Nano-Fe2O3 embedded in montmorillonite particles(Fe-Mt)were prepared to degrade di-ethyl phthalate(DEP)with citric acid(CA)under xenon light irradiation.Compared to pris-tine montmorillonite(Na-Mt),the embedding process increased 14.5-fold of iron content and 1.8-fold of specific surface area.The synthesized Fe-Mt have more oxygen vacancies than Fe2O3 nanoparticles(nFe2O3),which could induce more reactive oxygen species(ROSs)generation in the presence of CA under xenon lamp irradiation.Fe-Mt with CA enhanced photo-assisted degradation of DEP 2.5 times as compared to nFe2O3 with CA.Quenching ex-periments,electron paramagnetic resonance(EPR)spectroscopy and identification of prod-ucts confirmed that surface-bound *OH was the main radical to degrade DEP.Common an-ions(i.e.,NO3-,CO32-,Cl-)and humic acid could compete *OH with DEP and cause slower degradation of DEP.The removal efficiency of DEP was more than 56％with Fe-Mt after three recycles,and the dissolved Fe concentration from Fe-Mt was below 75 μmol/L,indicating Fe-Mt had a good stability as a catalyst.Fe-Mt together with CA appeared to be a promising strategy to remove organic pollutants in surface water,or topsoil under solar irradiation.