Layer-by-layer assembly of nanocomposite interlayers on a kaolin substrate for enhancing membrane performance of Pb(II) and Cd(II) removal.

Developing an ultra-thin polyamide selective layer with sufficient mechanical robustness on a highly porous ceramic substrate is challenging for removing heavy metal ions from wastewater. We synthesized a reliable ceramic-polyamide membrane by assembling nanocomposite interlayers of alumina and carbon black on the kaolin substrate. The surface morphology, pore size distribution, and roughness of ceramic substrates were improved by introducing the nanocomposite interlayer. The corresponding optimized water flux, Pb(II), and Cd(II) removal efficiency are 2.75 L m-2 h-1, 98.44%, and 97.51%, respectively, which are better than those of the polyamide films constructed directly on the ceramic substrate. This facile structure provides more active sites for forming ultrathin polyamide layers with satisfactory mechanical robustness. This paper provides a new perspective for fabricating efficient heavy metal ions filters.