Showing papers on "Ferric published in 2021"

Regulating activation pathway of Cu/persulfate through the incorporation of unreducible metal oxides: Pivotal role of surface oxygen vacancies

Abstract: In this paper, we surprisingly found that the incorporation of unreducible metal oxides MxOy (M = Mg, Zn, Ca, Ba, Al) onto CuO hybrid magnetic nano ferric oxide (Cu@Fe3O4) may alter the reaction pathway in persulfate activation, and increase the reaction rate constant. The activation of peroxymonosulfate (PMS) by Cu@Fe3O4 led to a classic sulfate radical based oxidation process (SR-AOP) with an acetaminophen (ACE) degradation rate constant of 0.004 min−1, while 1O2-dominated nonradical oxidation process was disclosed in CuM@Fe3O4 with wildly fluctuated reaction rate constants from 0.003 to 0.242 min−1. Mechanism studies indicated that singlet oxygen (1O2) derived from the direct oxidation of superoxide anions radicals (O2 −) or the recombination of O2 − was the main reactive oxygen species (ROS) in CuM@Fe3O4/PMS system. A series of characterization experiments (pHpzc tests, XPS, H2-TPR, et al.) and DFT calculation disclosed that the addition of an unreducible metal M yielded many positive effects: (1) the formation of surface oxygen vacancies (OV) raised the zero point charge (pHpzc) of CuM@Fe3O4, thus enhanced the adsorption and activation of PMS; (2) promoting the generation of a new Cu species (Cu3+) on the surface of CuM@Fe3O4, which then participated in the generation of 1O2. The different reducibility of Cu3+ led to differences in the catalytic properties of CuM@Fe3O4. In addition, the effects of various water matrix species and the results of reusability experiment, mineralization experiment, and ecotoxicity test exhibited that CuM@Fe3O4/PMS system possessed excellent practical application value.

Effect of Ferric Chloride Concentration on the Type of Magnetite (Fe3O4) Nanoparticles Biosynthesized by Aqueous Leaves Extract of Artemisia and Assessment of Their Antioxidant Activities

Abstract: In this study, green synthesis of iron oxide magnetite (Fe3O4-NPs) was successfully prepared from Artemisia leaves extract and Assessment of Their Antioxidant Activities. The effect of different ferric chloride concentrations 0.01-0.1 M on the nanoparticles’ iron oxide formation was studied. The obtained Fe3O4 nanoparticles were characterized using various techniques, such as UV–Visible, FT-IR, XRD, SEM and EDAX are used for this purpose. The antioxidant activity of Fe3O4-NPs was determined by total antioxidant capacity (TAC), DPPH• (2, 2- diphenyl-1-picrylhydrazyl), FRAP (Ferric ion reducing antioxidant power assay) assays. In addition, UV–Vis spectra showed maximum absorption at range 275–301 nm related to the Fe3O4-NPs. FTIR spectra exhibit a two weak peak at 510 and 594 cm−1 attributed to Fe3O4-NPs vibration, confirming the formation nanoparticles XRD confirmed the crystalline nature of Fe3O4-NPs with average size ranged in 19–24 nm. SEM showed that the green synthesizing magnetite nanoparticles having in general as cubical shape. The purpose of this study, it highlights the high antioxidant activity of magnetite Fe3O4-NPs green synthesized, as a result, the use of Artemisia leaves extract offers its ease, fast, low-cost and friendly to the environment compared to other synthesis methods.

The effect of Pulsed Electric Field as a pre-treatment step in Ultrasound Assisted Extraction of phenolic compounds from fresh rosemary and thyme by-products

Abstract: Emerging extraction techniques, including pulsed electric field (PEF) and ultrasound (US), are attracting considerable interest in the recovery of bioactives. Though, limited work has focused on PEF application as pre-treatment for US assisted extraction to enhance the release of phenolics from herbs. Hence, the present study investigated the use of an optimized PEF pre-treatment to enhance the recovery of phenolics from fresh rosemary and thyme by-products in a subsequent US assisted extraction step. Total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) were assessed as an index of extraction efficacy. Qualitative and quantitative analyses were performed through liquid chromatography-mass spectrometry analyses to evaluate the influence of the methods on individual phenolic compounds and the formation of potential derivatives. The results indicated that in a number of cases PEF pre-treatment enhanced (p

Immobilization of anthocyanin extract from red-cabbage into electrospun polyvinyl alcohol nanofibers for colorimetric selective detection of ferric ions

Abstract: An effective nanofibrous metallochromic sensor mat was developed. Electrospun nanofibers were generated from a solution of polyvinyl alcohol (PVA) as a host polymer and anthocyanin extract from red-cabbage as an active detection sites. Using PVA as a supramolecular hosting matrix and anthocyanin phenolic dye (AC) as a spectroscopic probe, a novel, simple, rapid, portable and colorimetric sensor was developed for ferric ions (Fe3+) in aqueous environments. Binding these toxic ferric cations causes an appreciable color change from colorless to pink as proved by the CIE Lab color parameters. The visible color variation was found to change proportionally depending on increasing the concentration of ferric ions. The naked-eye recognition of Fe3+ was rationalized on the basis of Fe(III)-phenolic anthocyanin complex formation. High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS) was applied to characterize the anthocyanin extract. The surface morphology and structural characterization of the generated nanofibers were explored by scanning electron microscopy (SEM) and energy-dispersive X-ray analyzer (EDS). The generated electrospun PVA-AC nanofibrous film displayed an average diameter of 150–250 nm. They were firstly cross-linked using the vapors of glutaraldehyde to turn them into water-insoluble nanofibers. Both selectivity and detection limit have been also studied. The anthocyanin-containing nanofibers display an excellent simplicity and reusability with a limit of detection in the range between 1 and 350 mg/L. The detection limit was monitored as low as 1 mg/L. PVA-AC showed excellent selectivity compared to other transition metal ions, including Cu2+, Mg2+, Hg2+, Co2+, Ba2+, Zn2+, Ni2+, Cr3+, Al3+, Ca2+, K+, Na+, Cd2+ and Mn2+. The best optimized conditions for the detection of Fe3+ was achieved in a pH range from 3.75 to 6.0. The proposed assay has the advantage of rapidity, simplicity, facile fabrication, low cost, environmental safety and easy to operate compared to other detection techniques.

Nano zero valent iron (nZVI) particles for the removal of heavy metals (Cd2+, Cu2+ and Pb2+) from aqueous solutions

Abstract: For the past 15 years, nanoscale metallic iron (nZVI) has been investigated as a new tool for the treatment of heavy metal contaminated water. The removal mechanisms depend on the type of heavy metals and their thermodynamic properties. A metal whose redox potential is more negative or close to the reduction potential of Fe(0) is removed by the reduction process, while the others will be mediated by precipitation, complexation or other sorption processes. This review summarises our contemporary knowledge of nZVI aqueous chemistry, synthesis methods, mechanisms and actions (practical experiences) of heavy metal (Cd, Cu and Pb) removal and challenges of nZVI practical applications. Its inner core (iron(0)) has reducing ability towards pollutants, while the iron oxide (FeO) outer shell provides reaction sites for chemisorption and electrostatic interactions with heavy metals. Emerging studies highlighted that nZVI surfaces will have negatively charged species at higher pH and have good affinity for the removal of positively charged species such as heavy metals. Different sizes, shapes and properties of nZVI have been produced using various methods. Ferric salt reduction methods are the most common methods to produce stable and fine graded nZVI. Higher uptake of copper(II), lead(II) and cadmium(II) has also been reported by various scholars. Practical pilot tests have been conducted to remove heavy metals, which gave highly satisfactory results. Challenges such as agglomeration, sedimentation, magnetic susceptibility, sorption to other fine materials in aqueous solution and toxicity of microbiomes have been reported. Emerging studies have highlighted the prospects of industrial level application of nano zero valent particles for the remediation of heavy metals and other pollutants from various industries.

ATF3 contributes to brucine-triggered glioma cell ferroptosis via promotion of hydrogen peroxide and iron

Abstract: Ferroptotic cell death is characterized by iron-dependent lipid peroxidation that is initiated by ferrous iron and H2O2 via Fenton reaction, in which the role of activating transcription factor 3 (ATF3) remains elusive. Brucine is a weak alkaline indole alkaloid extracted from the seeds of Strychnos nux-vomica, which has shown potent antitumor activity against various tumors, including glioma. In this study, we showed that brucine inhibited glioma cell growth in vitro and in vivo, which was paralleled by nuclear translocation of ATF3, lipid peroxidation, and increases of iron and H2O2. Furthermore, brucine-induced lipid peroxidation was inhibited or exacerbated when intracellular iron was chelated by deferoxamine (500 μM) or improved by ferric ammonium citrate (500 μM). Suppression of lipid peroxidation with lipophilic antioxidants ferrostatin-1 (50 μM) or liproxstatin-1 (30 μM) rescued brucine-induced glioma cell death. Moreover, knockdown of ATF3 prevented brucine-induced accumulation of iron and H2O2 and glioma cell death. We revealed that brucine induced ATF3 upregulation and translocation into nuclei via activation of ER stress. ATF3 promoted brucine-induced H2O2 accumulation via upregulating NOX4 and SOD1 to generate H2O2 on one hand, and downregulating catalase and xCT to prevent H2O2 degradation on the other hand. H2O2 then contributed to brucine-triggered iron increase and transferrin receptor upregulation, as well as lipid peroxidation. This was further verified by treating glioma cells with exogenous H2O2 alone. Moreover, H2O2 reversely exacerbated brucine-induced ER stress. Taken together, ATF3 contributes to brucine-induced glioma cell ferroptosis via increasing H2O2 and iron.