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Fulltext Dielectrical Properties of CeO2 Nanoparticles at Different Temperatures

Zamiri R, Ahangar HA, Kaushal A, Zakaria A, Zamiri G, Tobaldi D, et al.

PLoS One, 2015;10(4):e0122989.
PMID: 25910071 DOI: 10.1371/journal.pone.0122989

A template-free precipitation method was used as a simple and low cost method for preparation of CeO2 nanoparticles. The structure and morphology of the prepared nanoparticle samples were studied in detail using X-ray diffraction, Raman spectroscopy and Scanning Electron Microscopy (SEM) measurements. The whole powder pattern modelling (WPPM) method was applied on XRD data to accurately measure the crystalline domain size and their size distribution. The average crystalline domain diameter was found to be 5.2 nm, with a very narrow size distribution. UV-visible absorbance spectrum was used to calculate the optical energy band gap of the prepared CeO2 nanoparticles. The FT-IR spectrum of prepared CeO2 nanoparticles showed absorption bands at 400 cm(-1) to 450 cm(-1) regime, which correspond to CeO2 stretching vibration. The dielectric constant (εr) and dielectric loss (tan δ) values of sintered CeO2 compact consolidated from prepared nanoparticles were measured at different temperatures in the range from 298 K (room temperature) to 623 K, and at different frequencies from 1 kHz to 1 MHz.

Matched MeSH terms: Cerium/chemistry*
Selection of best impregnated palm shell activated carbon (PSAC) for simultaneous removal of SO2 and NOx

Sumathi S, Bhatia S, Lee KT, Mohamed AR

J Hazard Mater, 2010 Apr 15;176(1-3):1093-6.
PMID: 20018447 DOI: 10.1016/j.jhazmat.2009.11.037

This work examines the impregnated carbon-based sorbents for simultaneous removal of SO(2) and NOx from simulated flue gas. The carbon-based sorbents were prepared using palm shell activated carbon (PSAC) impregnated with several metal oxides (Ni, V, Fe and Ce). The removal of SO(2) and NOx from the simulated flue gas was investigated in a fixed-bed reactor. The results showed that PSAC impregnated with CeO(2) (PSAC-Ce) reported the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NOx. PSAC-Ce showed the longest breakthrough time of 165 and 115 min for SO(2) and NOx, respectively. The properties of the pure and impregnated PSAC were analyzed by BET, FTIR and XRF. The physical-chemical features of the PSAC-Ce sorbent indicated a catalytic activity in both the sorption of SO(2) and NOx. The formation of both sulfate (SO(4)(2-)) and nitrate (NO(3-)) species on spent PSAC-Ce further prove the catalytic role played by CeO(2).

Matched MeSH terms: Cerium/chemistry
Hydrophobic modification of cellulose isolated from Agave angustifolia fibre by graft copolymerisation using methyl methacrylate

Rosli NA, Ahmad I, Abdullah I, Anuar FH, Mohamed F

Carbohydr Polym, 2015 Jul 10;125:69-75.
PMID: 25857961 DOI: 10.1016/j.carbpol.2015.03.002

Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10(-3) and 5.63 × 10(-2)M, respectively, at 45°C for 3h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm(-1), attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component.

Matched MeSH terms: Cerium/chemistry
3D Flower-Like FeWO4/CeO2 Hierarchical Architectures on rGO for Durable and High-Performance Microalgae Biophotovoltaic Fuel Cells

Karthikeyan C, Jenita Rani G, Ng FL, Periasamy V, Pappathi M, Jothi Rajan M, et al.

Appl Biochem Biotechnol, 2020 Nov;192(3):751-769.
PMID: 32557232 DOI: 10.1007/s12010-020-03352-4

A facile chemical reduction approach is adopted for the synthesis of iron tungstate (FeWO4)/ceria (CeO2)-decorated reduced graphene oxide (rGO) nanocomposite. Surface morphological studies of rGO/FeWO4/CeO2 composite reveal the formation of hierarchical FeWO4 flower-like microstructures on rGO sheets, in which the CeO2 nanoparticles are decorated over the FeWO4 microstructures. The distinct anodic peaks observed for the cyclic voltammograms of studied electrodes under light/dark regimes validate the electroactive proteins present in the microalgae. With the cumulative endeavors of three-dimensional FeWO4 microstructures, phase effect between rGO sheet and FeWO4/CeO2, highly exposed surface area, and light harvesting property of CeO2 nanoparticles, the relevant rGO/FeWO4/CeO2 nanocomposite demonstrates high power and stable biophotovoltaic energy generation compared with those of previous reports. Thus, these findings construct a distinct horizon to tailor a ternary nanocomposite with high electrochemical activity for the construction of cost-efficient and environmentally benign fuel cells.

Matched MeSH terms: Cerium/chemistry*
Protective potential of cerium oxide nanoparticles in diabetes mellitus

Chai WF, Tang KS

J Trace Elem Med Biol, 2021 Jul;66:126742.
PMID: 33773280 DOI: 10.1016/j.jtemb.2021.126742

BACKGROUND: Diabetes mellitus (DM) is a non-communicable metabolic disease which is closely related to excessive oxidative stress after constant exposure to high plasma glucose. Although the current antidiabetic medications are effective in lowering blood glucose, these medications do not prevent or reverse the disease progression. Thus, there is a crucial need to explore new therapeutic interventions that could address this shortcoming. As cerium oxide nanoparticles (CONPs) possess antioxidant property, this agent may be used as a treatment option for the management of DM.
PURPOSE: This review aims to provide a critical evaluation of the pharmacological and antidiabetic effects of CONPs in cell and animal models. The roles of CONPs in attenuating DM complications are also presented in this report.
METHODS: We conducted a literature search in the PubMed database using the keywords "cerium oxide", "cerous oxide", "ceria", "nanoceria", and "diabetes" from inception to December 2020. The inclusion criteria were primary source articles that investigated the role of CONPs in DM and diabetic complications.
RESULTS: We identified 47 articles from the initial search. After the thorough screening, only 31 articles were included in this study. We found that CONPs can attenuate parameters that are related to DM and diabetic complications in various animals and cell culture models.
CONCLUSION: CONPs could potentially be used in the treatment of those with DM and complications caused by the disease.

Matched MeSH terms: Cerium/chemistry
Fulltext Cerium oxide nanoparticles: green synthesis and biological applications

Charbgoo F, Ahmad MB, Darroudi M

Int J Nanomedicine, 2017;12:1401-1413.
PMID: 28260887 DOI: 10.2147/IJN.S124855

CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. The physicochemical properties of CeO2-NPs, such as size, agglomeration status in liquid, and surface charge, play important roles in the ultimate interactions of the NP with target cells. Recently, CeO2-NPs have been synthesized through several bio-directed methods applying natural and organic matrices as stabilizing agents in order to prepare biocompatible CeO2-NPs, thereby solving the challenges regarding safety, and providing the appropriate situation for their effective use in biomedicine. This review discusses the different green strategies for CeO2-NPs synthesis, their advantages and challenges that are to be overcome. In addition, this review focuses on recent progress in the potential application of CeO2-NPs in biological and medical fields. Exploiting biocompatible CeO2-NPs may improve outcomes profoundly with the promise of effective neurodegenerative therapy and multiple applications in nanobiotechnology.

Matched MeSH terms: Cerium/chemistry*
Ceria and titania incorporated silica based catalyst prepared from rice husk: adsorption and photocatalytic studies of methylene blue

Adam F, Muniandy L, Thankappan R

J Colloid Interface Sci, 2013 Sep 15;406:209-16.
PMID: 23800370 DOI: 10.1016/j.jcis.2013.05.066

Titania and ceria incorporated rice husk silica based catalyst was synthesized via sol-gel method using CTAB and glycerol as surface directing agents at room temperature and labeled as RHS-50Ti10Ce. The catalyst was used to study the adsorption and photodegradation of methylene blue (MB) under UV irradiation. The powder XRD pattern of RHS-50Ti10Ce was much broader (2θ=25-30°) than that of the parent RHS (2θ=22°). The catalyst exhibited type IV isotherm with H3 hysteresis loop, and the TEM images showed partially ordered pore arrangements. The TGA-DTG thermograms confirmed the complete removal of the templates after calcination at 500°C. RHS-50Ti10Ce exhibited excellent adsorption capability with more than 99% removal of MB from a 40 mg L(-1) solution in just 15 min. It also decolorized an 80 mg L(-1) MB solution under UV irradiation in 210 min, which was comparable with the commercialized pure anatase TiO2.

Matched MeSH terms: Cerium/chemistry*
Coordination of Ce(III) and Nd(III) with pentaethylene glycol in the presence of picrate anion: spectroscopic and X-ray structural studies

Kusrini E, Saleh MI, Lecomte C

Spectrochim Acta A Mol Biomol Spectrosc, 2009 Sep 15;74(1):120-6.
PMID: 19560960 DOI: 10.1016/j.saa.2009.05.024

(1)H NMR evidence for direct coordination between the Ln(III) ion and the oxygen atoms of the pentaethylene glycol (EO5) ligand and the picrate anion (Pic) in [Ln(Pic)(2)(EO5)][Pic] {Ln=Ce and Nd} complexes are confirmed by single X-ray diffraction. No dissociation of Ln-O bonds in dimethyl sulfoxide-d solution was observed in NMR studies conducted at different temperatures ranging 25-100 degrees C. The Ln(III) ion was chelated to nine oxygen atoms from the EO5 ligand in a hexadentate manner and the two Pic anions in each bidentate and monodentate modes. Both compounds are isostructural and crystallized in monoclinic with space group P2(1)/c. Coordination environment around the Ce1 and Nd1 atoms can be described as tricapped trigonal prismatic and monocapped square antiprismatic geometries, respectively. The crystal packing of the complexes have stabilized by one dimensional (1D) chains along the [001] direction to form intermolecular O-Hcdots, three dots, centeredO and C-Hcdots, three dots, centeredO hydrogen bonding. The molar conductance of the complexes in DMSO solution indicated that both compounds are ionic. The complexes had a good thermal stability. Under the UV-excitation, these complexes exhibited the red-shift emission.

Matched MeSH terms: Cerium/chemistry*
Removal of fluoride ion from aqueous solution by a cerium-poly(hydroxamic acid) resin complex

Haron MJ, Yunus WM

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001 May;36(5):727-34.
PMID: 11460327

A cerium-loaded poly(hydroxamic acid) chelating ion exchanger was used for fluoride ion removal from aqueous solution. The resin was effective in decreasing the fluoride concentration from 5 mM down to 0.001 mM in acidic pH between 3 and 6. The sorption followed a Langmuir model with a maximum capacity of 0.5 mmol/g. The removal is accomplished by an anion exchange mechanism. The rate constant for the sorption was found to be 9.6 x 10(-2) min-1. A column test shows that the fluoride ion was retained on the column until breakthrough point and the fluoride sorbed in the column can be eluted with 0.1 M NaOH. The column can be reused after being condition with hydrochloric acid at pH 4. The resin was tested and found to be effective for removal of fluoride from actual industrial wastewater.

Matched MeSH terms: Cerium/chemistry*
Hierarchically structured ternary heterojunctions based on Ce3+/ Ce4+ modified Fe3O4 nanoparticles anchored onto graphene oxide sheets as magnetic visible-light-active photocatalysts for decontamination of oxytetracycline

Hassandoost R, Pouran SR, Khataee A, Orooji Y, Joo SW

J Hazard Mater, 2019 08 15;376:200-211.
PMID: 31128399 DOI: 10.1016/j.jhazmat.2019.05.035

The main prerequisite of an active visible-light-driven photocatalyst is to effectively utilize the visible light to induce electron-hole (e-/h+) pairs of expanded lifetime. To this end, for the first time, the ternary heterojunctions of CeO2/Fe3O4 /Graphene oxide and Ce3+/ Fe3O4 /Graphene oxide (CeO2/Fe3O4/GO and Fe2.8Ce0.2O4/GO) were prepared via facile ultrasonic-assisted procedures and employed for destruction of oxytetracycline (OTC) under visible light irradiation. The changes in the relative crystal structure, morphology, atomic and surface functional group composition, magnetic, and optic properties of magnetite were uncovered by various techniques. The substantial degradation and mineralization of OTC via visible light/Fe2.8Ce0.2O4/GO system were thoroughly discussed in terms of narrowed band gap energy, the principal function of Ce3+/Ce4+ and Fe2+/Fe3+ redox pairs and GO platelets, enhanced charge separation and transfer, and enlarged active surface area. Furthermore, the performance of visible light/Fe2.8Ce0.2O4/GO system was evaluated for treating real wastewater and its efficiency was investigated using a number of enhancers and scavengers. Finally, the generated byproducts in the course of photodegradation were determined and the oxidation pathway, photocatalytic kinetics, and plausible mechanism were proposed. The results confirmed that the introduced Ce ions and graphene oxide sheets boost the photo-catalytic efficiency of magnetite for photodegradation of OTC.

Matched MeSH terms: Cerium/chemistry*
Fulltext Green synthesis of metallic nanoparticles using pectin as a reducing agent: a systematic review of the biological activities

Devasvaran K, Lim V

Pharm Biol, 2021 Dec;59(1):494-503.
PMID: 33905665 DOI: 10.1080/13880209.2021.1910716

CONTEXT: Pectin is a plant heteropolysaccharide that is biocompatible and biodegradable, enabling it to be an excellent reducing agent (green synthesis) for metallic nanoparticles (MNPs). Nevertheless, in the biological industry, pectin has been left behind in synthesising MNPs, for no known reason.
OBJECTIVE: To systematically review the biological activities of pectin synthesised MNPs (Pe-MNPs).
METHODS: The databases Springer Link, Scopus, ScienceDirect, Google Scholar, PubMed, Mendeley, and ResearchGate were systematically searched from the date of their inception until 10th February 2020. Pectin, green synthesis, metallic nanoparticles, reducing agent and biological activities were among the key terms searched. The data extraction was focussed on the biological activities of Pe-MNPs and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations for systematic reviews.
RESULTS: A total of 15 studies outlined 7 biological activities of Pe-MNPs in the only three metals that have been explored, namely silver (Ag), gold (Au) and cerium oxide (CeO2). The activities reported from the in vitro and in vivo studies were antimicrobial (9 studies), anticancer (2 studies), drug carrier (3 studies), non-toxic (4 studies), antioxidant (2 studies), wound healing (1 study) and anti-inflammation (1 study).
CONCLUSIONS: This systematic review demonstrates the current state of the art of Pe-MNPs biological activities, suggesting that Ag and Au have potent antibacterial and anticancer/chemotherapeutic drug carrier activity, respectively. Further in vitro, in vivo, and clinical research is crucial for a better understanding of the pharmacological potential of pectin synthesised MNPs.

Matched MeSH terms: Cerium/chemistry
Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO2 and NO removal

Dahlan I, Lee KT, Kamaruddin AH, Mohamed AR

J Hazard Mater, 2009 Jul 30;166(2-3):1556-9.
PMID: 19147280 DOI: 10.1016/j.jhazmat.2008.12.028

In this work, the removal of SO(2) and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO(2) had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) species due to the catalytic role played by CeO(2). Apart from that, the catalytic activity of the RHA/CaO/CeO(2) sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).

Matched MeSH terms: Cerium/chemistry*
Novel Ag/cellulose-doped CeO2 quantum dots for efficient dye degradation and bactericidal activity with molecular docking study

Ikram M, Hayat S, Imran M, Haider A, Naz S, Ul-Hamid A, et al.

Carbohydr Polym, 2021 Oct 01;269:118346.
PMID: 34294353 DOI: 10.1016/j.carbpol.2021.118346

In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.

Matched MeSH terms: Cerium/chemistry*

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