Synthesis of Negatively Charged Polyol-Functional PSF Membranes with Good Hydrophilic and Efficient Boron Removal Properties

Abstract

Boron removal remains a major barrier to water purification, it is important to develop a specialized adsorption membrane for boron removal. By means of a simple and effective method, a hydrophilic membrane for boron removal with a polyhydroxy functional group on the surface was prepared. Firstly, a polysulfone (PSF) membrane was modified by co-depositing polyethyleneimine (PEI) with dopamine (DA) in one-step to produce amine-rich surfaces, then the DA/PEI-functionalized membranes were reacted with glycidol, with the prepared membranes corresponding to PSF-PDA/PEI membranes and PSF-diol membranes. The prepared membranes were characterized by water-uptake, FTIR, (X-ray photoelectron spectroscopy) XPS, (Field emission scanning electron microscope) FESEM, and zeta potential measurements. The hydrophilicity of the membrane was characterized by the static water contact angle (WCA) test. In addition, we systematically studied the impact of initial boron concentration, chelating time, and pH value on boron removal performance. The results showed that the PSF-diol membrane had strong hydrophilicity with a WCA of about 38°. The maximum adsorption capacity of boron appeared to be 1.61 mmol/g within 10 min at a boron concentration of 300 mg/L. Adsorption kinetics showed that saturation adsorption can be achieved in minutes at the initial concentration of 5 mg/L, which is beneficial to a rapid filtration process.