Flexible Superhydrophobic Metal-Based Carbon Nanotube Membrane for Electrochemically Enhanced Water Treatment

Abstract

Treatment of highly saline wastewaters via conventional technology is a key challenging issue, which calls for efficient desalination membranes featuring high flux and rejection, low fouling, and excellent stability. Herein, we report a high-strength and flexible electro-conductive stainless steel-carbon nanotube (SS-CNT) membrane, exhibiting significantly enhanced anticorrosion and antifouling ability via a microelectrical field-coupling strategy during membrane distillation. The membrane substrates exhibited excellent mechanical strength (244.2 ± 9.8 MPa) and ductility, thereby overcoming the critical bottleneck of brittleness of traditional inorganic membranes. By employing a simple surface activation followed by self-catalyzed chemical vapor deposition, CNT was grown in situ on SS substrates via a tip-growth mechanism to finally form robust superhydrophobic SS-CNT membrane. To address the challenging issues of significant corrosion and fouling, using a negative polarization microelectrical field-coupling strategy, simultaneously enhanced antifouling and anticorrosion performance was realized for treatment of organic high salinity waters while exhibiting stable high flux and rejection via an electrostatic repulsion and electron supply mechanism. This application-oriented rational design protocol can be potentially used to extend toward high performance composite membranes derived from other electro-conductive metal substrates functionally decorated with CNT network and to other applications in water treatment.

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

“…Omi et al [55] fabricated CNT-based ERMs via a vacuum-assisted layer-by-layer method. Also, electrophoretic deposition [56] and chemical vapor deposition [17] have been used to obtain hollow fiber type rGO-CNT and CNT-based ERMs, respectively.…”

“…With the assistance of external power, ERMs can conduct additional capabilities that conventional membranes cannot perform. In previous studies, it was demonstrated that electrically responsive membranes (ERMs) can be used to mitigate membrane fouling [17][18][19], monitor membrane fouling propensity [20], self-cleaning [21,22], electrochemically oxidizing organic contaminants [23], controlling permeability and selectivity [24][25][26], energy recovery [27], and controlling membrane wettability [28].…”

The preparation of cotton fabric with super‐hydrophobicity and antibacterial properties by the modification of the stearic acid

“…The superhydrophobic surface is one of the hot spots in the research of new materials due to its excellent properties of self‐cleaning, 1 water‐resistant, 2 ice‐resistant, 3 antibacterial, 4 and anticorrosive 5 . By controlling the roughness of the surface and introducing functional groups with low surface energy, great progress has taken place in the research of superhydrophobic material.…”

“…The superhydrophobic surface is one of the hot spots in the research of new materials due to its excellent properties of self-cleaning, 1 water-resistant, 2 ice-resistant, 3 antibacterial, 4 and anticorrosive. 5 By controlling the roughness of the surface and introducing functional groups with low surface energy, great progress has taken place in the research of superhydrophobic material. However, due to the inherent fragility of the hierarchy, the wettability of the surface of superhydrophobic materials is compromised under strict and complex physical or chemical conditions, which reduced the service life and application value of the products.…”

Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution

“…MD is a promising technology for desalting wastewater. It is a thermally driven separation process using a hydrophobic microporous membrane, different from the pressure-driven membrane process [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Heat and mass transfer through the membrane are both involved in the process [ 8 ].…”