Ensuring effective water purification is essential for addressing freshwater scarcity and achieving the United Nations Sustainable Development Goals (SDGs). An efficient hybrid mixture, composed of FeCr quantum dots doped into mesoporous silica SBA-15 support and activated carbon (AC) derived from olive mill solid wastes, has been developed for treating high optical density polluted aqueous environments. This hybrid, denoted as FeCr-SBA-15/AC, was examined for its efficacy in the adsorption and photo-Fenton degradation of met orange dye (MO), a model high-optical-density pollutant, under visible light exposure. Characterization of the prepared samples was conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Key parameters investigated included catalyst dosage, dye concentration, solution pH, and H₂O₂ concentration. Remarkably, the FeCr-SBA-15/AC hybrid exhibited superior photocatalytic activity, achieving a degradation efficiency of 97% for MO under optimized conditions (catalyst dosage = 0.75 g L⁻¹, dye concentration = 20 mg L⁻¹, pH = 5.47, and 0.5 mL H₂O₂) after 180 min of irradiation with visible light. This performance surpassed that of FeCr-SBA-15 alone by 20%, due to the synergistic effects of adsorption and photo-Fenton. The adsorption of MO onto AC followed the Freundlich model equilibrium isotherm, while the experimental data for the hybrid mixture aligned well with the pseudo-first-order Langmuir–Hinshelwood kinetic model with a rate constant of 0.0173 min⁻¹. The leaching of Cr in the solution was very low—0.1 ppm—which is below the detection limit. These findings underscore the potential of the synthesized FeCr-SBA-15/AC hybrid as a cost-effective, environmentally friendly, and highly efficient photo-Fenton catalyst for treating wastewater contaminated by industrial effluents.

Driven by growing environmental concerns and increasing regulatory pressures, bio‐based polyurethanes (Bio‐PUs) derived from renewable resources such as vegetable oils and lignocellulosic biomass are attracting significant interest as sustainable alternatives. This review critically examines their mechanical performance, with a particular emphasis on fundamental structure–property relationships. The inherent chemistry of bio‐derived polyols and isocyanates, including hydroxyl functionality, molecular weight, and aromatic or aliphatic nature, is a key determinant of tensile strength, elongation, modulus, and toughness. We highlight effective reinforcement strategies utilizing natural fibers, nanomaterials, and hybrid fillers to enhance stiffness, strength, and thermal stability without compromising sustainability. A comparative analysis with petrochemical PUs reveals that certain bio‐based formulations can achieve comparable elasticity, and toughness, and in some cases improved weathering resistance depending on the specific bio‐derived components and formulation strategies. However, challenges remain in consistently achieving the high rigidity, flame resistance, and long‐term durability typical of some petrochemical PU systems. Broader life‐cycle considerations are also discussed, including feedstock variability, cost competitiveness, and end‐of‐life management. Finally, emerging pathways such as non‐isocyanate polyurethanes (NIPUs), advanced nanocomposites, and digital manufacturing techniques are highlighted as promising strategies to address current limitations and expand the potential application scope of Bio‐PUs, including in structural and biomedical fields.

Hydrogels are widely used in biomedical applications because they are biocompatible, respond to external stimuli, and closely mimic the mechanical properties of natural tissues. However, conventional hydrogels often exhibit poor electrical conductivity, low mechanical strength, and limited functionality, hindering their use in advanced biomedical platforms. These challenges can be addressed by integrating 2D graphene and its derivatives into polymer‐based nanocomposite hydrogels (CHGs). Graphene‐enhanced CHGs offer superior mechanical strength, electrical conductivity, thermal stability, and optical properties, making them ideal for advanced biomedical applications. This review provides a comprehensive analysis of graphene's structural and functional properties and its incorporation into hydrogel matrices for CHG synthesis. It explores recent advancements in graphene‐based CHGs for drug delivery, tissue engineering, and photothermal therapy (PTT), highlighting their enhanced performance. Additionally, it examines the emerging role of machine learning (ML) in optimizing CHG properties, such as predictive modeling for wearable sensors in biomedical contexts. By bridging materials science and computational intelligence, this review outlines a roadmap for designing next‐generation smart hydrogels, emphasizing their transformative potential in addressing complex healthcare challenges.