Efficient and ultrafast collection of metal ions from water is indispensable for applications such as drinking water purification and precious elements recovery. Microporous titanate nanofiber (MPTNF), a new type of titanate nanomaterials, has exchangeable cations in the structure (K and H in K1.4H1.4-xTi2.15O5). We report, for the first time, that MPTNF can be used as an excellent ion exchanger to remove Ni and Cd from water, as well as to soften hard water.