Magnetic Fe3S4/MoS2 with visible-light response as an efficient photo-Fenton-like catalyst: Validation in degrading tetracycline hydrochloride under mild pH conditions

Magnetic Fe 3 S 4 /MoS 2 composites with a visible light response were prepared, and their degradation activity was tested using tetracycline hydrochloride (TCH) as a simulated pollutant. The mass ratios of Fe 3 S 4 and MoS 2 , pH change, temperature, H 2 O 2 concentration, and catalyst addition were investigated to determine the mechanism of TCH degradation. The results show that the removal rate of TCH by the Fe 3 S 4 /MoS 2 composites is much higher than that of the pure Fe 3 S 4 or MoS 2 under pH values ranging from 1.2 to 13.2. The removal rate of TCH by Fe 3 S 4 /MoS 2 was 376.37 and 5.45 times higher than that of pure Fe 3 S 4 and MoS 2 when the mass ratio of Fe 3 S 4 and MoS 2 was 1:1 at pH 7.2. The main free radicals and metal leaching changes are analyzed. The removal mechanism of TCH was proposed by the free radical scavenger test and the metal leaching test. The mechanism proposed in this paper shows that the high catalytic activity of Fe 3 S 4 /MoS 2 composite is due to the acidic microenvironment near the surface of the composite, which reduces the production of ferric hydroxide sludge.