Mechanism analysis of powdered activated carbon controlling microfiltration membrane fouling in surface water treatment

The mechanism of powdered activated carbon (PAC) mitigating microfiltration (MF) membrane fouling for surface water treatment was investigated via blocking models, resin adsorption fractionation, high performance size exclusion chromatography (HPSEC) with peak-fitting, and interaction free energy theory. The results identified cake formation as the major mechanism of membrane fouling. Also, PAC pre-treated water showed a relatively lower fouling rate than untreated raw water and PAC had a positive effect on improving membrane flux on account of the enhanced removal of neutral hydrophilic compounds (NEU) and strongly hydrophobic acids (SHA) (based on fractionation), and building blocks and low molecular weight acids (BB&LMW-A) (based on HPSEC). Analysis of the interfacial energy between membrane and foulants via the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory found that AB interaction energy played a dominating role in the components of interaction free energies during MF process. PAC, by decreasing AB interaction energy, could thus control membrane fouling. (C) 2017 Elsevier B.V. All rights reserved.