CARBON NANOTUBE-REINFORCED HOLLOW FIBER MEMBRANE FOR EXTRACTION OF METAL OXYANION

Abstract

Hollow fiber liquid phase microextraction (HF-LPME) is an excellent preconcentration technique, which provides high enrichment factor. Nevertheless, the extraction efficiency is limited. To improve the extraction efficiency, one is an application of electrical field so called electro-enhanced HF-LPME to enhance the transportation of ionic analyte; the other one is a reinforcement of nanoparticles to the hollow fiber membrane to provide interaction between nanoparticles and analytes. In this study, carbon nanotubes (CNTs) were combined with electro-enhanced HF-LPME for extraction of chromate ion. The effects of CNTs on the transportation of chromate ion across membrane were studied. The comparative study between CNTs-reinforced and conventional electro-enhanced HF-LPME was explored. CNTs-reinforced with electro-enhanced HF-LPME showed improved extraction efficiency compared to the conventional electro-enhanced HF-LPME. In order to obtain high extraction efficiency of CNTs-reinforced with electro-enhanced HF-LPME method, main parameters were optimized. Optimal extractions were accomplished with 3 mg/mL of CNTs/octanol as the organic solvent membrane. Applied voltage was 50 V, extraction time of 10 min. Under the optimized conditions, carbon nanotubes-reinforced with electro-enhanced HF-LPME method presented low limit of detection (1.3 µg/L), good linear of regression (0.9965) and high enrichment factor 133-134. The recoveries were in acceptable value of 112 and 113% for 20 and 50 ppb Cr(VI), repectively.