Pb Ratios Research Articles

Distribution Characteristics of <sup><sup>7</sup></sup>Be and <sup><sup>210</sup></sup>Pb in Near-Surface Aerosols in Mianyang Area and Their Significance to O<sub>3</sub> Tracer

In order to understand the quality of radiation environment in the near surface air in Mianyang area, to grasp the trend of its change, to explore the sources of aerosol substances near the surface and their significance in tracking the concentration of O₃ near the ground, a detailed gamma spectrum analysis of aerosol samples from March 2018 to February 2019 in Anzhou District, Jiangyou City, Zitong County and Pingwu County was carried out. In general, the activity concentration of ^⁷Be is higher in spring and autumn, while it is the lowest in summer. The annual average is 1.90-2.13mBq/m^³, which is basically the same as the distribution characteristics of inland, mid-latitude, and low-altitude areas in the world. The activity concentration of ^²¹⁰Pb is a "U" type distribution feature throughout the year. It is the lowest in late spring or early summer and has an annual average of 1.24-1.66mBq/m^³, which is a relatively high value of ^²¹⁰Pb activity concentration on global land. The correlation analysis between ^⁷Be and ^²¹⁰Pb and O₃ in near-surface aerosols showed that ^⁷Be and O₃ were weakly positively correlated, while the ratio of ^⁷Be/^²¹⁰Pb was significantly positively correlated with O₃, and ^²¹⁰Pb and O₃were significantly negatively correlated; The ^⁷Be/^²¹⁰Pb ratio can be used as a good tracer of O₃ sources in near-surface air. The O₃ source in the near surface air in Mianyang area is greatly affected by the vertical convection activity of the atmosphere.

Potential of montmorillonite and humus-like substances modified montmorillonite for remediation of Pb and Zn-contaminated soils

Pb and Zn pollution for soil are becoming more and more serious, strengthening the treatment of contaminated soils is conducive to the sustainable development of soil. In this study, the humus-like substances modified montmorillonite (HLS-MMT) were synthesized to remediate the Pb and Zn-contaminated soils. The application of HLS-MMT in simulated and actual contaminated soil were carried, and the long-term stability of HLS-MMT was evaluated. The results showed that the mobility, bioavailability and leachability of heavy metals (HMs) significantly decreased after remediating by HLS-MMT. Compared with MMT, the TCLP leaching ratio (TLr) of Pb and Zn reduced by 9.27–13.96% and 10.3–13.18%, while the DTPA effectiveness (DEr) Pb and Zn reduced by 9.11% and 8.76% in simulated soil, respectively. Moreover, the aging experiments proved that HLS-MMT possessed a stability to resistance the freeze-thaw cycles, wet and dry alternation, and acid rain leaching. This article provides some theoretical basis for the soil remediation.

Tolerance of Vallisneria sp. for Different Concentrations of Cadmium and Lead

This study was done to recognize the tolerance of Vallisneria sp. for different concentrations of cadmium and lead in aqueous ecosystem. The concentrations of 30, 40, 50 mg/L were used for Cd and Pb in three replications for each concentration for 30 days. 
 The results found that the plant was tolerated 50 mg/L of Pb, and 40 mg/L of Cd. Significant differences were found in removing capacity by plant for Cd and Pb, in all concentrations 30, 40, 50 mg/L during experiment period. There were no morphological changes in the first day of the experiment period, but it was appeared after the threeth days of the experiment, and it continued till the end of the experiment. 
 The highest removal ratio for Pb was 97.66% in the concentration 30 mg/L, and the lowest removal ratio was 57.4% in the concentration 50 mg/L. For Cd the highest removal ratio 80.06% in concentrations 30 mg/L and the lowest removal ratio was 76.2% mg/L in concentrations 50 mg/L.

Bioaccumulation and risk assessment of potential toxic elements in the soil-vegetable system as influenced by historical wastewater irrigation

To investigate the pollution status and probable health risk of potential toxic elements (PTEs) in soil and vegetables in historical wastewater irrigation region, eight types of vegetables (n = 73) and corresponding soils were collected to determine the contents of Pb, Cd, Cu, Zn, Ni and Cr, and their potential health risk to local vegetable consumers. The results showed that the mean contents of Pb, Cd, Cu, Zn, Ni and Cr in these soils were 39.72, 1.06, 38.47, 255.00, 27.45 and 61.83 mg/kg, respectively, with Cd exceeding the national standard of China (0.6 mg/kg, GB 15618–2018). Nemerow integrated pollution indices revealed that more than 50% of these soils were slightly or moderately polluted. The activity ratios of Pb, Cd, Cu and Zn ranged from 0.18 to 0.26, which was much higher than that of Ni and Cr. The average PTEs in vegetables were all within the limitation of China or FAO/WHO (except for Pb). However, the PTEs accumulation capacity in different vegetables varied greatly, with the bioaccumulation factor of cilantro (0.023, 0.232, 0.031, 0.063, 0.009 and 0.007 for Pb, Cd, Cu, Zn, Ni and Cr) and white radish (0.004, 0.058, 0.008, 0.021, 0.003 and 0.002 for Pb, Cd, Cu, Zn, Ni and Cr) being the highest and lowest, respectively. Health risk assessment revealed that local residents suffered both non-carcinogenic and carcinogenic risk, with the hazard index (HI) ranging from 0.73 to 2.45 and 2.02–6.53, and the target carcinogenic risk (TCR) ranging from 2.22 × 10−3 to 5.92 × 10−3 and 6.67 × 10−3 to 1.70 × 10−2 for adults and children, respectively. Pb and Cd contributed more than 62.37% of the HI, and Cd contributed more than 79.42% of the TCR. These results indicate that historical wastewater irrigation has a long-term impact on local food safety and potentially adverse consequences for human health.

Process analysis of Pb transformation in the coal devolatilization stage

The transformation of Pb during coal devolatilization affects its emission characteristics. Herein, devolatilization experiments were conducted at 1100–1300 °C in a fixed-bed experimental system using four types of coal samples. The occurrences of Pb in coal and devolatilization products were characterized. The release ratio of Pb first increased and then stabilized with time. The Pb release ratio and rate were higher at higher temperatures. Pb in some coal samples was completely released at 1100 °C. Pb in coal was mainly in carbonate- and oxide-bound, sulfide-bound, and residual forms. During devolatilization, carbonate-, oxide-, and sulfide-bound Pb gradually disappeared. Organic-bound and residual Pb first increased and then decreased owing to the conversion of gaseous Pb into Char-Pb by char, according to further form analysis of residual Pb and the experiments of char retaining PbCl2 and PbO. The effects of different volatile components on residual Pb were compared, and H2S was found to significantly promote the release of residual Pb in coal. The transformation paths of Pb during coal devolatilization were proposed, including the release of original Pb in coal and the reversible conversion between gaseous Pb and Char-Pb. The results help understanding Pb emission and developing control techniques for coal-fired plants.

Influence of temperature change on the immobilization of soil Pb and Zn by hydrochar: Roles of soil microbial modulation

Considering the potential effect of the ambient temperature on soil microorganisms during heavy metal immobilization by hydrochar, 60 days of soil incubation was conducted to explore the impact of ambient temperature (5, 25, and 35 °C) on the immobilization of Pb and Zn by chitosan-magnetic sawdust hydrochar (CMSH) and magnetic chitosan hydrochar (MCH). The results showed that soil pH was relatively high and total organic carbon (TOC) was slightly lower in the 35 °C treatment. The diethylenetriaminepentaacetic acid (DTPA) available state content decreased significantly with the temperature increasing. Meanwhile, the ratios of stable Pb and Zn in the sequential extraction method proposed by the European Community Bureau of Reference (BCR) gradually increased with increasing temperature. The heatmap based on microbial community showed that elevated temperature not only favored the enrichment of metal-stable phyla, such as Chloroflexi, but was also involved in inhibiting the growth of Firmicutes, Actinobacteriota, and Proteobacteria. Meanwhile, different genera (Fonticella and Bacillus) in the Firmicutes phylum had distinct responses to temperature as well as to heavy metal immobilization effects. Subsequently, redundancy analysis confirmed that Chloroflexi and Fonticella were positively correlated with temperature and stable state metal content, while Actinobacteriota and Bacillus were negatively correlated with temperature and were positively correlated with DTPA available metal content. Moreover, Pb and Zn indicators displayed significant correlations for the dominant genera (R2 > 0.8, p < 0.02).

Heavy metals, rare earth elements and isotopic fingerprint of Venetian Protected Designation of Origin sparkling wines

PurposeWorld imports of Italian sparkling wines fell by 9% in value and 5% in quantities. In view of this, the quality characterisation of these products is desirable to increase their market value and restore their global visibility.Design/methodology/approachFor this purpose, in this paper, heavy metals (Cd, Co, Cr, Cu, Fe, Ga, Hf, Hg, Mn, Mo, Nb, Ni, Pb, Re, Sb, Sn, Ta, Th, Tl, U, W, V, Zn, Zr), rare Earth elements (REEs) (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Tm, Yb) and isotopes ratio (208Pb/206Pb, 207Pb/206Pb, 206Pb/204Pb, 208Pb/207Pb, 87Sr/86Sr) were analysed in Italian sparkling wines with Protected Designation of Origin (PDO) certification by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) and MultiCollector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS). The samples were produced in the Veneto region, and they were compared to white and red wines from the same area.FindingsSparkling wines present a characteristic elemental pattern compared to white and red ones, with lower content of heavy metals and higher content in REEs. The ratio 87Sr/86Sr resulted in a powerful micro-scale geographical origins marker while Pb ratios as winemaking process one, both useful to prevent possible frauds. Multivariate data analyses, such as PCA and PLS-DA, were used to develop a model of recognition of Venetian sparkling wines.Originality/valueThe good classification of sparkling wines was achieved (95%), proving the suitable use of these analytes as markers for recognising sparkling wines and their geographical origin verification. To the best of the authors’ knowledge, this is the first study investigating heavy metals, REEs and isotopes in Venetian sparkling wine for their recognition.

Removal of arsenic, lead and bismuth from copper anode slime by a one-step sustainable vacuum carbothermal reduction process

A green and efficient method for removing arsenic (As), lead (Pb) and bismuth (Bi) from copper anode slime by a one-step vacuum carbothermal reduction process was proposed. In this paper, the Gibbs free energy and saturation vapor pressure for the reduction process were analyzed theoretically. The effects of temperature and holding time on the reduction and removal ratios for As, Pb and Bi were investigated experimentally. The results showed that the weight loss ratio of the feedstock was 48.28 %, and Pb and Bi decreased to levels below the lower limits for detection with inductively coupled plasma atomic emission spectrometry (ICP–AES), i.e., from 4.81 % and 7.32 %; these values were determined for the optimal vacuum carbothermal reduction conditions, which included a reaction temperature of 1073 K, a holding time of 2 h and a system pressure of 10 Pa. 81.81 % of the As and all of the Pb and Bi were removed. The amounts of Ag and Au recovered in the residue increased from 10.64 % and 510 (g/t) to 15.61 % and 742 (g/t), and the recovery efficiencies were 99.76 % and 99.9 %, respectively. The innovative process proposed in this paper thoroughly separated As, Pb, Bi and precious metals. Volatiles such as As2O3, PbS, and BiSe were placed in lead smelting plants, and the Ag and Au in the residue were placed in copper anode slime for extraction of precious metals, which greatly improved the efficiencies for recovering valuable metals from anode slime and avoided emission of arsenic-containing waste gas and wastewater.

Experimental study on the redistribution law of heavy metals in sludge disintegration

Aiming at the problems of large output of excess sludge, difficulty in treatment and disposal, and the potential toxicity of heavy metals restricting its resource utilization, this paper studies the redistribution law of heavy metals in the process of sludge disintegration. The dissertation investigates the distribution law of typical heavy metals such as Cu, Pb, Cd, Zn in the process of microwave and citric acid-microwave cracking sludge under different specific energy and fixed specific energy conditions. The Tessier five-step continuous extraction method was used to extract heavy metals, and the changes in their content and chemical forms were analyzed, which provided certain technical support for the subsequent harmless treatment and resource utilization of excess sludge. The main findings of this paper are as follows: The dissolution rate of heavy metals Cu, Pb, Cd, and Zn increased rapidly during the citric acid-microwave cracking process in the TS specific energy range of 0–45000 kJ/kg, and then gradually tended to be gradual. The maximum dissolution rates of Cu, Pb, Cd, Zn were 8.06%, 16.58%, 14.69%, and 24.11%, respectively. The concentrations of Cu, Pb, Cd, and Zn in the sludge were mainly F4; F3, F4; F2, F3. The proportions of stable states of Cu, Pb, Cd, and Zn in sludge increased to 88.6%, 55.91%, 35.7%, and 31.35%, respectively. When the specific energy was 45000 kJ/kg TS, the concentrations of Pb, Zn, and Cd in the solid phase of the sludge appeared to increase under microwave cracking alone and decrease under the combined action of citric acid and microwave. The concentration of Cu in the solid phase of the sludge increased slightly. The dissolution rates of Pb, Cd, and Zn by microwave alone and citric acid-microwave method were 14.23% and 16.58%, 10.34% and 14.69%, 17.53%, and 24.11%, respectively. The dissolution rates of Cu by both methods were lower. The steady state ratios of Pb and Zn in the citric acid-microwave method increased to 55.91% and 31.25%, respectively; the steady state ratio of Cd in the microwave alone method increased to 39.51%; both methods had no significant effect on the stability of Cu.

Enhanced washing of cadmium and lead from polluted river sediment using horizontal electroosmosis

Sediments are an important sink for heavy metals in river and lake waters, and their chemical compositions affects the circulation of these elements in the ecosystem. Therefore, the remediation of polluted sediments is critical for the health of the ecological environment. This work proposes a facile method for the enhancement of heavy metals extraction from contaminated sediment. In this work, horizontal electroosmosis was applied to improve extraction efficiency of Cd and Pb from river sediment. The effect of the washing reagent (distilled water, citric acid, nitric acid, acetic acid and EDTA) on remediation was investigated, and optimization of the operational parameters of remediation time, washing reagent concentration, electrode spacing, and applied voltage were also studied. Citric acid and EDTA were found to give rise to the greatest removal ratio for Cd and Pb, respectively, with electroosmosis enhancement. After electrokinetic washing for 13 days at cell voltage of 30 V, the removal ratio of Cd by citric acid was 77.0%, and that of Pb by EDTA was 88.3%, at the initial concentrations of 30.2 and 304.2 mg kg (dry solids), respectively. Decreases in exchangeable, carbonate-bound and iron-manganese oxide-bound fractions of the heavy metals were apparent upon their removal from the polluted river sediment.

Research for the recovery of Zn and Pb from electric arc furnace dust through vacuum carbothermal reduction

Isothermal kinetic methods were used to investigate reduction process in the Zn and Pb during the vacuum carbothermal reduction of electric arc furnace dust (EAFD). During the experiments, the volatilization ratios of Zn and Pb in EAFD increased with the increase of temperature and holding time, which was 96.29 % and 83.91 % for Zn and Pb respectively at a temperature of 1000 °C and holding time of 60 min. The main phase changes of Zn and Pb in the reduction process were ZnFe2O4 → ZnO → Zn and PbSO4 → PbO → Pb, and the generated Zn and Pb gases escaped and were collected via condensation. In the kinetic study, the volatilization of Zn was controlled by three-dimensional diffusion (Jander) with an apparent activation energy of 19.97 kJ/mol, whereas the volatilization of Pb was controlled by the interfacial chemical reaction with an apparent activation energy of 85.68 kJ/mol. The results show that higher purity of valuable metals Zn and Pb could be obtained, laying a theoretical foundation for the treatment of EAFD pollution.

Electric field-enhanced immobilization of Cd and Pb in contaminated river sediments

The immobilization of heavy metal pollutants in river and lake sediments is critical for environmental health and safety. In this study, combined electrokinetic and chemical immobilization were used to remediate Cd and Pb polluted river sediments. The effect of the concentrations of the immobilization reagents and the applied voltage were investigated. Immobilization ratios for Cd and Pb of 98.6% and 84.3%, respectively, was achieved at 7.5 V cm−1 using seven successive rounds of recycling of the immobilization solution of mixed 1.0 g L−1 CO32− and 3.0 g L−1 H2PO4− at the volume ratio of 1:9 with 100 mL immobilization solution to 100 g sediment. The enhancement effect of the electric field is mainly attributed to the increased contact between the immobilization reagents and the heavy metals due to electroosmosis. This study provides a new method for the treatment of heavy metal-polluted sediments.

Impacts of magnetic biochar from reed straw on anaerobic digestion of pigment sludge: Biomethane production and the transformation of heavy metals speciation

The effects of magnetic biochar (MBC) on the anaerobic digestion efficiency of pigment sludge and the passivation of heavy metals Cd, Pb were investigated. MBC participated in the dual direct interspecies electron transfer effects of biochar and Fe3O4, improved the anaerobic digestion efficiency. Compared with the control group, the maximum volatile fatty acids (VFAs) concentration, the VS (volatile solids) removal rate, cumulative methane production, average daily methane production, and average daily methane production rate increased by 51.4 %, 37.8 %, 56.3 %, 56.3 %, 37.2 %, respectively. Moreover, MBC addition signally reduced the distribution rate of the bioavailable state of heavy metals in the pigment sludge and improved the passivation efficiency. Compared with the feedstock, the mass ratios of exchangeable and reducible Cr were reduced by 43.6 % and 61.6 %, and the corresponding ratios of Pb were reduced by 41.0 % and 59.2 %, respectively. The results indicate MBC could improve the efficiency of the anaerobic digestion of pigment sludge and reduce the bioavailability of heavy metals Cd and Pb.

Synthesis of heated aluminum oxide particles impregnated with Prussian blue for cesium and natural organic matter adsorption: Experimental and machine learning modeling

Heated aluminum oxide particles impregnated with Prussian blue (HAOPs-PB) are synthesized for the first time using different molar ratios of aluminum sulfate and PB to improve the adsorption of cesium (133Cs+) and natural organic matter (NOM) from an aqueous solution. The Cs+ adsorption from various aqueous solutions, including surface, tap and deionized water by synthesized HAOPs-PB, is investigated. The influencing factors such as HAOPs-PB mixing ratio, pH and dosage are studied. In addition, pseudo 1st and 2nd order is tested for adsorption kinetics study. A machine learning model is developed using gene expression programming (GEP) to evaluate and optimize the adsorption process for Cs+ and NOM removal. Synthesized adsorbent showed maximum adsorption at a 1:1 M ratio of aluminum sulfate and PB in DI, tap, and surface water. The pseudo 2nd order kinetics model described the Cs + adsorption by HAOPs-PB more accurately that indicating physiochemical adsorption. Adsorption of Cs+ showed an increasing trend with higher HAOPs-PB concentration, while high pH also favored the adsorption. Maximum NOM adsorption is found at a higher HAOPs-PB dosage and a neutral pH value. Furthermore, the proposed GEP model shows outstanding performance for Cs+ adsorption modeling, whereas a modified-GEP model presents promising results for NOM adsorption prediction for testing dataset by learning the relationship between inputs and output with R2 values of 0.9348 and 0.889, respectively.

Zircon U Pb geochronology and petrology of the tholeiitic gabbro from the Kovanlık (Giresun) area: Constraints for the Late Cretaceous bimodal arc magmatism in the Eastern Pontides Orogenic Belt, NE Turkey

Mafic intrusions of the Eastern Pontides Orogenic Belt (EPOB) in NE Turkey are found rarely in varying ages, sizes and compositions. Of these, tholeiitic gabbro stocks, namely Kovanlık gabbro, consist of pyroxene gabbro and minor hornblende gabbro with a mainly granular texture. The pyroxene gabbro contains plagioclase, clino- and ortho-pyroxene, olivine, and Fe Ti oxides, whereas the hornblende gabbro includes mainly plagioclase, hornblende, rarely biotite and Fe Ti oxides. The clinopyroxene compositions of the pyroxene gabbro exhibit arc-related tholeiitic magmas. The Kovanlık gabbroic rocks have high U/Yb zircon ratios, implying continental arc-related tectonic settings. Zircon U Pb dating on the Kovanlık gabbro yielded a concordia age of ~92 Ma (Turonian). Petrochemically, the gabbroic rocks have a tholeiitic character and show arc- and MORB-like signatures. The gabbroic rocks show positive Rb, Ba, K, Pb, Sr, Ti and negative Nb, Ce, Nd, Hf, Zr anomalies in N-MORB normalized diagrams. The chondrite-normalized REE plots of the rocks show flat to feeble right-dipping REE patterns (La N /Lu N = 0.94–2.56) with positive Eu anomalies (Eu N /Eu* = 1.15–2.14; except for two pyroxene gabbro samples). The gabbroic rocks have 87 Sr/ 86 Sr (i) ratios (0.704533 to 0.706265), εNd (i) values (4.04–4.85), 206 Pb/ 204 Pb (18.56–18.68) and 207 Pb/ 204 Pb (15.61–15.64) ratios. Low Nb/La and Nb/Y ratios, as well as high Sr/Yb and Ba/Rb ratios, indicate that source regions were modified by slab-derived fluids and/or melts. The obtained zircon dating, isotopic and geochemical data, as well as regional geology, revealed that the tholeiitic mafic magma derived from a spinel-lherzolite mantle at a relatively shallow depth, and the Kovanlık gabbro in the EPOB represents one of the first mafic intrusions of Late Cretaceous bimodal arc magmatism related to the roll-back of the northwards subducting Tethys oceanic plate. • The Kovanlık tholeiitic gabbro formed in a continental arc with a MORB-like source. • The zircon U Pb dating of the gabbro gave a concordia age of ~92 Ma (Turonian). • The parent magma originated by partial melting of a spinel lherzolite mantle source. • The gabbro evolved by fractional crystallization and lesser crustal assimilation. • Cretaceous bimodal arc magmatism is related to the rollback of the subducting slab.

Morphology Control of PbZrxTi1-xO3 Crystallites under Alkaline Hydrothermal Conditions

Outstanding ferroelectric and piezoelectric properties of PbZrxTi1-xO3 (PZT) make nano and sub-micrometer particles of this material interesting for future nanotechnological applications as well as for fundamental studies of ferroelectricity at the nanoscale. In the present work, the prospects of a new hydrothermal approach were explored to control the particle size, aggregation stage, and composition of the PZT with the target composition of Zr/Ti = 60/40 (x = 0.6). Starting with water-soluble Zr-, Ti-, and Pb-precursors, the PZT formation was examined in the broad base (KOH) concentration range. The PZT particle size and composition were governed by the ratio of KOH with respect to Pb and not by the absolute KOH concentration (cKOH). The incorporation of Zr into the PZT perovskite phase began to decline at KOH:Pb ≤ 1.7 and at KOH:Pb &gt; 20. In the concentration range of 20 ≥ KOH:Pb &gt; 1.5, the PZT particles adopted a cube-like shape, the size of which decreased with a decrease in the KOH:Pb ratio. The smallest (&lt;200 nm) and well-separated PZT particles were obtained at KOH:Pb = 1.7. The prevailing PZT crystal structure at a Zr/Ti composition of around 60/40 was rhombohedral; the tetragonal phase also began to appear in Ti-richer PZT compositions (Zr/Ti ≤ 50/50). The developed understanding established the basis for further tailoring of PZT particle morphologies for application-oriented or fundamental research.

Co-roasting of tin tailings and waste cathode carbon for the recovery of Sn, Zn, Pb and F

Tin tailings are a common type of solid waste containing Sn, Pb, Zn, Fe, Si, and Ca. Currently, most tin tailings are being stored in piles or landfills. This study proposes the co-roasting of tin tailings and waste cathode carbon(WCC) to allow for proper waste disposal. The result shows that ZnCO3 was transformed into ZnS-FeS eutectic, which restricted the formation Fe-Sn alloy. Simultaneous separations and recoveries of Sn, Pb, and Zn from tin tailings was realized under strong reducing atmosphere. Under optimal experimental conditions, the Sn, Pb and Zn recovery ratios were 95%, 98% and 95%, respectively. Additionally, NaF in the WCC was mainly transformed to CaF2, and 98% F can be solidified. The F, Pb, Zn, As, and Cu leached contents of the roasted residue in the toxicity characteristic leaching procedure(TCLP) met the national allowable emission standards. Iron phase could be reduced to high value metallic Fe, and its contents reached 88.75 wt% after magnetic separation. The tailings of magnetic separation can be reused as building materials, and CaF2 can enhance material properties, minimizing environmental risks. In industrial production, WCC can act as a fuel and reducant, which can significantly reduce tin tailings processing costs.

Controllable Synthesis of Submicrometer Core–Shell Modifier and Its Effect on Toughening Polypheylene Ether/Polystyrene Blends

AbstractCore–shell polybutadiene‐graft‐polystyrene (PB‐g‐PS) graft copolymers with different ratios of PB to PS are synthesized by emulsion polymerization. Further, the PB‐g‐PS copolymers are blended with polypheylene ether (PPE) and PS to prepare PPE/PS/PB‐g‐PS blends. The effects of PB‐g‐PS copolymer structure and matrix composition on the morphological, mechanical properties, and deformation mechanism of the blends are studied. The results show that the synthesized submicrometer‐sized PB‐g‐PS copolymer has an excellent toughening efficiency, both the copolymer and PS are introduced into PPE resin to produce a ternary blend which is combined with high toughness and processing properties. The optimum toughening effect on PPE/PS matrix is observed at the core–shell weight ratio of 70/30 in PB‐g‐PS copolymer, and the impact strength of the blends increased from 101 to 550 J m−1. In addition, the dispersion pattern of rubber particles in the matrix gradually changes from uniform dispersion to aggregation as the core–shell ratio of PB‐g‐PS copolymers increases. On the other hand, with the increase of PPE content, the dispersion of rubber particles in PPE/PS matrix is improved, and the deformation mechanism is changed from cracking to a combination of crazing and shear yielding, which can lead to absorb more energy to achieve better toughness.

Blade-coated inverted perovskite solar cells in an ambient environment

To make the jump from laboratories to commercial production for perovskite solar cells, it is necessary to develop devices in an ambient environment using materials and methods that can be scalable. Here, blade coating followed by vacuum quenching is used to manufacture the FACs-based perovskite solar cells with the additive of MACl under an ambient environment (30%–57% RH), where FA is formamidinium and MA is methylammonium. The vacuum allows quick removal of solvent to initiate the nucleation process and create the intermediate phase. To control the nucleation and crystallization, the additive MACl is utilized to manipulate the intermediate phase. Besides perovskites, another key component is the hole transport material. Although nickel oxide exhibits good photostability and can be scalable for the inverted device architecture, the main drawback is low cell efficiency. This work solves it by tuning the cation ratio of Pb 2+ to A + and light soaking, achieving a champion efficiency of 19.5%. The encapsulated solar cells exhibit long-term photostability, maintaining 96% of their original efficiency and 91.5% of their maximum efficiency over 648 h under one sun at 45°C and 50%–60% relative humidity. This work demonstrates an economical and highly scalable process, promising for commercial-scale manufacturing. Highly scalable FACs-based perovskite solar cells with additive of MACl are developed. Perovskite film is blade coated in air, assisted by vacuum quenching. The substrate also needs to be scalable with a low price, so hot spray prepared NiOx is the choice. We overcome its drawback of low open-circuit voltage by tuning the Pb-A ratio and light soaking, achieving efficiency close to 20%. • Blade coating and vacuum-assisted method for making perovskite solar cells in air. • MACl is used to manipulate the intermediate phase during vacuum-assisted method. • Open-circuit voltage is improved by tuning organic cation/Pb ratio on NiOx. • Carrier lifetime at NiOx/perovskite interface becomes longer after light soaking.

In Situ U–Th–Pb Dating of Parisite: Implication for the Age of Mineralization of Colombian Emeralds

Parisite-Ce (Ca(Ce,La)2(CO3)3F2) is a rare-earth (REE) fluorocarbonate mineral first described from the world-famous emerald mines of the Muzo district, Boyacá Province, Colombia. Four samples of parisite-Ce collected from outcrops near Muzo have been geochemically studied and dated using the in situ laser ablation U–Th–Pb method. Our study shows that the REE abundance of parisite is controlled by the leaching of the wall rocks (black schist). Furthermore, we show that the parisite-Ce crystals formed in textural equilibrium with the emeralds, suggesting a similar time of crystallization. Our analysis demonstrates the capability of parisite as a geochronometer and shows that precise and accurate U–Th–Pb ages can be obtained from parisite after common 207Pb correction. A higher precision date was obtained with the Th–Pb ratio rather than with the U–Pb ratio because of the relatively higher content of Th than U in the samples. The samples yielded 208Th–232Pb ages ranging from ~47 to 51 Ma. The new ages are ~10 Ma older than previously reported Ar–Ar ages and ~10 Ma younger than previously reported Rb/Sr ages. These results will have significant implications for understanding the timing of mineralization and crystallization of emerald deposits in Colombia. Furthermore, this study opens new avenues for dating similar deposits worldwide.