Contaminant release from aged microplastic

2017 ◽  
Vol 14 (6) ◽  
pp. 394 ◽  
Author(s):  
Nicole Bandow ◽  
Verena Will ◽  
Volker Wachtendorf ◽  
Franz-Georg Simon
Keyword(s):  
Material Properties ◽  
High Density Polyethylene ◽  
Aging Process ◽  
Artificial Aging ◽  
Degradation Products ◽  
Total Content ◽  
Oxidation Reactions ◽  
Inorganic Species ◽  
Aging Conditions ◽  
Contaminant Release

Environmental contextIncreasing global plastic production adds plastic debris to the environment. We show that potentially harmful additives present in plastic particles are released to water at an increased rate when material properties change by aging due to exposure to high temperature and especially to UV radiation. For risk assessment of such plastic additives, more information on their degradation products and their toxicity is needed. AbstractRecycled plastic granules of high-density polyethylene, polyvinyl chloride and polystyrene the size of microplastics were exposed to artificial aging conditions (2000h; photooxidative and thermo-oxidative) to simulate their fate outdoors. Their potential to leach into water during the aging process was investigated using column percolation tests. Aging-related changes on the surface of the material were characterised by IR measurements indicating oxidation reactions with the formation of new adsorption bands (C=O, C–O and OH), especially in the case of photooxidative aging. These findings were confirmed by the identification of leachable organic compounds. Leaching of total organic carbon, Cl, Ca, Cu and Zn is clearly affected by changes due to aging, and their release is increased after photooxidative aging. In general, exposure to photooxidative conditions shows a greater influence on aging and thus on leaching and seems to be the more important mechanism for the aging of microplastic in the environment. Comparison with the total content of inorganic species revealed that, for most elements, less than 3% of the total content is released after 2000h of photooxidative aging.

scholarly journals Neural Model for the Prediction of Volume Losses in the Aging Process of Rums

2020 ◽  
Vol 29 (54) ◽  
pp. e10514
Author(s):  
Beatriz García-Castellanos ◽  
Osney Pérez-Ones ◽  
Lourdes Zumalacárregui-de-Cárdenas ◽  
Idania Blanco-Carvajal ◽  
Luis Eduardo López-de-la-Maza
Keyword(s):  
Aging Time ◽  
Aging Process ◽  
Neural Model ◽  
Correlation Factor ◽  
Coefficient Of Determination ◽  
Training Algorithms ◽  
The Neural Network ◽  
Aging Conditions ◽  
The Mean ◽  
Input Variables

The rum aging process shows volume losses, called wastage. The numerical operation variables: product, boardwalk, horizontal and vertical positions, date, volume, alcoholic degree, temperature, humidity and aging time, recorded in databases, contain valuable information to study the process. MATLAB 2017 software was used to estimate volume losses. In the modeling of the rum aging process, the multilayer perceptron neuronal network with one and two hidden layers was used, varying the number of neurons in these between 4 and 10. The Levenberg-Marquadt (LM) and Bayesian training algorithms were compared (Bay) The increase in 6 consecutive iterations of the validation error and 1,000 as the maximum number of training cycles were the criteria used to stop the training. The input variables to the network were: numerical month, volume, temperature, humidity, initial alcoholic degree and aging time, while the output variable was wastage. 546 pairs of input/output data were processed. The statistical Friedman and Wilcoxon tests were performed to select the best neural architecture according to the mean square error (MSE) criteria. The selected topology has a 6-4-4-1 structure, with an MSE of 2.1∙10-3 and a correlation factor (R) with experimental data of 0.9898. The neural network obtained was used to simulate thirteen initial aging conditions that were not used for training and validation, detecting a coefficient of determination (R2) of 0.9961.

Investigation on the Stress Relaxation Aging Behavior of 2195 Al-Li Alloy

2021 ◽  
Vol 315 ◽  
pp. 37-42
Author(s):  
Hai Long Liao ◽  
Li Hua Zhan ◽  
Yuan Gao ◽  
Xue Ying Chen ◽  
Ming Hui Huang
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
High Performance ◽  
Aging Process ◽  
Artificial Aging ◽  
Ageing Time ◽  
High Strength ◽  
Aging Behavior ◽  
Stress Corrosion Resistance ◽  
Scanning Electron

2195 Al-Li alloy is famous for high strength, excellent fatigue strength and good stress corrosion resistance, which is widely used in the manufacture of high-performance aerospace components. The aim of this study is to validate how the stress relaxation aging behavior effect on the mechanical properties of 2195 Al-Li alloy. Through mechanical property test, the research was found that the performance after stress relaxation aging is higher than artificial aging (AA). In addition, the analysis of scanning electron microscopy SEM and TEM revealed that dislocations should be introduced by the stress relaxation aging process, which is more conducive to the precipitation of the T1 phase and strengthened the material with prolong ageing time. The results show that stress relaxation aging can significantly promote the precipitation of the T1. Therefore, this paper sheds new light on how SRA can improve mechanical properties and that SRA make better improve the distribution of precipitates in the grain boundary.

scholarly journals Effects of Pre-Stretching on Creep Behavior, Mechanical Property and Microstructure in Creep Aging of Al-Cu-Li Alloy

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 333 ◽  
Author(s):  
Jin Zhang ◽  
Zhen Jiang ◽  
Fushun Xu ◽  
Mingan Chen
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Dislocation Density ◽  
Creep Behavior ◽  
Aging Process ◽  
Artificial Aging ◽  
Dislocation Motion ◽  
Nucleation And Growth ◽  
Blocking Effect ◽  
Creep Stage

The effects of pre-stretching on creep behavior, mechanical properties and microstructure during the creep aging process of Al-Cu-Li alloy were investigated. AA2195 was taken as the representative of Al-Cu-Li alloys. It is found that the total creep strain and strength property of creep aged AA2195 specimens can be improved through effective pre-stretching. Unlike with artificial aging, yield strength increased increasing by 47%. The TEM images show that the constitution of aging precipitates in the creep-aged specimens are obviously changed by pre-stretching. Precipitates in the 2% pre-stretched specimen are mainly composed of T1 phase, while a great amount of θ’ phase accompanied with a few T1 phase were found in the non-pre-stretched specimen. Moreover, pre-stretching introduces many dislocations which benefit the creep deformation, but the increasing dislocation density also accelerates the nucleation and growth of the precipitates as well. The premature T1 phase has a great blocking effect to the dislocation motion, creating a lower decrease rate but a longer duration in the early creep stage. Except for the initial dislocations, the dislocation motion in the creep aging process is also a favorable factor to precipitate the T1 phase.

Effect of Artificial Aging Process on Aluminum Foam Made of Etial 160

2020 ◽  
Vol 73 (11) ◽  
pp. 2739-2745
Author(s):  
Lütfiye Dahil ◽  
Ramazan Katirci ◽  
Halil İbrahim Sümbül
Keyword(s):  
Aging Process ◽  
Artificial Aging ◽  
Aluminum Foam

scholarly journals Functionality changes of natural antioxidants during food processing and storage

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S80-S83 ◽  
Author(s):  
J. Pokorný ◽  
Š. Schmidt ◽  
H. T T Nguyen
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Food Processing ◽  
Degradation Products ◽  
Raw Materials ◽  
Natural Antioxidants ◽  
Phenolic Antioxidants ◽  
Oxidation Reactions ◽  
Processing And Storage ◽  
And Storage

Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown.

Artificial aging of high-density polyethylene by ultraviolet irradiation

2001 ◽  
Vol 37 (7) ◽  
pp. 1457-1464 ◽  
Author(s):  
F Carrasco ◽  
P Pagès ◽  
S Pascual ◽  
X Colom
Keyword(s):  
Ultraviolet Irradiation ◽  
High Density Polyethylene ◽  
Artificial Aging ◽  
High Density

Anodic Degradation of Toxic Aromatic Compound in the Flow Through Cell with Carbon Fiber Electrode

2005 ◽  
Vol 277-279 ◽  
pp. 445-449 ◽  
Author(s):  
Jang Hee Yoon ◽  
Euh Duck Jeong ◽  
Yoon Bo Shim ◽  
Mi Sook Won
Keyword(s):  
Reaction Time ◽  
Carbon Fibers ◽  
Electrochemical Cell ◽  
Degradation Products ◽  
Oxidation Reactions ◽  
Applied Current ◽  
Current Input ◽  
Flow Through ◽  
Carbon Fiber Electrode ◽  
Fiber Electrode

The anodic degradation of aqueous phenol and 2-chlorophenol, which are model organic pollutants, has been studied using a flow-through electrochemical cell (FTEC) with carbon fibers as an anode material. For a controlled current electrolysis of an aqueous solution of 2-chlorophenol and phenol, experimental variables, including such as, the current input, the reaction time, and the flow rate of the solutions were considered. The degradation products of the oxidation reactions were identified with HPLC, GC/MS. Small aliphatic acids and CO2 were the main products. Depending on the values of the applied current and reaction time, a complete degradation or the partial oxidation of the compounds to other intermediates was obtained. At the flow rates of 2-6 mL/s were effective on the degradation efficiencies of the 2-chlorophenol and phenol.

Sign in / Sign up

Export Citation Format

Share Document