Mussel-inspired in-situ metallization of nano-Ag on ceramic membrane for catalytic degradation of dye wastewater

Catalytic membranes supported with nano-catalysts have been widely used for wastewater treatment. The traditionally catalyst immobilization methods, such as physical blending, chemical deposition and impregnation et al., involve complex preparation steps. Herein, Ag nanoparticles were in-situ immobilized on a ceramic microfiltration substrate by a mussel-inspired facile metallization process. Firstly, dopamine was deposited onto the substrate (∼200 nm) to form a uniform polydopamine coating. Then, Ag nanoparticles were in-situ metalized and immobilized on the polydopamine decorated ceramic membrane. The preparation conditions were relatively simple without sintering. FTIR, XRD, FESEM and EDS characterizations demonstrate the successful immobilization of the Ag nanoparticles. The obtained membrane exhibits good hydrophilicity and permeability (606.08 L m ⁻² h ⁻¹ at 0.1 MPa). The degradation rate of methyl orange achieves ∼95.6% within 20 min. The apparent reaction rate constant reaches the highest value of 568.1 min ⁻¹ at 0.5 MPa, which is several orders of magnitude higher than that of the feed side. The composite membrane can degrade mixed dyes. The catalytic membrane also shows excellent stability and antifouling property. In conclusion, this research provides a convenient and effective way for preparing a kind of composite catalytic membrane with high performance, which has potential applications in environmental remediation.