The Use of Magnetic Multiwalled Carbon Nanotubes Functionalized with Chitosan for Nitrate Removal from Wastewater

Abstract

In latest years, industrial development, intended using agricultural fertilizers and inappropriate treatment of wastewater have risen poisonous contaminants like metal ions, organic and inorganic ions such as nitrate in water and soil. The adsorption which consists of multiwall carbon nanotubes (MWCNTs) functionalized with chitosan have been synthesized in a composite to produce a magnetic adsorbent. Composites of MWCNT/nano-iron oxide were characterized by Transmission Electron Micrograph, Vibrating Sample Magnetometry, Thermogravimetric analysis and Fourier transform infrared spectroscopy. To investigate the adsorption efficiency for the adsorption of nitrate onto magnetic multiwalled carbon nanotubes functionalized with chitosan, the effect of solution conditions on each adsorption process were studied. These conditions involve the effect of contact time, pH value, temperature, adsorbent dose and the initial concentration of adsorbate. The best equilibrium isotherm model for each adsorption process was studied and the results showed the data follows Langmuir adsorption model with capacity (qm) more than 322 (mg/g). The kinetics of adsorption was also investigated, and the data were best fitted to pseudo-second order. In addition, Van’t Hoff plot was used to measure thermodynamics parameters to study the adsorption process which showed the spontaneous process. The synthesized adsorbent was also regenerated, and the percentage removal before and after adsorbent recovery was determined and showed high-efficiency removal. In conclusion, results showed that the resulting product has high adsorption efficiency and it showed strong complexation properties with nitrate ions.