Fabrication, optimization, and performance of a TiO2 coated bentonite membrane for produced water treatment: effect of grafting time

Abstract

The main problem usually faced by commercial ceramic membranes in the treatment of produced water (PW) is low water flux even though ceramic membrane was well-known with their excellent mechanical, thermal, and chemical properties. In the process of minimizing the problem faced by commercial ceramic membranes, titanium dioxide (TiO2) nanocomposites, which synthesized via a sol-gel method, were deposited on the active layer of the hydrolysed bentonite membrane. This paper studied the influence of grafting time of TiO2 nanocomposite on the properties and performance of the coated bentonite membranes. Several characterizations, which are Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray Spectroscopy (EDX), contact angle, porosity, and average pore size, were applied to both pristine and coated bentonite membranes to compare the properties of the membranes. The deposition of TiO2 nanoparticles on the surface of the coated bentonite membranes was successfully confirmed by the characterization results. The pure water flux performance showed an increment from 262.29 L h-1 m-2 bar-1 (pristine bentonite membrane) to 337.05 L h-1 m-2 bar-1 (Ti-Ben 30) and 438.33 L h-1 m-2 bar-1 (Ti-Ben 60) as the grafting time increase but when the grafting time reached 90 min (Ti-Ben 90), the pure water flux was decreased to 214.22 L h-1 m-2 bar-1 which is lower than the pristine membrane. The oil rejection performance also revealed an increase in the oil rejection performance from 95 to 99%. These findings can be a good example to further studies and exploit the advantages of modified ceramic membranes in PW treatment.