Adsorption of catecholamines from their aqueous solutions on hypercrosslinked polystyrene

Hypercrosslinked polystyrene Diapak P-3 was investigated as a high-capacity adsorbent for catecholamines (i.e. epinephrine, norepinephrine and dopamine). Morphological data for the sorbent were evaluated by scanning electron microscopy and nitrogen adsorption-desorption method. The results showed that Diapak P-3 possesses high microporous surface area of 1132 m(2) g(-1) and a bimodal pore size distribution. Batch adsorption studies were performed to evaluate effect of pH and contact time on catecholamines uptake. The molecular forms of catecholamines are favorable for the adsorption, best results (maximum adsorption capacity) were found at pH 7-9. The adsorption kinetic properties were obtained by application of the pseudo-first order kinetic model. From adsorption isotherms, the two-site Langmuir model showed the best fit and total adsorption capacity of 86, 68, and 52 mg g(-1) for dopamine, epinephrine, and norepinephrine, respectively. From the obtained results, the hypercrosslinked polystyrene Diapak P-3 has showed good adsorptive characteristic for catecholamines.