Treatment of high turbidity mine drainage with iron-based hybrid flocculants: Synthesis process and mechanism, and its interfacial flocculation mechanism

Mine drainage containing high turbidity and emulsified oil is constantly generated during mining. Emulsified oil and suspended solids quickly form super-stable systems, making it challenging for traditional flocculation agents to settle and remove them effectively. This study prepared polymerized ferric sulfate (PFS) by oxidation-hydrothermal polymerization method. P-AM-DMDAAC-ODMA (polymerized-acrylamide-dimethyl diallyl ammonium chloride-Octadecyl methacrylate, abbreviated as PADO) and iron-based hybrid flocculant (PFADO) were prepared by solution copolymerization method. Various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR), X-ray diffraction (XRD), and thermogravimetric (TG) analysis, confirmed that each organic monomer was successfully grafted onto the copolymer. PFADO achieved 98.94% and 75.93% removal rates for turbidity and oil content, respectively. Characterization of changes in –CH, –CH2, –CH3, –OH, and –NH2 content in the FTIR of the flocculated sediments confirms the hydrophobic interactions and hydrogen bonding that occur during the flocculation process. The zeta potential results confirm that electrical neutralization is the main mechanism contributing to the flocculation process.