Synthesis of a magnetically separable LDH-based S-scheme nano-heterojunction for the activation of peroxymonosulfate towards the efficient visible-light photodegradation of diethyl phthalate

Herein, a stable and S-scheme Fe₃O₄@CuCr-LDH nanocomposite was synthesized and used for the photocatalytic degradation of diethyl phthalate (DEP) through the activation of peroxymonosulfate (PMS). In comparison with pure Fe₃O₄, and LDH, the Fe₃O₄@CuCr-LDH nanocomposite demonstrated significantly enhanced photocatalytic activity due to its S-scheme charge-carrier migration mechanism. The prepared composite was also magnetically recoverable from the treated water which is favorable to avoid the production of secondary pollution. The integration of the composite and visible light showed the presence of a synergy factor of 14 for the degradation of diethyl phthalate. However, the photocatalytic performance of Fe₃O₄@CuCr-LDH was dependent on the different physicochemical parameters; wherein, the higher degradation efficiency was achieved using the solution pH of 8, the catalyst, DEP, and PMS concentrations of 1 g L⁻¹, 20 mg L⁻¹, and 8 mM, respectively. The high photocatalytic activity of the catalyst was maintained after 5 consecutive reaction runs and the stability of the material was proved by the XPS. Moreover, the ICP-AES analysis proved that the leaching of Fe, Cr, and Cu is lower than the standard concentration in the drinking water. Finally, the mineralization ability and the decreased toxicity of the treated solution of DEP were assessed.