Ultrasound-assisted Solid-liquid Trap Phase Extraction based on Functionalized Multi Wall Carbon Nanotubes for Preconcentration and Separation of Nickel in Petrochemical Waste Water

In this study, a novel sorbent based on phenylsulfonic acid functionalized multiwall carbon nanotubes (MWCNTs-Ph-SO3H) was used for preconcentration and separation of trace Ni(II) ions in petrochemical wastewater samples by ultrasound-assisted solid-liquid trap phase extraction. In this work, a mixture of MWCNTs-Ph-SO3H as a nanosorbent and ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate, IL) dispersed in acetone was rapidly injected by a syringe into 50 mL of a sample containing Ni(II). The metal was extracted by sulfonate group as (RSO3)2-Ni at optimized pH. After shaking and centrifuging, the nanoparticles of sorbent were trapped in IL phase and settled down in a conical centrifuge tube (IL/MWCNTs-Ph-SO3H). Hydrophobic IL was used to fast trap the Ni(II) loaded sorbent from the sample solution. Under the optimized conditions, the linear range (peak area), limit of detection and enrichment factor were obtained as 1.5–165 μg/L, 0.35 μg/L and 50, respectively.