Anti-Fouling Electroconductive Forward Osmosis Membranes: Electrochemical and Chemical Properties

Abstract

Forward osmosis (FO) has been emerging and gaining attention within the membrane-based processes because it can achieve high water fluxes while minimizing energy consumption, making it a cost-effective approach for wastewater treatment. However, membrane fouling remains an obstacle to this application. To address this concern, we fabricated an electroconductive membrane composed of polysulfone and polyaniline (PAni). These membranes have the potential to oxidize targeted organic compounds and/or electrostatically remove the fouling layer. After optimizing the PAni loading, we performed bench-scale tests using sodium alginate as model foulant. The membranes were fouled resulting in a decrease in FO efficiency of 72%. Fouled membranes were treated with a cathodic potential for 30 min, the fouling and antifouling processes were monitored with scanning electron microscopy (SEM), and contact angle and electrochemical methods were used. The fouled membrane exhibited a clogged surface and high electrical resistance, while the treated membrane recovered the PAni nanofibers morphology, its electrical and hydrophilic properties, and 84% of its FO efficiency. Thus, PAni can improve the overall membrane permeability while incorporating antifouling properties. Moreover, the EIS results of this study shed light on the mechanisms that govern the water separation process before and after fouling in the FO mode.

Lyotropic Liquid Crystal-Based Membranes for Water Remediation: Fabrication, Characterization and Performance Evaluation

“…As a strategy to understand the surface free energy aspects of the fabricated membranes, the contact angle technique was employed to determine the hydrophilicity/hydrophobicity of the membranes (Figure ). − The SupPAC membranes have a high contact angle and low surface energy; these indicate weaker attractive forces between the material surface and the water droplet. The results suggest that adding the polyanion and polycation layers creates a disturbance in the surface energy and promotes partial nonwetting. , Moreover, the LLC surface promotes complete wetting on the surface, which can be attributed to the exposed polar side of the LLC mixture.…”

Understanding the Relationship between Electrochemical Fouling Control and Electrode Surface Coverage

“…These trends are also observed at cathodic potentials of −1.0 and −0.5 V. The results shown in Figure 6 indicate that the attached biofilm introduces charge-transfer barriers that limit the passage of current at more negative potentials. 55 However, the presence of a charge-transfer barrier does not explain why fouling removal increases with electrode coverage initially and then attains a steady value. Instead, the relatively consistent current density measurements across electrode coverage values show that biofilm removal is not correlated with current density at all.…”

Preparation, modification and antifouling properties of polyaniline conductive membranes for water treatment: a comprehensive review

“…[80][81][82] For example, Cruz-Tato et al immersed a polysulfone (PSF) supported membrane in an acidic aniline monomer solution and accomplished in situ oxidative polymerisation of PANI by slow dropwise addition of an APS solution. 83 Scanning electron microscopy (SEM) confirmed crosslinking growth of the PANI network on the membrane surface. The ISCO method avoids prepolymerisation, multiple filtration and cleaning of the PANI, which simplifies the preparation process and shows potential for industrial application.…”