One-Step Electrochemically Prepared Graphene/Polyaniline Conductive Filter Membrane for Permeation Enhancement by Fouling Mitigation

Abstract

In the electrofiltration process, membrane conductivity plays a decisive role in improving the antifouling performance of the membrane. In this paper, combining the preparation of graphene (Gr) with the fabrication of the Gr layer on the surface of a polyaniline (PANI) membrane, a graphene/PANI (Gr/PANI) conductive membrane was prepared creatively by the one-step electrochemical method. The properties of the as-prepared Gr/PANI membrane were studied systematically. By the tests of Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and atomic force microscopy, it was confirmed that Gr was successfully produced and was combined with the PANI membrane well. Field scanning electron microscopy with energy-dispersive X-ray analysis further confirmed that the top surface and the upper layer pore walls of the membrane were randomly covered by Gr. The antifouling performance of the prepared membrane was evaluated by studying the permeation flux of the yeast suspension, compared with the ones with no electric field: the total permeation flux at 1 V direct current (dc) increased by 109%; besides, under 1 V dc, the average flux of the Gr/PANI membrane was approximately 1.4 times that of the PANI membrane. This approach may provide a promising strategy for the combination of Gr with conductive polymers to produce separation membranes.

Electrified Membranes for Water Treatment Applications

“…Conductive polymers possess a conjugated backbone that forms a series of alternating single and double carbon bonds. , The overlap of p-orbitals in the π-bonds allows the electrons to delocalize and move between atoms. Polypyrrole (PPy) and polyaniline (PANI) have been applied extensively for EM fabrication because of their stability under harsh conditions, such as high pressure and chemical exposure. , However, many polymer-based EMs suffer from low conductivity and water flux. , The combination of conductive polymers with carbonaceous materials, such as CNTs and graphene, can enhance the electrical performance of EMs. , …”

“…The most common method for EM preparation consists of modifying a porous substrate with conductive materials (Figure B 2 ). Conductive substrates such as carbon filter cloth, , Ti mesh, , stainless steel, , and PANI , are widely used. Functionalization of electrocatalytic materials, such as CNTs, − graphene, − and doped SnO 2 , ,, on the substrates improves their electrochemical performance and/or controls the membrane pore size.…”

Recent Progress in One- and Two-Dimensional Nanomaterial-Based Electro-Responsive Membranes: Versatile and Smart Applications from Fouling Mitigation to Tuning Mass Transport

“…The generated heat generated could result in microbial deactivation and thus prevent microbial attachment on the surface of the membrane. Recently, Li et al [73] prepared a conductive graphene/polyaniline (Gr-PANI) membrane with a one-step electrochemical process involving placing the PANI membrane and graphite foil vertically in an electrolyte 1 cm away from both the cathode and anode. The application of current to the electrode stripped Gr from the graphite foil and deposited it on the PANI membrane.…”

“…Compared to fouling and contaminant removal, fewer studies are focused on demonstrating controllable water and ion permeation across ERMs by adjusting externally applied voltage [73]. In a previous research performed by Zhou et al [85], the transport of water molecules across the nanochannel with conducting filaments created in a laminar GO membrane can be adjustable by applying external voltage to the GO membrane.…”

“…Figure 5. Fouling mitigation by electrically responsive membranes, (a) as illustrated by Chen et al[69] and (b) as illustrated by Li et al[73]. Reproduced with permission from[69,73].…”