A Highly Efficient Adsorbent Based on Starch-Graphene Oxide Architecture for Scavenging Aqueous Pb(II): Isotherms, Kinetics, Thermodynamics and Interaction Mechanism

Heavy metal pollution stems from the modern industry is a severe environmental problem. In this work, a highly efficient adsorbent based on starch-graphene oxide architecture (SGO) was fabricated, characterized and employed to scavenge aqueous Pb(II), a major water contaminant. The scavenging performance was evaluated, and the interaction mechanism between SGO and Pb(II) was elucidated. Results indicate, the starch introduction brought performance enhancement, consequently made SGO outperform either single starch or GO regarding adsorption efficiency. Specifically, SGO adsorbs 95.83% of Pb(II) in 16 min, with adsorption capacity 383.32 mgx2027;g(-1), manifesting some advantages over other analogous adsorbents, such as higher capacity and faster kinetics. The chemical interaction between Pb(OH)(+) and C = O, C-O related groups in SGO supported the adsorption, which was a spontaneous, exothermic and entropy increasing process. The adsorption was well described by the Freundlich, pseudo-second-order model and intra-particle diffusion models, adsorption rate simultaneously controlled by intra-particle diffusion and chemical interaction. Based on its high adsorption efficiency, SGO may have promising application in heavy metal scavenging from water.

Automated summary

A highly efficient adsorbent based on starch-graphene oxide architecture was fabricated to scavenge aqueous Pb(II), demonstrating excellent adsorption capacity and performance. The chemical interaction between SGO and Pb(II) supported the spontaneous and exothermic adsorption process.