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Bio-Removal of Phenol by the Immobilized Laccase on the Fabricated Parent and Hierarchical Nay and Zsm-5 Zeolites Publisher



Ameri A1, 2 ; Taghizadeh T3 ; Talebiankiakalaieh A4 ; Forootanfar H1, 2 ; Mojtabavi S1 ; Jahandar H3 ; Tarighi S4 ; Faramarzi MA1
Authors
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Authors Affiliations
  1. 1. Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, 1417614411, Tehran, Iran
  2. 2. Pharmaceutical Sciences and Cosmetic Products Research Center, Kerman University of Medical Sciences, Kerman, Iran
  3. 3. Pharmaceutical Sciences Research Center, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
  4. 4. Faculty of Petrochemicals, Iran Polymer and Petrochemical Institute, P.O. Box 14975-112, Tehran, Iran

Source: Journal of the Taiwan Institute of Chemical Engineers Published:2021


Abstract

This study was performed to synthesize and characterize NaY and ZSM-5 zeolites and their hierarchical forms (HR-Y and HR-Z) through dealumination and soft templating procedure. The Brunauer-Emmett-Teller (BET) analysis showed significant increase in the average pore diameter (DP) size for HR-Y (2.43 nm) and HR-Z (5.07 nm) compared to those of the parent types (NaY and ZSM-5: 1.85 and 2.01 nm, respectively). The mesoporous pore volumes (Vmeso) exhibited notable enhancement for HR-Y (114%) and HR-Z (566%) compared to their parent forms. Laccase (Lac) was subsequently immobilized on NaY and ZSM-5 zeolites, and their hierarchical forms by immobilization efficiency of 74.4 ± 1.4%, 71.6 ± 1.0%, 98±2.9%, and 94±1.8% for Lac@NaY, Lac@ZSM-5, Lac@HR-Y, and Lac@HR-Z, respectively. Thermal and pH stability of the immobilized laccases were enhanced compared with the free enzyme. The relative activity for the immobilized laccases was kept over 50% of its original activity after about 3 weeks of storage at 4 °C. Moreover, reusability of Lac@HR-Z and Lac@HR-Y was considerably higher (68% and 92%, respectively) than those of Lac@ZSM-5 and Lac@NaY (6% and 5.6%, respectively) after 10 cycles of reuse. Lac@HR-Z and Lac@HR-Y exhibited higher efficiency (80.5% and 89.3%, respectively) in phenol bio-removal compared with those of ZSM-5 (67.5%) and NaY (76.5%). Besides, 90.4 ± 1.3% of phenol was practically removed under optimal conditions including 12 U/mg of Lac@HR-Y, 2.6 mM of phenol, and 70 min of the reaction time. Lac@HR-Y also exhibited 56% efficiency after 10 cycles of phenol removal. Furthermore, three phenolic compounds were detected by GC-mass analysis due to phenol bio-removal in the optimal conditions after removing the dark brown precipitate of polymerized metabolites. Therefore, Lac@HR-Y could be suggested for the elimination of phenol-containing pollutants that merits further investigations. © 2021 Taiwan Institute of Chemical Engineers