Removal of Organics from Landfill Leachate by Heterogeneous Fenton-like Oxidation over Copper-Based Catalyst

Abstract

Landfill leachates are a mixture of high concentration organic and inorganic contaminants and need to be appropriately treated due to their toxicity and severe adverse effects on the environment. Here, we studied the treatment of landfill leachate through a heterogeneous Fenton-like oxidation process using a zirconia supported copper catalyst (Cu/ZrO2). Reaction conditions such as pH, amount of catalyst, oxidant dose, temperature, and reaction time were investigated and their effects on pollutant abatement discussed. AOS (average oxidation state) and COS (carbon oxidation state) parameters were used for the evaluation of the degree of oxidation of the process, obtaining some insight into the formation of oxidized intermediates (partial oxidation) and the total oxidation (mineralization) of the leachate during the reaction. A two-step oxidation process enhanced the overall performance of the reaction with an abatement of organic compounds of 92% confirming the promising activity of a copper-based catalyst for the treatment of liquid waste. Higher catalytic activity was achieved when the following reaction conditions were applied: 70 °C, pH 5, 200 mg/L of catalyst, 30 mL/L of H2O2 dose, and 150 min. In addition, durability of the catalyst under optimized reaction conditions was verified by repeated reaction cycles.

Abatement of the ecotoxicological risk of landfill leachate by heterogeneous Fenton-like oxidation

“…TDOC indicates the degree of mineralization (complete conversion to CO 2 and H 2 O), while COD is related to the degree of oxidation (degradation of organic compounds into more oxidized molecules). The treatment results in a similar abatement in TDOC and COD of around 65%, (COD/TOC ≈ 1) indicating that a strong mineralization occurs during the treatment (Hussain et al 2022 ). The degradation of the organics in the leachate is very fast, and the higher abatement is achieved in 30 min.…”

“…The surface area is 55 m 2 /g, the material is composed of tetragonal and monoclinic zirconia and copper is homogeneously dispersed on the surface of the support. The landfill leachate used in the study is in its intermediate phase, and it is characterized by an initial COD of 8700 mg/L, TDOC of 970 mg/L, pH 8.5 and a low concentration of heavy metal ions (Hussain et al 2022 ).…”

“…A heterogeneous Fenton process, generally referred to as Fenton-like process, remains the most viable solution for the treatment of liquid waste (Jain et al 2018;Molina et al 2020;Nidheesh 2015;Zhu et al 2019). Recently, in our laboratories we have developed a series of zirconia supported catalysts that have shown promising performance in the treatment of model aqueous solutions of ibuprofen (Hussain et al 2020(Hussain et al , 2021 and in the treatment of landfill leachate (Hussain et al 2022). Here, on the basis of previous studies, we have selected a copper supported on zirconia catalyst for leachate treatment with the aim of investigating a simple approach and methodology to monitor the ecotoxicological risk reduction in landfill leachate after treatment with heterogeneous Fenton-like oxidation.…”

Electro - Fenton processes for Landfill leachate treatment using different electrode materials

“…Initially the COD removal can be seen but after 30 minutes the removal was decreasing for different current densities. This may be due to formation of intermediates [21]. But again, removal noticed after reaction time of 60 minutes due to subsequent degradation of intermediates.…”

Zeolite and Activated Carbon as Catalysts on Leachate Clarification

“…Indeed, the biological process might be inhibited by heavy metals like lead, nickel, chromium, silver, cadmium, barium, and mercury (Wijekoon et al, 2022). Despite this, diverse technologies have been developed at the lab scale with important results: adsorption, chemical precipitation, electrocoagulation, ultrasonication, electrochemical advanced oxidation processes like electrochemical oxidation, electro-Fenton, and sono-electro-Fenton processes (Aziz et al, 2007;Zhang et al, 2012;Asaithambi et al, 2020;Kundariya et al, 2021;Dereli et al, 2021;Hussain et al, 2022).…”