Studies on removal of phenol using ionic liquid immobilized polymeric micro-capsules.

Phenol and phenolic compounds are pollutants of high priority concerns because of their toxicity and contribution to health problems. ( Lohumi et al., 2004 ) The most suitable industrial process for the removal of phenol from aqueous streams is liquid–liquid extraction, which has its own limitations. In order to avoid possible drawbacks, such as persistent emulsification and leaching of extractant in conventional extraction operations, room temperature ionic liquid (RTIL) encapsulated in microcapsules (MC) is used as extractant. The present study deals with the preparation of RTIL encapsulated microspheres by surfactant free emulsion polymerization under controlled conditions and the microspheres thus synthesized are characterized to ensure the desired particle size, morphology and surface area by using Scanning Electron Microscopy (SEM), FTIR and BET apparatus, respectively. The effects of process variables such as agitation speed, agitation time, temperature, and shell material and the effect of dispersant were studied to determine the yield and size of microcapsules. This was followed by equilibrium distribution studies. The extractant loading capacity in the microcapsules was also analyzed by solvent extraction using hexane as solvent. Batch Sorption studies were conducted to optimize the process variables in the removal of phenol and the data were validated using various isotherms and kinetic models. Thermodynamic parameters were also established. Regeneration studies were also attempted to ensure the stability and reusability of microcapsules. [ABSTRACT FROM AUTHOR]