Porphyrin-functionalized non-magnetic steel slag as bifunctional nanozymes for colorimetric detection and photocatalytic degradation of tetracycline

Abstract

Inspired by natural enzymes with various activities, controlling the catalytic activity of nanozymes through suitable strategies has received extensive attention. By modifying non-magnetic steel slag material (NMSS) with porphyrin, we developed a new kind of bifunctional nanozymes (NMSS-Por) with both simulated enzyme activity and photocatalytic activity. The NMSS-Por nanozymes exhibit outstanding colorimetric sensing and photodegradation performances, with a limit of detection (LOD) of 0.257 µM, 0.102 µM and 0.142 µM for tetracycline (TC), oxytetracycline, and doxycycline, while a removal rate of 79 % for TC after 60 min. Hydroxyl radical (·OH), positively charged hole (h+), singlet oxygen (1O2), and photogenerated electron transfer process play vital roles in both catalytic reactions. Besides, NMSS-Por nanozymes has excellent selectivity for TC detection and can also be used as promising photocatalysts for real water treatment. This work provides a new and promising strategy for the high value-added resource utilization of waste steel slag in environmental catalysis, which is in accordance with the sustainable development of green chemistry.