Novel Graphene oxide-Polyethylene Glycol mono-4-nonylphenyl Ether adsorbent for solid phase extraction of Pb2+ in blood and water samples.

Abstract

A novel and efficient Graphene Oxide-Polyethylene Glycol mono-4-nonylphenyl Ether (GO-PEGPE) nanocomposite was synthesized and used for solid phase extraction of trace levels of Pb2+ in different water and blood samples. The synthesized adsorbent was then characterized by the Fourier Transform-Infrared spectrophotometry (FT-IR), Field Emission-Scanning Electron Microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction analysis (XRD). To optimize the critical parameters including pH of samples solution, amounts of adsorbent and extraction time, the response surface methodology based on the central composite design (RSM-CCD) was used and based on the results, pH = 6.0, extraction time = 22min and amounts of adsorbent = 15mg were selected as the optimum conditions. The relative standard deviation based on seven replicate analysis of 2µg L-1 Pb2+ was 5.2% and the limit of detection was 0.023µg L-1 (n = 8). The results of adsorption isotherm investigation show that the adsorption of Pb2+ onto the GO-PEGPE nanocomposite obeyed by the Langmuir isotherm with the maximum adsorption capacity of 69.44mgg-1. Also, based on the Temkin and Dubinin-Radushkevich (DR) isotherms, the adsorption of Pb2+ onto the GO-PEGPE nanocomposite is a physisorption phenomenon and the consequences of the kinetic models illustrated that the adsorption of Pb2+ followed by the pseudo second order adsorption kinetic model. Finally, the proposed method was successfully applied for preconcentration of Pb2+ in different water and blood samples of turning industry workers.