minus signs of ∆G° [7.8 to 14.2], positive signs of ∆H° (58.9 KJ/mol), and ∆S° (0.23 KJ/mol·K)) demonstrated the spontaneous, endothermic, and chemical sorption of CIP. The level of cobalt leached from ZIF-67-SO4 structure varied 1.2–4.5 mg/L, depending on pH, mixing time, and agitation type. In conclusion, the excellent adsorption properties of ZIF-67-SO4 for CIP, made it an outstanding candidate for environmental protection purposes. [ABSTRACT FROM AUTHOR]