This study presents a novel layered magnesium oxide (MgO) adsorbent synthesized using a sodium dodecylbenzene sulfonate (SDBS)-assisted hydrothermal method aimed at enhancing fluoride removal from water. The optimized MgO sample exhibited a specific surface area of 164.7 m² g⁻¹ and an average pore size of 5.4 nm, achieving a fluoride removal rate of 91.95% at an initial concentration of 10 mg L⁻¹ over a wide range of pH. Adsorption studies revealed a maximum capacity of 126.405 mg g⁻¹, aligned with the Langmuir isotherm model and pseudo-second-order kinetics. The fluoride removal mechanism involves converting MgO to Mg(OH)₂ followed by ion exchange processes, elucidated through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The adsorbent demonstrated good regeneration potential and pH tolerance across varying conditions. Notably, fluoride-adsorbed MgO showed enhanced catalytic activity in Knoevenagel condensation reactions and plastic degradation, indicating its dual functionality in both water treatment and catalysis. This research offers valuable insights into developing multifunctional materials for environmental remediation and catalytic applications, addressing critical challenges in water treatment technologies.

The electrooxidation of organic compounds offers a promising strategy for producing value-added chemicals through environmentally sustainable processes. A key challenge in this field is the development of electrocatalysts that are both effective and durable. In this study, we grow gold nanoparticles (Au NPs) on the surface of various phases of titanium dioxide (TiO₂) as highly effective electrooxidation catalysts. Subsequently, the samples are tested for the oxidation of benzaldehyde (BZH) to benzoic acid (BZA) coupled with a hydrogen evolution reaction (HER). We observe the support containing a combination of rutile and anatase phases to provide the highest activity. The excellent electrooxidation performance of this Au-TiO₂ sample is correlated with its mixed-phase composition, large surface area, high oxygen vacancy content, and the presence of Lewis acid active sites on its surface. This catalyst demonstrates an overpotential of 0.467 V at 10 mA cm⁻² in a 1 M KOH solution containing 20 mM BZH, and 0.387 V in 100 mM BZH, well below the oxygen evolution reaction (OER) overpotential. The electrooxidation of BZH not only serves as OER alternative in applications such as electrochemical hydrogen evolution, enhancing energy efficiency, but simultaneously allows for the generation of high-value byproducts such as BZA.