Mohamad. M. Ayad

Terephthalic acid recovered from post-consumer PET waste was utilized to synthesize UiO-66, demonstrating a sustainable waste-to-resource strategy for the photocatalytic degradation of methylene blue in water.

Graphene oxide (GO) nanosheets exhibit good chemical stability for water treatment applications. However, strong van der Waals interactions between adjacent nanosheets often lead to structural collapse, thereby reducing the exposed surface area and limiting electron/ion transport, which diminishes the adsorption efficiency. EDTA-functionalization of GO results in the formation of EDTA-GO nanosheets with a high density of chelating groups. This functionalization provides better stability of the material in solution and a high number of active sites, which lead to a superior ability to capture and remove pollutant ions efficiently. The functionalization process was conducted using a modified Hummers' method, followed by surface modification with ethylenediaminetetraacetic acid (EDTA). The resulting nanomaterial was characterized by FT-IR, XRD, and TEM techniques, confirming successful functionalization and changes in surface morphology. The adsorption behavior of EDTA-GO toward Fe(III) ions in aqueous solution was investigated under various conditions. Adsorption kinetics followed the pseudo-second-order model, indicating chemisorption as the predominant mechanism. Isotherm models (Langmuir, Freundlich, and Temkin) demonstrated a high adsorption capacity (1034 mg g⁻¹) and favorable multilayer adsorption behavior. Thermodynamic parameters revealed that the adsorption process is spontaneous and endothermic. These results suggest that the EDTA-functionalized GO is a promising material for the efficient removal of heavy metals from water. The synthesized sample displayed a high maximum monolayer adsorption capacity of 1034 mg g⁻¹ based on the Langmuir model, which is mainly attributed to the application of a modified strategy of synthesis in order to provide more accessible active sites. Thermodynamic analysis also indicated that the adsorption is a spontaneous and endothermic chemical sorption process (ΔH° = +65.327 kJ mol⁻¹), which allows the mechanistic interpretation of the high complexation of Fe(III) ions with the EDTA functional moieties covalently bonded onto the GO matrix.

The detection of alcohol vapors is important in applications such as breathalyzers and environmental monitoring, yet achieving in situ, sensitive, and selective analysis remains challenging. In this work, a homogeneous in situ‐grown polypyrrole (PPy) thin film is developed directly on the Au‐electrode via the chemical polymerization of pyrrole and evaluated as a sensing layer using the quartz crystal microbalance (QCM) technique for the detection of primary aliphatic alcohol vapors, including methanol, ethanol, 1‐propanol, and 2‐propanol. Structural characterization by scanning electron microscopy, X‐ray diffraction, and Fourier Transform Infrared spectroscopy confirmed the formation of a uniform PPy surface with an amorphous nature. Adsorption of alcohol vapors into the PPy film induced frequency shifts (∆f) in the QCM response significantly enhancing sensor sensitivity. The magnitude of ∆f increased proportionally with alcohol vapor concentration, exhibiting a linear relationship. Diffusion coefficients were determined by examining the diffusion behavior of alcohol vapor in the PPy, and adsorption kinetics were analyzed. Furthermore, molecular dynamics simulations were employed to elucidate the interaction mechanisms between the alcohol and PPy, while enthalpies of mixing were estimated based on the cohesive energy density approach. The PPy‐coated QCM sensor demonstrated excellent reversibility and reproducibility throughout the testing process of volatile alcohols.

Robust chemical modification of mesoporous silica was conducted using 3-mercaptopropyltriethoxysilane via a chemical surface-engineered postgrafting of mesoporous silica KIT-6 with acidic propylsulfonate groups to obtain mesoporous KIT-6-SO₃H. A fabricated meso-KIT-6-SO₃H-modified quartz crystal microbalance sensor with KIT-6-SO₃H layers coating on a QCM electrode is utilized to detect Pb²⁺, Cd²⁺, and Cs⁺ ions with high sensing affinity. The functionalized KIT-SO₃H exhibits adsorption capacities (Q_e) of 123.5 mg g^-1, 117.5 mg g^-1, and 90.6 mg g^-1 for Pb²⁺, Cd²⁺, and Cs⁺, respectively, as determined by UV-vis measurements. These values coincide well with those obtained from the QCM sensor and ICP-OES measurements. The remarkable ability to adsorb metal ions is achieved by the synergistic cooperation of the large pore volume, high surface area, and abundant acidic -SO₃H groups within the mesoporous structure of KIT-6-SO₃H. A comprehensive study was carried out to investigate the influence of pH on the adsorption uptake of metal ions. Kinetic and isotherm studies demonstrate that the adsorptive removal of metal ions by KIT-6-SO₃H follows a second-order kinetic model and is well described by the Langmuir isotherm, reflecting monolayer adsorption behavior. Density functional calculations reveal that the adsorption of these metals is highly exothermic from a thermodynamic perspective, which aligns with and supports the experimental findings. All metals were exothermically adsorbed with binding energies of -1.790 eV for Pb²⁺, -0.181 eV for Cd²⁺, and -3.113 eV for Cs⁺, confirming the exergonic adsorption of the investigated metals on KIT-6-SO₃H.

Using raw egg yolk and phosphoric acid, a simple hydrothermal treatment for synthesizing carbon quantum dots (CQDs) has been developed for the manufacture of UV and blue light-blocking filters. Several samples with different doping ratios of phosphoric acid were prepared. Namely: reference (REF.), 25%, 50%, 75% and 100%. The synthesized CQDs were embedded in polyvinyl alcohol (PVA) to produce blocking-light films with desired optical properties. Six films were prepared, one of which was PVA alone, and the other five samples were the prepared CQDs, with different phosphorus doping levels, mixed with PVA in a 1:1 ratio. We aimed to test the ability of these films to block ultraviolet rays and blue light. The experimental results revealed that the prepared films were able to block the blue light, emitted from a 450 nm blue LED, with blocking ratios of 7%, 17.5%, 27%, 30%, 37% and 70% for the films: PVA alone, REF., 25%, 50%, 75% and 100%, respectively. Moreover, it was found that these phosphorus-doped CQDs films can prevent destructive UV light with substantial value reaching 86%. These results suggest that carbon dots, derived from raw egg yolk, can be effectively applied to block harmful UV and blue lights.

The emerging pharmaceutical contaminants diclofenac (DCF) and salicylic acid (SA) pose potential hazards to humans and living organisms due to their persistence in water environments. In this work, the conductive polymers polypyrrole (PPY) and polyaniline (PANI) were successfully coated on cotton fabrics, as confirmed by FTIR and SEM measurements. The coated fabrics efficiently removed DCF at pH 5.3 and SA at pH 4, with removal efficiencies that exceeded 90% and 70%, respectively. Adsorption was rapid for most of the tested contaminant–fabric systems and reached equilibrium within 20–30 min. The best adsorption performance for both contaminants was shown on the PPY-coated fabrics, which yielded adsorption capacities of about 65 and 21 mg/g for DCF and SA, respectively. This could be explained by molecular modeling simulations, which mostly estimated higher total cohesive energy densities for adsorption on the PPY-coated fabrics than on the PANI-coated ones. The adsorption mechanism involved both coulombic electrostatic attractions and non-coulombic van der Waals and π-π stacking. The fabrics could be reused for three adsorption–desorption cycles. Immobilization of the conductive polymers on cotton fabrics provides a facile method for their handling and collection during adsorption and regeneration cycles while maintaining their multi-functionality in adsorbing different contaminants.

Nitrogen-doped porous carbons (NPCs) derived from zeolitic imidazolate frameworks (ZIFs) are promising in a wide variety of applications, especially in electrochemical energy storage applications, due to their outstanding physical and chemical properties. Herein, the effect of different types of surfactants as capping agents on the morphology and surface activity of ZIF-derived NPCs was investigated. A series of NPCs were prepared by direct carbonization of ZIF-8 under an inert atmosphere in the presence of capping agents. MOF-derived NPCs with capping agents exhibited accessible pore aperture and relatively high nitrogen content. This affects the textural characteristics of NPCs in terms of morphology, particle size, and surface activity. All the samples were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD) technique. The influence of variation of specific surface area of ZIF-8-derived NPCs on its electrochemical properties was investigated. Additionally, the surface charge of the various samples was estimated by point of zero charges (pH_PZC) to find the optimal processing parameters and enhance the capacitive properties. The estimated experimental results showed the optimum results obtained by a higher specific surface areas NPCs prepared with the present of SDS as capping agent with specific surface area 967.5 m²/g and larger pore volume 0.78 cm³ /g, the point of zero charge 7.94 and the specific capacitance in 1.0 M H₂SO₄ is 490.96 F/g.