Sorption of caesium by sodium nickel hexacyanoferrate(II): column performance and prediction of breakthrough curves

The column performance of sodium nickel hexacyanoferrate(II) (NaNiHCF) for the removal of caesium from aqueous solution was investigated. Experimental breakthrough curves were determined using prepared samples of NaNiHCF in small glass columns with continuous analysis of the effluent solution. The adsorption isotherm was also determined experimentally and found to be extremely favourable, fitting a Freundlich type expression. The experimental breakthrough curves were fitted to a mathematical model which was solved numerically using the Freundlich isotherm and also analytically when the isotherm was assumed to be rectangular. It was found that both models allowed a good fit of the experimental data and therefore enabled the effect of flowrate, bed height and caesium concentration on the breakthrough volume to be predicted with some precision. (author)