Development and Application of Graphene Oxide/Poly-Amidoamines Dendrimers (GO/PAMAMs) Nano-Composite for Nitrate Removal from Aqueous Solutions

Graphene Oxide/Poly-Amidoamines Dendrimers (GO/PAMAMs) nano-composite was synthesized and activated by hydrochloride acid. It was then used for nitrate removal from aqueous solutions as a novel method. Experiments were conducted in batch mode. The prepared adsorbent was analyzed by Field Emission Scanning Electron Microscopy (FE-SEM) with Energy-dispersive X-ray spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and X-ray Diffraction (XRD). Additionally, adsorption isotherms and kinetic studies were investigated. Ninety percent of the nitrate was removed at pH 7.5, adsorbent 0.025 g L-1, 45 mg L-1 initial nitrate concentration and 15 min reaction time. Oxygen and chloride of activated GO/PAMAMs (A GO/PAMAMs) were approximately 19.1-21.6% and 0.4% in mass, respectively. Thermal stability of A GO/PAMAMs was more than that of Graphene Oxide (GO). Pseudo-second order kinetic model and Freundlich isotherm fitted the data well. Ion exchange between nitrate and chloride was the main mechanism of nitrate removal. The advantages of this technology include high removal efficiency, good adsorbability, good recyclability and non-toxic technology. This method can be used as a suitable method for in situ treatment of nitrate from aqueous solutions.