Fig. 4: Micropollutant removal by laccase-immobilized Cellulose-DNA hydrogels.

a Removal efficiency of micropollutants (Flu, 1-MFlu, 3-NFlu) at 2, 10, 50 μg/L by laccase-immobilized Cellulose-DNA hydrogels (the sum of sorption and degradation), immobilized laccase (net degradation), and free laccase. b Removal kinetics of three micropollutants at 50 μg/L by laccase-immobilized Cellulose-DNA hydrogels (the sum of sorption and degradation), immobilized laccase (net degradation), and free laccase. c Reusability of laccase-immobilized Cellulose-DNA hydrogels for three micropollutants removal at 50 μg/L over 7 cycles. d Removal efficiency of 16 USEPA priority PAHs, 1-MFlu and 3-NFlu in the first of two Coal Chemical Plant wastewater samples collected from Ningxia, China, by laccase-immobilized Cellulose-DNA hydrogels (the sum of sorption and degradation), immobilized laccase (net degradation), and free laccase, as well as their measured concentrations. e Comparison of removal performance of 16 USEPA priority PAHs in authentic wastewater, PFAS (e.g., perfluorooctanesulfonic acid: PFOS), antibiotics (e.g., sulfamethoxazole: SMX) and organic dyes (malachite green: MG) by the laccase-immobilized Cellulose-DNA hydrogels (sorption and biodegradation) in this work and other materials or approaches in previous reports. The relevant references and data are listed in Supplementary Table 8. f Degradation mechanism of micropollutants by immobilized laccase. Specifically, micropollutants underwent oxidation near the T1 copper center of laccase, leading to electron release; subsequently, these electrons were transferred through a tripeptide pathway consisting of Histidine-Cysteine-Histidine (His-Cys-His) to a trinuclear copper cluster site; finally, O₂ molecules in proximity to the trinuclear copper cluster site accepted these electrons, resulting in their reduction to H₂O. The sites where contaminants are most readily attacked and degraded are those most likely to lose electrons. g 3-NFlu molecular structure with labeled atomic positions, the HOMO of Flu, and the distribution of electrophilic (\({f}_{A}^{-}\)) attacking sites based on the compressed Fukui function (CFF). A greater \({f}_{A}^{-}\) value and the more HOMO distribution indicate a greater likelihood of losing electrons. h Proposed degradation pathways of 3-NFlu by immobilized laccase. In (a–d), data are presented as mean ± S.D. from three replicates (n = 3); the dosage of free laccase was equivalent to the immobilized amount of laccase on the Cellulose-DNA hydrogels.