In:
Environmental Science: Nano, Royal Society of Chemistry (RSC), Vol. 9, No. 12 ( 2022), p. 4433-4444
Abstract:
The coexistence of heavy metals and antibiotics in modern wastewater has caused unprecedented challenges for the simultaneous elimination of these contaminants, resulting in the urgent demand for developing highly-efficient photocatalysts. Herein, we devised and fabricated MIL-88B(Fe)@ZnIn 2 S 4 (M88B@ZIS) S-scheme heterojunction photocatalysts via attaching ZnIn 2 S 4 (ZIS) nanoflakes onto the surface of 24-faceted concave MIL-88B(Fe) (M88B) polyhedra, in situ . For a single pollutant system, all the M88B@ZIS hybrids exhibit obviously enhanced photocatalytic activities for Cr( vi ) or tetracycline (TC) removal compared with M88B and ZIS alone. The optimal M88B@ZIS hybrid (M88B@ZIS-10) exhibits the best photocatalytic activities with 55.46% of Cr( vi ) reduced and 73.14% of TC degraded singly after 80 min of reaction. More significantly, in a blended system of Cr( vi ) and TC, the photocatalytic activities for reducing Cr( vi ) and eliminating TC of M88B@ZIS-10 can be further improved to 92.46% and 87.14%, respectively, better than those of most of the reported photocatalysts. The corresponding reaction rate constants are 0.03249 min −1 and 0.02663 min −1 , about 3.3 and 1.7-fold that in the single pollutant systems, respectively. The enhanced photocatalytic activities can be attributed to the following synergism: (1) the unique S-scheme heterostructures with an intimate contact interface accelerate the spatial separation and migration of the useful photoexcited electrons and holes with the stronger redox abilities; (2) the synergistic effects of concurrent Cr( vi ) reduction and TC oxidative degradation from such a dual-function photocatalyst further improve the separation efficiency of the useful photoexcited charge carriers. Besides, the reaction pathway of TC degradation in the mixed system and the plausible S-scheme photocatalytic mechanism for synchronously removing Cr( vi ) and TC over M88B@ZIS-10 are analysed in detail via the combined results of LC-MS, XPS, Fermi levels, capture tests of active species, ESR spectra, etc. Therefore, this work provides a profound understanding for constructing high-efficiency S-scheme heterojunction photocatalysts towards synchronously removing heavy metals and organic contaminants in effluents.
Type of Medium:
Online Resource
ISSN:
2051-8153
,
2051-8161
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2022
detail.hit.zdb_id:
2758235-8
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