Graphene nanoplatelet-enhanced PANI-PAMPSA ultrafiltration membranes: influence of conductivity on fouling and electro-assisted cleaning.

Membrane fouling remains one of the major challenges limiting the efficiency and long-term operation of membrane separation processes. Although electro-assisted cleaning has emerged as a promising fouling mitigation strategy, membrane electrical properties can play an important role in determining the cleaning response. However, the relationship between membrane conductivity, intrinsic fouling behavior, and electro-assisted cleaning performance remains insufficiently understood. In this study, graphene nanoplatelet (GNP)-modified poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA)-doped polyaniline (PANI) ultrafiltration membranes were fabricated to investigate the relationship between membrane conductivity, fouling behavior, and electro-assisted cleaning performance. GNP incorporation increased membrane conductivity up to 2.16 × 10-3 S cm-1, representing a 4.2-fold enhancement over the pristine membrane. Although water permeability decreased, all membranes maintained excellent ultrafiltration performance, exhibiting >92% bovine serum albumin (BSA) rejection and >82% humic acid (HA) rejection. Notably, GNP incorporation did not improve intrinsic fouling resistance under hydraulic cleaning conditions, whereas electro-assisted cleaning performance progressively improved with increasing GNP loading and membrane conductivity. These results support the contribution of enhanced membrane conductivity to electro-assisted cleaning, while concurrent GNP-induced changes in membrane morphology and surface properties may also contribute to the observed response.