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Acetaminophen (ACT), an antipyretic analgesic, is one of the emerging pollutants that has been found in high concentrations in domestic and hospital wastewaters. This study 7the adsorption capacity of sugarcane bagasse (SB) and corn cob (CC) for the ACT removal through the dynamic simulation of the adsorption column using Aspen Adsorption® V10. The effects of flow rate (1.5–3.0 mL min− 1), ACT initial concentration (40–80 mg L− 1), and bed height (20–35 cm) on the breakthrough curves were studied. Finally, the simulation results were validated with experimental studies, and analyzed by error functions, sum of squared errors (SSE), absolute average deviation (AAD), and coefficient of determination (R2). Based on the predicted breakthrough curves, ACT is adsorbed in greater quantity on CC, with saturation times and adsorption capacity greater than SB in all simulations. The maximum adsorption capacity was 0.47 and 0.32 mg g− 1 for CC and SB, respectively, under condition of flow rate of 1.5 mL min− 1, bed height of 25 cm, and ACT initial concentration of 80 mg L− 1. Breakthrough and saturation times were higher when the column operated at low flow rates, large bed height, and low ACT concentrations, for both adsorbents. The predicted and experimental breakthrough curves satisfactorily coincided with R2 values greater than 0.97, SSE and AAD values ​​less than 5% and 0.2, respectively, for all studies. The experimental adsorption capacity was greater for CC than for SB, thus confirming that the software is able to predict which adsorbent may be more effective for ACT removal. The results of this study would speed up the search for effective materials to remove ACT from wastewaters.

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This paper presents a brief discussion with regard to the fixed-bed modeling results of a recent paper by Li et al. published in this journal.

The performance of solar thermal technology under high-altitude equatorial climatic and solar path conditions has not been determined. Evacuated tube solar collectors are more efficient than flat plate collectors in cold and cloudy regions; however, due to their dependence on orientation, the irradiation incidence between the tubes of these collectors can be blocked. In this study, the performance of these types of collectors was analyzed to determine the implications of their orientation under these specific climate conditions. Four solar thermal systems were installed: two of the systems used evacuated tube collectors, and two used flat plate collectors. Each collector was connected to storage and discharge points to simulate residential consumption when observing the real performance of the four systems in terms of irradiation availability. The evacuated tube collectors were more efficient and reduced the backup energy requirement by up to 20.6% more on average than the flat plate collectors. In addition, the performance of the evacuated tube collectors increased by up to 9.8% when the tubes were arranged parallel to the solar path, compared to when they were arranged perpendicular to the solar path, verifying that the blockage effect is an important parameter to consider for evacuated tube technology. The main novelty of this research is the comparison of these two technologies under different orientations, with perpendicular and parallel dispositions toward the solar path, in a high-altitude equatorial location where solar collectors are not typically oriented in any particular orientation. To the best of our knowledge, this is the first complete analysis of real systems deployed under these conditions.

Natural adsorbents are a good alternative to remove antibiotic residues from wastewater. In this study, the adsorption capacity of sulfamethoxazole (SMX) onto sugarcane bagasse (SB) and corn cob (CC) in a continuous fixed-bed was compared. Brunauer Emmett Teller, Fourier transform infrared (FTIR), Boehm titration, and point of zero charge (pHpzc) were used to characterize both adsorbents. The adsorption capacity (qe) and the removal percentage of SMX (% R) were investigated at different different flow rates (2, 5, and 7 mL min− 1) and adsorbent masses (4 and 6.4 g), and a constant initial concentration of 5 mg L− 1. The results of the characterization showed that SB has a morphology with more dispersed particles and a specific surface higher than CC (2.6 > 1.2 m2 g− 1). Boehm titration indicates that both the surface of SB and CC have a greater amount of acid groups, which is in agreement with FTIR and pHpzc results. The continuous fixed-bed experiments showed that % R and qe of SMX are higher with SB in all the tests. The highest qe and maximum % R was 0.24 mg g− 1 and 74% with SB, and 0.15 mg g− 1 and 65% using CC. In most cases, the qe of both adsorbents decreased with the increase of flow rate and bed height. An analysis suggests that hydrogen bonds could be the main factor favoring the SMX adsorption with SB. Finally, the intraparticle diffusion was the rate-controlling step, predominating the pore-volume diffusion resistance.