Sustainable removal of 17α-ethynylestradiol from aqueous environment using rare earth doped lanthanum manganite nanomaterials

Abstract

The pure water scarcity is a serious, emerging issue and this affects roughly the 40% of the world’s population thus new efficient wastewater treatment techniques are required. Lanthanum manganite (LaMnO3), is one of the most promising and efficient photocatalysts for the degradation of organic pollutants. In this work, undoped and Eu, Ho, Tb doped LaMnO3materials were successfully synthesized via sol–gel process using citric acid as chelating agent. The as-obtained samples are well crystallized within the perovskite structure and from the optical properties measurements it is determined that the value for the band gap energy is not influenced by the doping, i.e.Eg ~ 3.4 eV for all samples. In the photocatalytic studies,the potential water purification possibility is proved for the newly synthesized perovskite nanomaterials, and the best removal efficiency was reached in the presence of LMO:Ho, when 77% of endocrine disruptors EE2 (e.g. 17α-ethynilestradiol) was degraded after 30 min of UV irradiation. In addition, there usability of the LMO:Ho nanomaterials was also investigated. Based on the reutilization findings, it can be concluded that the mentioned photocatalyst has not lost its efficiency after three successive runs for photodegradation. Furthermore, the possible mechanism of the photocatalytic degradation of EE2, using different scavengers was also determined, and among the applied scavengers, the most important role had EDTA × 2Na, NaF and p-benzoquinone. According to our findings, the EE2 degradation mechanism mostly took place via positively charged holes,●OHadsradicals, as well as throughO2•−radicals, however they had a weaker effect on the degradation efficiency.