Immobilization of nano-Cu on ceramic membrane by dopamine assisted flowing synthesis for enhanced catalysis.

[Display omitted] • Dopamine-assisted flowing synthesis for immobilization of nano-Cu on ceramic membrane. • Nano-Cu with high loading amount and good dispersity throughout the membrane structure. • Synergistic effect between filtration and nano-Cu catalysis enhances 4-NP reduction. • Excellent stability and antifouling property of the composite membrane. Catalytic membranes containing metal nano-catalysts are effective in removing organic pollutants from wastewater. The relative low catalytic activity of the non-noble metals (such as Cu nanoparticles) presents a challenge for their widespread application. Herein, Cu nanoparticles were in-situ immobilized on ceramic substrate by a dopamine assisted flowing synthesis method to strengthen its catalytic property. Firstly, a precursor solution containing dopamine and Cu2+ was cyclically permeated through the ceramic microfiltration substrate to form a polydopamine coating with chelated Cu2+. Then, Cu nanoparticles were in-situ formed with the aid of NaBH 4. FESEM, EDS, XPS and XRD analyses demonstrate the successful formation of the Cu nanoparticles. The obtained membrane depicts good hydrophilicity and permeability (556.51 L m-2h−1 at 0.1 MPa). In the continuous catalytic degradation under cross-flow filtration mode, the membrane achieves 90.84 % reduction of 4-nitrophenol (4-NP) and 92.36 % degradation rate of methyl orange (MO). The large amount of Cu nanoparticles immobilized within the membrane pores (form inner-pore microreactors) enhance the catalytic activity of the membrane, resulting in an apparent reaction rate constant of 38.78 min−1 on the permeation side. The composite membrane has good antifouling and easy-cleaning properties (the flux recovery rate is 84.3 %). In long-term experiments, the catalytic degradation rate of MO remains above 96 % throughout 50 cycles, demonstrating good stability. This study provides a novel strategy for developing catalytic membrane with immobilized non-noble metal nanoparticles, which has potential applications in environmental remediation. [ABSTRACT FROM AUTHOR]