Polystyrene Pellets Research Articles

Preparation of polystyrene microplastic particles by solvent-dissolution-precipitation

The reliable characterisation of the physicochemical properties of micro-sized plastic particles requires quality reference materials for establishing, calibrating, and validating methods. Heterogeneity in particle size, shape and surface chemistry are important factors for reference materials for them to mimic environmental microplastics. This paper introduces a method for preparing model polystyrene micro and nano plastic reference materials using a solvent dissolution-precipitation approach. Polystyrene microplastic particles with mean particle sizes of 0.35, 15.7, 30.0 and 52.3 micron were produced using solvent precipitation under different synthesis conditions with the particle present in a well dispersed and partially dispersed system. The particle size can be controlled by reducing the initial polystyrene-cyclohexane concentration and adjusting the volume of methanol. At a fixed polystyrene-cyclohexane ratio, particles within the specified size range were consistently produced. Chemical analysis using pyrolysis-gas chromatography-mass spectrometry revealed that synthesized microplastics maintain their chemical properties, aligning with the original composition of virgin polystyrene pellets. A similar conclusion was drawn after examining the surface chemistry of the virgin and synthesised microplastic particles using ATR-FTIR analysis. The polystyrene particles produced in this way may be of use as reference materials and might be of interest for toxicological studies.

Microwave initiated synthesis of carbon nanosphere from plastic and its application as anode electrocatalyst support in direct methanol fuel cell

The term plastisphere was coined to describe the human-made plastic environment, addressing the challenges of plastic waste. This study presents a rapid method using microwave susceptor catalysts (Co/Mo/Biochar, Ni/Mo/Biochar, Fe/Mo/Biochar) for the catalytic degradation of polystyrene into valuable carbon in microwave synthesizer. Using SEM, we found that active metal nanoparticles are uniformly distributed and the sizes of the active porous sites varied depending upon the catalyst used where the porous active sites of catalyst Co/Mo/biochar, Ni/Mo/biochar and Fe/Mo/biochar ranges between 300 nm and 700 nm, 2.21 μm and 4.05 μm, and 5 μm to larger pore size respectively. The microwave initiated catalytic synthesis process transforms uniform-sized polystyrene pellets into carbon nanospheres within 90 s. From XRD characterization, the broadened peaks at (002) plane resulted from the graphitic flakes' waving structure, confirming that the carbon nanospheres formed are graphitic in nature which is in agreement with results obtained from Raman spectroscopy. This study also explores polystyrene as an energy feedstock, utilizing Co/Mo/Biochar synthesized carbon nanospheres (CNS) which is mesoporous in nature with BET average surface area about 1428.3 m2/g as anode electro catalyst support for methanol oxidation in direct methanol fuel cells. The Pt Ru (1:1) supported on CNS catalyst exhibited higher electro catalytic activity compared to commercial PtRu/C, as indicated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS).

Spherical polystyrene/zinc oxide nanocomposite powder fabricated by continuous process chain of melt mixing and indirect heating

Polymer powders are limited by particle size, shape, and properties in various applications. Preserving the chemical properties of the material throughout the process is a critical part of developing consistently shaped nanocomposite powders across diverse polymer types. The goal of this study is to demonstrate continuous methods to produce spherical Polystyrene (PS) and zinc oxide (ZnO) nanocomposites. A single-screw extruder is used to melt mix PS pellets with ZnO nanoparticles, followed by pelletization, dry grinding, and spheroidization in a Downer Tower to form spherical polymers. To minimize agglomeration, the process incorporates an ethanol treatment and a final sieving step. The resulting nanocomposite powder exhibits exceptional flowability and well-defined spherical morphology. Additionally, incorporating ZnO nanoparticles enhanced the thermal stability and glass transition temperature of the nanocomposite while reducing particle size distribution. Thermogravimetric analysis and X-ray diffraction confirm the preservation of the chemical structure of the spherical nanocomposite specimens throughout processing.

Features of the Neutralization of Fast Protons in a Hydrocarbon Pellet Cloud

To measure the high-energy part of the energy distribution function of ions in a hot plasma using the pellet charge exchange (PCX) diagnostic, it is necessary to know the energy dependence of the fraction F0(E) of fast ions neutralized when intersecting a pellet cloud. Using experimental and calculated data on the ablation of polystyrene macroparticles (pellets) in the LHD stellarator, the function F0(E) for protons in the hydrocarbon cloud has been calculated in the energy range of 50–1000 keV at pitch angles \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\geqslant {\\kern 1pt} 70^\\circ $$\\end{document}. At energies of 50‒200 keV, it is necessary to take into account the decrease in the flux of neutralized protons multiply intersecting the cloud. Energy losses of protons along the trajectory provide a lower bound E > 100 keV for the possible PCX measurements. The necessity of the control of the charge state composition and structure of the cloud limits the view area of the detector of atoms within ±30 mm from the position of a pellet along the magnetic field. For this reason, the injection axis should be aligned with the observation axis of the neutral particle analyzer for the optimal geometry of PCX measurements with polystyrene pellets.

Photocatalytic activity enhancement by noble metal deposition on faceted F-TiO2 synthesised by microwave assisted method. A study of selective oxidation of gas-phase ethanol in a FBPR reactor

In the present work, fluorinated titanium dioxide (TiO2-F) with high exposition of facet {001} was prepared by following a facile and high yield hydrothermal method assisted by microwave. This faceted TiO2 was then modified by Au or Ag deposition at two different metal loadings (0.125 and 0.25 wt%). A wide physicochemical characterisation of the materials was performed. X-ray difractograms showed high {001} facet exposition in all materials. By X-ray fluorescence it was found that the different samples contained about 5% of fluor. All samples presented high surface area and high uniformity and homogeneity of particles, which highlights the good properties that can be achieved by the microwave synthesis method compared to conventional hydrothermal methods. Oxidation state of the noble metals was studied by XPS. On the other side, TiO2-F and the metallised titania powders were immobilised on polystyrene pellets (PS) for evaluating their gas photocatalytic activity in volatile organic compounds (VOCs) decontamination by following the reaction of photoxidation of ethanol in gas phase. It was found that activity was considerably improved by the addition of noble metals, obtaining high conversion and selectivity to CO2. It is remarkable that the selectivity to CO is almost zero. The highest efficiency was found for the faceted TiO2-F sample with the lowest Au loading (0.125 wt%) immobilised on PS where 91% ethanol conversion and 100% CO2 selectivity were achieved. Different reaction variables were also studied.

Influence of a Secondary Plasma Cloud on the Ablation of Pellets in Magnetic Confinement Devices

The analysis of experimental data on the structure of hydrocarbon pellet clouds on the LHD stellarator has allowed one to estimate the relative contributions of neutral and plasma shielding at the ablation of macroparticles (pellets) in a high-temperature magnetized toroidal plasma. A method for the self-consistent calculation of the pellet ablation rate, the characteristic size of the pellet cloud, and the electron density in its singly ionized part including neutral gas and plasma shielding is described. This calculation for polystyrene pellets injected into the LHD plasma gives the results that agree with the experimental data obtained during the early ablation phase, when the ablation rate is determined by thermal electrons and the contribution of the superthermal component of the hot plasma to ablation can be neglected.

Iron-doped titania nanoparticles supported on polystyrene for photocatalytic treatment of contaminated water in a continuous system

A visible-light active photocatalyst based on Fe-doped TiO2 and supported by polystyrene pellets (PS) was synthesized for wastewater treatment. “Solid-state” synthesis and doping were carried out and optimized, and the catalyst was characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), UV–Vis-DRS and X-ray diffraction (XRD) analysis. A heat treatment method was developed to support the Fe/TiO2 onto 1 and 3 mm polystyrene pellets without waste production, and photocatalytic activity was investigated on methylene blue and rhodamine B at titania loading up to 50 wt%, both in batch and in a continuous system. Smaller pellets (1 mm) with low titania loading (4 wt%) proved to be the most efficient photocatalyst.Furthermore, the PS-Fe/TiO2 catalyst was easily separated from treated wastewater and reused for up to ten cycles without any loss of catalyst content and activity. The results showed the feasibility of scaling up a laboratory-scale water treatment into a continuous system.

Polystyrene and low-density polyethylene pellets are less effective in arsenic adsorption than uncontaminated river sediment

The adsorption process of inorganic arsenic (As) plays an important role in its mobility, bioavailability, and toxicity in the river environment. In this work, the adsorption of dissolved arsenite (As(III)) and arsenate (As(V)) by microplastics (MPs) pellets (polystyrene (PS) and low-density polyethylene (LDPE)), river sediment, and their mixture were investigated to assess the adsorption affinities and mechanism. The adsorption kinetics showed slow and mild rising zones from the natural behavior of the chemical adsorption. The results indicated that both MP characteristics and water properties played a significant role in the adsorption behavior of inorganic As species. The As adsorption equilibrium was modeled well by both Langmuir and Freundlich isotherms and partly fitted with the Sips model suggesting that both mono-layer and multi-layer adsorption occurred during adsorption The spontaneous adsorption process for both As(III) and As(V) was evidenced by the adsorption thermodynamics. The maximum adsorption capacities of As(III) and As(V) reached 143.3 mg/kg and 109.8 mg/kg on PS in deionized water, which were higher than those on sediment-PS mixture (119.3 mg/kg, 99.2 mg/kg), which were all lower than on sediment alone (263.3 mg/kg, 398.7 mg/kg). The Fourier transform infrared spectroscopy analysis identified that As(III) and As(V) interaction with sediment surface functional groups was the main adsorption mechanism from surface complexation and coordination. Two functional groups of polystyrene (-NH2, -OH) were mainly involved in the adsorption of inorganic As species on PS, while -COO- and -OH functional groups contributed to the adsorption mechanism of inorganic As species on LDPE. The findings provide valuable insight on the adsorption behavior and mechanisms of As(III) and As(V) in river systems in the presence of MPs particles. Both PS and LDPE were shown to be less effective than river sediment in the adsorption of As species from water, which provides a different perspective in understanding the scale of MPs impact in pollutant transport in the aquatic environment.Graphical

An effective way for the simultaneous valorization and treatment of olive mill wastewater by means of a photocatalytic process

This work hereby illustrates how to valorize olive mill wastewater (OMW) with a photocatalytic process able to produce hydrogen and simultaneously break down the polluting load of this waste. To achieve this objective, a comparison between the performances of commercial TiO2 and home-made sol–gel TiO2 on olive mill wastewater was first carried out. The hydrogen production and the ability of the catalyst to remove the organic matter present in wastewater were considered, with particular attention to the best combination (in terms of processing time and experimental phase sequence) between the anoxic phase (for the hydrogen production) and the oxidative phase (for the degradation of the organic residue). Once the best combination was identified, the photocatalyst in powder form was transferred on the surface of polystyrene pellets in order to make the catalyst easily separable and recyclable. The photocatalytic activity tests demonstrated that the proposed photocatalyst showed very good stability after ten reuse cycles, even in the presence of real OMW (with dilution 1:70), assuring a hydrogen production of about 16954 μmol/L. During the tests, the liquid samples were analyzed also with UHPLC technique that evidenced the phenol degradation and the presence of only hydroquinone as by-product.

Characterization of polystyrene-attached bacteria isolated by enrichment culture of estuarine sediments with polystyrene pellets

Characterization of polystyrene-attached bacteria isolated by enrichment culture of estuarine sediments with polystyrene pellets

Cluster-bomb type magnetic biosensor for ultrasensitive detection of Vibrio parahaemolyticus based on low field nuclear magnetic resonance.

Herein, a novel cluster-bomb type signal sensing and amplification strategy in low field nuclear magnetic resonance was proposed, and a magnetic biosensor for ultrasensitive homogeneous immunoassay of Vibrio parahaemolyticus (VP) was developed. The capture unit MGO@Ab was magnetic graphene oxide (MGO) immobilized by VP antibody (Ab) to capture VP. And, the signal unit PS@Gd-CQDs@Ab was polystyrene (PS) pellets covered by Ab to recognize VP and Gd-CQDs i.e. carbon quantum dots (CQDs) containing lots of magnetic signal labels Gd3+. In presence of VP, the immunocomplex signal unit-VP-capture unit could be formed and separated by magnetic force conveniently from the sample matrix. With the successive introduction of disulfide threitol and hydrochloric acid, signal units were cleaved and disintegrated, resulting in a homogeneous dispersion of Gd3+. Thus, cluster-bomb type dual signal amplification was achieved through increasing the amount and the dispersity of signal labels simultaneously. Under optimal experimental conditions, VP could be detected in the concentration range of 5-1.0×106CFU/mL, with a limit of quantitation (LOQ) 4CFU/mL. In addition, satisfactory selectivity, stability and reliability could be obtained. Therefore, this cluster-bomb type signal sensing and amplification strategy is powerful in designing magnetic biosensor and detecting pathogenic bacteria.

Risk of Expanded Polystyrene Ingestion by Climbing Perch Anabas testudineus

The climbing perch Anabas testudineus is widespread in the inland waters of Vietnam and according to its ecology could have contact with floating plastic waste. Fragments of expanded polystyrene (EPS) are detected in the fresh waters of Vietnam in Khanh Hoa, Lam Dong, and Phu Yen provinces. Our study focused on estimating the probability of ingestion of EPS pellets (size 2.5–3.5 mm) by adult climbing perch. In the experiments, 3 types of treatment pellets were offered to fish: 24 feed pellets (Fps), 24 expanded polystyrene pellets (Pps), and 12 feed and 12 expanded polystyrene pellets (FPps). Fish grasping time of the first pellet was independent in all treatment types. The grasping time of the 12th pellet was insignificant in Fps (63 s) and Pps (75 s). Climbing perch grasped and ingested the 24th Fp significantly (p = 0.02) earlier (143 s), than they grasped the 24th Pp (817 s). Fish with FPp treatment grasped feed along with EPS pellets, but grasping the 12th Fp was significantly (p = 0.02) earlier (49 s) than the 12th Pp (193 s). By the end of the tests, the fish had ingested all feed pellets. We discovered that climbing perch grasped Pps and kept them in the oral cavity, but rejected them in 100% of the cases. This result provided evidence that climbing perch have an effective defense mechanism for avoiding ingestion of expanded polystyrene pellets with a size of 2.5–3.5 mm.

On the Formation of a Plasma Cloud at the Ablation of a Pellet in a High-Temperature Magnetized Toroidal Plasma

The investigation of cold secondary plasma clouds near pellets ablating in the hot plasma of magnetic confinement devices (tokamaks and stellarators) provides valuable information on the physical characteristics of a pellet cloud. In this work, the characteristic sizes of emitting clouds around fusible polystyrene pellets and refractory carbon pellets have been analyzed. The calculation of the ionization length of C+ ions in both carbon and hydrocarbon clouds has shown that the contribution of only hot electrons is insufficient to ensure the experimentally observed decay lengths of the CII line intensity. Taking into account the strong shielding of the electron flux of the background plasma in the hydrocarbon pellet cloud, the ionization of C+ ions in this cloud is determined predominantly by electrons of the cold plasma of the cloud. Shielding near a refractory carbon pellet is weak because its ablation rate is lower. The contributions from hot electrons of the surrounding plasma and cold electrons of the pellet cloud to the ionization of C+ ions are comparable in the case of carbon pellets.

FABRICATION OF PLASTIC SCINTILLATOR USING POLYSTYRENE MATRIX BASED

Experiments on making a plastic scintillator with polystyrene as a base material mixed with fluorescent compounds (primary and secondary dopants) have been performed. Primary dopants (PTP) used to produce emission at wavelengths of visible light and secondary dopants (POPOP) to shift the visible wavelengths to wavelengths that could be detected by Photomultiplier Tube (PMT) ) were carried out. Experiments were performed on the melting points condition of these materials, which had previously been subjected to a thermo-mechanical analysis using a Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC) machine, where the melting point was in the range of 200-240°C. Furthermore, the fabrication was carried out using the extrusion technique, where polystyrene pellets mixed with PTP (1.5% by weight) and POPOP (0.05% by weight) were fed into an extrusion machine which has four hot areas to obtain a thin plate plastic scintillator. The plates were then analyzed with a UV-Vis Spectrophotometer to determine the absorption spectrum and Fluorescence Spectrophotometer to determine the emission spectrum. From the results of the analysis, it was found that the samples that went through scintillation pellets and without the addition of antioxidants had absorption spectrum data of 330 nm and emission spectrum of 421 nm. These values are in accordance with the characteristics of plastic scintillators on the market.

Comparative Study between Fabricated Plastic Scintillator and Existing Product for Gamma Detection

A plastic scintillator with an injection method has been developed for a gamma radiation detector. The scintillator was made from the main matrix of polystyrene (PS) pellets with the addition of primary dopant PTP (para-terphenyl) 1.5% wt and secondary dopant as wavelength shifter (WLS) POPOP (1,4-bis [2- (phenyloxazolyl) )] - benzene) 0.01 - 0.05% wt. The mixture of pellets and dopants was fed to the extruder machine to obtain scintillating pellets and then referred to the machine to obtain a 3 mm thin plate plastic scintillator. The evaluation of absorption using a spectrophotometer UV-Vis showed that PS absorbs photons at a wavelength of 310 – 340 nm and PS containing POPOP produces a maximum emission at a wavelength of 421 nm. The evaluation of cesium 137 (137Cs) and cobalt 60 (60Co) gamma spectrum using the photomultiplier tube (PMT) Hamamatsu R878 showed the results of Compton spectrum characters with a gross counting maximum of 0.78 and 0.89, respectively, compared to the commercial plastic scintillator. The results of this study are expected to be usefully utilized in the development of a large-volume plastic scintillator for the radiation portal monitor (RPM).

A novel composite thermal insulation system for concrete bridge box girder and its influence

The temperatures of a concrete box girder were observed through a field test, and the finite element method (FEM) model of the concrete box girder was established. The unknown parameters were inversed by using the constriction coefficient particle swarm optimization (CCPSO) algorithm, and hence the optimized numerical model of the temperature field close to the real-world temperature field was obtained. A novel set of composite thermal insulating system for a bridge is developed for the first time, in which the insulation coating on the outside surface of the box girder web and bottom plate is combined with the thermal insulation deck pavement layer of the bridge. The coating is insulating mortar consisting of gelatinous power and expanded polystyrene (EPS) pellets, and the insulation deck pavement layer is made of ceramsite asphalt mixture. The research results show that the proposed thermal insulation system can effectively reduce the average temperature and temperature gradient of the concrete box girder. In addition, the influence of the materials and thickness of deck pavement and coating on box girder temperature is analyzed. It provides theoretical guidance for reducing bridge temperature.

Early molecular responses of mangrove oysters to nanoplastics using a microfluidic device to mimic environmental exposure

This study assessed the effects of nanoplastics (NPs) using for the very first time microfluidic devices (chip) mimicking transition waters. Three kinds of NPs were tested: crushed NPs from polystyrene pellets (NP-PS), or from Guadeloupe beaches (NP-G); and latex PS (PSL-COOH). The eluted fractions from the microfluidic device showed a low aggregation of NPs. They remained stable over time in the exposure media, with a stabilization of NPs of small sizes (< 500 nm). These chips were thus used for the toxicological assessment of NPs on swamp oysters, Isognomon alatus. Oysters were exposed for 7 days to the chip elution fraction of either NP-G, NP-PS or PSL-COOH (0.34–333 µg.L−1). Gene transcription analyses showed that the tested NPs triggered responses on genes involved in endocytosis, mitochondrial metabolism disruption, oxidative stress, DNA repair, and detoxification. Highest responses were observed after NP-G exposure at low concentrations (1 µg.L−1), as they are originated from the natural environment and accumulated contaminants, enhancing toxicological effects. As salinity influences aggregation and then the bioavailability of NPs, our results demonstrated the importance of using microfluidic devices for ecotoxicological studies on swamp or estuarine species.

Catalytic cracking of polystyrene pyrolysis oil: Effect of Nb2O5 and NiO/Nb2O5 catalyst on the liquid product composition

The catalytic cracking of polystyrene pyrolysis oil was investigated over a Nb2O5 and a NiO/Nb2O5 catalyst in a fixed bed reactor. First, the pyrolysis of two different polystyrene feedstock (polystyrene foam and polystyrene pellet) was carried out in a semi-batch reactor, and the resulting polystyrene pellets pyrolysis oil was selected for catalytic cracking reaction because of its high liquid yield (85%). Catalytic cracking experiments were then performed at different temperatures (350–500 °C) using Nb2O5 or NiO/Nb2O5 catalyst. Gas chromatography–mass spectrometry analysis of liquid product obtained from the catalytic cracking process showed that the dimers in the pyrolysis oil were converted to monomers during the catalytic cracking process. The catalytic cracking results also showed that the NiO/Nb2O5 catalyst (having slightly higher acidic sites) had slightly higher activity for monomer conversion than the Nb2O5 catalyst (having less acidic sites). X-ray diffraction, transmission electron microscopy, pyridine Fourier transform infrared spectroscopy, NH3 Temperature Programmed Desorption and X-ray photoelectron spectroscopy were used to characterize the catalyst. The highest catalytic cracking activity was observed at 400 °C with the Nb2O5 catalyst with 4% toluene, 6% ethylbenzene, approximately 50% styrene, 13% α-methyl styrene, and only 6% of dimers in the liquid oil. The increase in temperature positively affected the yield of gases during catalytic cracking process.

Adsorption properties and influencing factors of Cu(II) on polystyrene and polyethylene terephthalate microplastics in seawater

As an emerging contamination in the ocean, microplastics can act as effective vectors of pollutants, the ecological risks caused by the combined pollution of microplastics and other pollutants have attracted growing attention. In this work, Copper (Cu(II)) was chosen as the classic pollutant, polystyrene (PS) and polyethylene terephthalate (PET) pellets were used as the typical marine microplastics, the adsorption performance of Cu(II) on PS and PET beads was investigated by adsorption kinetics and isotherm experiments, and other influencing conditions, such as pH, salinity, coexisting heavy metals ions and aging treatment, were evaluated. The results indicated that the adsorption behavior of Cu(II) on PS and PET was spontaneous and endothermic in the simulated seawater environment, and the batch experimental data can be effectively described by pseudo-second-order model and Freundlich isothermal model. Besides, the adsorption capacity of microplastics for Cu(II) was the best at pH 7, the change of salinity had no obvious effect on the adsorption in the natural marine environment. Moreover, co-existence of lead (Pb(II)) exhibited evident impacts on Cu(II) sorption onto PS and PET, which confirmed the adsorption competition effect between them. Additionally, high temperature aging treatment of microplastics in different environments for different duration time could obviously affect the properties of microplastics. It was found that the microplastics after being exposed to high temperature environment in the air for 168 h showed relatively stronger adsorption amount for Cu(II). In summary, these findings suggested that electrostatic interaction and distributed diffusion mechanisms may be the main mechanisms of adsorption, while no new functional groups were generated after the adsorption, indicating that physisorption may dominate the adsorption performance of PS and PET pellets for Cu(II). This study provides supplementary insights into the role of microplastics as carriers of heavy metals in the marine environment.

Concrete Hollow Block Production Using Fine Aggregates of Polyvinyl Chloride and Polystyrene

Population concurrently grows with demand for food and infrastructure, which are associated with plastic waste mismanagement and concrete hollow block (CHB) consumption, respectively. However, there is a dearth in the utilization of plastic pellets using polyvinyl chloride (PVC) and polystyrene (PS) in CHBs. Hence, this study aimed to characterize PVC and PS pellets, and evaluate and compare their potentials when incorporated as fine aggregates in CHBs in terms of workability and compressive strength. The pellets were characterized and used as a substitute to sand resulting in four batches of CHB specimen with 0, 10, 20, and 30% by volume of each pellet. Results revealed that PVC absorbed more and sank in the water while PS absorbed less and floated in water. The workability of both experimental groups increased as the substitution of pellets was increased. The compressive strengths of the PVC group dropped linearly with increasing pellet substitution and less than the minimum acceptable value. The batch with 30% PS pellets resulted in the highest compressive strength of 3.66 MPa among the experimental groups and greater than the minimum acceptable value of 3.45 MPa. Results implied that the incorporation of PS pellets in CHBs can be a promising solution to the plastic waste mismanagement and demand for stronger CHBs.