Buoyant polymer wrapped BiFeO3 heterostructure as a floatable, visible light-driven photocatalyst for ammonia wastewater treatment

Abstract

Inorganic/organic photocatalysts have been receiving attention owing to their attractive optical features. In this work, novel BiFeO3/MPVAA heterogeneous photocatalyst was prepared and its potential application as a floatable, visible light-driven photocatalyst was investigated by the photocatalytic degradation of aqueous ammonia. MPVAA refers to a buoyant polymer structure consisting of PVA and sodium alginate that has photocatalytic property. BiFeO3 was synthesized hydrothermally and immobilized over MPVAA by impregnation. The density of MPVAA was measured by a multipycnometer to be 0.92 g/cm3, which is less than that of water. FE-SEM images showed that the microcube particles of BiFeO3 were wrapped by the porous polymer structure. The optical characterization analyses revealed the enhanced visible light harvesting and effective suppressed charge recombination by BiFeO3/MPVAA. The best photocatalytic ammonia degradation was obtained to be 45% under visible light irradiation by 10 wt% BiFeO3/MPVAA. The kinetic study indicated that the photocatalytic performances of all BiFeO3, MPVAA and BiFeO3 samples follow the Langmuir–Hinshelwood model with zero-order reaction rates. The scavenging experiments were done using IPA, BQ and EDTA and the results showed the dominancy of photoexcited holes and hydroxyl radicals as the active species responsible for ammonia degradation.