Bio-inspired, fouling resistant, tannic acid functionalized halloysite nanotube reinforced polysulfone loose nanofiltration hollow fiber membranes for efficient dye and salt separation

Superficial functionalization of the hollow fiber membrane with progressive nanomaterials exhibits increased hydrophilicity, outstanding selectivity, and permeability. In the present study, a simple and novel loose nanofiltration (NF) membranes were prepared by the addition of tannic acid functionalized halloysite nanotubes (THNTs) in polysulfone (PSf) membrane matrix via phase inversion method. The successful modification of halloysite (HNTs) was confirmed by FT-IR, zeta potential measurement, TGA, TEM and EDX analysis. The membrane permeation studies were carried out with a sequence of salts (NaCl and Na2SO4) and dyes (reactive black 5 and reactive orange 16). The resulted membranes exhibited increased hydrophilicity, porosity, water uptake, antifouling performance, along with higher dye rejection (>99% for reactive black 5 and >90% of reactive orange 16) and low salt rejection (2.5% of NaCl and 7.5% of Na2SO4) properties. The nanocomposite membrane also exhibited the highest pure water flux of 92 L/m2 h compared to the pristine membrane of 18 L/m2 h made it a worthy candidate for the wastewater purification.