Browsing by Author "Zadra Filho, Paulo Cesar"
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- Occurrence of micropollutants in surface water and removal by catalytic wet peroxide oxidation enhanced filtration using polymeric membranes loaded with carbon nanotubesPublication . Silva, Adriano S.; Zadra Filho, Paulo Cesar; Ferreira, Ana Paula; Roman, Fernanda; Baldo, Arthur Pietrobon; Rauhauser, Madeleine; Díaz de Tuesta, Jose Luis; Pereira, Ana I.; Silva, Adrián; Pietrobelli, Juliana Martins Teixeira; Kalmakhanova, Marzhan; Snow, Daniel D.; Gomes, HelderMonitoring campaigns of contaminants of emerging concern (CECs) in surface waters is of utmost importance in evaluating the anthropogenic impact on riparian ecosystems. Beyond identifying pollutants and threats, treatment solutions are also needed to mitigate the adverse effects caused by polluted water discharged into the environment. For years, grab samples have been used to assess water quality, but the results can be misleading since contaminants are not always found due to the low and highly variable concentrations at which they are present in these matrices. Even in such small concentrations, the contaminants can be harmful to aquatic life. Therefore, for about three months, passive samplers were used to monitor the presence of pharmaceuticals in river water up- and downstream the discharge of a wastewater treatment plant (WWTP). Passive samplers were extracted, analyzed and the results were used to identify possible pollution composition and potential sources. Our campaign enabled the identification and quantification of 28 contaminants and showed that 27 increased in amount after WWTP discharge entered the river. The statistical analysis revealed the correlation between the pollutants, showed the oscillation in their amounts, and enabled the identification of specific pollutant groups that deserve attention for treatment, such as antibiotics and antidepressants. Moreover, an innovative catalytic wet peroxide oxidation (CWPO) intensified filtration process was investigated as a possible water treatment solution, using composite polymeric membranes loaded with carbon nanotubes (CNTs). Sulfamethoxazole (SMX) was selected as a model pollutant, and 85–90 % removals were achieved in continuous flow mode during 8 h (equivalent to 2255–2315 mg m-2 h-1).
- Synthesis of carbon nanotube composite membranes for catalytic wet peroxide oxidation of emerging contaminantsPublication . Zadra Filho, Paulo Cesar; Gomes, Hélder; Pietrobelli, Juliana Martins Teixeira de AbreuGlobal challenges of water contamination and plastic waste management demand innovative solutions to address emerging contaminants (CECs) and promote sustainable practices. This dissertation investigates the development and testing of catalytic nanocomposite membranes (CNMs), synthesized from polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), and carbon nanotubes (CNTs) with the potential to be derived from plastic solid waste (PSW). These CNMs were evaluated for their potential to degrade sulfamethoxazole (SMX), an antibiotic found in water sources worldwide, through catalytic wet peroxide oxidation (CWPO) in a continuous filtration system. Among AOPs, CWPO has demonstrated potential for the efficient decomposition of organic pollutants. CNTs, synthesized via catalytic chemical vapor deposition (CCVD) using iron oxide supported on alumina as a metal substrate, were incorporated into polymeric membranes to provide them with degradation capabilities. Experimental analysis included the synthesis of CNMs via phase inversion. Characterization was conducted using scanning electron microscopy (SEM), textural properties, overall membrane porosity, largest pore size, hydrophobicity and hydrophilicity, morphology, and thermal decomposition. The membranes were tested in CWPO-enhanced filtration systems to evaluate their SMX degradation potential. The results demonstrated that CNMs with incorporated CNTs significantly improved SMX removal, achieving up to 90% efficiency under continuous flow conditions, with a pollutant degradation mass of up to 2551 mg m-2 h-1. The CNMs exhibited enhanced hydrogen peroxide decomposition (over 80%) and uniform CNT distribution, as verified by SEM analysis, with no significant iron leaching during the CWPO-enhanced filtration processes. These findings suggest that CNT-based membranes can serve as efficient catalysts in wastewater treatment, facilitating both filtration and oxidative degradation of CECs.In conclusion, this research advances the field of water purification by demonstrating the effectiveness of CNMs in CWPO applications. It reinforces the role of plastic waste recovery in the development of functional nanocomposite membranes, supporting the upcycling of PSWs, contributing to the circular economy, and promoting environmental sustainability and water decontamination.