Batch Preparation of High Basicity Polyferric Sulfate by Hydroxide Substitution from Bipolar Membrane Electrodialysis

An experimental study was carried out on the batch preparation of high basicity polyferric sulfate (PFS) by hydroxide substitution from bipolar membrane electrodialysis (BMED) with BP-A configuration. Effects of operation time, current density, and molar feed ratio of FeSO4 to H2SO4 on PFS properties were investigated. Results show that increasing operation time and molar feed ratio may increase the PFS basicity, turbidity removal ratio, and energy consumption simultaneously; meanwhile, increasing current density could increase the basicity and turbidity removal ratio but decrease the energy consumption. When the current density is 20 mA/cm2, the basicity attains to 14.72%, turbidity removal ratio increases to 93.43%, and energy consumption decreases to 2.72 kW·h/(kg H2SO4). Moreover, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) were conducted to determine the structure and morphology analysis of solid PFS.