Insights into colloidal membrane fouling mechanisms for nanofiltration of surface water using single and hybrid membrane processes

Abstract

Colloidal membrane fouling mechanisms were modeled for experimental data provided for nanofiltration of surface water by single and hybrid membrane systems.The hybrid system is composed of coagulation/activated carbon adsorption and bare polyethersulfone or mixed-matrix membranes. The comprehensive modeling of these membrane systems was performed by three explicit equations to evaluate the effects of combined cake-filtration and pore-blocking on the fouling processes. These equations were derived from Darcy's law applied under constant operating pressure. The results showed that by using the nonlinear regression method, the combined cake-filtration/pore-blocking models demonstrated more accurate fits to the experimental permeate volume data compared to individual blocking models. The accuracy achieved by such nonlinear fits is expressed in terms of a mean squared error of approximately 10 −10 (m 3 /m 2 ) 2 and R 2 > 0.999. Furthermore, the impact of a pretreatment stage and the type of membrane used to prevent or reduce the fouling are also investigated. Experimental results reveal that the colloidal fouling depends on the type of membrane and the characteristics of raw water and is not only related to the cake filtration.

Progress in Research and Application of Nanofiltration (NF) Technology for Brackish Water Treatment

“…In order to mitigate membrane fouling and keep long-term stable operation, various measures can be taken according to actual conditions. Membrane fouling refers to the phenomenon that the adsorption and deposition of rejected foulants (including particles, colloid, inorganic salts, organic matters and microorganisms) on the membrane surface or in the membrane pores, which can decrease the permeate flux, change the effluent quality and increase energy consumption and operating costs [ 80 , 81 , 82 ]. In general, NF membrane fouling during the treatment of brackish water can be reduced by three aspects, including pretreatment and optimization of operating conditions, as well as the preparation or selection of anti-fouling membrane materials.…”

Fouling of the Nanofiltration Membrane NF270 Used for Separation of Fermentation Broths: Impact of Feed Pretreatment Process

“…Indeed, it is one of the most comprehensive fouling prediction models [51]. Several researchers investigated the possibility of applying this model to investigate the mechanism of the permeate flux decline during the NF process of various feed solutions, such as fermentation broth [13], surface water [51,52], wastewater [53], juice [54], acid whey [55], red dye [56] and propolis extract [57].…”