Low-Pressure UV-Initiated Synthesis of Hydrophobic Modified Flocculant P(AM-MAPTAC-TEMAC6) and Investigation of Its Flocculation-Dewatering Performance

The intractable mineral processing wastewater poses severe challenges to ecological environments and resource utilization. Developing novel flocculants for efficient treatment of complex mineral processing wastewater is an urgent problem that demands immediate resolution. In this study, a novel cationic polyacrylamide flocculant with hydrophobic modification, designated P(AM-MAPTAC-TEMAC 6 ), was synthesized via low-pressure ultraviolet (UV) -initiated polymerization using methacrylamido propyl trimethyl ammonium chloride (MAPTAC), acrylamide (AM), and perfluorohexyl ethyl methacrylate (TEMAC 6 ) as comonomers, with irgacure 2959 as the photo-initiator. The synthesis conditions were systematically optimized through single-factor experiments, culminating in optimal parameters: total monomer concentration of 35%, TEMAC 6 content of 10   wt%, photo-initiator dosage of 0.3   wt%, surfactant dosage of 0.8   wt%, UV irradiation time of 4   h, and urea dosage of 0.3   wt%. The successful synthesis of the copolymer was confirmed by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) revealed a well-developed porous structure, while thermogravimetric analysis (TG/DTG) demonstrated enhanced thermal stability. Flocculation and dewatering tests showed that P(AM-MAPTAC-TEMAC 6 ) exhibited superior turbidity removal and moisture reduction compared to three commercial flocculants in kaolinite, quartz, and montmorillonite suspensions. At a dosage of 50   g/t, residual turbidity values reached 99.63 NTU, 110.5 NTU, and 63.35 NTU, respectively, while the increments in moisture content of filter cakes consistently lower than that achieved by three commercial flocculants.