Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200–5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.

This work examines corncobs adsorption capacity sulfamethoxazole removal from aqueous solutions. Various parameters have been optimized and kinetic, equilibrium and thermodynamic evaluated. The characteristics of corncobs were determined by Brunauer-Emmett-Teller (BET), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), point of zero charge and chemical analysis. The adsorption kinetic of SMX followed the pseudo-second-order model, reaching the equilibrium at 60 min. In equilibrium, data fitted BET model, the removal efficiency was 48% (pH = 6, SMX concentration 5 mg L⁻¹, 30 g L⁻¹ of adsorbent). The adsorption was sensitive to the pH of solution. The thermodynamic indicates an exothermic process workable under ambient temperatures.

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 (pH_pzc) were used to characterize both adsorbents. The adsorption capacity (q_e) 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 pH_pzc results. The continuous fixed-bed experiments showed that % R and q_e of SMX are higher with SB in all the tests. The highest q_e 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 q_e 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.