Role of Adsorptive Concentration in Fenton‐Like Degradation of Organic Pollutants by Biopolymeric FeOOH/Graphene Oxide Composite Catalyst: Proof of Concept

Abstract

Despite advances in adsorption chemistry to mitigate water contaminants, the intact nature of contaminants after adsorption limits the technique's wide application. Here, a nanostructured material is engineered and a conceptual study developed—adsorption‐coupled Fenton‐like reaction (ACFLR)—and it is shown that adsorptive concentration of a pollutant on an adsorbent favors Fenton‐like degradation. Sodium alginate (SAG) is introduced as a soft‐gelling template for in situ generation of FeOOH, which stabilizes graphene oxide (GO) nanosheets (SAG‐FeOOH/GO) to yield active Fenton‐like catalytic adsorptive sites. The catalyst architecture—the biopolymer‐functionalized FeOOH‐supporting GO nanosheets—are responsible for the ACFLR. Methylene blue (MB) is concentrated on SAG‐FeOOH/GO via electrostatic and pi–pi interactions and these interactions are responsible for the adsorptive removal of MB. After adsorptive concentration of MB on the surface of SAG‐FeOOH/GO, the proximity of Fenton‐like catalytic sites enhances the efficient use of the short‐lived reactive oxygen species compared to that of the MB in bulk solution (nonadsorbed MB) for efficient Fenton‐like reactions. The role of adsorption during the Fenton‐like reaction is proved by the structural degradation of MB by the concentrated MB on SAG‐FeOOH/GO under Fenton‐like conditions followed by desorption, which gives the concentration of degraded MB after the step‐wise action of adsorption and Fenton‐like degradation.

Green Coffee Bean Extract Assisted Facile Synthesis of Reduced Graphene Oxide and Its Dye Removal Activity

“…[38,[40][41][42] Although desorption is one of the major obstacles, the adsorption of MB onto graphene derivatives has been extensively documented in the literature. [21,[43][44][45][46] Therefore, in this study, we illustrate a simple and ecofriendly synthetic protocol of rGO by optimizing the synthetic conditions using green coffee bean as a prominent plant source, where its aqueous extract will be employed as an efficient and sustainable reducing source for the reduction of GO and utilization of the synthesized rGO as a prospective adsorbent to remove MB as one of the model dye.…”

“…[ 38,40–42 ] Although desorption is one of the major obstacles, the adsorption of MB onto graphene derivatives has been extensively documented in the literature. [ 21,43–46 ]…”