A high-flux phytic acid functionalized SiO₂ blend polysulfone ultrafiltration membrane for extraction of uranium from seawater

Uranium is a strategic resource which is found in quantities of 4.5 billion tons in seawater. For exacting U(VI) efficiently from seawater, this study involves the preparation of a polysulfone (PSF)-based phytic acid-silica blended membrane (PA-SiO₂/PSF) through the incorporation of silicon dioxide particles (SiO₂) and phytic acid (PA) into the polysulfone ultrafiltration membrane. A large number of adsorption sites was contributed by PA, serving as the primary factor in enhancing the U(VI) adsorption performance of PSF. Meanwhile, silica can be used as a carrier of PA to improve the performance of PSF. The addition of hydrophilic SiO₂ and PA increases the water flux (380 L·h⁻¹·m⁻²) and hydrophilicity (contact angle = 61.8°) of PSF. The modified PSF demonstrates a negative potential under neutral pH conditions. Notably, at pH = 7, PA-SiO₂/PSF exhibits the highest adsorption performance (q_e = 1052.01 mg/m²) and selectivity (K_d = 16161.96 mL/m²) for U(VI), with an 82 % recovery ratio of U(VI) achieved after five adsorption-desorption cycles. Moreover, the dynamic adsorption effect of PA-SiO₂/PSF surpasses that of static adsorption. Therefore, this study presents a straightforward method of modifying polysulfone membranes, with potential applicability in uranium adsorption from seawater.