Water contamination by iodide has attracted much public attention in recent years due to its potential threat to the quality of drinking water. In this work, a reduced graphene oxide aerogel functionalized with Cu2O/Cu (Cu2O/Cu@RGO) was prepared and used as an adsorbent to selectively capture iodide from water. Experiments showed that solution pH exerted a major impact on iodide adsorption. Higher iodide removal rate was observed in the acidic and neutral pH range, while the adsorption process was substantially depressed when pH was above 7.5. At pH 6, the material achieved a maximum iodide adsorption capacity of 1178 mg/g. The material also had a fast kinetic in iodide capture. At a solid loading rate of 0.5 g/L, the material achieved 96% removal of iodide in 10 min, from a neutral solution containing 270 mg/L iodide. Water constituents commonly encountered in the environment such as SO42-, NO3-, HCO3- and humic acid had no obvious impact on iodide adsorption, except for chloride which inhibit the material’s adsorption capacity to 70% of the control at 30 g/L chloride concentration. An adsorption mechanism was proposed by analyzing the batch experimental data and characterization of the material by XRD and XPS. The existence of metallic Cu in the functionalized aerogel was found to be able to protect Cu2O from oxidation. At both acid and neutral solution pH, nano Cu2O particles immobilized on RGO interlayers sequestrated aqueous iodide through formation of CuI precipitate. At alkaline solution, CuI formation would be inhibited by competitive adsorption of hydroxide ions. This material would be potentially useful in treating iodide-contaminated water with complex water matrix, as impacted by wastewater that has extremely high salt concentrations generated from shale gas extraction.

Selective removal of iodide from water using reduced graphene oxide aerogel functionalized with Cu2O/Cu

2019 Spring National Meeting

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