The potential health and environmental hazards of carbon nanotubes (CNTs) have been a concerned issue. However, in contrast to the wide recognition of the toxicity of CNTs, little attention has been paid to the decontamination/remediation of CNT pollution. In this study, we report that CNTs can be removed from aqueous environment. In the presence of Ca 2+ , CNTs aggregate quickly to micron size and then enable easy and effective removal via normal filtration. After filtration, CNT suspension becomes colorless with the remnant CNT concentration less than 0.5μgmL −1 , a safe dose based on the published data. The filtration approach also works well in the presence of typical surfactant and dissolved organic matter. The removal efficiency is Ca 2+ concentration-dependent and regulated by the initial pH value and ionic strength. Our study is helpful for future decontamination of CNTs from aqueous environment.