E. coli@UiO-67 composites as a recyclable adsorbent for bisphenol A removal

Assessing the efficiency and reusability of zirconium-based MOF-biochar composite for the removal of Pb (II) and Cd (II) in single and multi-ionic systems

Recent studies have highlighted the promising properties of metal-organic frameworks (MOF) and biochar composites as cost effective adsorbents. Although MOF-biochar composites have shown significant potential for contaminant removal in aquatic environments, further research is needed for their scalable performance in removing a wide range of emerging contaminants from wastewater. In this paper, we introduce a novel UiO67-biochar composite (MBC) for the first time, synthesised via an in-situ solvothermal method, as an innovative solution for removing heavy metals from water. The composite was characterised by various analytical techniques (SEM, TEM, XRD, FTIR, XPS, BET, and TGA) and the results demonstrated that the specific surface area of the composite (≈540 m2/g) elevated 28 times compared to the unmodified biochar (≈20 m2/g). The adsorption tests indicate remarkable adsorption capacity and removal efficiency in the range of 121.1 mg/g and 90.8 % as well as 59.7 mg/g and 89.5 % for Pb (II) and Cd (II), respectively, which sustained under impacts of co-existing ions. Kinetic studies demonstrated that the experimental data for both heavy metal ions were best described by the Pseudo-second order kinetic model, inferring that chemical interactions mainly control adsorption. The formulated material showed promising stability (retained crystallinity confirmed by XRD analysis) over reusability tests with approximately 87 % removal efficiency. The ion exchange, surface complexation, and electrostatic interactions were the main adsorption mechanisms of the heavy metal ions on the MBC composite. The formulated composite proposed in this study offers scalable, sustainable, and affordable material to treat heavy metal-polluted water and wastewater.

Harnessing the UiO-67 metal-organic framework for advanced detection of cadmium ions in water bodies

Heavy metal ions are hazardous pollutants that pose serious threats to ecosystems and human health, making it imperative to detect and monitor their presence in water for environmental protection. This paper highlights the synthesis of the UiO-67 Metal-Organic Framework (MOF) without any dopants, offering a novel approach specifically for the detection of cadmium ions (Cd2+) in aqueous environments. Following solvothermal synthesis, Powder X-ray Diffraction (PXRD), BET nitrogen adsorption-desorption analysis, X-ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM) were used to characterize the structural and morphological features of UiO-67. The MOF exhibited a high pore volume and surface area, which are essential for enhancing its detection capabilities for Cd2+ ions. Based on experimental findings, the proposed sensor exhibits excellent selectivity towards Cd2+ ions and a sensitivity of 3.008 μA nM-1. Further, it achieves a low Limit of Detection (LoD) of 1.43 nM μA-1 and a Limit of Quantification (LoQ) of 4.34 nM μA-1. The sensitivity and reliability of the UiO-67-modified electrode are demonstrated by these values, which qualify it for trace-level cadmium ion detection. The ground-breaking potential of undoped UiO-67 serves as a cutting-edge and effective tool for environmental monitoring, particularly in the detection of toxic metal ions in water bodies.

A novel univariate interpolation and bivariate regression hybrid method application to biodegradation of bisphenol A diglycidyl ether using laccases from Geobacillus stearothermophilus and Geobacillus thermoparafinivorans strains

Bisphenol A diglycidyl ether (BADGE), a derivative of the well-known endocrine disruptor Bisphenol A (BPA), is a potential threat to long-term environmental health due to its prevalence as a micropollutant. This study addresses the previously unexplored area of BADGE toxicity and removal. We investigated, for the first time, the biodegradation potential of laccase isolated from Geobacillus thermophilic bacteria against BADGE. The laccase-mediated degradation process was optimized using a combination of response surface methodology (RSM) and machine learning models. Degradation of BADGE was analyzed by various techniques, including UV-Vis spectrophotometry, high-performance liquid chromatography (HPLC), Fourier transform infrared (FTIR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). Laccase from Geobacillus stearothermophilus strain MB600 achieved a degradation rate of 93.28% within 30 min, while laccase from Geobacillus thermoparafinivorans strain MB606 reached 94% degradation within 90 min. RSM analysis predicted the optimal degradation conditions to be 60 min reaction time, 80°C temperature, and pH 4.5. Furthermore, CB-Dock simulations revealed good binding interactions between laccase enzymes and BADGE, with an initial binding mode selected for a cavity size of 263 and a Vina score of -5.5, which confirmed the observed biodegradation potential of laccase. These findings highlight the biocatalytic potential of laccases derived from thermophilic Geobacillus strains, notably MB600, for enzymatic decontamination of BADGE-contaminated environments.

The Selective Removal of Bisphenol A Using a Magnetic Adsorbent Fused with Bisphenol A-Binding Peptides

The potential of bisphenol A (BPA)-binding peptides fused to magnetic beads is demonstrated as novel adsorbents that are reusable and highly selective for BPA removal from aqueous environments, in which various interfering substances coexist. Magnetic beads harboring peptides (peptide beads) showed a higher BPA removal capacity (8.6 mg/g) than that of bare beads without peptides (2.0 mg/g). The BPA adsorption capacity of peptide beads increased with the number of peptides fused onto the beads, where monomeric, dimeric, or trimeric repeats of a BPA-binding peptide were fused to magnetic beads. The BPA-adsorbing beads were regenerated using a methanol-acetic acid mixture, and after six regeneration cycles, the adsorption capacity remained above 87% of its initial capacity. The selective removal of BPA was confirmed in the presence of BPA analogs with high structural similarity (bisphenol F and bisphenol S) or in synthetic wastewater. The present work is a pioneering study that investigates the selective affinity of peptides to remove specific organics with high selectivity from complex environmental matrices.

Microorganisms@aMIL-125 (Ti): An Amorphous Metal-Organic Framework Induced by Microorganisms and Their Applications

Amorphous metal-organic framework (aMOF)-based materials have attracted considerable attention as an emerging class of nanomaterials. Herein, novel microorganisms@aMIL-125 (Ti) composites including yeast@aMIL-125 (Ti), PCC 6803@aMIL-125 (Ti), and Escherichia coli@aMIL-125 (Ti) composites were respectively synthesized by self-assembling aMOFs on the microorganisms' surface. The functional groups on the microorganisms' surface induced structural defects and participated in the formation of aMIL-125 (Ti) composites. Finally, the application of microorganisms@aMIL-125 (Ti) composites for the removal of glyphosate from aqueous solution was selected as a model reaction to illustrate their potential for environmental protection. The present method is not only economical but also has other advantages including ease of operation, environmentally friendly assay, and high adsorption. The maximum adsorption capacity of aMIL-125 (Ti) was 1096.25 mg g^-1, which was 1.74 times that of crystalline MIL-125 (Ti). Therefore, the microorganisms@aMOFs composites will have broad application prospects in energy storage, drug delivery, catalysis, adsorbing toxic substances, sensing, encapsulating and delivering enzymes, and in other fields.

Adsorption and convenient ELISA detection of sulfamethazine in milk based on MOFs pretreatment

Metal-organic frameworks (MOFs) has excellent adsorption performance, herein, three kinds of common MOFs were used for the adsorption of sulfamethazine (SM₂) in milk, then enzyme-linked immunosorbent assay (MOF-ELISA) was established. Firstly, NH₂-UiO-66, NH₂-MIL-101, and ZIF-8 were successfully prepared and their adsorption characteristics for SM₂ were investigated. The kinetic models of the three MOFs were more in line with the pseudo-second-order adsorption kinetics, and the saturated adsorption capacity of NH₂-UiO-66, NH₂-MIL-101, and ZIF-8 for SM₂ at 298 K were 139.64, 29.98, and 36.5 mg/g, respectively. Using three different MOFs as adsorbents, the pretreatment of milk samples could be completed within 1 h, the half inhibitory concentrations (IC₅₀) of MOF-ELISA were 1.26, 1.86 and 2.74 ng/mL, the limit of detections (LOD) were 0.05, 0.12, and 0.19 ng/mL and the recovery rate were from 82.30% to 105.62% with the intra-day coefficient of variations (CVs) below 5.81% and inter-day CVs below 7.21%. Detection results showed good correlations with LC-MS/MS (R² > 0.99), indicated that MOFs could effectively eliminate the interference of sample matrix, and has the potential to become a general pretreatment method for the detection of various matrices residues in food safety monitoring.

Low-Cost Synthesis of Alumina Nanoparticles and Their Usage for Bisphenol-A Removal from Aqueous Solutions

Gamma-alumina nanoparticles (γANPs) were obtained from a low-cost process by using natural bauxites. The γANPs materials were characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, scanning electron microscopy (SEM), atomic force microscopy (AFM), and were functionalized with N-cetyl-N, N, N, trimethylammonium bromide (CTAB), leading to CTAB modified γ-alumina nanoparticles (γANPs-CTAB). These novel functionalized γANPs-CTAB were characterized by XRPD, FTIR, and were used as an adsorbent for bisphenol-A (BPA) removal from water. Batch investigations were conducted under different experimental conditions (e.g., adsorbent dose, agitation time, initial concentration, and pH and surfactant loading) in order to optimize BPA adsorption and to identify the adsorption mechanisms in the system γANPs-CTAB-BPA. The effect of pH on the adsorption showed that the quantity of BPA removed increased remarkably until the pH value was 4, then remained almost constant until the pH value was up to 10, and then decreased for pH values greater than 10. For an initial BPA concentration of 20 mg/L and an adsorbent dose of 12.5 g/L at a pH value of 10, the removal efficiency achieved was 91.80 ± 0.21%. The adsorption mechanism was perfectly described by pseudo-second-order kinetics and the Langmuir isotherm. γANPs-CTAB materials were found to be effective adsorbents for BPA removal from water.