Modelling and optimisation of Rhodamine B adsorption on a BPDC-based Zn-MOF prepared via mechanochemical synthesis

In this study, a biphenyl dicarboxylic acid (BPDC)-based Zn-metal organic framework was mechanochemically synthesised to remove RhB dye from aqueous systems via adsorption. The features of the synthesised adsorbent were investigated using Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) to investigate its surface functional groups and morphology, respectively. For modelling and optimisation, the Box-Behnken design (BBD) of response surface methodology (RSM) was applied, using adsorbent dosage, ionic strength, contact time, and pH as factors, with dye removal as the response. The findings of the RSM-BBD showed that the optimisation outcome was obtained at an adsorbent dosage of 0.497 g, ionic strength of 0.110 mol/L, time of 69.72 min, and pH of 11.97. The removal efficiency of about 97% RhB by the synthesised BPDC-based Zn-MOF under optimised conditions was relatively higher than previous studies in the existing literature. The statistical results demonstrated a good correlation between experimental and predicted values (R 2 > 0.99), suggesting the effectiveness and satisfactoriness of the model. The study equally showed that the synthesised adsorbent is effective for the adsorptive removal of RhB dye from aqueous systems.