MnCeO/diatomite catalyst for persulfate activation to degrade organic pollutants.

Persulfate (PS)-based oxidation technologies are attracting increasing attentions in water treatment due to their high efficiency and stability. In this study, a novel diatomite supported MnCeO composite (MnCeO/diatomite) was prepared and characterized for activation of PS to degrade organic pollutants. Results indicated that diatomite not only dispersed MnCeO and increased the specific surface area of catalyst, but also improved the low-valence metal site (Mn and Ce) and reactive oxygen species site (-OH) of MnCeO, thus enhancing the activities of MnCeO. MnCeO/diatomite/PS showed high efficiency for multiple dyes and pharmaceutical pollutants. Constant rate (k) of MnCeO/diatomite (k) was three times higher than the sum of constant rate of MnCeO (k) and constant rate of diatomite (k). In addition, MnCeO/diatomite showed wide pH application (5-9). Cl and NO had no effect while SO and humid acid had slightly negative effects on MnCeO/diatomite/PS system. Moreover, MnCeO/diatomite showed good reusability and stability. Mechanism analyses indicated that electron transfer of Mn and Ce attributed to the activation of PS and oxygen to produce free radicals. SO, OH and O on the surface of catalyst were the main active free radicals to attack pollutants.