Green fabrication of SH-modified GO composite for heavy metal ions removal in aqueous solution

Humic acid (HA) sodium salt (SH)-modified graphene oxide (GO) composite, which could snatch Pb (II), Cd (II) and Cu (II) effectively from aqueous solution, was fabricated by a green hydrothermal method. Here, the morphology and structure of as-synthesised SH–GO composite was presented through scanning electron microscopy, Roman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis. Owing to the introduction of cheap and readily available HA sodium salt, the adsorption capacity of SH–GO toward heavy metals was improved obviously, and the corresponding removal behaviours were further investigated in detail. Besides, the adsorption results were in good agreement with Langmuir isotherm and the pseudo-second kinetic model, where the thermodynamic parameters revealed the adsorption process was spontaneous and endothermic in essence. Adsorption–desorption result showing its stable adsorption capacity confirmed its great potential as adsorbent for removal of heavy metal ions from aqueous solution.