Simultaneous Removal of Acetaminophen, Diclofenac, and Cd(II) byTrametes versicolorLaccase Immobilized on Fe3O4/SiO2-DTPA Hybrid Nanocomposites

For simultaneous water purification from both inorganic and organic pollutants, a novel multifunctional hybrid nanoadsorbent has been produced. Core–shell magnetic submicro-particles with iron oxide core and silica shell were used as substrate for immobilization of different functions. The activity toward heavy metals was provided via attachment of 3-aminopropyl-triethoxysilane (APTES) through the silanol group to the silica surface with subsequent chemical grafting of diethylenetriamine pentaacetic acid (DTPA) onto the APTES via an amide bonding. The residual APTES amino functions were partially converted into aldehyde ones via treatment with glutaraldehyde. Both aldehyde and carboxylic functions turned to be involved in laccase immobilization. The obtained hybrid multifunctional adsorbent exhibited relatively high capacity for Cd(II) removal. On average, the composite removed 76% of Cd(II) ions from the 0.1 μM model solution. At the same time, due to the immobilized laccase, high performance for drug removal was revealed. Immobilized laccase retained up to 100% activity in 50 ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) oxidation cycles, even in the presence of Cd(II). The adsorbent was able to remove up to 99% of acetaminophen in 1 mg/mL solution during 18 h, and a total of 95% of acetaminophen and 85% diclofenac removal reached in acetaminophen/diclofenac mixtures (0.5 mg/mL + 25 μg/mL, respectively). Comparable results were achieved with acetaminophen/diclofenac mixtures also in the presence of Cd(II) ions (99% of acetaminophen and 95% of diclofenac removal). Obtained composites as well as the products of the drug oligomerization were characterized by SEM, AFM, NMR, FTIR, and UV–vis spectroscopy. Chemical mechanisms of drug removal via oxidation/polymerization have been elucidated.