Synergistic effects of graphene oxide grafted with barbituric acid nanocomposite for removal of heavy metals from aqueous solution

Abstract

Graphene oxide (GO) was chemically modified (MGO) by reaction with tetraethyl orthosilicate and barbituric acid to obtain its modified form. The chemical structures of GO and its modified form were established using XRD, FTIR, SEM, and BET (N2-adsorption/desorption) analysis. The prepared GO and MGO were evaluated as efficient metal ions adsorbents during the remediation of copper and iron ions in wastewater. The parameters controlling the adsorption process were examined including: the mass of adsorbents, pH of the medium, and concentration of ionic species, temperature, and process time. The results revealed that the maximum adsorption capacities of Cu(II) and Fe(III)metal ions were GO's 19.99 and 21.6 mg/g, compared to MGO at 24.1 mg/g and 25.13 mg/g, receptively. After 105 min in a solution pH = 6 at 25 °C, using 0.35 g/L of the adsorbent. Additional increase in contact time did not show considerable change in equilibrium concentration. That indicates to the adsorption stage reach equilibrium. The adsorption isotherms could be fitted well by the Langmuir model referring to correlation factor around 1, indicating that the adsorption of the metal ion onto GO and MGO is favorable. DFT study described the increasing in the adsorption efficiency of the MGO.