Unveiling the catalytic ability of carbonaceous materials in Fenton-like reaction by controlled-release CaO2 nanoparticles for trichloroethylene degradation

Highlights: • Various CMs as catalysts were investigated in Fe(III) activated PVA@nCP reaction for TCE removal. • Besides adsorption, BC and AC degraded 66.2% and 65.2% TCE by catalytic mechanism. • Fe(II) generation on CMs-surface contributed to TCE degradation via active radicals. • XPS, FTIR, and quenching tests unveiled the catalytic-degradation routes of TCE. • The suggested techniques anticipated a new direction towards green environmental remediation for prolonged benefits. Carbonaceous materials (CMs) have been applied extensively for enhancing the catalytic performance of environmental catalysts, however, the self-catalytic mechanism of CMs for groundwater remediation is rarely investigated. Herein, we unveiled the catalytic ability of various CMs via Fe(III) reduction through polyvinyl alcohol-coated calcium peroxide nanoparticles (PVA@nCP) for trichloroethylene (TCE) removal. Among selected CMs (graphite (G), biochar (BC) and activated carbon (AC)), BC and AC showed enhancement of TCE removal of 89% and 98% via both adsorption and catalytic degradation. BET and SEM analyses showed a higher adsorption capacity of AC (27.8%) than others. The generation of solution-Fe(II) and surface-Fe(II) revealed the reduction of Fe(III) on CMs-surface. The role of O-containing groups was investigated by the FTIR technique and XPS quantified the 52% and 57% surface-Fe(II) in BC and AC systems, respectively. EPR and quenching tests confirmed that both solution and surface-bound species (HO• , O₂⁻• and ¹O₂) contributed to TCE degradation. Acidic pH condition encouraged TCE removal and the presence of HCO₃⁻ negatively affected TCE removal than other inorganic ions. Both schemes (PVA@nCP/Fe(III)/BC and PVA@nCP/Fe(III)/AC) exhibited promising results in the actual groundwater, surfactant-amended solution, and removal of other chlorinated-pollutants, opening a new direction towards green environmental remediation for prolonged benefits.