Enhanced performance of lanthanum orthoferrite/chitosan nanocomposites for adsorptive photocatalytic removal of Reactive Black 5

Abstract

New lanthanum orthoferrite (LaFeO3)/chitosan nanocomposites were synthesized with different chitosan loadings (15 and 35%). Their adsorptive photocatalytic activity in the removal of Reactive Black 5 (RB5) was studied by manipulating the pH of the RB5 solution (pH 3, pH 6, pH 9), the catalyst loading (1 g L-1, 2 g L-1, and 3 g L-1), and the initial concentration of RB5 (30 mg L-1, 50 mg L-1, and 70 mg L-1) under 100 W LED light. The nanocomposites have a nanocrystalline structure similar to LaFeO3 with a lower SBET and PV but a higher PR. The LaFeO3 was distributed well on chitosan matrices with variations in the elemental composition. The band gap was gradually decreased with increased chitosan loading. The nanocomposite with 15% chitosan loading (LC15) resulted as the most prominent photocatalyst with the highest removal of RB5 up to 98.5% under experimental conditions of pH 6, 2g L-1 of catalyst loading, and 30 mg L-1 of initial RB5 concentration. The LC15 showed good stability, wherein the degradation efficiency was more than 90% after the fifth cycle with no significant change in the chemical properties. This work provides a technique to improve the removal of recalcitrant dyes through the processing of adsorptive photocatalysis utilizing adsorbent and perovskite.