Insights into Photocatalytic Degradation Pathways and Mechanism of Tetracycline by an Efficient Z-Scheme NiFe-LDH/CTF-1 Heterojunction

Abstract

Photocatalysis offers a sustainable approach for recalcitrant organic pollutants degradation, yet it is still challenging to seek robust photocatalysts for application purposes. Herein, a novel NiFe layered double hydroxide (LDH)/covalent triazine framework (CTF-1) Z-scheme heterojunction photocatalyst was rationally designed for antibiotics degradation under visible light irradiation. The NiFe-LDH/CTF-1 nanocomposites were readily obtained via in situ loading of NiFe-LDH on CTF-1 through covalent linking. The abundant coupling interfaces between two semiconductor counterparts lay the foundation for the formation of Z-scheme heterostructure, thereby effectively promoting the transfer of photogenerated electrons, inhibiting the recombination of carriers, as well as conferring the nanocomposites with stronger redox ability. Consequently, the optimal photocatalytic activity of the LDH/CTF heterojunction was significantly boosted for the degradation of a typical antibiotic, tetracycline (TC). Additionally, the photodegradation process and the mineralization of TC were further elucidated. These results envision that the LDH/CTF-1 can be a viable photocatalyst for long-term and sustainable wastewater treatment.

MoS2 Nanoflowers Decorated on Graphene Aerogels for Visible-Light-Driven Photocatalytic Degradation of Tetracycline

“…Attributing to the successive action of • OH radical and other ROS, T1 undergoes further dehydration, yielding T2 ( m / z = 410) . In a parallel manner, deamination as well as N -demethylation by primary oxidants (i.e., • OH and • O 2 – ) can also transform TC to T3 ( m / z = 396) . On subsequent oxidation by holes and the multiple ROS synchronously generated, these intermediates (i.e., T2 and T3 ) are converted to T4 ( m / z = 318), T5 ( m / z = 302), and T6 ( m / z = 274), primarily through ring-opening reactions.…”

“…59 In a parallel manner, deamination as well as Ndemethylation by primary oxidants (i.e., • OH and • O 2 − ) can also transform TC to T3 (m/z = 396). 60 On subsequent oxidation by holes and the multiple ROS synchronously generated, these intermediates (i.e., T2 and T3) are converted to T4 (m/z = 318), T5 (m/z = 302), and T6 (m/z = 274), primarily through ring-opening reactions. As the reaction progresses, all the fragmentation compounds are ultimately dissociated into low-molecular-weight hydrocarbons and other ring-scission products, such as T7 (m/z = 109) and T8 (m/z = 148), and thereafter gradually mineralized to CO 2 , H 2 O, NH 4 + , and NO 3 − .…”

Strategies to improve the photocatalytic performance of covalent triazine frameworks

“…Various types of semiconductor–semiconductor heterojunctions exist, including type-I (straddling gap), type-II (staggered gap), type-III (broken gap), Z-scheme, n–p, p–p, and n–n heterojunctions. 161 Among them, type-II 162 and Z-scheme 163 heterojunctions are commonly formed structures when combining CTFs with other semiconductor materials (Table 3).…”

Nanomaterials for Potential Detection and Remediation: A Review of Their Analytical and Environmental Applications

“…Further, it has been reported that photocatalytic degradation can be improved by utilizing nanomaterials, nanocomposites, or nanostructures. Nanomaterials for photodegradation must feature an appropriate bandgap (~3 eV), controllable electron-hole recombination rates, electrical conductivity, and corrosion resistance [178][179][180]. In that regard, photodegradation assisted by semiconductor nanomaterials or nanocomposites is promising because of their charge separation and ability to effectively absorb light in the visible region.…”