Bulk poled and unpoled La-added SrBi4Ti4O15 for piezocatalytic dyes degradation in Wastewater

Abstract

This study investigates piezocatalysis in SrBi4-xLaxTi4O15 (SBLxT, x = 0, 0.25, 0.5, 0.75, 1.0) ceramic for the degradation of the methylene blue (MB) dye. Lanthanum (La) substitution increases the piezoelectric coefficient (d33) and decreases the dielectric constant (εr)

thus, the d33/εr ratio increases, resulting in improved dye degradation. The MB dye decomposition increases from 49% to 85% in 60 min with La-substitution from x = 0 to 0.75 when the catalyst is used in powder form. However, catalyst recovery from powder suspensions is time-consuming and inefficient

this work explored pellet (bulk) based piezocatalysts. The SBL0.75T bulk composition shows a maximum dye degradation of ∼89% compared to other compositions because of its better electrical properties. The influence of dye concentration, solution volume, and electrical poling was also investigated. Although poled samples exhibit superior dye degradation, unpoled samples reduce fabrication complexity, energy consumption, costs, and scalability barriers while maintaining effective catalytic performance. The unpoled pellets were also used for the degradation of Rhodamine B (RhB) and methylene orange (MO). The scavenger experiments are performed to determine the role of hydroxyl (•OH), superoxide (•O2˗) radicals and holes (h+) in the complete degradation process. The reusability test confirms piezocatalyst effectiveness, stability, and reliability. These findings demonstrate that unpoled SrBi4-xLaxTi4O15 (x = 0.75) pellets can serve as a practical, durable piezocatalyst for dye degradation in wastewater, enabling large-scale fabrication. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.