Exploiting the ion-exchange ability of titanate nanotubes in a model water softening process.

Highlights: [•] Titanate nanotubes were utilized in Ca2+ and Mg2+ removal in an ion-exchange unit. [•] The highest measured value of the total ion-exchange capacity was 1.2mmolg−1. [•] The ion-exchange capacity decreased to 0.66mmolg−1 in the third cycle. [•] Capacity loss was due to irreversible binding of Ca2+ to strong adsorption sites. [•] The Mg2+/Na+ exchange was reversible. [ABSTRACT FROM AUTHOR]