Highly efficient (MFe)zeolite catalysts were employed to degrade and mineralize the non-steroidal anti-inflammatory drug nimesulide (NIM) via a Fenton-type reaction. NIM was successfully extracted from generic tablets with an 80% yield, and its purity was confirmed through FTIR, 1H NMR, and UV–Vis spectroscopy. The (MFe)zeolite catalysts—where M represents Co, Ni, Cu, or Zn—were prepared via ion exchange starting from NaY zeolite and thoroughly characterized by different techniques. In the absence of metal species, both NIM and total organic carbon (TOC) removals were low (<17%). Conversely, a significant enhancement was observed with the (CoFe)NaY catalyst, which achieved 47% NIM degradation and 25% TOC removal at natural pH and 25 °C. The optimal reaction conditions obtained by the central composite design (CCD), pH 3.0, 48 °C, 100 mg/L H2O2, 0.5 g/L (CoFe)NaY catalyst, and 180 min of reaction time, allowed achieving complete NIM removal (100%) and TOC reduction (88%). The catalyst demonstrated high stability, maintaining activity over five consecutive reuse cycles in a batch reactor and for ∼200 h of time-on-stream in a continuous flow reactor. The oxidation mechanism was confirmed to be hydroxyl radical-based, as demonstrated by the inhibition in the presence of dimethyl sulfoxide (DMSO) as scavenger. Temperature influenced the nature of intermediate by-products: at the optimal temperature (48 °C), only oxalic acid was detected, while at 25 °C, both oxalic and oxamic acids were quantified. In the experiment conducted under optimal operating conditions, in addition to oxalic acid, other intermediate compounds were identified, however their concentrations were negligible.
Highly efficient (MFe)zeolite catalysts for nimesulide degradation via Fenton-type oxidation
Rombi, Elisabetta;
2026-01-01
Abstract
Highly efficient (MFe)zeolite catalysts were employed to degrade and mineralize the non-steroidal anti-inflammatory drug nimesulide (NIM) via a Fenton-type reaction. NIM was successfully extracted from generic tablets with an 80% yield, and its purity was confirmed through FTIR, 1H NMR, and UV–Vis spectroscopy. The (MFe)zeolite catalysts—where M represents Co, Ni, Cu, or Zn—were prepared via ion exchange starting from NaY zeolite and thoroughly characterized by different techniques. In the absence of metal species, both NIM and total organic carbon (TOC) removals were low (<17%). Conversely, a significant enhancement was observed with the (CoFe)NaY catalyst, which achieved 47% NIM degradation and 25% TOC removal at natural pH and 25 °C. The optimal reaction conditions obtained by the central composite design (CCD), pH 3.0, 48 °C, 100 mg/L H2O2, 0.5 g/L (CoFe)NaY catalyst, and 180 min of reaction time, allowed achieving complete NIM removal (100%) and TOC reduction (88%). The catalyst demonstrated high stability, maintaining activity over five consecutive reuse cycles in a batch reactor and for ∼200 h of time-on-stream in a continuous flow reactor. The oxidation mechanism was confirmed to be hydroxyl radical-based, as demonstrated by the inhibition in the presence of dimethyl sulfoxide (DMSO) as scavenger. Temperature influenced the nature of intermediate by-products: at the optimal temperature (48 °C), only oxalic acid was detected, while at 25 °C, both oxalic and oxamic acids were quantified. In the experiment conducted under optimal operating conditions, in addition to oxalic acid, other intermediate compounds were identified, however their concentrations were negligible.
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