The removal of non-steroidal anti-inflammatory drug naproxen in tap water by hydroxyl radicals (▪OH ) formed by electro-Fenton process was conducted either with Pt or DD anodes and a 3D carbon felt cathode. 0.1 mM ferrous ion was proved to be the optimized dose to reach the best naproxen removal rate in electro-Fenton process. Both degradation and mineralization rate increased with increasing applied current intensity. The degradation of naproxen by ▪OH vs. electrolysis time was well fitted to a pseudo–first–order reaction kinetic. An almost complete mineralization was achieved under optimal catalyst concentration and applied current values. Considering efficiency of degradation and mineralization of naproxen, electro-Fenton process with DD anode exhibited better performance than that of Pt anode. The absolute rate constant of the second order kinetic of the reaction between naproxen and ▪OH was evaluated by competition kinetics method and the value (3.67 ± 0.3) × 10λ M-1·s-1 was obtained. Identification and evolution of the intermediates, as aromatic compounds and carboxylic acids, were deeply investigated, leading to the proposition of oxidation pathway for naproxen. The evolution of the degradation products and solution toxicity were determined by monitoring the luminescence of bacteria Vibrio fischeri (Microtox method).
Table of Contents
1. Introduction
2. Review of Literature
2.1 Advanced Oxidation Processes
2.2 Electro-Fenton Process
2.3 Fenton Reagent
2.4 Fundamentals of Electro – Fenton Process
2.5 Pharmaceuticals
2.6 Naproxen Sodium
3. Degradation of Nonsteroidal Anti-Inflammatory Drug Naproxen by Electro-Fenton Process
3.1 Materials
3.2 Electrolytic systems
3.3 Apparatus and analytical procedures
3.4 Electro – Fenton Process
4. Results and discussion
4.1 Influence of iron concentration on naproxen electro-Fenton removal
5. Conclusions
Research Objectives and Core Themes
This research aims to investigate the degradation of the non-steroidal anti-inflammatory drug (NSAID) Naproxen in aqueous solutions using the electro-Fenton process. The study evaluates optimal operational parameters, such as catalyst concentrations and the influence of different anode materials, to achieve efficient removal and mineralization of this emerging environmental contaminant.
- Evaluation of the electro-Fenton process for pharmaceutical degradation.
- Optimization of iron catalyst dosage for naproxen removal efficiency.
- Comparative analysis of Pt and DD anode performance in pollutant mineralization.
- Assessment of oxidation pathways and toxicity evolution of degradation by-products.
Excerpt from the Book
Influence of iron concentration on naproxen electro-Fenton removal
Catalyst concentration is an important parameter in the EF processes which is strongly influencing organic pollutants removal efficiency [43 . The electro-Fenton experiments at a low current intensity (i.e. 100 mA) with Pt/carbon felt cell (EF-Pt) were performed with 45.6 mg L-1 naproxen solution (0.1λ8 mM), in order to determinethe optimal catalyst concentrations for naproxen degradation by EF process.
The degradation curves of naproxen by OH within electrolysis time followed pseudo-first-order reaction kinetics, whose rate expression can be given by the following [45 μ Ln (C0/Ct) = kapp t (4.7) which kapp is apparent (pseudo-first-order) rate constant, and C0 and Ct are the concentrations of naproxen at the beginning and at the given time t, respectively.
Table 4.2 shows the apparent rate constants (kapp) of naproxen at various Fe2+concentrations. The degradation curves (data not shown) were fitting well as showed by the R-squared values above 0.λ87. The apparent rate constants reported in Table 4.2 shows that ferrous ion concentration significantly influenced the removal rate of naproxen by electro-Fenton treatment. A ferrous ion concentration of 0.1 mM shows the highest kapp value followed by that of 0.05 mM and 0.2 mM. However, higher ferrous ion concentrations (i.e. 0.5 mM and 1 mM) displayed lower kapp value, which means that the naproxen removal rate decreased with increasing ferrous ion concentration from 0.2 to 1 mM.
Summary of Chapters
1. Introduction: Discusses the environmental concerns regarding pharmaceutical pollutants in aquatic systems and the limitations of conventional wastewater treatment plants.
2. Review of Literature: Provides a theoretical background on Advanced Oxidation Processes, the Fenton mechanism, and the characteristics of Naproxen as a persistent micro-pollutant.
3. Degradation of Nonsteroidal Anti-Inflammatory Drug Naproxen by Electro-Fenton Process: Details the experimental methodology, including materials, electrolytic cell setup, and analytical procedures for monitoring degradation.
4. Results and discussion: Analyzes the experimental data, specifically focusing on how ferrous ion concentrations affect the kinetics and removal efficiency of Naproxen.
5. Conclusions: Summarizes the study's findings, highlighting that the electro-Fenton process is an effective, environmentally friendly technology for eliminating Naproxen.
Keywords
Naproxen, Electro-Fenton, BDD Anode, Degradation Pathways, By-Products, Toxicity, Wastewater Treatment, Advanced Oxidation Processes, Pharmaceuticals, Micro-pollutants, Iron Catalyst, Mineralization, Environmental Engineering, Kinetic Studies
Frequently Asked Questions
What is the primary objective of this research?
The research focuses on the effective removal of the pharmaceutical pollutant Naproxen from water using the electro-Fenton process and determining the optimal parameters for this degradation.
Which scientific method is employed in this study?
The study utilizes the electro-Fenton process, which is an electrochemical advanced oxidation method, to generate hydroxyl radicals for the mineralization of organic pollutants.
What are the main thematic fields covered?
The work covers environmental water pollution, advanced oxidation technologies, pharmaceutical chemistry, and the kinetics of pollutant degradation.
What is covered in the main section of the paper?
The main section covers the experimental design, the influence of catalyst concentrations on reaction kinetics, and the identification of oxidation pathways and toxicity reduction.
Why are pharmaceutical pollutants a concern?
Pharmaceuticals are resistant to conventional degradation, and their continuous release into water bodies leads to unknown environmental risks and negative impacts on aquatic biota.
Which keywords best characterize this work?
Key terms include Naproxen, Electro-Fenton, BDD Anode, Degradation Pathways, By-products, Toxicity, and Mineralization.
How does the catalyst concentration affect Naproxen removal?
The study found that an optimal ferrous ion concentration of 0.1 mM provides the best removal rate, as excessive iron can lead to the scavenging of hydroxyl radicals, reducing overall efficiency.
How is the toxicity of treated solutions determined?
Toxicity is monitored using the Microtox method, which measures the luminescence inhibition of the marine bacterium Vibrio fischeri after exposure to the treated solutions.
What advantage does the DD anode offer?
The experimental results indicated that the DD anode exhibits better performance than the Pt anode, due to its capacity for generating additional hydroxyl radicals and higher overall mineralization power.
- Arbeit zitieren
- Chemical Engineer Jeremy Allan Bartolo (Autor:in), 2015, Degradation of NSAID Naproxen in Wastewater by Electro-Fenton, München, GRIN Verlag, https://www.grin.com/document/507970
