Hosam El-Din Mostafa Saleh

Cement, the most widely used binding agent in concrete, is responsible for approximately 5% of global CO ₂ emissions, and cement-based materials are further limited by pronounced brittleness, porosity, and reduced tensile strength and fracture resistance. Over the past decade, this has driven interest in nanoparticle-modified cement, since nanomaterials refine the microstructure, densify the cement paste, and improve the mechanical and transport properties of cementitious composites; however, the high cost of many engineered nanomaterials has created demand for alternative, low-cost, and environmentally friendly substitutes. Eggshell, a calcium carbonate-rich biological waste generated in large volumes worldwide, has emerged as one such candidate: eggshell powder improves the mechanical performance of stabilized soils and bricks, and its incorporation as a partial cement or aggregate replacement in concrete and mortar affects compressive, flexural, and tensile strength depending on the replacement ratio and processing method. This review examines the physical and chemical properties of eggshell powder and the factors governing its contribution to the strength of construction materials. It evaluates recent work on nano-scale eggshell (nano-eggshell) as a further refinement of this approach, including its rheological and mechanical performance in cement mortar. The review further considers the use of eggshell-based composites in radiation shielding, where the same calcium carbonate content relevant to cementitious performance also contributes to gamma-ray attenuation. Through a critical comparative analysis of divergent findings across the literature and integration of the most recent studies (2024–2026), this review identifies the mechanistic basis - a competition between nucleation and dilution effects—that explains the apparently contradictory optimal replacement ratios reported in previous work. Collectively, the evidence indicates that eggshell powder and its nano-scale derivatives represent a viable, safe, and economical additive for sustainable construction and radiation-shielding applications.

The physiological vulnerability of specific tissues to radionuclides must directly dictate the molecular design of waste containment chemistries. Unlike conventional reviews that treat radiobiology and radiochemistry separately, we establish a continuous feedback loop between cellular injury mechanisms (e.g., strontium-90 in pancreatic β‑cells via calcium mimicry) and chemical sequestration strategies (e.g., cryptand‑2.2.2‑functionalized geopolymers). We first reinterpret fundamental radionuclide properties through a physiological lens, revealing why half‑life alone fails to predict biological risk. Second, we propose a Physiological Vulnerability Index (PVI) that quantifies how ion‑mimicry and organ‑specific transport proteins (e.g., sodium iodide symporter (NIS), transient receptor potential vanilloid 6 (TRPV6), Na+/K+‑ATPase) amplify hazard beyond standard dosimetry, using the effective half-life of each radionuclide (combining physical and biological half-life) rather than physical half-life alone. Third, we design waste forms using reverse physiology: supramolecular hosts that replicate the failed selectivity of biological channels, radiation‑tolerant geopolymers that block mitochondrial fragmentation, and redox‑active barriers that disrupt ferroptosis triggered by plutonium. Finally, we introduce the Biocompatible Waste Matrix Score (BWMS) – a hybrid metric that combines chemical leach rate with a panel of five physiological biomarkers (mtDNA fragments, insulin secretion inhibition, thyroid NIS silencing, lymphocyte γ‑H2AX foci, and plasma selenoprotein P). This review transforms radioactive waste management from a purely geochemical discipline into a biology‑driven engineering field, offering testable hypotheses for next‑generation containment systems.

Triple quadrupole inductively coupled plasma mass spectrometry was utilized to determine Lu and Hf isotopic ratio in some geological samples. Mass interferences with different isotopes were studied using oxygen as a reaction gas in the triple quad mode. The examined samples were digested in 14 M HNO₃, 28 M HF and 2 M HCl, Dowex 50-WX8 resin was used to separate lutetium (Lu) from hafnium (Hf). Thallium isotopic standard SRM 997 was used to correct the mass bias of the measured isotopes. The obtained fractions were analyzed using single quad mode without reaction gas. The results of analysis showed good agreement with the direct analysis using the reaction gas. The obtained results led to the age determination of the samples according to the Lu-Hf method of dating the obtained age was 446±117 million years. This technique is favored due to its relative simplicity and how quickly and easily samples can be digested chemically as a novel method to prepare samples for Lu-Hf isotopic analysis.

This study investigates the radiation shielding performance of lead borosilicate waste glass when incorporated as an additive into cement–bitumen composites. The utilization of lead borosilicate glass, a byproduct of industrial processes, offers a dual advantage: it enhances the gamma-ray attenuation capacity of the composite achieving a mass attenuation coefficient of 7.85 × 10⁻² cm²/g and simultaneously contributes to the sustainable management of radioactive waste by improving the compressive strength to 32.9 MPa. Cement–bitumen mixtures were prepared with varying concentrations of the waste glass and evaluated through both experimental measurements and theoretical modeling. The linear attenuation coefficients demonstrated a marked improvement in shielding efficiency with increasing lead content. Computational tools, including XCOM and Geant4, were employed to simulate photon interactions and validate the experimental findings. The simulation results were in strong agreement with experimental data, confirming the enhanced attenuation properties at higher glass concentrations. These findings suggest that lead borosilicate waste glass is a promising additive for improving the gamma radiation shielding properties of cement–bitumen matrices, with potential applications in nuclear waste immobilization and radiation protection. Furthermore, the approach promotes sustainable recycling of industrial waste, aligning with environmental conservation goals. Further research is recommended to optimize glass loading and assess the long-term durability and structural performance under diverse environmental conditions.

This study presents the preparation and structural elucidation of a Schiff base ligand (HL) synthesized by the reaction between 1H-indole-2,3-dione (Isatin) and 2-amino thiophenol and its metal complexes with Co(II), Cd(II), Fe(III), and La(III) metal ions. The characterization of the ligand and its metal complexes was accomplished through various analytical methods including elemental analysis, IR, ¹H-NMR, UV–Vis spectroscopy, mass spectrometry, thermogravimetric analysis (TGA), magnetic susceptibility assessments, powder XRD (PXRD), and scanning electron microscopy (SEM). The IR spectra elucidated the coordination of the ligand HL to the metal ions via azomethine nitrogen, carbonyl oxygen, and deprotonated thiol sulfur, resulting in a tridentate N, O, S coordination mode. The ¹H-NMR spectra confirmed this coordination through the absence of the SH proton signal in the metal complexes. Mass spectrometry revealed molecular ion peaks that aligned with the suggested stoichiometry of the ligand and its complexes. Thermal analysis demonstrated the stability of the metal complexes. The electronic spectra and magnetic susceptibility data pointed to octahedral geometries for the synthesized metal complexes supporting the diamagnetic characteristics of Cd(II) and La(III) complexes. XRD analysis showed that the ligand and its metal complexes exhibited nanocrystalline structures, with average crystallite sizes between 4.21 and 14.67 nm. SEM imaging revealed notable alterations in surface morphology following complexation validating the formation of the metal complexes. Additionally, theoretical investigations utilizing density functional theory (DFT) provided optimized geometries and electronic characteristics that were in good agreement with the experimental findings. Furthermore, the DFT and quantum chemical calculations were performed using a 6-31G(d) basis set in conjunction with Becke’s three-parameter hybrid (B3LYP) method. The results indicated that the metal chelates exhibited six coordination sites in an octahedral configuration which aligned with the experimental findings.

This study investigated the effectiveness of a ligand known as (2-Mercapyo-phenylimino)-1,3-dihydro-indol-2-one-based ligand, in removing stable/radioactive cesium and cobalt from contaminated wastewater. Several parameters, such as contact duration, temperature, adsorbent quantity, pH of the medium, and concentration of adsorbate, have been investigated as primary active parameters impacting the adsorption process. Regarding the stable isotopes, the concentrations of Co²⁺ and Cs⁺ were measured before and after the treatment processes using the Optical Emissions Spectroscopy with Inductively Coupled Plasma (ICP-OES) technique. Additionally, kinetic and equilibrium isotherm models were applied to understand the equilibrium data. Both Cs⁺ and Co²⁺ were ideally eliminated after 120 and 60 min, respectively. The optimal pH for Cs⁺ was 6.3, while that for Co²⁺ was 5. The results indicate that the adsorption process is endothermic for Co²⁺ and exothermic for Cs⁺. Three thermodynamic parameters (∆G°, ∆H°, and ∆S°) were calculated. The reported R² values for the Freundlich and Langmuir models showed that the adsorption process for Cs⁺ and Co²⁺ always followed these isotherms, regardless of the temperature used. For Cs⁺, the maximum single-layer capacity (q_max) was 15.10 mg g⁻¹, while for Co²⁺, it was 62.11 mg g⁻¹. When the aqueous medium was spiked with both radioisotopes individually, the elimination of ⁶⁰Co and ¹³⁴Cs achieved maximum values of 99 and 86%, respectively, within 120 min. It can be concluded that the ligand effectively removed cobalt and cesium from wastewater, with higher adsorption for cobalt.

Open access peer-reviewed chapter

Open access peer-reviewed chapter