Robust PANI-entangled CNTs Electro-responsive membranes for enhanced In-situ generation of H2O2 and effective separation of charged contaminants

• Published in: Separation and purification technology 2022-12, Vol.303, p.122274, Article 122274
• Main Authors: Jiang, Longxin, Rastgar, Masoud, Wang, Chunrong, Ke, Shu, He, Lei, Chen, Xiaoya, Song, Yifan, He, Can, Wang, Jianbing, Sadrzadeh, Mohtada
• Format: Article
• Language: English
• Subjects: Charged contaminants; CNTs membrane; Electro-generation of H2O2; Electro-responsive membranes; Polyaniline
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.122274

[Display omitted] •Conductive PANI was incorporated on CNTs via in-situ polymerization to fabricate electro-responsive membranes through a sequential laminating strategy.•PANI@O-CNTs membranes exhibited excellent mechanical and electrochemical stability.•Nitrogen-rich PANI on CNTs boosted their reactivity for electro-generation of H2O2.•Charged contaminants were significantly rejected through the synergistic effect of electrostatic interactions and H2O2 oxidation.•In-situ generation of H2O2 endowed PANI@O-CNTs membranes with good antifouling property. Electro-responsive membranes provide a promising strategy to overcome the trade-off between water recovery and water quality in membrane-based wastewater treatment. However, the successful deployment of these membranes is restricted by their low mechanical stability and poor electrochemical reactivity. Herein, we strived to overcome these challenges by constructing a polyaniline-entangled oxidized CNTs (PANI@O-CNTs) cathodic membrane via a sequential laminating technique. The effective in-situ polymerization of the PANI network on the CNTs skeleton and the superior conductivity of the PANI@O-CNTs membrane was demonstrated by extensive characterizations. Durability test results showed the excellent mechanical and electrochemical stability of the robust PANI@O-CNTs membranes. Cyclic voltammetry (CV) analysis confirmed that the modification of nitrogen-rich PANI on CNTs boosted their reactivity for electro-generation of H2O2. By applying an external voltage of −2.0 V, the PANI@CNTs membrane displayed an enhanced rejection from 35.2 % to 77.4 % for negatively charged methyl orange (MO) dye and from 41.5 % to 79.8 % for positively charged methylene blue (MB) dye at 50 min operation time. Moreover, the rejection efficiencies further increased to 89.7 % for MO and 93.4 % for MB through the synergistic effect of electrostatic interactions and H2O2 oxidation. Additionally, antifouling experiments performed with oppositely charged dyes indicated that H2O2 oxidation played a critical role in flux recovery and fouling alleviation. Our results raise the prospect of utilizing electro-responsive membranes to remove specific organic matter from wastewater.