Escalado, modelación y simulación de la adsorción de sulfametoxazol en columna de lecho fijo utilizando bagazo de caña de azúcar y residuos de mazorca de maíz

Abstract

The use of agricultural residues as natural adsorbents constitutes a potential alternative for the removal of emerging pollutants present in wastewaters. Sulfamethoxazole (SMX) is a bacteriostatic antibiotic and one of the emerging pollutants that has been detected in high concentrations in domestic and hospital wastewaters. The objective of this work was to model, simulate, and scale up an adsorption column for sulfamethoxazole removal using sugarcane bagasse (SB) and corn cob (CC). Laboratory-scale experiments resulted in sugarcane bagasse having a higher adsorption capacity than corn cob. The maximum adsorption capacity obtained for SB and CC was 0.235 and 0.146 mg/g, respectively. Furthermore, it was observed that at lower bed heights and high flow rates, the breakthrough and saturation times are shorter with both adsorbents. The adsorption column was scaled to pilot plant under the criteria of geometric, kinematic, and dynamic similarity. The experimental breakthrough curves obtained at the laboratory and pilot level were adjusted to eight mathematical models, and the Wang model was the best which reproduced the experimental results with the two biosorbents. The shape of the laboratory and pilot-scale breakthrough curves were similar throughout the trajectory. However, the adsorption capacity decreased, and the removal percentage of SMX increased with the change of scale, from 0.22 to 0.19 mg/g and 59.94 to 69.24%, respectively. Additionally, a dynamic model was proposed to predict the breakthrough curves of sulfamethoxazole adsorption with SB and CC using Aspen Adsorption® and Comsol Multiphysics®. This model gave good correlation between the predicted and experimental curves for adsorption with SB, but it was inaccurate with CC, which gives the possibility of a local balance of SMX with this adsorbent. The inclusion of Darcy's Law in Comsol provided a breakthrough curve closer to the experimental data than that obtained in Aspen Adsorption. Finally, an economic estimation was developed in the SuperPro Designer software, it stated that it is necessary USD $ 215,123 for the process to be implemented on an industrial scale with an annual operating cost of USB $ 53,000 for a capacity of 150 L/h. The results of this research serve as support for subsequent studies of removal of antibiotics and other emerging contaminants on a pilot scale using natural adsorbents.