Co/Ni/Cu-NH2BDC MOF@natural Egyptian zeolite ore nanocomposite for calcium ion removal in water softening applications.

Water softening is a treatment process required to remove calcium (Ca(II)) and magnesium (Mg(II)) cations from water streams. Nanocomposites can provide solutions for such multiple challenges and have high performance and low application costs. In this work, a multimetallic cobalt, nickel, and copper 2-aminoterephthalic acid metal-organic framework ((Co/Ni/Cu-NH2BDC) MOF) was synthesized by a simple solvothermal technique. This MOF was supported on an Egyptian natural zeolite ore and was used for the adsorption of Ca(II) ions for water-softening applications. The adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), N2 adsorption-desorption isotherms, and zeta potential measurements. The adsorption isotherm data for the prepared adsorbent toward Ca(II) were best fit using the Redlich-Peterson model and showed a maximum adsorption capacity of 88.1 mg/g. The adsorption kinetics revealed an equilibrium time of 10 min, which was best fit using the Avrami model. The intermolecular interactions of Ca(II) ions with zeolite and MOF were investigated by Monte Carlo simulations, molecular dynamics simulations, and FTIR and XRD analyses. The adsorption sites in the zeolite structure were oxygen atoms, while those in the MOF structure were amine nitrogen atoms. The Ca(II) ions are coordinated with the solvent molecules in both structures. Finally, the in vitro cytotoxicity of this nanocomposite was assessed, revealing viability levels of 74.57 ± 2.1% and 21 ± 2.79% for Vero and African green monkey kidney and human liver (HepG2) cells, respectively. Cytotoxicity assays help assess the environmental impact of these materials, ensuring that they do not harm aquatic organisms or disrupt ecosystems. Thus, this study demonstrated the valorization of MOF/zeolite as a valuable and industry-ready adsorbent that can appropriate Ca(II) contaminants from aqueous streams.

Antifungal and antibacterial investigation of quinary Zr Al Fe Co Ni layered double hydroxide and its Al Fe Co Ni quaternary and Fe Co Ni tertiary roots.

Layered double hydroxides (LDH) are promising 2D nanomaterials being investigated for several engineering and biomedical applications. In this work, quinary Zr Al Fe Co Ni LDH and its Al Fe Co Ni LDH quaternary and Fe Co Ni LDH tertiary roots were prepared and characterized. All samples showed an aggregated, layered morphology with zero surface charge and approximately 300 nm of hydrodynamic size. BET surface area of Al Fe Co Ni LDH showed a remarkable value of 143.25 m2 g-1 as opposed to 26.2 m2 g-1 and 45.4 m2 g-1 for Fe Co Ni LDH and Zr Al Fe Co Ni LDH, respectively. The antimicrobial activity of the prepared samples was assessed against the many pathogenic bacteria; Bacillus (B.) subtilis, Escherichia (E.) coli, Haemophilus (H.) influenza, Listeria (L.) monocytogenes, Staphylococcus (S.) aureus, and Streptococcus (St.) pneumonia, and six fungal species. Furthermore, anti-biofilm activity, growth curve assay, and effect of UV illumination were examined against various pathogenic microbes. Zr Al Fe Co Ni displayed remarkable antibacterial activity, as indicated by the lowest values of the minimum inhibitory concentrations (MIC) of 4-166.7 µg mL-1. Results for fungal strains varied in terms of their susceptibilities for the different samples tested. Zn Al Fe Co Ni was able to inhibit the biofilm formation of S. aureus (96.09%), E. coli (98.32%), and Candida (C.) albicans (95.93%). This study shown that certain LDH categories, particularly Zr Al Fe Co Ni, may be promising antibacterial agents against variety of pathogenic microorganisms that cause serious infections.

Investigation of ternary Zn-Co-Fe layered double hydroxide as a multifunctional 2D layered adsorbent for moxifloxacin and antifungal disinfection.

Layered double hydroxides have recently gained wide interest as promising multifunctional nanomaterials. In this work, a multifunctional ternary Zn-Co-Fe LDH was prepared and characterized using XRD, FTIR, BET, TEM, SEM, and EDX. This LDH showed a typical XRD pattern with a crystallite size of 3.52 nm and a BET surface area of 155.9 m2/g. This LDH was investigated, for the first time, as an adsorbent for moxifloxacin, a common fluoroquinolones antibiotic, showing a maximum removal efficiency and equilibrium time of 217.81 mg/g and 60 min, respectively. Its antifungal activity, for the first time, was investigated against Penicillium notatum, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, and Mucor fungi at various concentrations (1000-1.95 µg/mL). This LDH was found to be effective against a variety of fungal strains, particularly Penicillium and Mucor species and showed zones of inhibition of 19.3 and 21.6 mm for Penicillium and Mucor, respectively, with an inhibition of 85% for Penicillium species and 68.3% for Mucormycosis. The highest antifungal efficacy results were obtained at very low MIC concentrations (33.3 and 62 µg/ml) against Penicillium and Mucor, respectively. The results of this study suggest a promising multifunctional potential of this LDH for water and wastewater treatment and disinfection applications.

Cellulose-based activated carbon/layered double hydroxide for efficient removal of Clarithromycin residues and efficient role in the treatment of stomach ulcers and acidity problems.

The terrible rise of antibiotic residues which possesses a serious threat to the ecological and aquatic environments. So, the development of highly cost-effective, highly operation-convenient and recyclable adsorbents was a must. In our study, we utilized the ternary layered double hydroxide (CoZnAl LDH) as an efficient adsorbent and nano-carrier for Clarithromycin (CLA) residues for their biodegradability and biocompatibility. Also, we enhanced the removal efficiency of the synthesized ternary LDH using cellulose-based activated carbon which was obtained using the hydrothermal carbonization method followed by chemical activation via static air converting the cellulose derivative (hydroxy ethyl cellulose HEC) into highly porous activated carbon that played an important role in the adsorption process. Full characterization of the synthesized activated carbon (AC) and the adsorbents before and after the adsorption processes were carried out using different techniques. The differences between the two adsorbents were investigated in a comparative study in terms of factors affecting the adsorption process like pH, the dose of adsorbent, time, and temperature. The adsorption isotherm was investigated at pH 10 with high regression coefficient (R2) of 0.99 showing maximum adsorption capacity (qmax) of 61.5 mg/g for (CLA) using LDH as adsorbent, whereas, the investigation using the modified LDH (LDH-AC) with high regression coefficient (R2) of 0.99 shows maximum adsorption capacity (qmax) of 495 mg/g for (CLA). Kinetic studies were estimated. The thermodynamic parameters such as ΔS°, ΔG° and ΔH° were estimated showing that the adsorption processes undergo exothermic and spontaneous routes. The safety and cytotoxicity of the modified, synthesized LDH (LDH-AC) were investigated besides the investigation of the gastroprotective efficacy against generated stomach ulcers. (LDH-AC) showed significant reduction for the generated ulcer in addition to the enhancement of the gastro protective efficacy revealing the safe use of LDH-AC/CLA for biological purposes like ulcer reduction and the enhancement of the ulcer inhibition.

LDH Nanocubes Synthesized with Zeolite Templates and Their High Performance as Adsorbents.

In this work, the efficiency of the adsorptive removal of the organic cationic dye methylene blue (MB) from polluted water was examined using three materials: natural clay (zeolite), Zn-Fe layered double hydroxide (LDH), and zeolite/LDH composite. These materials were characterized via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) diffraction (XRF), low-temperature N2 adsorption, pore volume and average pore size distribution and field emission scanning electron microscopy (FE-SEM). The properties of the applied nanomaterials regarding the adsorption of MB were investigated by determining various experimental parameters, such as the contact time, initial dye concentration, and solution pH. In addition, the adsorption isotherm model was estimated using the Langmuir, Freundlich, and Langmuir-Freundlich isotherm models. The Langmuir model was the best-fitting for all applied nanomaterials. In addition, the kinetics were analyzed by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, and the pseudo-second-order model was an apparent fit for all three applied nanomaterials. The maximum Adsorption capacity toward MB obtained from the materials was in the order zeolite/LDH composite > zeolites > Zn-Fe LDH. Thus, the zeolite/LDH composite is an excellent adsorbent for the removal of MB from polluted water.

Understanding the physicochemical properties of Zn-Fe LDH nanostructure as sorbent material for removing of anionic and cationic dyes mixture.

In our work, the removal of cationic and anionic dyes from water was estimated both experimentally and computationally. We check the selectivity of the adsorbent, Zn-Fe layered double hydroxide (LDH) toward three dyes. The physical and chemical properties of the synthesis adsorbent before and after the adsorption process were investigated using X-ray photoelectron spectroscopy, energy dispersive X-ray, X-ray diffraction, FT-IR, HRTEM, and FESEM analysis, particle size, zeta potential, optical and electric properties were estimated. The effect of pH on the adsorption process was estimated. The chemical stability was investigated at pH 4. Monte Carlo simulations were achieved to understand the mechanism of the adsorption process and calculate the adsorption energies. Single dye adsorption tests revealed that Zn-Fe LDH effectively takes up anionic methyl orange (MO) more than the cationic dyes methylene blue (MB) and malachite green (MG). From MO/MB/MG mixture experiments, LDH selectively adsorbed in the following order: MO > MB > MG. The adsorption capacity of a single dye solution was 230.68, 133.29, and 57.34 mg/g for MO, MB, and MG, respectively; for the ternary solution, the adsorption capacity was 217.97, 93.122, and 49.57 mg/g for MO, MB, and MG, respectively. Zn-Fe LDH was also used as a photocatalyst, giving 92.2% and 84.7% degradation at concentrations of 10 and 20 mg/L, respectively. For visible radiation, the Zn-Fe LDH showed no activity.

Removal of Cu2+ metal ions from water using Mg-Fe layered double hydroxide and Mg-Fe LDH/5-(3-nitrophenyllazo)-6-aminouracil nanocomposite for enhancing adsorption properties.

Herein, a new adsorbent was prepared by modifying Mg-Fe LDH for the removal of Cu2+ metal ions from wastewater. Mg-Fe LDH with 5-(3-nitrophenyllazo)-6-aminouracil ligand has been successfully prepared using direct co-precipitation methods and was fully characterized using FTIR analysis, X-ray diffraction, BET surface area theory, zeta potential, partial size, TGA/DTA, CHN, EDX, FESEM, and HRTEM. The surface areas of Mg-Fe LDH and Mg-Fe LDH/ligand were 73.9 m2/g and 34.7 m2/g respectively. Moreover, Cu2+ adsorption on LDH surfaces was intensively examined by adjusting different parameters like time, adsorbent dosage, pH, and Cu2+ metal ion concentration. Several isotherm and kinetic models were investigated to understand the mechanism of adsorption towards Cu2+ metal ions. Adsorption capacity values of LDH and ligand-LDH rounded about 165 and 425 mg/g respectively, applying nonlinear fitting of Freundlich and Langmuir isotherm equations showing that the ligand-LDH can be considered a potential material to produce efficient adsorbent for removal of heavy metal from polluted water. The adsorption of Cu2+ metal ions followed a mixed 1,2-order mechanism. The isoelectric point (PZC) of the prepared sample was investigated and discussed. The effect of coexisting cations on the removal efficiency of Cu2+ ions shows a minor decrease in the adsorption efficiency. Recyclability and chemical stability of these adsorbents show that using Mg-Fe LDH/ligand has an efficiency removal for Cu2+ ions higher than Mg-Fe LDH through seven adsorption/desorption cycles. Moreover, the recycling of the Cu2+ ions was tested using cyclic voltammetry technique from a neutral medium, and the Cu2+ ion recovery was 68%.

Zn/Fe LDH as a clay-like adsorbent for the removal of oxytetracycline from water: combining experimental results and molecular simulations to understand the removal mechanism.

Pharmaceuticals are detected at trace levels in water. Their adverse effects on human health and aquatic ecosystems required novel pharmaceutical remediation methods for treating wastewater effluents. Layer double hydroxide (LDH) is abundantly available by simple preparation methods and with low costs. The extensive use of antibiotics nowadays leads to increasing the appearance of antibiotic resistance between bacteria and decreasing the effectiveness of antibiotics. In this work, the removal of one of these antibiotics named "oxytetracycline hydrochloride (OTC)" by Zn/Fe LDH was investigated. The Zn/Fe LDH before and after adsorption was characterized by X-ray diffraction, FT-IR analysis, zeta potential, particle size, BET surface area, HRTEM, FESEM, and XPS. The effects of different factors on the OTC adsorption performance were investigated. The removal percentage of OTC was 77.23% by Zn/Fe LDH. The isothermal and kinetic study of OTC adsorption was carried out at pH 6 at 25 °C using different models. The adsorption mechanism was investigated by Monte Carlo and molecular dynamic simulations.

Sustainable waste management and recycling of Zn-Al layered double hydroxide after adsorption of levofloxacin as a safe anti-inflammatory nanomaterial.

Inorganic nano-layered double hydroxide (LDH) materials are used in the catalytic field, and have demonstrated great applicability in the pharmacological fields. In the current study, we report Zn-Al LDH as an adsorbent for levofloxacin (levo). The physical and chemical properties of the prepared material before and after adsorption were monitored using X-ray diffraction, Fourier-transform infrared (FT-IR) spectroscopic analysis, energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) surface area measurements, high-resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). Density functional theory (DFT) calculations for levo and its protonated species were studied at the B3LYP/6-311G (d,p) level of theory. The removal percentage of levo was 73.5%. The adsorption isotherm was investigated using nine different models at pH 9, where the obtained correlation coefficients (R 2) using the Redlich-Peterson and Toth models were 0.977. The thermodynamic parameters ΔS°, ΔG° and ΔH° were estimated and discussed in detail. Also, to support the adsorption research field, the applicability of the formed waste after the adsorption of levo onto Zn-Al LDH was investigated for medical purposes. The toxicity of levo in both normal and nanocomposite form was studied. Neither toxicological symptoms nor harmless effects were exhibited throughout the in vivo study. The oral anti-inflammatory activity, tested using 6% formalin to produce edema in the footpad, was manifested as a significant increase of 37% in the anti-inflammatory effect of the Zn-Al LDH/levo nanocomposite compared to levo in its normal form.

Correction: Sustainable waste management and recycling of Zn-Al layered double hydroxide after adsorption of levofloxacin as a safe anti-inflammatory nanomaterial.

[This corrects the article DOI: 10.1039/D0RA04898D.].