Removal of metal ions and organics from real refinery wastewater using double- functionalized graphene oxide in alginate beads

The treatment of produced and refinery wastewaters is a challenging task in industries. In this study, for the first time, double-functionalized graphene oxide (GO) embedded in alginate biopolymer matrix (ffGOCA) was developed as an efficient, environmentally friendly adsorbent for the removal of toxic heavy metal ions, poly aromatic hydrocarbons (PAHs) and phenols from real refinery wastewater. The developed ffGOCA beads showed superior adsorption performance due to synergetic effects between the beads and two multi-functional polymers. The adsorption capacity and efficiency of the synthesized ffGOCA were studied by various kinetic and thermodynamic models. Pseudo-second-order and Langmuir models well represented the kinetic and equilibrium data, respectively. The maximum adsorption capacity of the ffGOCA beads at pH of 7 and 298 K was found to be 116.7 mg/g for naphthalene, 111.1 mg/g for phenol, 105.2 mg/g for p-cresol, 102.04 mg/g for fluorene, 588.2 mg/g for Pb, 434.7 mg/g for Hg and 476.19 mg/g for Cd. The adsorption performance of the ffGOCA was successfully maintained for 6 consecutive cycles. The developed environmentally friendly ffGOCA adsorbent exhibited significant potential for the removal of organic and inorganic pollutants from real refinery wastewater.