Functional Ag-EDTA-modified MnO2 nanocoral reef for rapid removal of hazardous copper from wastewater.

A novel MnO2@EDTA-Ag nanocoral reef was constructed via a simplified redox reaction followed by EDTA and Ag nanoparticles impregnation to capture hazardous copper (II) from wastewater. A comprehensive characterization of the synthesized materials was conducted. The morphology of MnO2@EDTA-Ag in the form of a nanocoral reef was constructed of two-dimensional nanoplatelets and nanorod-like nanostructures. The optimal adsorption conditions proposed by the Plackett-Burman design (PBD) that would provide a removal % of 99.95 were pH 5.5, a contact time of 32.0 min, a Cu(II) concentration of 11.2 mg L-1, an adsorbent dose of 0.05 g, and a temperature of 40.3 °C. The loading of Ag nanoparticles onto MnO2@EDTA improved the adsorption capability of MnO2@EDTA-Ag. Additionally, the recyclability of MnO2@EDTA-Ag nanocoral reef was maintained at 80% after three adsorption-desorption cycles, and there was no significant change in the XRD analysis before and after the recycling process, implying its stability. It was found that nanocoral reef-assisted EDTA formed a chelation/complexation reaction between COO- groups and C-N bonds of EDTA with Cu(II) ions. In addition, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis proved the synergistic effect of the electrostatic interaction and chelation/complexation was responsible for the removal mechanism of Cu(II). Also, the results demonstrated no significant variation in MnO2@EDTA-Ag removal efficiency for all the tested real water samples, revealing its efficacy in wastewater treatment. Therefore, the current study suggests that MnO2@EDTA-Ag has substantial potential to be used as a feasible adsorbent for probable hazardous metals remediation.

A comprehensive study for the potential removal of 152+154Eu radionuclides using a promising modified strontium-based MOF.

A facile modification of a strontium-based MOF using oxalic acid was carried out to prepare MTSr-OX MOF, which was used as a potential substance for eliminating 152+154Eu radioisotopes. Various analytical techniques were used to characterize MTSr-OX-MOF. The prepared MOF had a rod-like structure with a BET surface area of 101.55 m2 g-1. Batch sorption experiments were used to investigate the sorption performance of MTSr-OX-MOF towards 152+154Eu radionuclides where different parameters like pH, contact time, initial 152+154Eu concentration, ionic strength, and temperature were scrutinized to determine the optimum conditions for 152+154Eu removal. MTSr-OX-MOF showed superior effectiveness in the elimination of 152+154Eu with a maximum sorption capacity of 234.72 mg g-1 at pH 3.5. Kinetics fitted with the pseudo-second-order model and the Langmuir model correctly described the sorption mechanism. The thermodynamic variables were carefully examined, demonstrating that the 152+154Eu sorption was endothermic as well as spontaneous. The MTSr-OX-MOF has been found to be a significantly more effective sorbent towards 152+154Eu than that of many other adsorbents. When applied to real active waste, MTSr-OX-MOF demonstrated excellent removal performance for a wide range of radionuclides. As a result, the MTSr-OX-MOF can be recognized as an attractive solution for the 152+154Eu purification from active waste.

Recent progress in high-performance environmental impacts of the removal of radionuclides from wastewater based on metal-organic frameworks: a review.

The nuclear industry is rapidly developing and the effective management of nuclear waste and monitoring the nuclear fuel cycle are crucial. The presence of various radionuclides such as uranium (U), europium (Eu), technetium (Tc), iodine (I), thorium (Th), cesium (Cs), and strontium (Sr) in the environment is a major concern, and the development of materials with high adsorption capacity and selectivity is essential for their effective removal. Metal-organic frameworks (MOFs) have recently emerged as promising materials for removing radioactive elements from water resources due to their unique properties such as tunable pore size, high surface area, and chemical structure. This review provides an extensive analysis of the potential of MOFs as adsorbents for purifying various radionuclides rather than using different techniques such as precipitation, filtration, ion exchange, electrolysis, solvent extraction, and flotation. This review discusses various MOF fabrication methods, focusing on minimizing environmental impacts when using organic solvents and solvent-free methods, and covers the mechanism of MOF adsorption towards radionuclides, including macroscopic and microscopic views. It also examines the effectiveness of MOFs in removing radionuclides from wastewater, their behavior on exposure to high radiation, and their renewability and reusability. We conclude by emphasizing the need for further research to optimize the performance of MOFs and expand their use in real-world applications. Overall, this review provides valuable insights into the potential of MOFs as efficient and durable materials for removing radioactive elements from water resources, addressing a critical issue in the nuclear industry.

Mesoporous Ag-functionalized magnetic activated carbon-based agro-waste for efficient removal of Pb(II), Cd(II), and microorganisms from wastewater.

Herein, eco-friendly mesoporous magnetic activated carbon-based agro-waste nanosorbents incorporating antimicrobial silver nanoparticles (Mag@AC1-Ag and Mag@AC1-Ag) have been prepared. Various techniques (XRD, SEM/EDX, TEM, FTIR, and BET analysis) were employed to characterize the prepared nanosorbents before being utilized as novel nanosorbents to remove Pb+2 and Cd+2 ions. Mag@AC1-Ag and Mag@AC1-Ag exhibited rapid and excellent uptake of Pb+2 and Cd+2. The pseudo-second-order kinetics and the Langmuir isotherm are more suitable for the explanation of the experimental results. The thermodynamic parameters showed that the Pb+2 and Cd+2 sorption by the nanosorbents was a spontaneous and endothermic reaction. The prepared nanosorbents can be effectively regenerated using HCl and recycled up to the fifth cycle. These nanosorbents' potential uses for eliminating Pb+2 and Cd+2 from real water samples were evaluated. Moreover, the results revealed that both Mag@AC1-Ag and Mag@AC2-Ag exhibited high antimicrobial activity against fecal coliform (gram-negative) and Bacillus subtilis (gram-positive).

A novel strontium-based MOF: synthesis, characterization, and promising application in removal of 152+154Eu from active waste.

Removal of hazardous radioactive materials such as 152+154Eu from active waste using the batch approach has attracted attention nowadays. In this work, a novel melamine-terephthalic strontium metal-organic framework (MTSr-MOF) was prepared via a hydrothermal method. The MTSr-MOF was characterized by various analytical techniques such as FT-IR, 1H/13C-NMR, mass spectroscopy, XPS, XRD, TGA, BET, FE-SEM/EDX, TEM, and UV. The obtained data revealed that MTSr-MOF exhibited brick-like building blocks that were bridged together by the linkers, and each block had a thickness of ∼120 nm. The BET surface area was 74.04 m2 g-1. MTSr-MOF was used for the removal of 152+154Eu radionuclides from active waste. Further functionalization using various modifiers, including oxalic acid, EDTA, sulfuric acid, and sodium hydroxide was carried out to improve the sorption efficiency of MTSr-MOF towards 152+154Eu radionuclides. Among them, MTSr-MOF modified with oxalic acid (MTSr-OX-MOF) demonstrated a superior removal efficiency toward 152+154Eu radionuclides when compared to MTSr-MOF or other published reports, with a removal efficiency of more than 96%. The higher sorption efficiency of the MTSr-OX-MOF indicates that it could be a promising candidate for the removal of 152+154Eu radionuclides from radioactive waste.

Facile synthesis of mesoporous nano Ni/NiO and its synergistic role as super adsorbent and photocatalyst under sunlight irradiation.

Tailoring a material that has a synergistic role as an adsorbent and a photocatalyst for environmental application is an attractive field for research. This article presents a study of facile synthesis of NiO and Ni/NiO with a synergistic role as super adsorbents in the lake of light and photocatalysts under light irradiation. Nano flower-like mesoporous NiO and Ni/NiO were synthesized by the co-precipitation method. XRD, SEM, EDAX, XPS, BET, and DR/UV-Vis spectroscopy techniques were employed for samples' analysis. The point of zero surface charge of prepared samples was detected by the batch equilibrium method. The adsorption efficiency was investigated in the absence of light using aniline blue as a pollutant model dye. The synergistic effect as an adsorbent and a photocatalyst was investigated under UV and sunlight irradiation. Different parameters affecting the adsorption in the dark have been optimized. The results showed that in the absence of light, the prepared samples are super adsorbents with a maximum adsorption capacity ranging from 210 to 230 mg g-1 and a removal % ranging from 95 to 100% within 2 h. Under UV or sunlight irradiation, the adsorbent/photocatalyst attained a dye removal % of 99.8% within 30 min. The adsorption data matched the pseudo-second-order model, and the equilibrium adsorption data showed compatibility with Langmuir model. The findings of experiments revealed that the adsorption is spontaneous, exothermic, and results in less entropy. Under sunlight irradiation, the dye removal efficiency increased by 19% in the case of Ni/NiO hybrid; it showed a removal efficiency of 99.5% within 30 min under sunlight irradiation versus 80% after 120 min in the dark.

A novel HCV electrochemical biosensor based on a polyaniline@Ni-MOF nanocomposite.

Hepatitis-C virus ribonucleic acid (HCV-RNA) recognition and quantification based on real-time polymerase chain reaction (RT-PCR) is key to infection control, management, and response to treatment due to its specificity, sensitivity, and quantification capabilities. However, the high cost, time requirements, and need for sophisticated laboratory infrastructure have limited the use of this method in rapid screening, blood banks, and point-of-care testing (POCT). In this work, a novel label-free electrochemical biosensor constructed using a polyaniline@nickel metal-organic framework (Ni-MOF) nanocomposite was developed for direct detection of unamplified HCV nucleic acid. A robust biosensor was fabricated using smooth layer-by-layer deposition of the polyaniline@Ni-MOF nanocomposite, deoxyribonucleic acid (DNA) probe, and bovine serum albumin (BSA) onto a glassy carbon electrode (GCE) and was subsequently monitored real-time via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensitivity and specificity of the newly developed biosensor were specifically examined using the EIS approach. The results revealed that the novel biosensor is highly efficient in quantitative sensing of the HCV target in the presence of nonspecific nucleic acids over the range of 1 fM-100 nM with a detection limit of 0.75 fM (at a S/N ratio of 3). To the best of the authors' knowledge, the proposed biosensor is superior to other MOF platforms. These research findings are expected to have a positive influence on the quantitative detection of HCV RNA and other nucleic acids by offering exceptional accuracy and cost effectiveness, especially in low resource countries. Moreover, this biosensor could be simply adopted for full automation and used in point-of-care testing.

Nucleic acids biosensors based on metal-organic framework (MOF): Paving the way to clinical laboratory diagnosis.

Development of ultra-sensitive, high specific and cost-effective nucleic acids (NAs) biosensors is critical for early diagnosis of cancer, genetic diseases and follows up response to treatment. Metal-organic frameworks (MOFs) as sensing materials underwent significant development in recent years due to their unique merits, such as structural diversity, tunable pore scale, large surface area, remarkable adsorption affinities, and good thermal stability. MOFs have shown potential contribution in nucleic acids biosensors research. Herein, a comprehensive overview on NAs biosensors state of the art based on MOFs has been discussed extensively, including different MOFs platforms sensing strategies (fluorescence, electrochemistry, electrochemiluminescence, and colorimetric techniques), their analytical performance and figures of merit in clinical diagnostics, with the future perspective in introducing MOFs in clinical laboratory diagnostics. Moreover, the different MOFs synthesis methods have been highlighted to serve as a guide for the researchers in selecting the appropriate platform that suits their research needs, and applications.

Validated derivative and ratio derivative spectrophotometric methods for the simultaneous determination of levocetirizine dihydrochloride and ambroxol hydrochloride in pharmaceutical dosage form.

Three simple, precise, accurate and validated derivative spectrophotometric methods have been developed for the simultaneous determination of levocetirizine dihydrochloride (LCD) and ambroxol hydrochloride (ABH) in bulk powder and in pharmaceutical formulations. The first method is a first derivative spectrophotometric method ((1)D) using a zero-crossing technique of measurement at 210.4 nm for LCD and at 220.0 nm for ABH. The second method employs a second derivative spectrophotometry ((2)D) where the measurements were carried out at 242.0 and 224.4 nm for LCD and ABH, respectively. In the third method, the first derivative of the ratio spectra was calculated and the first derivative of the ratio amplitudes at 222.8 and 247.2 nm was selected for the determination of LCD and ABH, respectively. Calibration graphs were established in the ranges of 1.0-20.0 µg mL(-1) for LCD and 4.0-20.0 µg mL(-1) for ABH using derivative and ratio first derivative spectrophotometric methods with good correlation coefficients. The developed methods have been successfully applied to the simultaneous determination of both drugs in commercial tablet dosage form.