Rational design of a novel magnetically recoverable and environment-friendly Z-scheme SnFe2O4/Bi2WO6 heterojunction with enhanced photocatalytic performance for rhodamine B degradation and toxicity elimination

Photocatalysis is considered a promising strategy for environmental remediation, and the preparation of an efficient, stable, and green photocatalyst is a current urgent need. In this work, a magnetically recoverable SnFe2O4/Bi2WO6 (SFO/BWO) Z-scheme heterojunction was successfully prepared by a simple one-step hydrothermal process. The prepared 7.5%SFO/BWO nanocomposite exhibited excellent photocatalytic performance, with a degradation efficiency of 96.12% for Rhodamine B (RhB) within 120 min, which were respectively 1.64 and 2.07 times greater than that of pure Bi2WO6 (BWO) and SnFe2O4 (SFO). This obvious improvement in the photocatalytic performance benefited from the increase in the separation efficiency of photogenerated carriers and was based on the construction of Z-scheme heterojunction. Additionally, the radical capture tests demonstrated the main reactive radicals were electron (e−), hole (h+), and hydroxy radical (•OH) in the photodegradation system. Furthermore, the composite retains excellent photocatalytic performance after five cycles and is easily recoverable due to its magnetic behavior. Notably, during the toxicity assessment, it was proved that SnFe2O4/Bi2WO6 could be used to eliminate the toxicities of dyes and antibiotics rapidly. Consequently, SnFe2O4/Bi2WO6 is a promising and competitive photocatalyst in wastewater remediation.