Performance improvement of PES membrane decorated by Mil-125(Ti)/chitosan nanocomposite for removal of organic pollutants and heavy metal

The Mil-125(Ti)-CS nanocomposite was successfully synthesized and characterized by using scanning electron microscopy (SEM) images, Fourier-transform infrared (FTIR) analysis and X-ray diffraction (XRD). Then, to improve the membrane performance, the synthesized Mil-125(Ti)-CS nanocomposite was embedded into the polyethersulfone (PES) membrane matrix. The nanofiltration membranes were fabricated via phase inversion method. Presence of chitosan in the structure of Mil-125(Ti) has increased the compatibility of nanoparticles with the polymer and also improved the hydrophilicity of the resulted membranes. The water contact angle of bare membrane (58 degrees) was reduced to 40 degrees by blending of 1 wt% nanocomposite led to increasing the pure water flux. However, the incorporation of more than 1 wt% of the nanocomposite caused the accumulation of nano composites and this was reduced the pore radius and permeability. The membrane containing 1 wt% nano composite was displayed the highest flux recovery ratio (FRR) similar to 98% in bovine serum albumin (BSA) filtration. The membranes containing Mil-125(Ti)-CS also showed good performance against fouling. The performance of membranes was evaluated by treatment of six reactive dyes, antibiotic (cefixime), heavy metal, NaCl and Na2SO4 solutions. Addition of Mil-125(Ti)-CS NPs at low concentrations resulted in membranes with high pure water flux, higher separation efficiency, and remarkable anti-fouling behavior.

Automated summary

The Mil-125(Ti)-CS nanocomposite was successfully synthesized and embedded into PES membrane matrix to fabricate nanofiltration membranes with improved performance. Addition of 1wt% nanocomposite led to increased pure water flux, while higher concentrations reduced pore radius and permeability. Membranes containing 1wt% nano composite showed the highest flux recovery ratio (FRR) of 98% in BSA filtration.