Highly efficient surface sequestration of Pb and Cr from water using a MnO anchored reduced graphene oxide: Selective removal of Pb from real water.

Owing to the ubiquitous existence of detrimental heavy metals in the environment, simple adsorption-oriented approaches are becoming increasingly appealing for the effective removal of Pb and Cr from water bodies. These techniques use nanocomposites (NC) of reduced graphene oxide (rGO) and MnO (rGO-MnO), they employ a hydrothermal technique featuring NaBH and NaOH solutions. Here, spectroscopic and microscopic instrumental techniques were used to evaluate the morphological and physicochemical characteristics of prepared reduced graphene oxide manganese oxide (rGO-MnO), revealing that it possessed a well-defined porous structure with a specific surface area of 126 m g. The prepared rGO-MnO had significant adsorption efficiencies for Pb and Cr, achieving maximum sequestration capacities of 130.28 and 138.51 mg g for Pb and Cr, respectively, according to the Langmuir model. These adsorption capacities are comparable to or greater than those of previously reported graphene-based materials. The Langmuir isotherm and pseudo-second-order models adequately represented the experimental results. Thermodynamic analysis revealed that adsorption occurred through spontaneous endothermic reactions. Recycling studies showed that the developed r-GO-MnO had excellent recyclability, with <70% removal at the 5th cycle; its feasibility was evaluated using industrial wastewater, suggesting that Pb was selectively removed from Pb and Cr contaminated water. The instrumental analysis and surface phenomena studies presented here revealed that the adsorptive removal processes of both heavy metals involved π electron donor-acceptor interactions, ion exchange, and electrostatic interactions, along with surface complexation. Overall, the developed rGO-MnO has the potential to be a high-value adsorbent for removing heavy metals.