Integration of efficient LaSrCoO4 perovskite and polyacrylonitrile membrane to enhance mass transfer for rapid contaminant degradation

Abstract

A2BO4-type perovskite with Ruddlesden-Popper structure performed favorable catalytic activity in the activation of peroxymonosulfate (PMS) for the degradation of organic pollutants than ABO3, but the higher forming temperature limits its further application. In this work, a series of A-site Sr doped La2CoO4-δ perovskites were prepared and used for the degradation of tetracycline hydrochloride (TC). The introduction of Sr lowered the formation temperature of the perovskite and improved the catalytic capability. The LaSrCoO4 perovskite with 50 % Sr doping possessed the best TC degradation efficiency (complete degradation in 14 min). Besides, to overcome the mass transfer limitation caused by catalyst powder agglomeration and the difficulty of recovery, perovskite powder catalysts were embedded in polyacrylonitrile (PAN) ultrafiltration membrane by phase conversion method. The resulting PAN/LSC catalytic separation membranes achieved efficient degradation of TC due to the partial increase in the concentration of contaminants inside the membrane pores. The membrane embedded with 5 wt% LaSrCoO4 perovskite degraded 94 % TC in 3 min, which improved over 24 % compared to the perovskite powder. The catalytic degradation mechanism of TC and the toxicity of the intermediates were then analyzed. The effectiveness of catalytic membranes in practical applications was also evaluated. Overall, PAN/LSC membranes provide the potential for rapid purification of organic wastewater.