Search query: cerium oxide polishing

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abstract: Cerium oxide (CeO2) nanoparticles (NPs) are massively used as abrasives in the chemical mechanical polishing (CMP) an essential process to manufacture semiconductor wafers. The CMP process for arsenide based semiconductor materials produces a wastewater with co occurring ionic arsenic (As) ions and CeO2 NPs. We found CeO2 NPs adsorbed both arsenite (As(III) and arsenate (As(V) ions and the adsorption isotherms suggested different adsorption energies and capacities of the two species. Applying the ferric reducing ability for nanoparticles (FRAN) assay, we revealed that the adsorbed As(III) and As(V) each reduced CeO2 NP surface reactivity but followed different mechanisms. The adsorbed As(III) ions below the critical coverage (110 mmol/kg) increased occupation of Ce 4f orbitals and thus reduced electron mobility of the original CeO2 NPs. Adsorbed As(V) ions withdrew electrons from Ce 4f orbitals and likely became oxidizing agents that greatly inhibited the original surface reducing ability. Electron paramagnetic resonance (EPR) analysis further revealed that adsorbed As(III) and As(V) ions decreased the propensity of CeO2 NPs to produce reduced reactive oxygen species (ROS) This work highlights the importance of examining NPs in their post use phases, in which surface reactivity and hazard potential can be greatly altered by chemical exposure history and NP surface transformations.
author_names: Xiangyu Bi

Chao Zeng

Paul K Westerhoff
title: Adsorption of arsenic ions transforms surface reactivity of engineered cerium oxide nanoparticles.
venue: Environmental science technology
year: 2020

abstract: Cerium oxide (CeO2) is extensively used in a range of applications like in television tubes, glass/ceramic polishing agent, fuel cells, solar cells, gas sensor andultraviolet absorbents. In current study, Allium ana telophase and comet assays were employed to evaluate the cytotoxic and genotoxic effects of CeO2 microparticles (CMPs, <5 um, bulk) and CeO2 nanoparticles (CNPs, 25 nm) on the root meristem cells of Allium cepa by using mitotic phases, mitotic index (MI) chromosomal aberrations (CAs) and DNA damage. A cepa roots were treated with the CMPs and CNPs at four different concentrations (12.5, 25, 50, and 100 ppm) for 4 h. Methyl methane sulphonate (MMS,10 ppm) and distilled water were used as positive and negative control groups, respectively. All the applied doses statistically decreased MIs. MI values of CMPs were found higher than CNPs. CMPs and CNPs significantly increased CAs such as chromosome laggards, disturbed anaphase telophase, stickiness and bridges and also DNA damage. Characterization of CMPs and CNPs showed the particle size as 4.24 0.7 um and 20.28 2.33 nm, respectively. The average diameter of CMPs and CNPs in solution were in the range of 372.75 70.23 nm and 167.74 38.7 nm, respectively. These results demonstrated that CMPs and CNPs had cytotoxic and genotoxic effects in A. cepa root meristematic cells.
author_names: Recep Liman

Yaser Acikbas

Ibrahim Hakki Cigerci
title: Cytotoxicity and genotoxicity of cerium oxide micro and nanoparticles by Allium and Comet tests.
venue: Ecotoxicology and environmental safety
year: 2019

abstract: Cerium (IV) oxide (CeO2) which is used as a biomaterial, has wide application in areas such as the biomedical, glass polishing, electronic, automotive, and pharmacology industries. Comparing with the literature, in this study, the genotoxic effects of cerium (IV) oxide microparticles (COMPs) and cerium (IV) oxide nanoparticles (CONPs) were investigated for the first time in human peripheral blood cultures at concentrations of 0.78, 1.56, 3.125, 6.25, 12.5, 25, and 50 ppm for 72 h under in vitro conditions. Particle sizes of COMPs and CONPs were determined using scanning electron microscopic analysis. Micronucleus and chromosome aberration tests were used to determine the genotoxicity of COMPs and CONPs. The average particle sizes of COMPs and CONPs were approximately 148.25 and 25.30 nm, respectively. It was determined that CeO2 particles in both micro and nano sizes were toxic at all concentrations compared to the negative control group (distilled water) Importantly, COMPs and CONPs were genotoxic even at the lowest concentration (0.78 ppm) Comparing particle sizes, the data indicated that COMPs were more toxic than CONPs. The results suggest that genotoxicity of COMPs and CONPs may be a function of applied concentrations and particle sizes.
author_names: Kader Arslan

Giray Bugra Akbaba
title: In vitro genotoxicity assessment and comparison of cerium (IV) oxide micro and nanoparticles
venue: Toxicology and industrial health
year: 2020

abstract: Cerium oxide (CeO2) nanoparticles (NPs) are used in polishing products and absorbents, as promoters in wound healing, and as organopesticide decontaminants. While systemic bioaccumulation and organ toxicity has been described after inhalation, data on CeO2 NPs' transdermal permeation are lacking. Our study was an in vitro investigation of the permeation of 17 nm CeO2 NPs dispersed in synthetic sweat (1 g L 1) using excised human skin on Franz cells. Experiments were performed using intact and needle abraded skin, separately. The average amount of Ce into intact and damaged skin samples was 3.64 0.15 and 7.07 0.78 ug cm 2, respectively (mean SD, p 0.04) Ce concentration in the receiving solution was 2.0 0.4 and 3.3 0.7 ng cm 2 after 24 h (p 0.008) The Ce content was higher in dermal layers of damaged skin compared to intact skin (2.93 0.71 ug cm 2 and 0.39 0.16 ug cm 2, respectively; p 0.004) Our data showed a very low dermal absorption and transdermal permeation of cerium, providing a first indication of Ce skin uptake due to contact with CeO2.
author_names: Marcella Mauro

Matteo Crosera

Matteo Monai

Tiziano Montini

Paolo Fornasiero

Massimo Bovenzi

Gianpiero Adami

Gianluca Turco

Francesca Larese Filon
title: Cerium Oxide Nanoparticles Absorption through Intact and Damaged Human Skin
venue: Molecules
year: 2019

abstract: The polishing process in high tech industries produces a large amount of waste polishing slurry, which is harmful to the environment, and the solid powders in the slurry contain a lot of La and Ce, which have been widely used as catalyst materials. The aim of this study was to convert this hazardous material into hazardous material decomposition catalyst. A novel and simple approach was successfully developed for the recovery of La and Ce from hazardous waste polishing powders to synthesize a composite metal oxide catalyst for decomposition of harmful ammonia. Here, La and Ce were leached from waste polishing powder by using nitric acid, and the Ce, La, and total REE recovery rates were approximately 100% 83.3% and 96.4% respectively. The elemental concentrations of leached acidic solution was analyzed, after which stoichiometry was performed to replenish elements with insufficient mole numbers. Finally, the catalyst material was prepared using the glycine nitrate combustion process. The catalyst prepared from the recovered polishing powders achieved a 100% ammonia conversion rate at the relatively low temperature of 250 degC. The proposed environmentally friendly method does not require complex purification and separation procedures and can be used for the synthesis of catalysts for decomposing other harmful pollutants.
author_names: Bing-Sheng Yu

Jun-Lun Jiang

Chu-Chun Yang
title: Conversion of lanthanum and cerium recovered from hazardous waste polishing powders to hazardous ammonia decomposition catalysts.
venue: Journal of hazardous materials
year: 2019

abstract: Abstract Nanostructured cerium oxide (CeO2) commonly known as nanoceria is a rare earth metal oxide, which plays a technologically important role due to its versatile applications as automobile exhaust catalysts, oxide ion conductors in solid oxide fuel cells, electrode materials for gas sensors, ultraviolet absorbents and glass polishing materials. However, nanoceria has little or weak luminescence, and therefore its uses in high performance luminescent devices and biomedical areas are limited. In this review, we present the recent advances of nanoceria in the aspects of synthesis, luminescence and biomedical studies. The CeO2 nanoparticles can be synthesized by solution based methods including co precipitation, hydrothermal, microemulsion process, sol gel techniques, combustion reaction and so on. Achieving controlled morphologies and enhanced luminescence efficiency of nanoceria particles are quite essential for its potential energy and environment related applications. Additionally, a new frontier for nanoceria particles in biomedical research has also been opened, which involves low toxicity, retinopathy, biosensors and cancer therapy aspects. Finally, the summary and outlook on the challenges and perspectives of the nanoceria particles are proposed.
author_names: Liying He

Yumin Su

Jiang Lanhong

Shi-kao Shi
title: Recent advances of cerium oxide nanoparticles in synthesis, luminescence and biomedical studies: a review
year: 2015

abstract: The applications of cerium oxide nanoparticles (CeO2 NPs; nanoceria) extend to polishing agents, diesel fuel additives and as a putative antioxidant in therapeutics. Therefore, understanding the long term toxic effects of CeO2 NPs is of particular importance. This study investigated the 28 days of repeated toxicity of 30, 300 and 600 mg/kg body weight (bw)/day of nanoceria and CeO2 microparticles (MPs) in Wistar rats after oral exposure. Genotoxicity was analysed using comet, micronucleus (MN) and chromosomal aberration (CA) assays. The results demonstrated a significant increase in DNA damage in peripheral blood leukocytes and liver, MN and CA in bone marrow as well as MN in peripheral blood after exposure to CeO2 NPs at 300 and 600 mg/kg bw/day. Significant alterations were observed in alkaline phosphatase and lactate dehydrogenase activity in serum and reduced glutathione content in the liver, kidneys and brain at 300 and 600 mg/kg bw/day in a dose dependent manner. Conversely, CeO2 MPs did not induce any significant toxicological changes. A much higher absorptivity and significant tissue distribution of CeO2 NPs was perceived in comparison to CeO2 MPs in a dose dependent manner. A substantial fraction of CeO2 NPs was cleared by urine and faeces. Histopathological analysis revealed that CeO2 NPs caused alterations in liver, spleen and brain. Further, distinct difference in the data among genders was not obvious. In general, the results suggested that prolonged oral exposure to nanoceria has the potential to cause genetic damage, biochemical alterations and histological changes after retention in vital organs of rats at high concentrations.
author_names: Monika Kumari

Srinivas Indu Kumari

Paramjit Grover
title: Genotoxicity analysis of cerium oxide micro and nanoparticles in Wistar rats after 28 days of repeated oral administration.
venue: Mutagenesis
year: 2014

abstract: Nanostructured cerium oxide(CeO 2) commonly known as nanoceria is a rare earth metal oxide, which plays a technologically important role due to its versatile applications as automobile exhaust catalysts, oxide ion conductors in solid oxide fuel cells, electrode materials for gas sensors, ultraviolet absorbents and glass polishing materials. However, nanoceria has little or weak luminescence, and therefore its uses in high performance luminescent devices and biomedical areas are limited. In this review, we present the recent advances of nanoceria in the aspects of synthesis, luminescence and biomedical studies. The CeO 2 nanoparticles can be synthesized by solution based methods including co precipitation, hydrothermal, microemulsion process, sol gel techniques, combustion reaction and so on. Achieving controlled morphologies and enhanced luminescence efficiency of nanoceria particles are quite essential for its potential energy and environment related applications. Additionally, a new frontier for nanoceria particles in biomedical research has also been opened, which involves low toxicity, retinopathy, biosensors and cancer therapy aspects. Finally, the summary and outlook on the challenges and perspectives of the nanoceria particles are proposed.
title: Recent advances of cerium oxide nanoparticles in synthesis, luminescence and biomedical studies: a review
year: 2015

abstract: Cerium oxide nanoparticles (CeO2 NPs) are increasingly used in polishing, engine enhancement agents and many other products. Even though the acute toxicity of CeO2 NPs to plants has been investigated, the long term effects of CeO2 NPs in the environment are still unknown. The main objective of this study was to investigate whether the treatment of tomato plants with relatively low concentrations of CeO2 NPs (10 mg L( 1) through their lifecycle would affect the seed quality and the development of second generation seedlings. The results indicated that second generation seedlings grown from seeds collected from treated parent plants with CeO2 NPs (treated second generation seedlings) were generally smaller and weaker, as indicated by their smaller biomass, lower water transpiration and slightly higher reactive oxygen species content. An interesting phenomenon noticed in the study was that the second generation seedlings grown from treated seeds developed extensive root hairs compared with the control second generation seedlings (seedlings grown from seeds collected from untreated parent plants) regardless of the treatment. Treated second generation seedlings also accumulate a higher amount of ceria than control second generation seedlings under the same treatment conditions even though such differences are not statistically significant.
author_names: Qiang Wang

Stephen D Ebbs

Yongsheng Chen

Xingmao Ma
title: Trans generational impact of cerium oxide nanoparticles on tomato plants.
venue: Metallomics integrated biometal science
year: 2013

abstract: ABSTRACT Cerium oxide (CeO2) one of many engineered nanomaterials (ENMs) is composed primarily of metal oxides, such as cerium oxide (CeO2) CeO2 containing materials are widely used as a polishing agent for glass mirrors, plate glass, television tubes, ophthalmic lenses, and precision optics. The widespread use of this nanomaterial (NM) resulted in increased environmental contamination levels and consequent human exposure. However, the influence of Ce on humans remains to be determined. The aim of this study was to expose female ICR mice to varying nanoparticle sizes of 35 nm, 300 nm as well as a mixture of 1 5 uM CeO2 particles through intranasal (i.n. instillation at 40 mg/kg dose on day 1, 3 and 5, and the experiment terminated on day 7. Histopathology findings demonstrated that hydropic degeneration was prominently associated with hemorrhage in renal cortex and medulla in all CeO2 administered groups. In liver of CeO2 exposed mice, hydropic degeneration was also prominent. Serum chemistries also indicated signs of renal and hepatic lesion as evidenced by significantly decreased serum levels of total bilirubin (TBIL) and total phosphate (TP) and activity of alkaline phosphatase (ALP) ICP MS analysis group demonstrated that Ce levels were not significantly higher in liver and kidneys of mice exposed to 35 nm CeO2. An increase in Ce content was observed in hepatic and renal tissues of mice exposed to 300 nm or 1 5 uM CeO2. The levels of Ce were similar in these two groups suggesting a threshold level of Ce was attained regardless of NP size. Data thus demonstrated that i.n. instillation of different sized CeO2 particles translocated to liver and kidney and that size difference of CeO2 particles did not exert significant in the observed histopathology responses.
author_names: Yang Liu

Jun Ji

Le Ji

Yuanyuan Li

Bowen Zhang

Tongwang Yang

Jing Yang

Liping Lv

Gang Wu
title: Translocation of intranasal (i.n. instillation of different sized cerium dioxide (CeO2) particles: potential adverse effects in mice
venue: Journal of toxicology and environmental health. Part A
year: 2019