Heterogeneous Fenton oxidation of ofloxacin drug by iron alginate support

Polymer-Supported Heterogeneous Fenton Catalysts for the Environmental Remediation of Wastewater

Materials based on polymer hydrogels have demonstrated potential as innovative Fenton catalysts for treating water. However, developing these polymer-supported catalysts with robust stability presents a significant challenge. This paper explores the development and application of polymer-supported heterogeneous Fenton catalysts for the environmental remediation of wastewater, emphasizing the enhancement of metal incorporation into catalysts for improved efficiency. The study begins with an introduction to the heterogeneous Fenton process and its relevance to wastewater treatment. It further delves into the specifics of polymer-supported heterogeneous Fenton catalysts, focusing on iron oxide, copper complexes/nanoparticles, and ruthenium as key components. The synthesis methods employed to prepare these catalysts are discussed, highlighting the innovative approaches to achieve substantial metal incorporation. Operational parameters such as catalyst dosage, pollutant concentration, and the effect of pH on the process efficiency are thoroughly examined. The catalytic performance is evaluated, providing insights into the effectiveness of these catalysts in degrading pollutants. Recent developments in the field are reviewed, showcasing advancements in catalyst design and application. The study also addresses the stability and reusability of polymer-supported heterogeneous Fenton catalysts, critical factors for their practical application in environmental remediation. Environmental applications are explored, demonstrating the potential of these catalysts in addressing various pollutants. The Conclusions offers future perspectives, underlining the ongoing challenges and opportunities in the field, and the importance of further research to enhance the efficacy and sustainability of polymer-supported heterogeneous Fenton catalysts for wastewater treatment.

Recent progress in mineralization of emerging contaminants by advanced oxidation process: A review

Emerging contaminants are chemicals generated due to the usage of pesticide, endocrine disrupting compounds, pharmaceuticals, and personal care products and are liberated into the environment in trace quantities. The emerging contaminants eventually become a greater menace to living beings owing to their wide range and inhibitory action. To diminish these emerging contaminants from the environment, an Advanced Oxidation Process was considered as an efficient option. The Advanced Oxidation Process is an efficient method for mineralizing fractional or generous contaminants due to the generation of reactive species. The primary aim of this review paper is to provide a thorough knowledge on different Advanced Oxidation Process methods and to assess their mineralization efficacy of emerging contaminants. This study indicates the need for an integrated process for enhancing the treatment efficiency and overcoming the drawbacks of the individual Advanced Oxidation Process. Further, its application concerning technical and economic aspects is reviewed. Until now, most of the studies have been based on lab or pilot scale and do not represent the actual scenario of the emerging contaminant mineralization. Thus, the scaling up of the process was discussed, and the major challenges in large scale implementation were pointed out.

Pattern, Forms and Bibliometric Analysis for Systematic Study of Silica-Supported Heterogeneous Solar Photocatalyst for Lannate Insecticide Abatement from Aqueous Stream

Agro-industrial streams with high toxic loadings must undergo for treatment prior to final disposal. Thus, the current investigation aimed to apply cheap and naturally available materials to explore sustainable heterogeneous solar/Fenton reaction for insecticide abatement form waste streams. Iron was collected from the wastewater stream after coal industry. The sand pellets were used as iron support material which acts as a heterogeneous solar photo-catalyst like modified Fenton reaction. The prepared catalysts were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM) for characterization. System parameters variables were studied using the modified catalysts. Although the acidic pH showed maximal removal efficiency, the catalyst could also work at a wide pH range with a reduced activity. The optimum conditions of the newly synthesized modified Fenton composite showed 103, 45 mg/L for H2O2 and catalyst, respectively, at pH 2.8 within 90 min under solar irradiation for maximal Lannate oxidation reached to 98%. Moreover, the increase in Lannate concentration loading results in a reduction in the removal efficiency from 98 to 96% when the Lannate loading increased from 10 to 50 ppm, although further increase of Lannate (100 ppm) results in only 2% removal. Also, temperature effect was displayed and the high temperature range was unfavorable. The kinetics of Lannate removal was dependent on operation temperature and following the first-order kinetic model. The thermodynamic parameters values settled the system is non-spontaneous in nature, proceeds in endothermic circumstances and working in a low energy barrier (34.54 kJ mol−1). Recyclability confirms the sustainability of the catalyst, and the third cycle catalytic use attained 28% Lannate removal.

Heterogeneous Advanced Oxidation Processes: Current Approaches for Wastewater Treatment

Nowadays, water pollution is one of the most dangerous environmental problems in the world. The presence of the so-called emerging pollutants in the different water bodies, impossible to eliminate through conventional biological and physical treatments used in wastewater treatment plants due to their persistent and recalcitrant nature, means that pollution continues growing throughout the world. The presence of these emerging pollutants involves serious risks to human and animal health for aquatic and terrestrial organisms. Therefore, in recent years, advanced oxidation processes (AOPs) have been postulated as a viable, innovative and efficient technology for the elimination of these types of compounds from water bodies. The oxidation/reduction reactions triggered in most of these processes require a suitable catalyst. The most recent research focuses on the use and development of different types of heterogeneous catalysts, which are capable of overcoming some of the operational limitations of homogeneous processes such as the generation of metallic sludge, difficult separation of treated water and narrow working pH. This review details the current advances in the field of heterogeneous AOPs, Fenton processes and photocatalysts for the removal of different types of emerging pollutants.

Synthesis of nano-FeS2 and its application as an effective activator of ozone and peroxydisulfate in the electrochemical process for ofloxacin degradation: A comparative study

In this work, nanopyrite particles (NP) were synthesized by ball mill method and used as a novel source of Fe²⁺ in the electro-activation of ozone and peroxydisulfate (PDS) for ofloxacin (OFX) removal. Fourier transform infrared spectroscopy, X-ray powder diffraction, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy analyzes were performed to characterize the as-made NP. Optimal values of operating parameters in NP/PDS and NP/O₃ processes were obtained. The OFX (10 mgL^-1) removal efficiency and molar ratio of OFX: oxidant in NP/PDS and NP/O₃processes were 92%, 0.1:11 and 89%, 0.1:9, respectively. Although the synergistic effect was observed in both systems, it was more significant in the NP/PDS. The results of free radical tracing showed that HO^•and SO₄^•- had the more contribution in NP/O₃ and NP/PDS systems for OFX degradation, respectively. In this way, the OFX removal mechanism was the effective release of Fe²⁺ from the NP in the electro-activation of O₃ and PDS. Moreover, the effect of electrocoagulation process on OFX removal was negligible. The as-made NP overcame the disadvantages of iron electrode corrosion and iron sludge production in the Fe-based classical electro-activation processes. Overall, the performance of the synthesized NP in the OFX oxidation was very successful in terms of sustainability, Fe²⁺distribution, removal efficiency, energy consumption and PDS or O₃ activation.

Oxidative degradation and mineralization of the endocrine disrupting chemical bisphenol-A by an eco-friendly system based on UV-solar/H2O2 with reduction of genotoxicity and cytotoxicity levels

A solar-driven advanced oxidation process at a lab scale was studied for the degradation and mineralization of the known endocrine disrupting chemical (EDC), bisphenol A (BPA). Preliminary tests were performed varying the irradiation source, BPA/H₂O₂ ratio, temperature, initial H₂O₂ concentration, initial solution pH, and initial BPA concentration, then, the operational conditions of the UV-solar/H₂O₂ were optimized by a response surface methodology (RSM), providing the following responses: UV-solar/H₂O₂ process at pH 3.0, [BPA]₀ = 25 mg L^-1, [H₂O₂] = 350 mg L^-1, T = 50 °C, achieving BPA degradation of 77.4% and BPA mineralization of 38.2%, H₂O₂ consumption of 230 mg L^-1. From the optimized condition, different pH ranges were tested (3.0; 5.0; 7.0; 9.0; and 11.0), where, at solution pH 5.0 the best removal rates were achieved (89.2% BPA degradation and 49.0% BPA mineralization). The BPA amount in solution was monitored by High Performance Liquid Chromatography (HPLC) and a study of the intermediate reaction by-products was performed by Gas Chromatography-Mass Spectrometry (GC-MS) analyses, highlighting the lower amount of by-products identified when the solution pH 5.0 was employed, rather than the solution pH 3.0. Genotoxicity tests with Zebrafish (Danio rerio) and cytotoxicity tests with Allium cepa were performed aiming to evaluate errors in the cells and nuclear abnormalities of the tested organisms induced by BPA raw samples, as well as by the BPA samples treated by the UV-solar/H₂O₂ process. Therefore, the bio-toxicity levels for an animal and a vegetal bio-indicator were reduced by applying a renewable source of energy as the irradiation source for the UV/H₂O₂ process, representing an efficient and eco-friendly alternative for BPA treatment in aqueous solutions.

Acceleration of goethite-catalyzed Fenton-like oxidation of ofloxacin by biochar

While carbon materials have been well studied to stimulate the homogeneous Fenton-like processes, little was known about their impacts on iron mineral-catalyzed heterogeneous Fenton-like reactions. Here, it was found that biochar prepared at 300 °C or 600 °C (BC300 or BC600) greatly stimulated the degradation of ofloxacin (OFX) in a goethite (Gt)-mediated Fenton-like system. In 4 h, while only 38.4 % and 48.4 % OFX were removed in Gt/H₂O₂ and BC600/H₂O₂ systems, the removal efficiency reached over 94.0 % in Gt/BC600/H₂O₂ system. And the pseudo-first-order rate constant of Gt/H₂O₂, BC600/H₂O₂ and Gt/BC600/H₂O₂ systems were 0.12, 0.16 and 0.72 h^-1, respectively, indicating the occurrence of synergistically catalytic degradation. •OH was identified as the major oxidant. Both the •OH yield and the H₂O₂ utilization efficiency of Gt/BC600/H₂O₂ system were higher than those of Gt/H₂O₂ and BC600/H₂O₂ systems. BC600 showed better stimulation effects than BC300. The persistent free radicals (PFRs) of BC could activate H₂O₂ and partly contribute to •OH production in the Gt/BC/H₂O₂ system. While BC could not directly reduce Fe(III) in Gt, it improved the cycling of Fe(III)/Fe(II) through complexing Fe(III) with its carboxyl group. Potential pathways were proposed for OFX degradation in the Gt/BC/H₂O₂ system.

Degradation of high-concentration p-nitrophenol by Fenton oxidation

This work aimed to degrade high-concentration p-nitrophenol (PNP) by Fenton oxidation. We studied various reaction parameters during Fenton oxidation, such as the iron dosage (as Fe²⁺), the initial concentration and temperature of PNP, and the dosage of hydrogen peroxide (H₂O₂), especially the influence of temperature on the PNP degradation rate and degree. Under the addition of the same molar ratio of H₂O₂/Fe²⁺ and H₂O₂ dosage according to the theoretical stoichiometry, the PNP degradation rate and the removal rate of total organic carbon (TOC) increased significantly with the increase in the initial PNP concentration. Moreover, the oxidative degradation effect was significantly affected by temperature. The increased reaction temperature not only significantly reduced the Fe²⁺ dosage, but also greatly promoted the removal rate of chemical oxygen demand (COD) and TOC, and improved the utilization efficiency of H₂O₂. For example, when the initial concentration of PNP was 4,000 mg·L^-1, and the dosage of Fe²⁺ was 109 mg·L^-1 (H₂O₂/Fe²⁺ = 200), the removal rates of COD and TOC at 85 °C reached 95% and 71% respectively. Both were higher than the 93% COD removal rate and 44% TOC removal rate when the dosage of Fe²⁺ was 1,092 mg·L^-1 (H₂O₂/Fe²⁺ = 20) at room temperature.

Degradation of antibiotics by advanced oxidation processes: An overview

Antibiotics are becoming emerging contaminants due to their extensive production and consumption, which have caused hazards to the ecological environment and human health. Various techniques have been studied to remove antibiotics from water and wastewater, including biological, physical and chemical methods. Among them, advanced oxidation processes (AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability, which are effective for the degradation of antibiotics in aquatic environments. In this review paper, a variety of AOPs, such as Fenton or Fenton-like reaction, ozonation or catalytic ozonation, photocatalytic oxidation, electrochemical oxidation, and ionizing radiation were briefly introduced, including their principles, characteristics, main influencing factors and applications. The current applications of AOPs for the degradation of antibiotics in water and wastewater were analyzed and summarized, the concluding remarks were given and their future perspectives and challenges were discussed.

Degradation of acetamiprid using graphene-oxide-based metal (Mn and Ni) ferrites as Fenton-like photocatalysts

This study aims to explore the photocatalytic potential of graphene-oxide-based metal ferrites for the degradation of acetamiprid (an odorless neonicotinoid pesticide). Metal (Mn and Ni) ferrites (along with their graphene oxide composites) were prepared by the hydrothermal method while graphene oxide (GO) was synthesized using a modified Hummer's method. The composites were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The photocatalysts were studied for their Fenton-like advanced oxidation process to degrade acetamiprid. The composites showed excellent activity against acetamiprid degradation (>90%) in 60 min under UV irradiation. The detailed optimization study was carried out to investigate the influential variables (such as pH, catalyst dose, pollutant concentration, irradiation time, oxidant dose, etc.) to achieve enhanced degradation efficiency. Moreover, the findings were endorsed by central composite design (CCD). It was concluded that degradation was enhanced in an appropriate combination of photocatalyst and hydrogen peroxide. The magnetic character of the metal ferrites and their composites played an important role in the easy separation and reusability of these materials. The present findings result in highly effective, easy to handle and stable heterogeneous photo-Fenton materials for wastewater remediation.

Lipid Oxidation in Emulsions Fortified with Iron-Loaded Alginate Beads

The potential use of iron-loaded alginate beads to fortify oil-in-water (O/W) emulsions was studied. Iron-loaded alginate beads with different sizes (0.65, 0.84, 1.5 and 2 mm) were produced by ionic gelation with calcium chloride, leading to 81% encapsulation efficiency (EE) of ferrous sulfate. These beads were added to O/W emulsions to investigate their effect on lipid oxidation. The use of iron-loaded alginate beads inhibited lipid oxidation in emulsions, compared to a control emulsion with the same concentration of free ferrous sulfate in the continuous phase, but did not totally prevent it. Results obtained with scanning electron microscopy and energy dispersive X-ray spectroscopy (EDX) analysis showed that some reactive iron was present at the surface of the beads. Oxidation of the lipid droplets was slightly higher for smaller alginate beads, suggesting that the reaction could be linked to the total bead surface. When covering iron-loaded beads with an extra layer of alginate, lipid oxidation was inhibited, which confirmed the role of reactive surface-bound iron. This study shows that the location of iron within the encapsulates plays a crucial role in the chemical stability of fortified foods and should be taken as a starting point in the design of iron-fortified food products.