Synthesis of magnetic porous γ-Fe2O3/C@HKUST-1 composites for efficient removal of dyes and heavy metal ions from aqueous solution

Preparation and application of KCC-1@ZIF-8 for the solid extraction of tetracycline with high adsorption capacity

In this study, three different materials were prepared: dendritic fiber-type silica (KCC-1), zeolitic imidazolate framework-8 (ZIF-8), and a new composite material called KCC-1@ZIF-8. These materials were synthesized using microemulsion, stirring, and coating methods, respectively. The properties of the materials were characterized using various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), TGA and X-ray diffraction (XRD). The results showed that KCC-1@ZIF-8 exhibited a significant increase in the BET surface area and pore size compared to the individual components KCC-1 and ZIF-8. These improved properties of the composite material were beneficial for enhancing the adsorption capacity. The effects of initial concentrations, solution pH and reaction time on the adsorption capacity were investigated. The adsorption kinetics and isothermal data of ZIF-8 and KCC-1@ZIF-8 fitted well with pseudo-second-order and Langmuir isotherm models. The results of adsorption thermodynamics show that the adsorption process is spontaneous and endothermic. KCC-1@ZIF-8 exhibited a very high adsorption capacity (751.46 mg g-1) at an initial TC hydrochloride concentration of 80 mg L-1 in an aqueous solution at 301.15 K, and the value was higher than that of ZIF-8 (549.80 mg g-1) under the same conditions. KCC-1 exhibited a relatively lower capacity (37.860 mg g-1). Based on these findings, KCC-1@ZIF-8 was considered a promising adsorbent for the treatment of wastewater contaminated with TC hydrochloride. Additionally, the composite material, when combined with high-performance liquid chromatography (HPLC), could be used as a solid-phase extraction adsorbent for the adsorption of TC hydrochloride in animal foodstuff samples. The calibration curves showed a linear range of 20-500 μg L-1, and the recovery rate ranged from 85.216% to 90.717%. No one has made adsorbents with this new structure before, and KCC-1@ZIF-8 possessed excellent adsorption properties, which make it a potential candidate for environmental remediation and analytical applications involving TC hydrochloride.

Metal-Organic Framework-Based Composites for the Adsorption Removal of Per- and Polyfluoroalkyl Substances from Water

The increasing health risks posed by per- and polyfluoroalkyl substances (PFASs) in the environment highlight the importance of implementing effective removal techniques. Conventional wastewater treatment processes are inadequate for removing persistent organic pollutants. Recent studies have increasingly demonstrated that metal-organic frameworks (MOFs) are capable of removing PFASs from water through adsorption techniques. However, there is still constructive discussion on the potential of MOFs in adsorbing and removing PFASs for large-scale engineering applications. This review systematically investigates the use of MOFs as adsorbents for the removal of PFAS in water treatment. This primarily involved a comprehensive analysis of existing literature to understand the adsorption mechanisms of MOFs and to identify factors that enhance their efficiency in removing PFASs. We also explore the critical aspects of regeneration and stability of MOFs, assessing their reusability and long-term performance, which are essential for large-scale water treatment applications. Finally, our study highlights the challenges of removing PFASs using MOFs. Especially, the efficient removal of short-chain PFASs with hydrophilicity is a major challenge, while medium- to long-chain PFASs are frequently susceptible to being captured from water by MOFs through multiple synergistic effects. The ion-exchange force may be the key to solving this difficulty, but its susceptibility to ion interference in water needs to be addressed in practical applications. We hope that this review can provide valuable insights into the effective removal and adsorption mechanisms of PFASs as well as advance the sustainable utilization of MOFs in the field of water treatment, thereby presenting a novel perspective.

ZnO-based Cu metal-organic framework (MOF) nanocomposite for boosting and tuning the photocatalytic degradation performance

Although metal-organic frameworks (MOFs) are a viable choice for photocatalysts with large surface area and tunable pore structure, the rapid recombination of excited photogenerated charges results in low activity towards photodegradation. Aiming at improving the photocatalytic activities of MOFs, different strategies to incorporate MOF with light-harvesting semiconductors have been developed. In this research, we report an effective photocatalyst designed by incorporating Cu-MOF with ZnO for the photocatalytic degradation of Rose Bengal exhibiting excellent degradation efficiency of 97.4% in 45 min under natural sunlight with catalyst dosage of 320 mg/L. The optical, morphology and surface characteristics of the prepared nanocomposite were studied using scanning electron microscopy (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET) analysis, thermogravimetric (TGA) analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and ultraviolet diffused reflectance spectroscopy (UV-DRS) techniques. Further studies showed that the degradation followed first-order kinetics with a rate constant of 0.077869 min-1. The degradation mechanism was investigated by photoluminescence (PL) study, XPS, zeta potential and quenching experiment in presence of different scavengers. Meanwhile, the fabricated composite displayed good recovery and reuse properties up to 5 cycles as revealed by XRD analysis proving itself a potential MOF-based photocatalyst towards environmental remediation process.

Overview on recent advances of magnetic metal-organic framework (MMOF) composites in removal of heavy metals from aqueous system

Developing a novel, simple, and cost-effective analytical technique with high enrichment capacity and selectivity is crucial for environmental monitoring and remediation. Metal-organic frameworks (MOFs) are porous coordination polymers that are self-assembly synthesized from organic linkers and inorganic metal ions/metal clusters. Magnetic metal-organic framework (MMOF) composites are promising candidate among the new-generation sorbent materials available for magnetic solid-phase extraction (MSPE) of environmental contaminants due to their superparamagnetism properties, high crystallinity, permanent porosity, ultrahigh specific surface area, adaptable pore shape/sizes, tunable functionality, designable framework topology, rapid and ultrahigh adsorption capacity, and reusability. In this review, we focus on recent scientific progress in the removal of heavy metal ions present in contaminated aquatic system by using MMOF composites. Different types of MMOFs, their synthetic approaches, and various properties that are harnessed for removal of heavy metal ions from contaminated water are discussed briefly. Adsorption mechanisms involved, adsorption capacity, and regeneration of the MMOF sorbents as well as recovery of heavy metal ions adsorbed that are reported in the last ten years have been discussed in this review. Moreover, particular prospects, challenges, and opportunities in future development of MMOFs towards their greener synthetic approaches for their practical industrial applications have critically been considered in this review.

Magnetic Nanoparticle Composites: Synergistic Effects and Applications

Composite materials are made from two or more constituent materials with distinct physical or chemical properties that, when combined, produce a material with characteristics which are at least to some degree different from its individual components. Nanocomposite materials are composed of different materials of which at least one has nanoscale dimensions. Common types of nanocomposites consist of a combination of two different elements, with a nanoparticle that is linked to, or surrounded by, another organic or inorganic material, for example in a core-shell or heterostructure configuration. A general family of nanoparticle composites concerns the coating of a nanoscale material by a polymer, SiO2 or carbon. Other materials, such as graphene or graphene oxide (GO), are used as supports forming composites when nanoscale materials are deposited onto them. In this Review we focus on magnetic nanocomposites, describing their synthetic methods, physical properties and applications. Several types of nanocomposites are presented, according to their composition, morphology or surface functionalization. Their applications are largely due to the synergistic effects that appear thanks to the co-existence of two different materials and to their interface, resulting in properties often better than those of their single-phase components. Applications discussed concern magnetically separable catalysts, water treatment, diagnostics-sensing and biomedicine.

Sustainable method towards magnetic ordered mesoporous polymers for efficient Methylene Blue removal

The difficulty in achieving high removal efficiency for contaminants in textile wastewater over a wide range of pH impedes the progress of its treatment technique greatly. Herein, a facile and sustainable strategy was adopted for constructing magnetic ordered mesoporous polymers (M-OMPs) without the assistance of organic solvent and catalyst. The prepared M-OMPs were endowed with high special surface area and good superparamagnetism simultaneously, and exhibited high removal efficiency (>99%) for Methylene Blue (MB) within a short time (10 min) at a concentration of 50 mg/L. What's more, high removal efficiency was achieved over a wide range of pH 2-12 and the adsorption capacity for MB on M-OMPs was substantially retained even after 5 adsorption-desorption cycles, further demonstrating the application potential of M-OMPs in the decontamination of textile wastewater.

Preparation of NH2-Functionalized Fe2O3 and Its Chitosan Composites for the Removal of Heavy Metal Ions

NH2-Fe2O3 and NH2-Fe2O3/chitosan (NH2-Fe2O3/CS) with excellent physical properties and high adsorption capacities for several heavy metal ions were synthesized using a one-pot hydrothermal method. The materials were characterized by scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Physicochemical properties were determined by the Fourier transform infrared spectra (FTIR) and nitrogen adsorption analysis (Brunauer–Emmett–Teller (BET) method). The results of the characterization studies show that the material is uniformly dispersed and has good crystallinity and well-defined porous particles. The material is mesoporous, and the particles have a specific surface area of 55.41–233.03 m2·g−1, a total pore volume of 0.24–0.54 cm3·g−1, and a diameter of 3.83–17.56 nm. Additional results demonstrate that NH2-Fe2O3 and NH2-Fe2O3/CS are effective adsorbents for the removal of heavy metal ions from solution. In a ternary system, the order of their selective adsorption was determined to be Pb(II) > Cu(II) > Cd(II), and the adsorption rate of Pb(II) was much higher than that of Cu(II) and Cd (II). The metal ion adsorption capacity of NH2-Fe2O3 and NH2-Fe2O3/CS makes them promising adsorbents for wastewater cleanup.

Environmental remediation of heavy metal ions by novel-nanomaterials: A review

Recently, novel-nanomaterials with excellent sorption capacities, mild stability, and environmental-friendly performance, have enabled massive developments in capturing heavy metal ions. This review firstly introduces the preparation and modification of novel-nanomaterials (e.g., MOFs, nZVI, MXenes, and g-C₃N₄). Then, the heavy metal ions' sorption properties and the impact of environmental conditions have been discussed. Subsequently, the sorption mechanisms are verified through batch experiments, spectral analysis, surface complexation models, and theoretical calculations. Finally, the applications prospects of novel-nanomaterials in removing heavy metal ion polluted water have also been discussed, which provide perspective for future in-depth research and practical applications.

Composites of Anthraquinone Dyes@HKUST-1 with Tunable Microstructuring: Experimental and Theoretical Interaction Studies

The metal-organic framework (MOF) HKUST-1 was employed as an interaction matrix for fundamental loading studies of anthraquinone dyes. Chosen dyes were alizarin (A), alizarin S (AS), disperse blue 1 (B1), disperse blue 3 (B3), disperse blue 56 (B56) and purpurin (P). All materials were characterized by XRD, FTIR, TGA and SEM. Hence the interaction of dyes with the framework was characterized by theoretical-experimental differential analysis. One-pot loading strategy resulted in more efficient scavenging of dyes, and reached 100 % for B56 using 50 mg L^-1 . SEM revealed important microstructural changes, the smaller crystals ranged 0.8-3 μm in size and almost all composite sizes were from this to higher values, reaching 70 μm, with varying shapes. Two composites were larger in size range (about 2500-1000 μm), and were shaped as rods, octahedrons and coffin lids. Indeed, the microstructure could be modulated depending on preparation conditions and type of loaded dye. For the higher loading series, N₂ adsorption and XPS experiments were carried on to further evidence dye-MOF interactions. Ab initio prediction of structural properties for A@HKUST-1 and P@HKUST-1 were obtained by means of solid-state CRYSTAL14 code at the PBE0 level of theory. Computed findings evidenced two O→Cu coordinative bonds, one from O-ketone and the other from O-phenolate moiety as main interactions towards CuNET centers.

Combining the Photocatalysis and Absorption Properties of Core-Shell Cu-BTC@TiO₂ Microspheres: Highly Efficient Desulfurization of Thiophenic Compounds from Fuel

A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO₂ was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO₂ shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure. The morphology and structure of the fabricated Cu-BTC@TiO₂ microspheres were verified by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, X-ray powder diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy analyses. A potential formation mechanism of Cu-BTC@TiO₂ is proposed based on complementary experiments. The sulfur removal efficiency of the microspheres was evaluated by selective adsorption of benzothiophene (BT) and dibenzothiophene (DBT) from a model fuel with a sulfur concentration of 1000 ppmw. Within a reaction time of 20 min, the BT and DBT conversion reached 86% and 95%, respectively, and achieved ADS capacities of 63.76 and 59.39 mg/g, respectively. The BT conversion and DBT conversion obtained using Cu-BTC@TiO₂ was 6.5 and 4.6 times higher, respectively, than that obtained using Cu-BTC. A desulfurization mechanism was proposed, the interaction between thiophenic sulfur compounds and Cu-BTC@TiO₂ microspheres was discussed, and the kinetic behavior was analyzed.

Facile Fabrication of Magnetic Metal-Organic Framework Composites for the Highly Selective Removal of Cationic Dyes

In this work, we show a novel magnetic composite material Fe₃O₄@HPU-9 (HPU-9 = {[Cd(L)0.5(H₂O)](DMA)(CH₃CN)}n) (H₄L = 1,1′-di(3,5-dicarbonylbenzyl)-2,2′bimidazoline, DMA = N,N-dimethylacetamide) constructed by in situ growth of HPU-9 on Fe₃O₄, which has excellent absorption of cationic dyes from aqueous solution. The Fe₃O₄@HPU-9 particle possesses a well-defined core-shell structure consisting of a Fe₃O₄ core (diameter: 190 nm) and a HPU-9 shell (thickness: 10 nm). In the composite, the HPU-9 shell contributes to the capsulation of cationic dyes through electrostatic attractions between HPU-9 and cationic dyes, while the Fe₃O₄ core serves as magnetic particle. The maximum absorption capacity of Fe₃O₄@HPU-9 for R6G was 362.318 mg·g−1. The absorption kinetics data were well described by a psedo-second-order model (R² > 0.99), and the equilibrium data were also well fitted to Langmuir isotherm model (R² > 0.99). Our data confirmed that the proposed magnetic composite could be recycled and reused several times without centrifugal separation, making it more convenient, economic and efficient than common adsorbents.

Magnetic Zr-MOFs nanocomposites for rapid removal of heavy metal ions and dyes from water

Amino-decorated Zr-based magnetic Metal-Organic Frameworks composites (Zr-MFCs) were prepared by a facile and efficient strategy. The nano-sized Fe₃O₄@SiO₂ core (about 15 nm) was coated with a shell of Zr-MOFs (about 5 nm) by means of in-situ growth. And, Fe₃O₄@SiO₂@UiO-66 and its amino derivatives (Fe₃O₄@SiO₂@UiO-66-NH₂ and Fe₃O₄@SiO₂@UiO-66-Urea) were successfully prepared by using different precursors. The obtained Zr-MFCs were demonstrated to be efficient adsorbents for metal ions/organic dyes removal from aqueous solution, with high adsorption capacity and fast adsorption kinetics. It was found that the amine-decorated MFCs were highly efficient for metal ions/dyes removal compared to raw MFC-O. Among them, MFC-N exhibited the highest capacity for Pb²⁺ (102 mg g^-1) and methylene blue (128 mg g^-1), while MFC-O exhibited the highest capacity for methyl orange (219 mg g^-1). Moreover, anionic and cationic dyes could be selectively separated and removed from the mixed solution just by adjusting the solution pH with Zr-MFCs as the adsorbents. And these Zr-MFCs materials can be easily regenerated by desorbing metal ions/organic dyes from the sorbents with appropriate eluents, and the adsorption capacity can be remained unchanged after 6 recycles. The obtained results demonstrated the great application potential of the prepared MFCs as fascinating adsorbents for water treatment.

Metal-organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions

Highly efficient removal of metal ion pollutants, such as toxic and nuclear waste-related metal ions, remains a serious task from the biological and environmental standpoint because of their harmful effects on human health and the environment. Recently, highly porous metal-organic frameworks (MOFs), with excellent chemical stability and abundant functional groups, have represented a new addition to the area of capturing various types of hazardous metal ion pollutants. This review focuses on recent progress in reported MOFs and MOF-based composites as superior adsorbents for the efficient removal of toxic and nuclear waste-related metal ions. Aspects related to the interaction mechanisms between metal ions and MOF-based materials are systematically summarized, including macroscopic batch experiments, microscopic spectroscopy analysis, and theoretical calculations. The adsorption properties of various MOF-based materials are assessed and compared with those of other widely used adsorbents. Finally, we propose our personal insights into future research opportunities and challenges in the hope of stimulating more researchers to engage in this new field of MOF-based materials for environmental pollution management.

Spatial confinement of a cationic MOF: a SC–SC approach for high capacity Cr(vi)-oxyanion capture in aqueous solution

Compound 1 could be used as a single crystal container to capture Cr(vi)-oxyanions via ion exchange with high capacity and selectivity. It is the first report that demonstrates that CrO₄²⁻ ions could be traced and confirmed through a single-crystal to single-crystal (SC–SC) pattern.

Rapid and high-capacity ultrasonic assisted adsorption of ternary toxic anionic dyes onto MOF-5-activated carbon: Artificial neural networks, partial least squares, desirability function and isotherm and kinetic study

The present paper focused on the ultrasonic assisted simultaneous removal of fast green (FG), eosin Y (EY) and quinine yellow (QY) from aqueous media following using MOF-5 as a metal organic framework and activated carbon hybrid (AC-MOF-5). The structure and morphology of AC-MOF-5 was identified by SEM, FTIR and XRD analysis. The interactive and main effects of variables such as pH, initial dyes concentration (mgL^-1), adsorbent dosage (mg) and sonication time (min) on removal percentage were studied by central composite design (CCD), subsequent desirability function (DF) permit to achieved real variable experimental condition. Optimized values were found 7.06, 5.68, 7.59 and 5.04mgL^-1, 0.02g and 2.55min for pH, FG, EY and QY concentration, adsorbent dosage and sonication time, respectively. Under this conditions removal percentage were obtained 98.1%, 98.1% and 91.91% for FG, EY and QY, respectively. Two models, namely partial least squares (PLS) and multi-layer artificial neural network (ANN) model were used for building up to construct an empirical model to predict the dyes under study removal behavior. The obtained results show that ANN and PLS model is a powerful tool for prediction of under-study dyes adsorption by AC-MOF-5. The evaluation and estimation of equilibrium data from traditional isotherm models display that the Langmuir model indicated the best fit to the equilibrium data with maximum adsorption capacity of 21.230, 20.242 and 18.621mgg^-1, for FG, EY and QY, respectively, while the adsorption rate efficiently follows the pseudo-second-order model.

Ultrasmall Fe2O3 nanoparticles/MoS2 nanosheets composite as high-performance anode material for lithium ion batteries

Coupling ultrasmall Fe₂O₃ particles (~4.0 nm) with the MoS₂ nanosheets is achieved by a facile method for high-performance anode material for Li-ion battery. MoS₂ nanosheets in the composite can serve as scaffolds, efficiently buffering the large volume change of Fe₂O₃ during charge/discharge process, whereas the ultrasmall Fe₂O₃ nanoparticles mainly provide the specific capacity. Due to bigger surface area and larger pore volume as well as strong coupling between Fe₂O₃ particles and MoS₂ nanosheets, the composite exhibits superior electrochemical properties to MoS₂, Fe₂O₃ and the physical mixture Fe₂O₃+MoS₂. Typically, after 140 cycles the reversible capacity of the composite does not decay, but increases from 829 mA h g⁻¹ to 864 mA h g⁻¹ at a high current density of 2 A g⁻¹. Thus, the present facile strategy could open a way for development of cost-efficient anode material with high-performance for large-scale energy conversion and storage systems.

Facile synthesis of low-cost biomass-based γ-Fe2O3/C for efficient adsorption and catalytic degradation of methylene blue in aqueous solution

In this study, a novel and low-cost method was developed for synthesizing magnetic porous γ-Fe₂O₃/C as an adsorbent and catalyst for removal of methylene blue (MB) from aqueous solution.

Novel thiosalicylate-based ionic liquids for heavy metal extractions

This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1-24h using model solutions (pH 7; 0.1M CaCl2) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P66614][PTB] and 2-(benzylthio)benzoate [P66614][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P66614][BTB] exclusively.

Ultrasonically assisted hydrothermal synthesis of activated carbon-HKUST-1-MOF hybrid for efficient simultaneous ultrasound-assisted removal of ternary organic dyes and antibacterial investigation: Taguchi optimization

Activated carbon (AC) composite with HKUST-1 metal organic framework (AC-HKUST-1 MOF) was prepared by ultrasonically assisted hydrothermal method and characterized by FTIR, SEM and XRD analysis and laterally was applied for the simultaneous ultrasound-assisted removal of crystal violet (CV), disulfine blue (DSB) and quinoline yellow (QY) dyes in their ternary solution. In addition, this material, was screened in vitro for their antibacterial actively against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) bacteria. In dyes removal process, the effects of important variables such as initial concentration of dyes, adsorbent mass, pH and sonication time on adsorption process optimized by Taguchi approach. Optimum values of 4, 0.02 g, 4 min, 10 mg L(-1) were obtained for pH, AC-HKUST-1 MOF mass, sonication time and the concentration of each dye, respectively. At the optimized condition, the removal percentages of CV, DSB and QY were found to be 99.76%, 91.10%, and 90.75%, respectively, with desirability of 0.989. Kinetics of adsorption processes follow pseudo-second-order model. The Langmuir model as best method with high applicability for representation of experimental data, while maximum mono layer adsorption capacity for CV, DSB and QY on AC-HKUST-1 estimated to be 133.33, 129.87 and 65.37 mg g(-1) which significantly were higher than HKUST-1 as sole material with Qm to equate 59.45, 57.14 and 38.80 mg g(-1), respectively.

General Deposition of Metal-Organic Frameworks on Highly Adaptive Organic-Inorganic Hybrid Electrospun Fibrous Substrates

Electrospun nanofibrous mats are ideal substrates for metal-organic frameworks (MOFs) crystal deposition because of their specific structural parameters and chemical tenability. In this work, we utilized organic-inorganic hybrid electrospun fibrous mats as support material to study the deposition of various MOF particles. HKUST-1 and MIL-53(Al) were produced through solvothermal method, while ZIF-8 and MIL-88B(Fe) were prepared using microwave-induced heating method. The synthesis procedure for both methods were simple and effective because the hybrid nanofibrous mats showed considerable affinity to MOF particles and could be used without additional modifications. The obtained MOF composites exhibited effective incorporation between MOF particles and the porous substrates. MIL-53(Al) composite was applied as fibrous sorbent and showed enhanced adsorption capacity and removal rate, as well as easier operation, compared with thepowdered sample. Moreover, MIL-53(Al) composite was easier to be regenerated compared with powder form.

Rapid collection and re-dispersion of MOF particles by a simple and versatile method using a thermo-responsive polymer

An easy but versatile method for fast thermal-responsive dispersion and collection of MOF particles in water.

Biosorption of Pb(ii) and Fe(iii) from aqueous co-solutions using chemically pretreated oil palm fronds

The removal of Pb(ii) and Fe(iii) from aqueous solutions using specially pretreated oil palm fronds (OPF) as biosorbents was investigated.

Ultra-high uptake and selective adsorption of organic dyes with a novel polyoxomolybdate-based organic–inorganic hybrid compound

[(4-Hap)₄(Mo₈O₂₆)] was used to conduct rapid and efficient selective uptake of organic dyes.