Competitive Removal of Cationic Pollutants Using GO and GO-NH2 Nano-adsorbents and Efficiency Comparison of Single and Binary Component Systems

Many industrial wastewater containing various cationic pollutants including heavy metals and organic dyes with non-degradable structures that are considered as a serious threat to public health and the environment. In this study, nano-absorbers including graphene oxide (GO) and graphene oxide modified with 3-aminopropyltriethoxysilane (GO-NH2) was successfully synthesized and characterized by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis. GO and GO-NH2 were applied to remove Pb2+ and Cd2+ metal ions, and methylene blue (MB) cationic dye from aqueous solution in single and binary component systems (Pb2+-Cd2+, Pb2+-MB, Cd2+-MB). In the single component system, the maximum absorption of 99%, 72.5% and 49.5% was obtained for MB, Cd2+ and Pb2+, respectively, by using GO. In the case of GO-NH2, maximum absorption of 90%, 73% and 35% was obtained for Pb2+, Cd2+ and MB, respectively, in single-component system. In the presence of MB dye, removal percentage of Pb2+ and Cd2+ showed a reduction of 10% compared to the single component system (Rq <1) by using GO. By using GO-NH2, in the metal-dye binary systems, the removal percentage of Pb2+ and Cd2+ showed a reduction of 15% and around zero, respectively, to the single component system. The adsorption rate of MB onto GO and Pb2+ onto GO-NH2 were in good agreement with pseudo-second order model (R2=99; k2=0.0002g mg-1 min-1, R2=95; k2=0.001g mg-1 min-1 respectively).