Heterogeneous activation of peroxymonosulfate via a Ag-La0.8Ca0.2Fe0.94O3-δ perovskite hollow fibre membrane reactor for dye degradation

Perovskite oxides have been investigated for their catalytic efficiency for fast aqueous-phase advanced oxidation of dye contaminant. These catalysts in powder are usually dispersed in water but may cause the secondary pollution. In this work, Ag-La0.8Ca0.2Fe0.94O3-delta (Ag-LCF), one typical example of these perovskite catalysts, was fabricated into hollow fibre membrane by the combined phase inversion and sintering method. Such hollow fibres can be readily used as the membrane reactors for dye containing wastewater treatment. The process is based on direct peroxymonosulfate (PMS, HSO5-) oxidation by Ag-LCF membrane material itself therefore avoiding the catalyst loading that is usually required in normal membrane reactor. The catalytic performance of one Ag-LCF hollow fibre membrane was demonstrated by the degradation of methylene blue (MB) with removal efficiency up to 90% compared favourably with other operation modes. Sulfate and hydroxyl radicals play important roles on methylene blue decolouration. Backwashing by acid solution was used to accomplish 94% membrane catalytic efficiency regeneration.