Work

Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study

Year: 2025

Type: article

Abstract: Ferrous oxalate dihydrate (α-FOD) was synthesized from Ecuadorian black sands for phenol removal from aqueous solutions. Visible light-driven photodegradation kinetics were studied by varying the initial pollutant concentration, solution pH, and α-FOD dosage and by adding peroxydisulfate (PDS), including quenching tests. A representative model of phenol photodegradation was obtained by the Langmuir–Hinshelwood mechanism over a large range of concentrations (apparent kinetic constant, k = 0.524 h−1). Almost complete removal was reached within 1 h under dark + 9 h under visible irradiation. The degradation rate was slightly affected by pH in the range of 3 to 9, with a significant improvement at pH 11 (k = 1.41-fold higher). The optimal α-FOD dosage was ~0.5 g/L. Two regimes were observed when using PDS: first, a heterogeneous Fenton-like process during the first few minutes after PDS addition; second, pure photocatalysis to completely remove the phenol. When comparing the two systems, without and with PDS, the half-life time for pure photocatalysis was 2.5 h (after the lamp was switched on). When adding PDS (1.0 mM), the half-life time was reduced to a few minutes (5 min after PDS addition, phenol removal was 66%). The photocatalyst presented remarkable degradation efficiency up to five repeated cycles.

Source: Molecules

DOI: 10.3390/molecules30092059

Authors: Salomé Galeas, Víctor H. Guerrero, Patricia I. Pontón, Vincent Goetz

Institutions: Centre National de la Recherche Scientifique, Université de Perpignan, Laboratoire Procédés, Matériaux et Energie Solaire, National Polytechnic School

Language: English

Topic: Advanced oxidation water treatment

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $3,258