Heterogeneous catalytic activation of BaCu-based M-hexaferrite nanoparticles for methylene blue degradation under photo-Fenton-like system

A series of Gd-Tl substituted Ba0.75Cu0.25(GdxTl0.5-x)Fe11.5O19 (pure: Ba0.75Cu0.25Fe12O19, x = 0.0, 0.25 and 0.50) M-hexaferrite nanoparticles, named as BGT-NPs, were synthesized through co-precipitation technique and investigated as a heterogeneous catalyst for methylene blue (MB) degradation. NPs were characterized by XRD, FTIR, XPS, SEM, BET, UV and VSM. Feasible active species accumulated during heterogeneous photo-Fenton-like reactions were identified by the scavenger's technique. Advantage of larger surface area and composition of the Ba0.75Cu0.25Fe12O19 NPs exposed excellent degradation of MB with maximum reaction rate (4.34 x 10(-2) min(-1)). The nanoparticles exhibited the best performance, with 99 % (pure sample) and 98 % (x = 0.50) degradation at pH 7 solution in the existence of 16 mM of H2O2 in 120 min. TOC removal 88.15-75.60% was achieved in the presence of BGT-NPs. The pure sample showed high catalytic behavior for MB degradation in a broad pH range. Moreover, NPs demonstrated outstanding stability and reusability. Expressively lower concentrations (<= 0.110 mg/L) of ions (Ba, Cu, Gd, Tl and Fe) leaching were observed after MB degradation, which provides a remarkable edge over the homogeneous Fenton system. The findings of the study reveal that copper and gadolinium intervention strengthened the reactivity and broadened the possible pH range of M-hexaferrite NPs.