Fabrication and prospective applications of graphene oxide-modified nanocomposites for wastewater remediation

Abstract

Water bodies have become polluted with heavy metals and hazardous contaminants as a result of fast development. Many strategies have been devised by researchers in order to remove hazardous contaminants from the aquatic environment. Utilizing graphene oxide-based composite materials as efficient adsorbents for waste water treatment, desalination, separation, and purification is gaining attraction nowadays. Some of their defining properties are high mechanical strength, hydrophilicity, remarkable flexibility, ease of synthesis, atomic thickness, and compatibility with other materials. In water treatment, high separation performance and stable graphene-based laminar structures have been the main goals. Magnetic separation is among the methods which received a lot of attention from researchers since it has been shown to be quite effective at removing harmful pollutants from aqueous solution. Graphene oxide-modified nanocomposites have provided optimal performance in water purification. This review article focusses on the fabrication of GO, rGO and MGO nanocomposites as well as the primary characterization tools needed to assess the physiochemical and structural properties of graphene-based nanocomposites. It also discusses the approaches for exploiting graphene oxide (GO), reduced graphene (rGO), and magnetic graphene oxide (MGO) to eliminate contaminants for long-term purification of water. The potential research hurdles for using fabricated MGOs as an adsorbent to remediate water contaminants like hazardous metals, radioactive metal ions, pigments, dyes, and agricultural pollutants are also highlighted.

Fig. 1. (a) Structure of graphene (b) structure of single, double and multi-walled carbon nanotubes.

Fig. 2. Graphene-based materials.

Fig. 3. Nano porous graphene membrane.

Fig. 4. Synthesis of graphene oxide.

Fig. 5. Filtration mechanism.

Fig. 6. Desalination across a graphene oxide membrane via direct contact membrane distillation.

Fig. 7. Synthesis of reduced graphene oxide.

Fig. 8. SEM image of graphene oxide (GO) nanosheets. This figure has been adapted/reproduced from ref. with permission from Elsevier, copyright 2020.

Fig. 9. Raman spectra of graphene oxide (GO), and reduced graphene oxide (rGO). This figure has been adapted/reproduced from ref. with permission from American Institute of Physics, copyright 2017.

Fig. 10. Fourier transform infrared (FT-IR) spectrum for MGO before and after adsorption. This figure has been adapted/reproduced from ref. with permission from Taylor & Francis, copyright 2019.

Fig. 11. UV-Vis absorption spectra of graphene oxide (GO), and reduced graphene oxide (rGO). This figure has been adapted/reproduced from ref. with permission from Elsevier, copyright 2019.

Fig. 12. X-ray diffraction patterns of (a) graphene oxide (GO), (b) reduced graphene oxide (rGO). This figure has been adapted/reproduced from ref. with permission from Elsevier, copyright 2013.

Fig. 13. XPS spectra of (a) before and (b) after adsorption of Pb(ii) onto β-cyclodextrin enhanced GO. This figure has been adapted/reproduced from ref. with permission from Elsevier, copyright 2020.