The synergistic action of cyclodextrin-based adsorbent and advanced oxidation processes for sulfamethoxazole removal from water

Abstract

In this work, the removal of sulfamethoxazole from water was studied by adsorption on a cyclodextrin–epichlorohydrin copolymer and through Advanced Oxidation Processes. The adsorption was efficient and fast, requiring only 10 min to reach the equilibrium; it was also highly favored, with adsorption efficiency higher than 80%, at slightly acidic pH and at room temperature. The desorption of sulfamethoxazole was obtained by raising the temperature to 80 °C. The regenerated polymer has been reused multiple times without any loss in performance, allowing a reduction in costs associated with the process. As an alternative method to regenerate the adsorbent material, the photodegradation of sulfamethoxazole adsorbed on the polymer alone and in the presence of TiO2 as a catalyst through continuous irradiation with UV light and Pulsed Light was attempted and studied. For this purpose, polymeric adsorbents containing different amounts of TiO2 were synthesized and tested. The Pulsed Light showed the highest efficiency since it allowed the complete removal of sulfamethoxazole, regardless of the presence of TiO2 which, however, reduces adsorption efficiency of the material. Furthermore, a qualitative assessment of formed pulsed light by-products was also attempted. The remains of SMX in solution were decomposed by Pulsed Light technology and the effect of the presence of hydrogen peroxide on the photodegradation process was also studied. Despite the presence of by-products after Advanced Oxidation Processes, the procedure proposed in this work is effective and easy to apply to water treatment plants, thanks to the use of environmental-friendly adsorbents and light sources. Graphical abstract

Photocatalytic Systems Based on ZnO Produced by Supercritical Antisolvent for Ceftriaxone Degradation

“…The hybrid photocatalytic system with micronized β-CD showed better performance than ZnO only, which is in agreement with the literature [43,45]. This result implies an improvement in the photocatalytic performances because the β-CD can encapsulate the ceftriaxone, leading to the formation of inclusion complexes that increase the contact between the guest antibiotic molecules and the catalyst surface [56,57]. In more detail, the presence of β-CD allows for the capturing of the ceftriaxone inside its hydrophobic cavity by generating inclusion complexes, thereby increasing the contact between the antibiotic adsorbed on the catalyst surface and the reactive oxygen species created from UV light irradiation.…”

“…The hybrid photocatalytic system with micronized β-CD showed a better performance than ZnO only, which is in agreement with the literature [43,45]. This result implies an improvement in the photocatalytic degradation of organic compounds by forming the inclusion complex with cyclodextrins, which helps the overall reaction mechanism of contaminant degradation [56,57]. The hybrid photocatalytic system with micronized β-CD showed better performance than ZnO only, which is in agreement with the literature [43,45].…”

A Comprehensive Strategy for Stepwise Design of a Lab PROTOTYPE for the Removal of Emerging Contaminants in Water Using Cyclodextrin Polymers as Adsorbent Material

“…If the duration needed to attain adsorption equilibrium between the β-CDs-EPI adsorbent and wastewater is excessively long, in-flux operational feasibility is compromised, limiting the potential applications in real-world scenarios. Following a comprehensive assessment of these factors, as previously described by our research group working with the same polymer [ 41 , 42 ], the experimental findings revealed that using 1 g of polymer at pH 7.0 working in a reaction volume of 50 mL at room temperature, with an agitation speed of 500 rpm yielded the most favorable conditions for conducting subsequent experiments.…”

Technical–Economic Feasibility of a New Method of Adsorbent Materials and Advanced Oxidation Techniques to Remove Emerging Pollutants in Treated Wastewater

“…In addition, a treatment capacity between 1000 and 100,000 m 3 /d has been considered. Due to the limitation of the Clean Up system's treatment capacity to 1000 m 3 /d, as obtained in previous studies [35], a linear trend has been considered for the following orders of magnitude (10 units and 100 units of Life Clean Up in parallel).…”

“…The Clean Up solution is based on the combination of these two technologies (adsorption and oxidation), but with an innovative approach that enables obtaining a treatment that can compete in efficiency with the aforementioned technologies. In previous research works, the Clean Up solution technology is described in detail [30][31][32][33][34][35]. This research proceeds to conduct the technical-economic feasibility study of the Clean Up technology.…”