This study focused on the generation and characterization of sludge produced by electrocoagulation (EC) combined with Moringa oleifera seed extract (MOSE) to remove water hardness. First, an experimental data set was generated and used as the baseline data for mathematical modeling to identify the effects of different parameters on Ca²⁺ and Mg²⁺ ion hardness removal. Then, using the generated data set, operational conditions were optimized using neural networks integrated with a genetic algorithm, resulting in the selection of Fe electrodes, 12.5 mL of MOSE per 100 mL of water, a current density (j) of 49.16 mA cm⁻², and a reaction time of 5.3 min, considering Ca²⁺ ions as the sample contaminant. Additionally, machine learning analysis identified contaminant type, reaction time, and cathode material as the most influential variables affecting sludge formation, with optimal conditions identified for both Ca²⁺ and Mg²⁺ ion systems. For all the mathematical models, experimental validation was performed. The MOSE extract was characterized for the presence of proteins, polyphenols, flavonoids, and polysaccharides, which provide functional groups that promote aggregation and floc development. Sludge characterization by FT-IR, TGA, and TEM revealed the formation of organic–inorganic hybrid matrices composed of biomolecules interacting with electrochemically generated Fe³⁺ and Al³⁺ species, as well as Ca²⁺ and Mg²⁺ ions. These results highlight the role of plant-derived biomolecules in modulating the sludge structure and composition, providing insight into the mechanisms of sludge formation and the implications for handling and valorization of EC-based water treatment systems.

Recalcitrant azo dyes in textile wastewater are a significant environmental concern due to their persistence and potential impacts on human and ecosystem health. Heterogeneous Fenton-like processes offer a promising approach for their removal, although catalyst performance depends strongly on the physicochemical characteristics of the active material. This study investigated Fe-functionalized silicon oxide (Fe-SiO) catalysts for sodium percarbonate (SPC)-activated removal of Reactive Orange 84 (RO84). The catalysts were prepared using silicon oxide supports with and without thermochemical pretreatment and different amounts of Fe during synthesis. Their structural, morphological, and elemental characteristics were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS), complemented by textural analysis. Increasing the amount of Fe used during synthesis shifted removal from adsorption-influenced to oxidation-associated, as reflected in the kinetic behavior. Thermochemical pretreatment promoted more homogeneous Fe dispersion and reduced aggregation in the S2 series, consistent with its higher catalytic response under several evaluated conditions. The PFO model empirically described the observed removal kinetics. Overall, the Fe-SiO materials showed potential for SPC-assisted RO84 removal under the evaluated conditions.

Biogenic synthesis based on microorganisms and plants utilizes biomolecules and metabolites that act as reducing and stabilizing agents. Furthermore, these biomolecules confer enhanced properties, increasing their effectiveness as antibacterial agents, even against multidrug-resistant bacteria. However, there is currently a lack of knowledge regarding the characteristics of the biomolecules involved and their mechanisms during synthesis, which limits their wider application. This research study focused on the synthesis of AgNPs using extracellularly secreted biomolecules from the filamentous fungus R. stolonifer. The results indicated that the concentration of the biomolecules depends on the response of the fungus to specific operational conditions. Furthermore, a relationship was found between the concentrations of total proteins and polyphenols, an optimal protein-to-polyphenol ratio, and the formation of AgNPs. Characterization of the fungus extracts revealed a complex mixture of over 100 metabolites, primarily phenolic compounds, proteins, and methoxylated compounds, thereby identifying a synergistic mechanism that enables the reduction and stabilization of AgNPs. Disinfection tests confirmed the antibacterial efficacy of all biosynthesized AgNPs, achieving 100% elimination of Escherichia coli and Staphylococcus aureus. The study outcomes highlight the important role of fungal biomolecules for creating a sustainable and efficient method for synthesizing antimicrobial nanoparticles with high efficacy for disinfectant applications.