Chemical Compatibility of Modified Bentonite Permeated with Inorganic Chemical Solutions

摘要

The chemical compatibility of multiswellable bentonite (MSB), permeated with sodium chloride (NaCl) and calcium chloride (CaCl_2) solutions, were evaluated to discuss its applicability as landfill barrier material. From the results of free swell, liquid limit, and hydraulic conductivity tests, MSB was found to exhibit higher swelling power and lower hydraulic conductivity than natural bentonite (NB) for all levels of concentration of 0-2 mol/L NaCl and 0-0.5 mol/L CaCl_2 solutions. In particular, the hydraulic conductivity values of MSB were one to two orders of magnitude lower than those of NB for all concentration levels tested. There is a possibility that the liquid limit, rather than the swelling power, may provide appropriate predictions for the hydraulic conductivity as an index. It is concluded that MSB is expected to be an excellent alternative barrier material for landfill liner systems.