Design and evaluation of solvent impregnated resins (SIRs) for the removal of cyanopyridine from a mixture of organic acids

A process for the removal of the pyridine derivative 4-cyanopyridine from an aqueous stream using solvent impregnated resin (SIR) technology for fixed bed operation was explored. The studies consisted of a solvent screening by liquid-liquid extraction, and column testing. In the solvent screening, acidic functional groups containing solvents were evaluated. Phenol based solvents showed the highest potential for the application. Distribution coefficients up to 1000 and selectivities up to 700 have been measured. Evaluation of the SIR containing nonylphenol as extractant in laboratory scale column experiments showed that 14 bed volumes of 0.5 g/L of 4-cyanopyridine can be treated until breakthrough occurs, corresponding with a capacity of 12 g 4-cyanopyridine per kg resin. Regeneration can be achieved by using pH-swing, after 6 bed volumes complete regeneration is obtained and after 2 bed volumes 86 % regeneration is obtained. 10 Loading and regeneration cycles were performed without observing decrease in capacity, indicating that the designed SIR is very stable.