Sorption capacity on lead,copper and zinc by clay soils from South Wales,United Kingdom

The sorption capacity of five clay soils from South Wales in the United Kingdom was investigated using two main tests; physico-chemical and batch equilibrium (BET). The physico-chemical property results show that soil weathered mudrocks (MR1), glacial till (GT1), and estuarine alluviums (NEA4, PEA3 and CEA3) are capable of being used as landfill liners and are chosen for further sorption tests. The batch tests (i.e. sorption tests) on soil suspension produce adsorption-pH curves, showing increasing adsorption at higher pH levels. The sorption data are also presented using adsorption isotherm curves and are best fitted using the Langmuir adsorption equation that yields the maximum adsorption capacity of the soils. The sorption capacity of soils are ranked as estuarine alluvium soils>glacial till>weathered mudrocks. Estuarine alluvium soils show a good buffering capacity and high sorption capability compared to glacial till and weathered mudrocks. The study also discovers that the maximum sorption capacities are highly influenced by the chemical properties of the soils.