Removal and Extraction of Para-Nitrophenol from Aqueous Samples Using Graphene Magnetic Nanocomposite

Graphene magnetic nanocomposite was synthesized and characterized for surface morphology, functional groups and thermal stability using scanning electron microscopy, Fourier transformed infrared spectrometry and thermogravimetric analysis. The composite was investigated for the extraction and removal of p-nitrophenol from aqueous samples. Different experimental factors such as pH, composite dose, time, temperature and concentration of p-nitrophenol were studied for the removal. At pH 4, p-nitrophenol removal efficiency was high and then decreased with increase in pH up to 10. The removal of p-nitrophenol was high with 60 min time and the % sorption remained constant up to 90 min. Experimental data of kinetic models were explained best by the pseudo-second-order kinetic model with sorption capacity and correlation coefficient values of 45.87 mg/g and 0.9998, respectively. The isotherm data followed Langmuir isotherm with correlation coefficient of 0.9903 and sorption capacity (Q∘)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(\hbox {Q}_{{{\circ }}})$$\end{document} of 500 mg/g. The sorption of p-nitrophenol was found exothermic in nature and physisorption process involved in the sorption of p-nitrophenol on graphene magnetic nanocomposite. Electron donor–acceptor and hydrogen-bonding interactions were the mechanism involved in sorption. The results revealed that graphene magnetic nanocomposite has faster rate of removal of p-nitrophenol and can be used as a sorbent.