Heterogeneous Photo-Fenton Reaction for Olive Mill Wastewater Treatment—Case of Reusable Catalyst

Abstract

Heterogeneous catalysts can be an efficient and economical option for olive mill wastewater (OMW) treatment by an advanced oxidation process if they could be reused. In this work, OMW was treated using a heterogeneous photo-Fenton reaction (artificial ultraviolet light/H2O2/HFeO2). For this purpose, different concentrations of HFeO2 were tested: 0.04; 0.3; 0.8; 5.0; 10.0; 20.0; 30.0, and 50.0 g/L. The following operational conditions were chosen: pH = 3.0, temperature = 20 °C, agitation rate = 700 rpm. The experimental results showed high removal percentages of the main OMW characterization parameters at 50 g/L of HFeO2: %CODremoval = 62.8%; %total phenolic compounds (TPCs) = 88.9%. These results were also compared with those of other control oxidation systems, i.e., UV, H2O2, and UV/H2O2, which provided 35.5 and 56.1%; 46.2 and 74.0%; 48.0 and 76.8% removal, respectively. In addition, the catalyst was reused three times, recovering more than 90.5% of it.

Recovery of Hydroxytyrosol from Olive Mill Wastewater Using the Promiscuous Hydrolase/Acyltransferase PestE

“…[4][5][6][7][8] Several methods have been developed to facilitate the degradation or extraction of phenolic compounds, such as chemical oxidation, solvent extraction, membrane systems or adsorbents. [9][10][11][12][13][14][15][16][17][18][19][20] However, all these systems require several laborious steps. In the case of solvent extraction, several extraction steps are required due to the hydrophilic nature of the contained phenols, e. g., the major phenolic compound 3hydroxytyrosol (HT).…”

“…The phenols of olives have several health‐promoting properties, e. g., neuroprotective, which are associated with their antioxidant and anti‐inflammatory benefits [4–8] . Several methods have been developed to facilitate the degradation or extraction of phenolic compounds, such as chemical oxidation, solvent extraction, membrane systems or adsorbents [9–20] . However, all these systems require several laborious steps.…”

An Enzyme Cascade Reaction for the Recovery of Hydroxytyrosol Dervatives from Olive Mill Wastewater

“…More than half of the total phenols are disposed of with the olive mill wastewater (OMWW), which therefore has phytotoxic and antimicrobial properties and requires special treatment to degrade the organic matter [2,3]. While various methods such as chemical oxidation, solvent extraction, membrane systems, or adsorbents have been investigated for phenol removal, open pond treatment is still widely used [4][5][6][7][8][9][10]. Recently, our group developed a system for the lipophilization and recovery of the main phenol 3-hydroxytyrosol (HT) in a biphasic ethyl acetate/ OMWW system using an engineered variant of the promiscuous hydrolase/acyltransferase from the hyperthermophilic archaeum Pyrobaculum calidifontis VA1 (PestE) [11].…”

Advanced oxidation processes for the degradation of microplastics from the environment: A review

“…In the conventional Fenton process, the removal of dissolved iron from the treated water is the main challenge that could be resolved by the utilization of heterogeneous catalysts (Hussain, Aneggi, & Goi, 2021). Heterogeneous catalysts in Fenton processes get separated effectually from water and can function in a wide range of pH (Agabo‐García, Calderón, & Hodaifa, 2021). Catalytic Fenton reaction happens at the reactive site of the solid catalyst, thereby avoiding iron leaching and the consequent production of iron sludge at wider pH (Mazivila et al, 2019).…”