Synergetic Adsorption-Catalysis in Potassium Oxide Modified High-Entropy Relaxor Ferroelectrics for Efficient Dye Removal Strategy

Abstract

Water scarcity caused by extreme weather events has become a global issue, leading to the necessity of wastewater recycling. Developing new materials with fast pollutant removal efficiency has become a research focus in related fields for producing clean water resources quickly and stably from wastewater. Herein, a relaxor ferroelectric type of piezoelectric high entropy perovskites, Pb(Mg,Nb,Hf,Zr,Ti)O3 (PMNHZT), is used and prepared for industrial dye removal. The synthesized PMNHZT exhibits high dark adsorption of the methylene blue dye (removal efficiency of ≈60% in 30 min) and further catalytic dye degradation (removal efficiency of ≈80–90% in 30 min) through light illumination, sonication, or a combination of both. In the dark adsorption process, K2O compounds from the synthesized environment attached to the surface of PMNHZT play a significant role in the remarkable dark adsorption by promoting a large specific surface area and more negative surface potential. Furthermore, a self-decomposition of dye into smaller fragments by PMNHZT is also observed during dark adsorption. The piezocatalysis mechanism dominates the dye degradation process in catalytic experiments, where hydroxyl radicals are the main reactive species. Herein, a promising adsorbent and catalyst is disclosed using high-entropy perovskites for efficient wastewater treatment.