Sulfonated electrospinning nanofibrous membranes for high-efficient removal of cationic dyes

Wastewater containing dyes is generated in diverse industrial processes, and its treatment has become more crucial owing to increasing environmental concerns recently. Herein, we report a versatile strategy to fabricate a sulfonated electrospinning nanofibrous membrane for high-efficient removal of cationic dyes from their aqueous solution via electrostatic adsorption. The resulting sulfonated polyetherketone-cardo (SPEK-C) membranes have controllable sulfonation degree (SD), uniform nanofibrous structures, large specific surface areas and strong hydrophilicity. Particularly, they show excellent adsorption efficiency for cationic dyes, outstanding sustainability and renewability in filterable adsorption-desorption experiments. For example, the membrane consisting of ∼150 nm-thick SPEK-C nanofibers with the SD of 78 % has the specific surface area of 40.2 m⁻² g⁻¹, water contact angle of 35.8°, and high adsorption capacity for cationic dyes, such as 171.9 mg g⁻¹ for methylene blue (MB). Moreover, the membrane keeps over 90 % adsorption percentage and over 80 % desorption percentage after several circulations in filterable adsorption-desorption experiments. The presented strategy has great potential in the fabrication of nanofibrous membranes for high-efficient removal of charged contaminants.