Fixed-bed adsorption of Escitalopram onto a niobium-based nanozeolite

Fixed-bed adsorption of Escitalopram onto a niobium-based nanozeolite

• Autor
• Leandro Rodrigues Oviedo
• Co-autores
• Daniel Moro Druzian , Sthéfany Nunes Loureiro , Lissandro Dorneles Dalla Nora , William Leonardo Da Silva
• Resumo

• Drugs (e.g., Escitalopram) are challenging to remove from water due to their chemical/thermal stability, low biodegradability and resistance to conventional water treatments. Nanozeolites have been attracted to the adsorption field due to their high surface area, thermal stability, and acidity. Nanozeolite acidity can be enhanced by the incorporation of metals/semi-metals in its structure. Thus, the present work aims to synthesize and characterize a niobium-based zeolitic nanoadsorbent for the removal of the Escitalopram drug from water, in a fixed-bed operation. Niobium-based nanozeolite (nFAU@10_Nb) was obtained by hydrothermal method combining zeolite precursors and ammonium niobium(V) oxalate (10 wt.%), followed by calcination at 500°C for 120 min. The nFAU@10-Nb was characterized by XRD, DLS, and pH_ZCP. XRD identified faujasite, niobium pentoxide, and lueshite for nFAU@10_Nb and ZP = -5.05 ± 2.25 mV. nFAU and nFAU@10_Nb showed pH_ZCP 7.06 and 6.72, respectively. The fixed-bed adsorption showed 80% drug removal up to breakthrough time (35 min) for nFAU, whereas 89% removal was reported up to 50 min under 20 mL min^-1, pH 7.71, and 1.0 g of nanoadsorbent. The experimental data were better fitted by Thomas model, indicating a high affinity between the Escitalopram and the nanoadsorbent. nFAU@10_Nb showed higher column adsorption capacity (q_e = 3.39 mg g^-1) than nFAU (q_e = 0.87 mg g^-1). The maximum adsorption capacity for nFAU and nFAU@10_Nb were 81.8 and 74.6 mg g^-1, respectively. Therefore, this work confirms that niobium can enhance the adsorption capacity and acidity of alternative nanozeolites, being useful as a starting point for scale-up studies.
• Palavras-chave
• Niobium, Nanozeolites, Drugs, Nanoadsorbents, Sustainability
• Área Temática
• Adsorção aplicada ao meio ambiente