Immobilization of peroxidase-like G-quadruplex/hemin on CNTs-NH2 for efficient degradation of phenol

• Published in: New journal of chemistry 2024-09, Vol.48 (37), p.16546-16556
• Main Authors: Ren, Xiubin, Huang, Chun, Gao, Zhengxuan, Zhai, Ruichen, Zhu, Youyu, Duan, Yingfeng, Chen, Linyong, Zhao, Weiqin, Li, Guofu
• Format: Article
• Language: English
• Subjects: Chemical bonds; Chemical engineering; Degradation; Enzymes; Fragments; Hydrogen peroxide; Immobilization; Peroxidase; Phenols
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d4nj03317e

The presence of phenol in coal-chemical engineering wastewater is considered a serious environmental issue. The use of enzymes to degrade phenol has received wide attention. G-quadruplex can combine with hemin to form G-quadruplex/hemin, which shows peroxidase-like activity and can be used to degrade phenol. In this work, a novel CNTs-NH2@G-quadruplex/hemin was designed using a single-stranded DNA (ssDNA) that contained G-rich fragments and T-rich fragments. The G-rich fragments assembled with the hemin to form G-quadruplex/hemin; the pyrimidine group of the T-rich fragment could form stable chemical bonds with the amino group, which could be used for immobilization. Characterization analysis of FTIR, XRD and TEM showed that the CNTs-NH2@G-quadruplex/hemin was successfully prepared. Meanwhile, the activity and phenol degradation ability for CNTs-NH2@G-quadruplex/hemin were studied in detail, and the effects of pH, temperature, initial phenol concentration, H2O2 concentration and reusability on the degradation efficiency of phenol were also explored. The results showed that when immobilized, the CNTs-NH2@G-quadruplex/hemin presented good activity, especially under conditions of temperature 30 °C and pH 7.0. Notably, the maximum reaction velocity of CNTs-NH2@G-quadruplex/hemin was increased from 0.016 mM mg−1 min−1 (free enzyme) to 0.056 mM mg−1 min−1. For phenol degradation ability, it was observed that under the conditions of temperature 30 °C, pH 7.0, initial phenol concentration 40 mg L−1, H2O2 concentration 120 mM, enzyme dose 40 mg L−1, more than 90% of phenol could be degraded within 600 min. In addition, the CNTs-NH2@G-quadruplex/hemin still maintained high activity after 10 cycles of phenol removal, demonstrating its appealing potential for practical applications.