Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl₂, NaCl, MgCl₂, and synthetic urines. Reuse cycles demonstrated that xerogels could be reused for up to three cycles without any loss in adsorptive efficiency. The adsorption mechanisms of metformin in the adsorption process highlight the strong electrostatic interactions and hydrogen bonds between the adsorbate and the adsorbent material. Xerogels synthesized show promise as efficient adsorbents to remove metformin from aqueous solutions, helping to mitigate its environmental impact.

Fixed-bed adsorption is widely employed in the scaling-up of liquid-phase adsorption processes because it offers significant operational advantages over batch systems. However, conventional approaches for scaling up adsorption columns are subject to important limitations. In this regard, the Axial Dispersion Model (ADM) coupled with the Pore Volume and Surface Diffusion Model (PVSDM) provides a framework capable of overcoming these constraints. In this study, ADM–PVSDM was applied predictively using equilibrium relationships and diffusion coefficients obtained from batch experiments. Model validity was assessed against nine experimental breakthrough curves, yielding an average deviation of 7.6% in breakthrough time. Furthermore, the model successfully predicted system behavior across a feed-flux range of 18–174 g h⁻¹m⁻². The integration of ADM–PVSDM was supported by the characterization of the Mass Transfer Zone (MTZ), which underpins the scaling approach proposed herein. The predicted breakthrough curves were also used to estimate MTZ length and velocity, which ranged from 0.97 to 8.7 cm and from 0.56 × 10⁻³ to 20 × 10⁻³ cm min⁻¹, respectively, with mean percentage deviations of 6.4% and 7.3%. These predictions enabled the development of a methodology which is capable of scaling adsorption columns over a wide operational range while requiring substantially fewer experiments compared to conventional scaling methods. Finally, it was demonstrated that commonly used empirical models, such as the Bohart–Adams model, failed to predict breakthrough curves with sufficient accuracy, thus rendering them unsuitable for developing this scaling methodology.

Due to continuous use and environmental factors (humidity and continuous exposure to the sun), the leather upholstery experiences cracking, discoloration and possible yellowing. The above factors significantly decrease the life of leather upholstery in cars. The objective of this work is to synthesize zinc oxide nanoparticles, which have optical properties that allow it to absorb UV radiation and then incorporate them into a polymeric matrix to develop a coating with UV protection for leather finishing in the automobile industry. The particles of zinc oxide were synthesized by the sol-gel method to obtain a nanometric particle size, the method represent a low-cost synthesis method, without the use of surfactants and easily scalable. With monoethylene glycol was formed a stable colloid with the zinc oxide nanoparticles and the polymer matrix. Finally, the final leather finishing obtained for the automotive industry has greater resistance to bending, also thermal stability was improved. In consequence, the lifetime of the leather finishing has improved.