Salt-assisted thermal desorption of mercury from contaminated dredging sludge

► We treated dredging sludge polluted by mercury using thermal desorption assisted by organic salts. ► We conducted test on ionic exchange between mercury and organic salts performed at the boiling point of the solution. ► We demonstrated that thermal decontamination temperature can be significantly lowered by cationic exchange of the pollutant with an appropriate salt. ► At lowered temperature thermal treatment method can become economically competitive compared to other remediation methods.