Green remediation of Cd and Hg contaminated soil using humic acid modified montmorillonite: Immobilization performance under accelerated ageing conditions.

•A novel clay-based Cd and Hg stabilization approach was proposed.•FESEM/EDS, BET, FTIR, XRD results reveal the characteristics of HA-Mont.•Quantitative accelerated ageing was adopted to examine the long-term stability.•Ageing features of immobilization processes were depicted by a Weibull model.