Correcting the Effect of the Sorbent to Solution Ratio on Sorption Isotherms from Batch Tests with Soils and Sediments

摘要

There is evidence in the literature that the ratio of mass of sorbent (M) to volume of solution (V) affects the results of batch tests with soils and sediments. This restricts the use of such data to conditions with the same M/V ratio they were derived with, unless its influence is corrected. To find a correction, we conducted batch tests with soil and zinc solution using fourM/V ratios. For each ratio, the experiments produced a different relationship between the mass of zinc sorbed per unit mass of soil (a_s) and the zinc concentration in the solution after shaking and removal of the solid phase (C_(det)), which is usually taken as the equilibrium concentration (C_(eq)). Arntheoretical analysis revealed that the M/V effect can be accounted for by dividing C_(det) by the M/Vratio, if it is caused by the presence of a "third phase". The relationship between a_s and C_(det)×V/M is the same for all ratios then.