Comparative investigation on the adsorption behavior of bromate in aqueous solutions using Zn/Ni/Al-LDH and Ni/Al-LDH: optimization, equilibrium analysis, and mechanistic insights.

Unlabelled: The presence of bromate in water poses a significant health risk. In order to effectively eliminate bromate from water, this study synthesized a series of ternary Zn-Ni-Al layered double hydroxides with varying Zn/Ni/Al atomic ratios using a co-precipitation method. The adsorbents were characterized using various techniques including XRD, Fourier transform infrared spectroscopy, and N adsorption-desorption isotherms. Among them, ZnNiAl-2 exhibited the highest crystallinity and largest specific surface area (316.1 m g), which was compared to the binary hydrotalcite NiAl-LDH for its ability to adsorb bromate from water. Results demonstrated that the adsorption isotherm of bromate on ZnNiAl-2 followed the Langmuir model, with a maximum adsorption capacity of 120.5 mg g, significantly higher than that of NiAl at 75.5 mg g, indicating strong adsorption capability and reusability performance. The adsorption kinetics were also found to be in accordance with the pseudo-second-order kinetic model. The mechanism involved both surface adsorption and anion exchange.

Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-025-00932-6.