The impact of surface properties and dominant ions on the effectiveness of G-nZVI heterogeneous catalyst for environmental remediation

Abstract

The surface properties of nanocomposites are influenced by the existence of inorganic species that may affect its performance for specific catalytic applications. The impact of different ionic species on particular catalytic activity had not been investigated to date. In this study, the surface charge (zeta potential) of graphene-oxide-supported nano zero valent iron (G-nZVI) was tested in definitive cationic (Na + , K + , Ca 2+ and Mg 2+) and anionic (Br − , Cl − , NO 3 − , SO 4 2− , and HCO 3 −) environments. The efficiency of G-nZVI catalyst was inspected by measuring the generation of reactive oxygen species (ROS) for the degradation of 1,1,1-trichloroethane (TCA) in sodium percarbonate (SPC) system. Tests conducted using probe compounds confirmed the generation of OH • and O 2 •− radicals in the system. In addition, the experiments performed using scavenging agents certified that O 2 •− were primary radicals responsible for TCA removal, along with prominent contribution from OH • radicals. The study confirmed that G-nZVI catalytic capability for TCA degradation is notably affected by various cationic species. The presence of Ni 2+ and Cu 2+ significantly enhanced (94%), whereas Na + and K + had minor effects on TCA removal. Overall, the results indicated that groundwater ionic composition may have low impact on the effectiveness of G-nZVI-catalyzed peroxide TCA treatment.

Arsenic Adsorption on Nanoscale Zerovalent Iron Immobilized on Reduced Graphene Oxide (nZVI/rGO): Experimental and Theoretical Approaches

“…The point of zero charge (pH PZC ) for nZVI/rGO occurs at pH 6.5 (Figure ), which indicates that the surface of nZVI/rGO is positively charged below this pH value and negatively charged above pH 6.5. These data agree with similar systems in the literature. ,, …”

“…These data agree with similar systems in the literature. 57,95,96 According to the TEM images (Figure 1), the surface area of the nZVI/rGO material is predominantly associated with the rGO support, which should, thus, contribute more effectively for the surface-charge pH dependence observed for this material (Figure 3). GO may be represented as a single layer of graphite oxide heterogeneously decorated with functional groups, such as epoxide, carboxyl, and hydroxyl.…”

The development history and evolutionary trends of percarbonate: Bibliometric analysis from 2000 to 2022

“…58 Among them, transition metals (e.g., Fe 2+ , Ag + , Mn 2+ , Co 2+ , and Cu 2+ ) are used as homogeneous catalysts to activate percarbonate, which has the advantages of high reaction efficiency, mild experimental conditions, and without external assistance. 53 Heterogeneous catalysts can stabilize in the reaction system, are easy to separate and reuse, and can reduce secondary pollution, 59 for example, graphene-oxide-supported nano zero-valent iron composites, 60 zeolite supported nano zero valent iron copper bimetallic composites, 32 and ferrocene. 61 Although there are many methods to activate percarbonate, the appropriate activation method should be selected in practical application by considering efficiency, stability, economy, and environmental friendliness.…”