Removal of Acid Orange G Azo Dye by Polycation-Modified Alpha Alumina Nanoparticles.

Highly positively charged poly(vinyl benzyl trimethylammonium chloride) (PVBMA) was successfully synthesized with approximately 82% of yield. The PVBMA was characterized by the molecular weight (M _w ) of 343.45 g mol ^-1 and the molecular weight distribution, (Đ) of 2.4 by ¹ H NMR and SEC measurements. The PVBMA was applied as an effective agent for α-Al ₂ O ₃ surface modification in the adsorptive removal of the azo dye acid orange G (AOG). The AOG removal performance was significantly enhanced at all pH compared to without surface modification. The experimental parameters were optimal at pH 8, free ionic strength, 15 min of adsorption time, and 5 mg mL ^-1 α-Al ₂ O ₃ adsorbents. The AOG adsorption which was mainly controlled by the PVBMA-AOG electrostatic attractions was better applicable to the Langmuir isotherm and the pseudo-second kinetic model. The PVBMA-modified α-Al ₂ O ₃ demonstrates a high-performance and highly reusable adsorbent with great AOG performances of approximately 90.1% after 6 reused cycles.
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