To enhance the performance of diffusion dialyzers for acid recovery, new hollow-fiber anion-exchange membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) by following the procedures of bromination, spinning, and quaternary amination. The best membranes prepared had the following inherent properties: ion-exchange capacity = 2.2-2.5 mmol/g, water content (W-R) = 0.6-0.8 g of water/g of dry fiber, and dimension change ratio (L-R) < 20%. When used to treat a simulated aluminum polishing waste liquor (HCl, 3.5 mol/L; AlCl3, 0.036 mol/L), the membranes could achieve an acid recovery ratio of 0.6-0.7 and an aluminum rejection ratio above 90%. These performances, plus favorable equipment size/productivity ratio, make hollow-fiber-type dialyzers more competitive than plate-and-frame-type ones. For industrialization in the near future, further improvement on membrane properties is under-way.