Enhanced Peroxydisulfate (PDS) Activation for Sulfamethoxazole (SMX) Degradation by Modified Sludge Biochar: Focusing on the Role of Functional Groups
In this study, biochar (TSBC) prepared by co-pyrolysis of sludge and tannin extract was investigated as a catalyst for PDS to effectively degrade SMX in aquatic environments. The active species within the TSBC/PDS system and the catalytic sites on TSBC were systematically investigated by quenching experiments and advanced characterization techniques. Additionally, the enhancement of PDS activation by various N- and O-containing functional groups on the TSBC surface was analyzed by Density Functional Theory (DFT) calculations, providing an in-depth investigation of the adsorption dynamics of PDS on TSBC and revealing the role of these functional groups. Moreover, the identification of SMX degradation intermediates, coupled with theoretical calculations, shed light on the degradation pathways of SMX. This study aims to clarify the role of functional groups on sludge biochar in facilitating PDS activation. It can contribute to a deeper understanding of the mechanical aspects and provide guidance for targeted modification of sludge biochar to improve its effectiveness as a catalyst.
In summary, we focused on exploring the impact of O- and N-containing functional groups on augmenting the catalytic efficiency of modified sludge biochar (TSBC) to activate PDS for SMX degradation. The TSBC/PDS system exhibited exceptional efficiency in degrading SMX, achieving a removal rate of 96.83% within 120 min. Notably, the reaction rate of SMX degradation via TSBC-catalyzed PDS was seven times higher than that achieved with conventional sludge biochar (SDBC). In addition, this system demonstrated remarkable stability and efficiency, maintaining over 90% degradation efficiency across a broad pH range (3–10), making it a promising solution for varied applications. The quenching experiment and characterization results indicate that the C=O and C-N groups in TSBC primarily served as catalytic sites, mainly facilitating the non-radical pathway degradation of SMX by activating PDS to produce . Further theoretical analysis demonstrated that, among various N- and O-containing functional groups, graphitic N predominantly enhanced the integration of biochar with PDS, consequently facilitating the activation of PDS. SMX exhibited pronounced electrophilic properties, facilitating its reactivity with . Theoretical calculations and experimental evidence suggested that SMX degraded by two mechanisms: S-N cleavage and direct oxidation by . This research investigated the influence of various N and O species on PDS activation, emphasizing the significant role of graphitic N in enhancing PDS adsorption by biochar. These findings provide a fundamental framework for subsequent advances in improving the catalytic efficiency of sludge-derived biochar through specific modifications. The proposed improvements will streamline the application of sludge biochar in AOPs, thereby reducing operating costs. Furthermore, considering the similarities between certain industrial and sewage sludges, this approach can potentially extend to treating industrial sludges, particularly in the tannery and paper industries with low heavy metal concentrations, pending further validation.
Disasters Expo USA, is proud to be supported by Inergency for their next upcoming edition on March 6th & 7th 2024!
The leading event mitigating the world’s most costly disasters is returning to the Miami Beach
And in case you missed it, here is our ultimate road trip playlist is the perfect mix of podcasts, and hidden gems that will keep you energized for the entire journey-