Preparation of nickel-doped nanoporous carbon microspheres from metal-organic framework as a recyclable magnetic adsorbent for phthalate esters.

In this work, magnetic Ni doped nanoporous carbon (Ni-C) microspheres were prepared by directly calcinating Ni based metal-organic framework at 400 °C in nitrogen. The morphology and surface area of Ni-C microspheres were characterized by electron microscopy and N adsorption-desorption isotherms. The results demonstrated that Ni nanoparticles were wrapped by the carbon matrix, resulting in the Ni-C microspheres with a strong magnetic response. The Ni-C microspheres also showed high surface area and micro/meso-porous structure, which make them efficient and recyclable magnetic adsorbent. The Ni-C microspheres were employed for magnetic solid phase extraction of phthalate esters from juice and water samples before high performance liquid chromatographic analysis. The limits of detection (S/N = 3) of the method were 0.2-0.3 ng mL for juice sample and 0.02-0.03 ng mL for water sample. The recoveries of all analytes were between 90.0%-100.6%. The Ni-C microspheres showed a great deal of potential to be an adsorbent for enrichment of other organic pollutants in different samples.