Artículos SCI

The objective of this study was to determine the ability of sugar scum (SS), an industrial waste, as a novel biosorbent for the removal of Basic Blue 41 (BB 41) from aqueous solutions. The biosorbent was characterized by SEM/EDS, BET, FTIR, and pH_pzc measurements, respectively. To reach a maximum adsorption capacity of 26.45 mg.g^–1, impacting operational factors such as pH, biosorbent dose, contact duration, starting dye concentration, and temperature were adjusted, when the removal efficiency reached 84% during 60 min at pH 10, 1.5 g.L^–1 of biosorbent and C_o = 10 mg.L^–1. The experimental data were modeled by various isotherm models, whereas the best fit was found for Freundlich with a high correlation coefficient (R² = 0.991). Other kinetic models including pseudo-first, pseudo-second order, and intra-particle diffusion models were tested to fit the kinetic data. The biosorption of BB 41 onto SS was spontaneous (∆G° < 0) and exothermic (∆H° < 0), while the biosoprtion mechanism of BB41 over SS was proposed with repeated reuse showing that SS could be regenerated after four successive runs. Furthermore, this study revealed that sugar scum is an underutilized bioresource in Algeria, with the potential to provide low-cost environmental removal of additional contaminants in the wastewater treatment domain.

The utilization of biomass and bio-waste, particularly through hydrothermal processes, has shown promise as a technology for converting these materials into valuable products. While most research has traditionally focused on the solid and liquid byproducts of these hydrothermal treatments, the gaseous phase has often been over-looked. This study specifically investigates the conversion of off-gases produced during hydrothermal carbonation (HTC) into synthetic natural gas, offering a readily marketable product with economic potential. Although the methanation of conventional flue gases has been extensively studied, dealing with non-standard off-gases from processes like HTC presents challenges due to the presence of minor impurities like CO and CH4. This novel research seeks to experimentally evaluate the methanation of HTC off-gases using nickel-based catalysts and analyze how these impurities affect the catalytic performance. The studied catalysts include nickel supported by ceria and alumina, as well as alumina supported nickel-cobalt systems. The results demonstrate that these catalysts exhibit high CO2 conversion and CH4 selectivity under ideal gas conditions. However, when real gas compositions with impurities are considered, CO2 conversion decreases at lower temperatures (ca. 20% lower conversion for real gas vs. ideal), probably due to side reactions such as CH4 cracking. This difference becomes less pronounced at higher temperatures. Nevertheless, the catalysts perform satisfactorily, especially at temperatures exceeding 350 degrees C. In conclusion, this study sheds light on the methanation of HTC off-gases and underscores the significance of understanding how impurities in real gases impact the process, providing potential directions for future research.