Dr. Valdés-Morales, Héctor

In this work, the landfll leachate of Fez city (Morocco) is characterized physicochemically and the feasibility to apply a Fenton process is evaluated. A design of experiments based on Box–Behnken combined with a response surface methodology was used to assess the efect of three operating variables (pH, Fe2+ and H2O2 dosages) on two target responses: COD and color removal. The results of the analysis of variances demonstrate that both responses are signifcantly afected by Fe2+ dosage and pH. Statistical and graphical analyses show that maximum efciencies of 85% and 96% are obtained in terms of COD and color removal, respectively, when operating conditions are set in pH=2.8, [Fe2+]=1621 mg L−1 and [H2O2]=2500 mg L−1.

Recently, bismuth oxyiodide (BiOI) is an attractive semiconductor to use in heterogeneous photocatalysis processes. Unfortunately, BiOI individually shows limited photocatalytic efficiency, instability, and a quick recombination of electron/holes. Considering the practical application of this semiconductor, some studies show that synthetic zeolites provide good support for this photocatalyst. This support material permits a better photocatalytic efficiency because it prevents the quick recombination of photogenerated pairs. However, the optimal conditions (time and temperature) to obtain composites (BiOI/ synthetic zeolite) with high photocatalytic efficiency using a coprecipitation-solvothermal growth method have not yet been reported. In this study, a response surface methodology (RSM) based on a central composite design (CCD) was applied to optimize the synthesis conditions of BiOI/mordenite composites. For this purpose, eleven BiOI/mordenite composites were synthesized using a combined coprecipitation-solvothermal method under different time and temperature conditions. The photocatalytic activities of the synthesized composites were evaluated after 20 min of photocatalytic oxidation of caffeic acid, a typical organic pollutant found in agro-industrial wastewater. Moreover, BiOI/mordenite composites with the highest and lowest photocatalytic activity were physically and chemically characterized using nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS). The optimal synthesis conditions prove to be 187 ◦C and 9 h. In addition, the changes applied to the experimental conditions led to surface property modifications that influenced the photocatalytic degradation efficiency of the BiOI/mordenite composite toward caffeic acid photodegradation.