Pore Size Tailoring of Nickel Porous Hollow Fiber Membrane by Adjusting Redox Conditions

Porous metal membranes have broad applications in separation processes, membrane reactors, electronic catalysis, and membrane supports. These applications require a high membrane surface area and packing density to achieve high efficiency. Hollow fiber membrane configurations offer such high packing densities and thus significantly enhance the membrane module performance. However, regulating the pore size of metal hollow fiber membranes remains challenging. In this study, the pore size of fabricated nickel (Ni) hollow fiber membranes (NHFMs) was tuned under redox conditions. The influence of the oxidation–reduction temperature on pore morphology and separation performance was systematically investigated. Optimized redox conditions yielded NHFMs with a narrow pore size distribution (mean pore size ∼60 nm, maximum ≤70 nm) and high porosity (∼47%), achieving a N2 permeance of 2.7 × 104 GPU. Additionally, the pore size of NHFMs was tuned to a mean pore size of 162–177 nm, which demonstrated excellent bovine serum albumin (BSA) separation, exhibiting a 96.6% rejection rate and a water flux of 71 L/(m2·h). This work presents a simple strategy for tailoring the pore size of Ni hollow fiber membranes for diverse applications.