Polyvinyl chloride (PVC) is one of the most commonly used plastics. The treatment and recycling of PVC waste is still challenging, due to its non-biodegradability, low thermal stability, high Cl ...content and low product value. In this study, a one-pot method was developed to upcycle PVC into valuable carbon materials, pipeline-quality pyrolysis gas and chlorides. The well-designed process included dechlorination by Cl-fixative (ZnO or KOH), carbonization of dechlorinated polyenes, and modification of carbon materials in sequence. ZnO and KOH converted 84.48% and 94.15% of total Cl into corresponding chlorides, respectively. CH4 and H2 accounted for 81.87–99.34 vol% of pyrolysis gas with higher heat values of 30.11–32.84 MJ m−3, which can be used as substitute natural gas. As high as 83.13% of the C element was converted into carbon materials. The morphology, structure and property of carbon materials can be modified by different Cl-fixatives. Millimeter-scale carbon spheres with mono-dispersity and porous carbon with a high specific surface area of 1922 m2 g−1 were obtained when ZnO and KOH were added, respectively. Moreover, the reaction mechanisms of PVC with Cl-fixatives were also deciphered through thermogravimetric analysis and thermodynamic simulation.
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•PVC were upcycled through one-pot dechlorination-carbonization-modification.•High-yield carbon, pipeline-quality pyrolysis gas and chlorides were obtained.•Structure and property of carbon was modified by adding different Cl-fixatives.•Mechanism of the one-pot reaction has been explored and discussed.
A Pure polyvinyl chloride (PVC) is a white, brittle material and it is the third-largest polymers produced after polyethylene and polypropylene as 40 million tons of PVC are produced yearly. The ...basic structure of PVC is (C2H3Cl)n and it is produced by polymerization of the vinyl chloride monomer (VCM) with a polymerization degree ranges from 300 to 1500. The chlorine content in PVC is about 57% by weight, which makes it less dependent on hydrocarbon content. In this paper, we are going to reveal the PVC additives and applications.
Abstract
Aims
This study aimed to examine the clinical benefits of targeted ablation of all Premature ventricular complex (PVC) morphologies vs. predominant PVC only.
Methods and results
A total of ...171 consecutive patients with reduced left ventricular ejection fraction (LVEF) and ≥2 PVC morphology with high burden (>10%/day) undergoing their first ablation procedure were included in the analysis. At the initial procedure, prevalent PVC alone was ablated in the majority. However, at the redo, all PVC morphologies were targeted for ablation. : At the first procedure, 152 (89%) patients received ablation of the dominant PVC only. In the remaining 19 (11%) patients, all PVC morphologies were ablated. At two years, high PVC burden was detected in 89 (52%) patients. Repeat procedure was performed in 78 of 89, where all PVC morphologies were ablated. At 5 years after the repeat procedure, 71 (91%) had PVC burden of <5% 3.8 ± 1.1% vs. 15.4 ± 4.3% in successful vs. failed subjects (P < 0.001). In patients with low PVC burden after the initial procedure, LVEF improved from 37.5% to 41.6% mean difference (MD): 3.39 ± 2.9%, P < 0.001, whereas a reduction in LVEF from 39.8% to 34.5% (MD: 6.45 ± 4.7%, P < 0.001) was recorded in patients with high PVC burden. One year after the repeat procedure, LVEF improved from 36.2% to 41.7% (MD: 5.5 ± 4.3%, P < 0.001) in patients with successful ablation.
Conclusion
In this observational series, ablation of all PVC morphologies was associated with significantly lower PVC burden and improvement of LVEF at long-term follow-up, compared with ablation of the dominant morphology only.
Graphical Abstract
Graphical Abstract
Investigating microplastics (MPs) in groundwater suffers from problems already faced by surface water research, such as the absence of common protocols for sampling and analysis. While the use of ...plastic instruments during the collection, processing, and analysis of water samples is usually avoided in order to minimize unintentional contamination, groundwater research encompassing MPs faces unique challenges. Groundwater sampling typically relies on pre-existing monitoring wells (MWs) and water wells (WWs) that are often constructed with polyvinyl chloride (PVC) casings or pipes due to their favorable price-performance ratio. Despite the convenience, however, the suitability of PVC casings for MP research is questionable. Unfortunately, the specifics of these wells are often not detailed in published studies. Current literature does not indicate significant pollution risks from PVC casings, suggesting these wells might still be viable for MP studies. Our preliminary analysis of the existing literature indicates that if PVC exceeds 6 % of the total MP concentration, it is likely that casings and pipes made of PVC are a source of pollution. Above this threshold, additional investigations in MWs and WWs with PVC casings and pipes are suggested.
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•A strict correlation between PVC fragments and PVC well casings is not observed.•Specific information on groundwater well construction is essential for MP research.•Water wells with PVC casings can be included in MP analyses.•Pollution sources should be investigated if PVC exceeds 6 % of the total MPs.
Investigations of the pyrolysis of poly(vinyl chloride) (PVC) in the presence of copper metal (Cu), copper(II) oxide (CuO) and copper(II) chloride (CuCl
2) are of potential importance because of the ...likelihood of the formation of these copper compounds during the thermal degradation of PVC-coated copper wires, a step in the recovery of copper from waste. The presence of Cu, CuO and CuCl
2 (i) retards the thermal degradation of PVC in air and in nitrogen and (ii) decreases the percentages of volatile products produced at both stages of the decomposition. These effects are greatest for PVC–CuO. The presence of copper, CuO or CuCl
2 in PVC has a major effect on the nature of the gaseous emissions of the thermal decomposition in air and in nitrogen. The concentrations of total chlorine, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons and soot particulates are all affected relative to an equivalent amount of PVC. These changes are greatest for the PVC–CuO system for which total chlorine emissions in air and nitrogen are reduced by 40% in air and 20% in nitrogen, benzene emissions are reduced by greater than 90% in air and nitrogen, other aromatic and chloroaromatic emissions are reduced, and soot particulate emissions are reduced by more than 50% as the concentrations of aliphatic compounds are increased. These changes are consistent with the presence of copper or its compounds permitting more efficient combustion of the carbon content of the PVC and particularly in the case of PVC–CuO with the removal of chlorine during pyrolysis in the inorganic phase.
In this study, the electrical and dielectric characteristics of the Au/(RuO2:PVC)/n-Si structures were analyzed using the impedance spectroscopy method, including capacitance/conductance (C - G/ω) ...measurements in wide voltage and frequency ranges (±4 V, 5 kHz – 5 MHz) at room temperature. The main electrical parameters such as concentration of donor atoms (ND), diffusion potential (VD), depletion layer thickness (WD), Fermi energy level (EF), barrier height (ΦB), and maximum electric field (Em) were extracted for each measured frequency. The ΦB, WD, and EF values are increasing with increased frequency, while ND and Em exponentially decrease. The surface-states (NSS) were evaluated using the low–high-frequency capacitance technique. Furthermore, the basic dielectric parameters such as tangent-loss (tan δ), electrical conductivity (σac), real and imaginary parts of ε*, electric-modulus (M*), and complex impedance (Z*) were investigated. The obtained results indicate that the NSS, and RuO2:PVC organic interlayer are more effective on C and G/ω measurements.
•In order to improve the electric and dielectric behavior of Ag/n-Si (MS) structure (RuO2-doped PVC) interlayer was grown by electrospinning technique between Ag and n-Si.•To illustrate the electric/dielectric behavior of the “RuO2-PVC” interface layer, the frequency-dependent Capacitance-Voltage (C-V) and frequency-dependent Conductance-Voltage (G/ω-V) characteristics of Ag/ RuO2-doped PVC /n-Si (MPS) structures were done.•The main electric/dielectric parameters of the fabricated Au/(PVC:RuO2)/n-Si structures such as concentration of donor atoms (ND), diffusion potential (VD), depletion layer thickness (WD), Fermi energy level (EF), barrier height (ΦB), maximum electric field (Em), surface-states (NSS), tangent-loss (tan δ), electrical conductivity (σac), real and imaginary parts of the dielectric constant (ε*), electric-modulus (M*), and complex impedance (Z*) were investigated using both C-V-f and G/ω-V-f characteristics.
Microplastics (MPs), widely presented in cultivated soil, have caused serious stresses on crop growth. However, the mechanism by which MPs affect legumes and rhizobia symbiosis is still unclear. ...Here, peanut seedlings were inoculated with Bradyrhizobium zhanjiangense CCBAU 51778 and were grown in vermiculite with 3 %/5 % (w/w) addition of PVC (polyvinyl chloride)-MPs/PBAT (polybutylene adipate)-MPs. PVC-MPs and PBAT-MPs separately decreased nodule number by 33–100 % and 2.62–80.91 %. Transcriptome analysis showed that PVC-MPs affected more DEGs (differentially expressed genes) than PBAT-MPs, indicating PVC-MPs were more devastating for the symbiosis than PBAT-MPs. Functional annotation revealed that PVC-MPs and PBAT-MPs enriched DEGs related to biosynthesis pathways such as flavonoid, isoflavonoid, and phenylpropanoid, in peanut. And when the dose increased from 3 % to 5 %, PVC-MPs mainly enriched the pathways of starch and sucrose metabolism, alanine, aspartate and glutamate metabolism, diterpenoid biosynthesis, etc.; PBAT-MPs enriched cysteine and methionine metabolism, photosynthesis, MAPK signaling, and other pathways. These significantly enriched pathways functioned in reducing nodule number and promoting peanut tolerance to MPs stresses. This study reveals the effect of PVC-MPs and PBAT-MPs on peanut and rhizobium symbiosis, and provides new perspectives for legume production and environmental safety.
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•Polyvinyl chloride (PVC)-MPs and polybutylene adipate (PBAT)-MPs significantly reduce peanut nodule number.•PVC-MPs is more devastating than PBAT-MPs for the symbiosis between peanut and rhizobium.•Peanut differential transcriptional response is existed according to the type and concentration of MPs.
The Front Cover illustrates a concept to switch the raw material basis for plasticizer production from fossil to bio‐based feedstocks. The bicyclic plasticizers, which were synthesized as target ...molecules, are accessible from bio‐based 2‐methylfuran, maleic anhydride and 2‐ethylhexanol. Evaluating the performance of this new bio‐based plasticizer generation revealed promising plasticizing properties. More information can be found in the Full Paper by R. Otter, A. Liese, H. Gröger et al.
•A flexible uncertainty subset for high-correlation and multi-peaked distribution uncertainty is established.•A two-stage robust optimization model based on scenario clustering for the PVC production ...is proposed.•The effectiveness of proposed method is demonstrated with a PVC case study.
In this paper, a data-driven robust optimization method based on scenario clustering is proposed for addressing energy consumption uncertainty characterized by correlation and multi-peaked distribution within the PVC production process. Firstly, principal component analysis (PCA) and kernel density estimation (KDE) methods are used to capture the correlation and distribution information effectively across multidimensional uncertain parameters; then a modified K-means clustering method based on density peaks is applied to cluster energy consumption scenarios and the flexible uncertainty subsets is established. A two-stage robust optimization model for the vinyl chloride production section is then proposed, and the column and constraint generation algorithm is applied to solved. Finally, the effectiveness of the proposed method is validated through a PVC production case study. Comparative results demonstrate that the proposed model reduces energy consumption under uncertainty and improves the robustness of PVC production scheduling.
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•A novel soft planar PVC gel actuator (PPGA) using PVC gel and flexible electrodes is proposed.•The proposed PPGA demonstrated performances at low voltage (<120V) that are comparable ...to those ofbiological muscle.•The strain and stress are increased by more than 3 times and 6 times respectively, with respect to the traditional stainless electrodes-based multilayered PVC gel actuator.•The PPGA is compared with the typical planar dielectric elastomer actuator (DEA) both in experiment and theory.•The operating voltage and response time are reduced by one order of magnitude with respect to the typical DEA.
In this work, a novel planar actuator based on plasticized poly (vinyl chloride) gel and flexible silicone grease electrodes is proposed to realize a new soft actuator with high performance under low driving voltages. The proposed planar PVC gel actuator (PPGA) can demonstrate a strain of 21%, an output stress of over 0.6 MPa and a respond time of about 90 ms, only at a low driving voltage of 120 V. These performances are comparable to those of the biological muscle and are much better as compared to 10–12% strain and 0.09 MPa stress at 400 V for the traditional stainless electrodes-based multilayered PVC gel actuator (MPGA). In addition, compared to the typical planar dielectric elastomer actuator (DEA) (3 M VHB4905), the operating voltage and response time for the PPGA are reduced by one order of magnitude. A theoretical model is used to discuss the difference between the two types of actuators, finding a good agreement with the experimental results. Furthermore, the PPGA can be continuously actuated for more than 1 million times which shows a good durability. These results demonstrate the feasibility of PPGA as a soft actuator, so a wide application is expected.
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