the disclosure relates to the field of lining materials which are used to isolate landfill sites in order to avoid pollution of surrounding soil by ions such as heavy metals . further disclosed is a process to increase the ion adsorption capacity of clay or dredged sediment . more specifically , the disclosed is a process comprising : a ) mixing the clay or dredged sediment with an anionic polymer , and b ) subsequently drying the mixture , results in a lining material having superior ion adsorption characteristics .