scholarly journals Measuring impacts of microplastic treatments via image recognition on immobilised particles below 100 μm

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Robin Lenz ◽  
Kristina Enders ◽  
Franziska Fischer ◽  
Josef Brandt ◽  
Dieter Fischer ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Acrylonitrile Butadiene Styrene ◽  
Post Treatment ◽  
Particle Identification ◽  
Particle Level ◽  
Purification Methods ◽  
Analysis Package ◽  
Sodium Polytungstate ◽  
Treatment Procedures

AbstractThe treatment of samples for microplastic (MP) analysis requires purification steps that sufficiently reduce the non-MP content while preserving the targeted particles integrity. Besides their macromolecular structure this also encompasses their in situ numbers and sizes. However, any step of sample manipulation will come at a cost: particle loss, fragmentation, coagulation or degradation may lead to distorted results, predominantly in the smaller fraction of the MP size range. Therefore, the evaluation of MP resistivity against applied methods such as chemical digestions is a vital criterion for obtaining meaningful results on MP content of a sample. We developed a framework to test the applicability of MP purification methods and apply it to four protocols commonly used to prepare environmental samples for MP particle identification. The approach was designed for MP particles being too small to be handled manually (i.e. 10–70 μm). The evaluation consists of a two-tiered assay: a simple particle suspension approach is used to confirm a post-treatment qualitative recognisability of the target polymers by the analysis method of choice (here Raman and FTIR). In a following quantitative part, immobilised particles are used to evaluate the preservation of particle numbers and areas after the treatment on an individual particle level. A Python image analysis package was written that identifies, matches and measures particles on pairs of pre- and post-treatment images, and is available as open source software. Our results show that the chemical digestions using hydrogen peroxide, cooled Fenton’s and a combined alkaline / oxidative treatment using potassium hydroxide and sodium hypochlorite are suitable methods for preparing MP samples for a microspectroscopic analyses. Also acidic sodium polytungstate solution used for MP density separations and a pentane based protocol for lipid removal were found applicable for small sized MP. Certain degradative effects were found when acrylonitrile butadiene styrene is exposed to acidic treatments, as well as for MP from acrylate and epoxy based paint resins in strong oxidative regimes. Several paint resins tested here were spectroscopically not identifiable by polymer attributed bands even before treatment, indicating that these materials might slip through analyses of environmental samples and consequently being underreported. We conclude that evaluating chemical treatment procedures on MP < 100 μm is feasible, despite limitations of the current methodology which we discuss. Our results provide more certainty on the tested methods for MP studies specifically targeting small sizes and should be extended for more protocols used in MP laboratory practises.

Postmortem and in situ TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin

1996 ◽  
Vol 54 ◽  
pp. 178-179
Author(s):  
R. C. Cieslinski ◽  
M. T. Dineen ◽  
J. L. Hahnfeld
Keyword(s):  
Poisson Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
High Impact ◽  
In Situ Tem ◽  
Styrene Copolymers ◽  
Controlled Morphology ◽  
Point Bend ◽  
Mechanism Of Failure ◽  
Impact Energies

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical's contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shell rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

Promoting Hydrogen Evolution of g-C3N4 Based Photocatalyst by Indium and Phosphorus Co-doping

2021 ◽  
Author(s):  
Xiao-Hang Yang ◽  
Chi Cao ◽  
Zilong Guo ◽  
Xiaoyu Zhang ◽  
Yaxin Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Post Treatment ◽  
Experimental Results ◽  
Indium Chloride ◽  
Co Doping ◽  
In Situ Copolymerization ◽  
Co Doped

Indium and phosphorus co-doped g-C3N4 photocatalyst (In,P-g-C3N4) was prepared by K2HPO4 post-treatment of indium doped g-C3N4 photocatalyst (In-g-C3N4) derived from in-situ copolymerization of dicyandiamide and indium chloride. The experimental results...

scholarly journals Fabrication of High-Performance Thin-Film Composite Nanofiltration Membrane by Dynamic Calcium-Carboxyl Intra-Bridging during Post-Treatment

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 137
Author(s):  
Hongyi Han ◽  
Ruobin Dai ◽  
Zhiwei Wang
Keyword(s):  
Thin Film ◽  
Water Purification ◽  
High Performance ◽  
Rejection Rate ◽  
Post Treatment ◽  
Nanofiltration Membrane ◽  
Film Composite ◽  
Thin Film Composite ◽  
Post Modification

Widespread applications of nanofiltration (NF) and reverse osmosis (RO)-based processes for water purification and desalination call for high-performance thin-film composite (TFC) membranes. In this work, a novel and facile modification method was proposed to fabricate high-performance thin-film composite nanofiltration membrane by introducing Ca2+ in the heat post-treatment. The introduction of Ca2+ induced in situ Ca2+-carboxyl intra-bridging, leading to the embedment of Ca2+ in the polyamide (PA) layer. This post modification enhanced the hydrophilicity and surface charge of NF membranes compared to the pristine membrane. More interestingly, the modified membrane had more nodules and exhibited rougher morphology. Such changes brought by the addition of Ca2+ enabled the significant increase of water permeability (increasing from 17.9 L·m−2·h−1·bar−1 to 29.8 L·m−2·h−1·bar−1) while maintaining a high selectivity (Na2SO4 rejection rate of 98.0%). Furthermore, the intra-bridging between calcium and carboxyl imparted the NF membranes with evident antifouling properties, exhibiting milder permeability decline of 4.2% (compared to 16.7% of NF-control) during filtration of sodium alginate solution. The results highlight the potential of using Ca2+-carboxyl intra-bridging post-treatment to fabricate high-performance TFC membranes for water purification and desalination.

Single-Particle Identification of Encoded Nanospheres

2010 ◽  
Vol 15 (2) ◽  
pp. 218-223 ◽  
Author(s):  
Hendrik Hippchen ◽  
Wiebke H. Pohl ◽  
Peter J. Walla
Keyword(s):  
Single Particle ◽  
Correlation Spectroscopy ◽  
Particle Identification ◽  
Carbohydrate Binding ◽  
Binding Affinities ◽  
Focal Volume ◽  
Receptor Ligand ◽  
Ligand Interactions ◽  
Particle Level ◽  
20 Nm

Recently, it has been shown that 2-photon fluorescence correlation spectroscopy of single glycosylated 20-nm fluorescent spheres allows measurement of the relative carbohydrate binding affinities of unlabeled proteins and that these modified spheres can mimic the glycocalix of cell or virus surfaces. An especially useful extension would be the analysis of mixtures of nanospheres that each contain different fluorescent labels and are thus differentially “encoded.” If the surfaces of these encoded nanospheres are modified with various receptors, many different biomolecule-surface interactions and concurrent reactions can be measured quickly and simultaneously in a single-reaction vessel. An essential prerequisite for this general assay principle is the ability to identify with an accuracy of nearly 100% any encoded nanosphere present in a mixture on a single-particle level. Here the authors present a method that indeed allows certain identification of differently encoded nanospheres during single transits through the focal volume of a microscope objective (ø~200-500 nm) in aqueous solution. This opens the way for using the encoded nanospheres in 1-well measurements of a large variety of biomolecular receptor-ligand interactions, inhibition and concurrent reactions, and thus either for testing the behavior of ligands in a mimicked complex biomolecular environment or for a fast simultaneous measurement of a multitude of receptor-ligand interactions.

Tailoring In Situ Healing and Stabilizing Post-Treatment Agent for High-Performance Inverted CsPbI3 Perovskite Solar Cells with Efficiency of 16.67%

2020 ◽  
Vol 5 (10) ◽  
pp. 3314-3321 ◽  
Author(s):  
Sheng Fu ◽  
Li Wan ◽  
Wenxiao Zhang ◽  
Xiaodong Li ◽  
Weijie Song ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Perovskite Solar Cells ◽  
Post Treatment ◽  
Treatment Agent

Wear debris from hip prostheses characterized by electron imaging

Open Medicine ◽  
2013 ◽  
Vol 8 (4) ◽  
pp. 476-484 ◽  
Author(s):  
Matevž Topolovec ◽  
Ingrid Milošev ◽  
Andrej Cör ◽  
Roy Bloebaum
Keyword(s):  
Spatial Relationship ◽  
Particle Identification ◽  
Submicron Particles ◽  
Metal Particles ◽  
Wear Particles ◽  
Scattered Electron ◽  
Tissue Samples ◽  
Tissue Sections ◽  
Electron Imaging

AbstractThe characterization of wear particles is of great importance in understanding the mechanisms of osteolysis. In this unique study, thirty-one tissue samples were retrieved at revision surgeries of hip implants and divided into four groups according to the composition of metal prosthetic components. Tissue samples were first analyzed histologically and then by scanning electron microscopy (SEM) combined with back-scattered electron imaging and energy dispersive X-ray spectroscopy. Therefore, particles were studied directly in situ in tissue sections, without the requirement for particle isolation. The composition of metal wear particles detected in the tissue sections corresponded to the composition of the implant components. A considerable number of large metal particles were actually clusters of submicron particles. The clustering of submicron particles was observed primarily with CoCrMo (cobalt-chromiummolybdenum) and, to a lesser extent, for stainless steel particles. SEM secondary and back-scattered electron imaging was an appropriate and selective method for recognizing the composition of metal particles in the in situ tissue sections, without destroying their spatial relationship within the histology. This method can be used as a screening tool for composition of metal and ceramic particles in tissue sections, or as an additional method for particle identification.

scholarly journals Adsorption of Polycyclic Aromatic Hydrocarbons (PAHS) from Aqueous Solutions on Different Sorbents

2014 ◽  
Vol 13 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Marzena Smol ◽  
Maria Włodarczyk-Makuła ◽  
Dariusz Włóka
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Aqueous Solutions ◽  
Aromatic Hydrocarbons ◽  
Environmental Samples ◽  
Sorption Process ◽  
Mineral Sorbent ◽  
Polycyclic Aromatic ◽  
Individual Hydrocarbons ◽  
Treatment Procedures

Abstract This paper presents the results of the possibility and effectiveness of PAHs removal from a model aqueous solution, during the sorption on the selected sorbents. Six PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene) listed by EPA for the analysis in the environmental samples were determined. Model aqueous solution was prepared with RESTEK 610 mix PAHs standard. After the sorption process, decrease in the concentration of individual hydrocarbons was observed. The removal percentage was dependent on the type of sorbent (quartz sand, mineral sorbent, activated carbon). The highest efficiency (98.1%) was observed for activated carbon.. The results shows that the sorption processes can be used in aqueous solutions treatment procedures.

Characterisation of morphological, antimicrobial and leaching properties of in situ prepared polyurethane nanofibres doped with silver behenate

RSC Advances ◽  
2016 ◽  
Vol 6 (28) ◽  
pp. 23816-23826 ◽  
Author(s):  
Jan Dolina ◽  
Lukáš Dvořák ◽  
Tomáš Lederer ◽  
Taťana Vacková ◽  
Šárka Mikmeková ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Free Surface ◽  
Antimicrobial Properties ◽  
Post Treatment ◽  
Free Surface Electrospinning

PU nanofibersin situdoped with silver nanoparticles were prepared using free-surface electrospinning and no post-treatment. Nanofibres with silver behenate exhibited homogenous morphology, strong antimicrobial properties and low silver leaching.

Development of polymerase chain reaction and fluorescent in situ hybridisation techniques for the detection of a bacterial strain that degrades the cyanobacterial toxin microcystin LR

2005 ◽  
Vol 56 (8) ◽  
pp. 1127 ◽  
Author(s):  
D. G. Bourne ◽  
R. L. Blakeley ◽  
P. Riddles ◽  
G. J. Jones
Keyword(s):  
Polymerase Chain Reaction ◽  
Environmental Samples ◽  
In Situ Hybridisation ◽  
Cyanobacterial Blooms ◽  
Chain Reaction ◽  
Fluorescent In Situ Hybridisation ◽  
Cyanobacterial Toxin ◽  
Specific Amplification ◽  
Polymerase Chain

Polymerase chain reaction (PCR) and fluorescent in situ hybridisation (FISH) techniques were developed for the detection of a Sphingomonas bacterium (strain MJ-PV), previously demonstrated to degrade the cyanobacterial toxin microcystin LR. A PCR amplification protocol using the primer set Sph-f1008/Sph-r1243 demonstrated specific amplification of the target 16S ribosomal DNA (rDNA) of strain MJ-PV. A 16S ribosomal RNA (rRNA) targeted probe, Sph-r1264, labelled with a rhodamine fluorescent dye was successfully used in whole-cell FISH for the detection of MJ-PV in seeded controls. DNA primers and a PCR protocol were developed for the specific amplification of a gene, mlrA, which codes for the enzyme MlrA, responsible for hydrolysis of the cyanobacterial toxin microcystin LR. A survey using 16S rDNA and mlrA primers on extracted DNA from environmental samples of a lake that suffers regular toxic cyanobacterial blooms demonstrated no amplified products indicative of the presence of MJ-PV or mlrA. Although not detecting the MJ-PV strain in the tested environmental samples, these developed methods are useful to study the distribution of strain MJ-PV demonstrated to degrade mycrocystin LR in seeded bioremediation trails, as well as the distribution and the regulation of mlrA shown to be involved in mycrocystin LR degradation.

scholarly journals Comparison between manta trawl and in situ pump filtration methods, and guidance for visual identification of microplastics in surface waters

2019 ◽  
Vol 27 (5) ◽  
pp. 5559-5571 ◽  
Author(s):  
Therese M. Karlsson ◽  
Anna Kärrman ◽  
Anna Rotander ◽  
Martin Hassellöv
Keyword(s):  
Surface Waters ◽  
Field Tests ◽  
High Volume ◽  
Expanded Polystyrene ◽  
Particle Identification ◽  
Surface Microlayer ◽  
Sea Surface Microlayer ◽  
Spatial Differences ◽  
The Difference

AbstractOwing to the development and adoption of a variety of methods for sampling and identifying microplastics, there is now data showing the presence of microplastics in surface waters from all over the world. The difference between the methods, however, hampers comparisons, and to date, most studies are qualitative rather than quantitative. In order to allow for a quantitative comparison of microplastics abundance, it is crucial to understand the differences between sampling methods. Therefore, a manta trawl and an in situ filtering pump were compared during realistic, but controlled, field tests. Identical microplastic analyses of all replicates allowed the differences between the methods with respect to (1) precision, (2) concentrations, and (3) composition to be assessed. The results show that the pump gave higher accuracy with respect to volume than the trawl. The trawl, however, sampled higher concentrations, which appeared to be due to a more efficient sampling of particles on the sea surface microlayer, such as expanded polystyrene and air-filled microspheres. The trawl also sampled a higher volume, which decreased statistical counting uncertainties. A key finding in this study was that, regardless of sampling method, it is critical that a sufficiently high volume is sampled to provide enough particles for statistical evaluation. Due to the patchiness of this type of contaminant, our data indicate that a minimum of 26 particles per sample should be recorded to allow for concentration comparisons and to avoid false null values. The necessary amount of replicates to detect temporal or spatial differences is also discussed. For compositional differences and size distributions, even higher particle counts would be necessary. Quantitative measurements and comparisons would also require an unbiased approach towards both visual and spectroscopic identification. To facilitate the development of such methods, a visual protocol that can be further developed to fit different needs is introduced and discussed. Some of the challenges encountered while using FTIR microspectroscopic particle identification are also critically discussed in relation to specific compositions found.

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