scholarly journals Recovery of Gallium from Smartphones—Part II: Oxidative Alkaline Pressure Leaching of Gallium from Pyrolysis Residue

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1565
Author(s):  
Benedikt Flerus ◽  
Bernd Friedrich
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Alkaline Solution ◽  
Elevated Temperatures ◽  
Water Soluble ◽  
Pressure Leaching ◽  
Carbon Oxidation ◽  
Metal Dissolution ◽  
Gaseous Oxygen ◽  
Pyrolysis Residue

In this article, we examine the selective hydrometallurgical extraction of gallium from pyrolyzed smartphones. Gallium-enriched pyrolysis residue originating from pyrolyzed smartphones was leached using NaOH and gaseous oxygen at elevated temperatures and pressures. The high content of organic carbon in the material strongly influenced the leaching performance. Oxygen, which is indispensable for the dissolution of gallium, also oxidized the organic carbon in the feed so that CO2 was released, which had a neutralizing effect on the alkaline solution. As a result, the CO2 formation complicated the accurate process control as the leaching temperature increased. The highest gallium yield of 82% was obtained at 180 °C, 5 g/L NaOH and 5 bar oxygen pressure. Decreased temperatures, NaOH concentrations and oxygen pressures resulted in lower leaching yields but with a higher selectivity for Ga. Temperatures higher than 180 °C resulted in extensive carbon oxidation, NaOH consumption and the coextraction of Cu and Ag. We propose that those conditions also facilitated the formation of water-soluble organic compounds, which would also influence the metal dissolution.

scholarly journals On the implications of aerosol liquid water and phase separation for organic aerosol mass

2017 ◽  
Vol 17 (1) ◽  
pp. 343-369 ◽  
Author(s):  
Havala O. T. Pye ◽  
Benjamin N. Murphy ◽  
Lu Xu ◽  
Nga L. Ng ◽  
Annmarie G. Carlton ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Water Uptake ◽  
Liquid Water ◽  
Transport Model ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Organic Nitrates ◽  
Monitoring Networks ◽  
Chemical Transport Model

Abstract. Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM ∕ OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM ∕ OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH  >  SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM ∕ OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically derived semivolatile species in the Community Multiscale Air Quality (CMAQ) model were highly water soluble and expected to contribute to water-soluble organic carbon (WSOC). Organic aerosol and SOA precursors were abundant at night, but additional improvements in daytime organic aerosol are needed to close the model–measurement gap. When taking into account deviations from ideality, including both inorganic (when RH  >  SRH) and organic water in the organic partitioning medium reduced the mean bias in SOA for routine monitoring networks and improved model performance compared to observations from SOAS. Property updates from this work will be released in CMAQ v5.2.

scholarly journals Chemical composition, optical properties, and oxidative potential of water- and methanol-soluble organic compounds emitted from the combustion of biomass materials and coal

2021 ◽  
Vol 21 (17) ◽  
pp. 13187-13205
Author(s):  
Tao Cao ◽  
Meiju Li ◽  
Chunlin Zou ◽  
Xingjun Fan ◽  
Jianzhong Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Organic Compounds ◽  
1H Nmr ◽  
Water Soluble ◽  
Proton Nuclear Magnetic Resonance ◽  
Oxidative Potential ◽  
Strong Light ◽  
Soluble Organic Carbon ◽  
Biomass Materials

Abstract. Biomass burning (BB) and coal combustion (CC) are important sources of brown carbon (BrC) in ambient aerosols. In this study, six biomass materials and five types of coal were combusted to generate fine smoke particles. The BrC fractions, including water-soluble organic carbon (WSOC), humic-like substance carbon (HULIS-C), and methanol-soluble organic carbon (MSOC), were subsequently fractionated, and their optical properties and chemical structures were then comprehensively investigated using UV–visible spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), and fluorescence excitation–emission matrix (EEM) spectroscopy combined with parallel factor (PARAFAC) analysis. In addition, the oxidative potential (OP) of BB and CC BrC was measured with the dithiothreitol (DTT) method. The results showed that WSOC, HULIS-C, and MSOC accounted for 2.3 %–22 %, 0.5 %–10 %, and 6.4 %–73 % of the total mass of combustion-derived smoke PM2.5, respectively, with MSOC extracting the highest concentrations of organic compounds. The MSOC fractions had the highest light absorption capacity (mass absorption efficiency at 365 nm (MAE365): 1.0–2.7 m2/gC) for both BB and CC smoke, indicating that MSOC contained more of the strong light-absorbing components. Therefore, MSOC may represent the total BrC better than the water-soluble fractions. Some significant differences were observed between the BrC fractions emitted from BB and CC with more water-soluble BrC fractions with higher MAE365 and lower absorption Ångström exponent values detected in smoke emitted from BB than from CC. EEM-PARAFAC identified four fluorophores: two protein-like, one humic-like, and one polyphenol-like fluorophores. The protein-like substances were the dominant components of WSOC (47 %–80 %), HULIS-C (44 %–87 %), and MSOC (42 %–70 %). The 1H-NMR results suggested that BB BrC contained more oxygenated aliphatic functional groups (H-C-O), whereas CC BrC contained more unsaturated fractions (H-C-C= and Ar−H). The DTT assays indicated that BB BrC generally had a stronger oxidative potential (DTTm, 2.6–85 pmol/min/µg) than CC BrC (DTTm, 0.4–11 pmol/min/µg), with MSOC having a stronger OP than WSOC and HULIS-C. In addition, HULIS-C contributed more than half of the DTT activity of WSOC (63.1 % ± 15.5 %), highlighting that HULIS was a major contributor of reactive oxygen species (ROS) production in WSOC. Furthermore, the principal component analysis and Pearson correlation coefficients indicated that highly oxygenated humic-like fluorophore C4 may be the important DTT active substances in BrC.

Chemical composition and light absorption of brown carbon emitted from residential coal combustion in China

2020 ◽  
Author(s):  
Jianzhong Song ◽  
Meiju Li ◽  
Xingjun Fan ◽  
Peng'an Peng
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Light Absorption ◽  
Coal Combustion ◽  
Extraction Methods ◽  
Water Soluble ◽  
Brown Carbon ◽  
Smoke Particles ◽  
Soluble Organic Carbon

<p>Brown carbon (BrC) is a type of light-absorbing organic compounds with a high capacity to absorb light in the low-wavelength visible and near-ultraviolet regions, which is ubiquitous in atmospheric aerosols, rainwater, and cloudwater samples. BrC can not only alter the light absorption and radiative forcing of aerosols but can also influence the formation of cloud condensation nuclei; therefore, it has a potential impact on atmospheric chemistry and climate change. Numerous studies have demonstrated that combustion processes are significant sources of atmospheric BrC, however most of these studies were focused on the emissions of biomass burning. Knowledge of primary BrC from coal combustion is still limited. In the study, smoke particles emitted from the combustion of residential coals with different geological maturity were collected in a combustion system. Then BrC fractions, including water soluble organic carbon (WSOC), water soluble humic-like substances (HULIS<sub>w</sub>), alkaline soluble organic carbon (ASOC) and methanol soluble organic carbon (MSOC) were extracted and characterized for their abundances, chemical, and light absorption properties.</p><p> </p><p>Our results showed that the abundance and light absorption of the coal combustion-derived BrC fractions were strongly dependent on the extraction methods used and the coal maturity. The abundances of MSOC fraction was significantly higher than WSOC and ASOC fractions and even higher than the sum of WSOC and ASOC, indicating that most organic compounds in smoke particles were soluble in pure methanol. The WSOC and MSOC fractions from the combustion of low maturity coal had relatively low SUVA<sub>254</sub> and MAE<sub>365</sub> values, indicated that they had relatively low levels of aromatic structures and light absorption.</p><p> </p><p>The WSOC and MSOC fractions were characterized by ultrahigh-resolution mass spectrometry. The results showed that S-containing compounds (CHOS and CHONS) are found to be the dominant components of the WSOC, whereas CHO and CHON compounds make a great contribution to the MSOC samples. Noted that a greater abundance of S-containing compounds was found in the smoke produced from coal combustion compared to biomass burning and atmospheric samples, indicated that coal combustion could be an important source of atmospheric S-containing compounds in certain areas. The findings also suggest that organic molecules with a high aromaticity index and low polarity showed stronger light absorption. In summary, our study indicated that coal combustion is a potential source of atmospheric BrC and their abundance, chemical, and light absorption were strongly dependent on the extraction methods used and the coal maturity.</p>

Molecular characterisation of ambient aerosols by sequential solvent extractions and high-resolution mass spectrometry

2018 ◽  
Vol 15 (3) ◽  
pp. 150 ◽  
Author(s):  
Jingyi Zhang ◽  
Bin Jiang ◽  
Zhiheng Wang ◽  
Yongmei Liang ◽  
Yahe Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Fine Particles ◽  
High Resolution Mass Spectrometry ◽  
Water Soluble ◽  
Aerosol Sample ◽  
Large Contribution ◽  
Nitrogen Containing Compounds

Environmental contextOrganic compounds generally make a large contribution to ambient aerosol fine particles, and can influence atmospheric chemistry. Solvent extraction before mass spectrometry is widely used for the determination of organic compounds in aerosols, but the molecular selectivity of different solvents is unclear. We extracted an aerosol sample with various solvents and show how the organic compound profile obtained by mass spectrometry changes depending on the extracting solvent. AbstractFor a comprehensive characterisation of organic compounds in aerosols, samples collected on a hazy day from Beijing were sequentially extracted with various solvents and analysed by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Electrospray ionisation (ESI) was used for the MS analysis. Aerosol samples were extracted in an apolar-to-polar solvent order of n-hexane (n-C6), dichloromethane (DCM), acetonitrile (ACN) and water, and also extracted in reverse sequence. The separated fractions were defined as non-polar, low-polarity, mid-polarity and high-polarity organic compounds respectively. Approximately 70 % of the total organic carbon (TOC) was extractable, of which the water-soluble organic carbon (WSOC) and non-polar organic carbon accounted for 30 and 25 % of the TOC respectively. Non-polar and low-polarity compounds with a high degree of molecular condensation such as oxidised polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing compounds (CHN) were extracted by n-C6 and DCM. Water-soluble organic matter (WSOM) was predominant with aliphatic and aromatic organosulfates (CHOS) and nitrooxy-organosulfates (CHONS). Most oxygen-containing compounds (CHO) and oxygen- and nitrogen-containing compounds (CHON) with high double-bond equivalents (DBEs) and long carbon chains tended to be extracted into organic solvents.

scholarly journals Contribution of dust inputs to dissolved organic carbon and water transparency in Mediterranean reservoirs

2012 ◽  
Vol 9 (7) ◽  
pp. 8307-8336
Author(s):  
I. de Vicente ◽  
E. Ortega-Retuerta ◽  
R. Morales-Baquero ◽  
I. Reche
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Organic Compounds ◽  
Western Mediterranean ◽  
Water Soluble ◽  
Water Transparency ◽  
Saharan Dust ◽  
Western Mediterranean Basin ◽  
Run Off ◽  
Atmospheric Inputs

Abstract. Mediterranean reservoirs receive frequent Saharan dust inputs with soil-derived organic compounds mostly during stratification periods, when run-off inputs are particularly limited. Here, we quantified and optically characterized the water-soluble organic carbon (WSOC) of the (dry and wet) atmospheric deposition in collectors located near three reservoirs from the Western Mediterranean Basin. In addition, we determined, during the stratification period, the WSOC contribution to the pool of dissolved organic carbon (DOC) and the influence of the chromophoric organic compounds from the dust on water transparency. We found synchrony both in the WSOC atmospheric inputs among collectors and in the DOC dynamics among the three reservoirs. DOC concentrations and WSOC atmospheric inputs were positive and significantly correlated in the two reservoirs more sensitive to atmospheric inputs: the most oligotrophic reservoir (Quentar) and the reservoir with the highest ratio of surface area to mixing water depth (Cubillas). Nevertheless, WSOC atmospheric inputs, during the stratification period, represented less than 10 % of the total DOC pool, suggesting that indirect effects of dust inputs such as primary productivity stimulation may also induce these synchronic patterns. Chromophoric compounds from dust inputs can significantly reduce water transparency to ultraviolet radiation (UVR). The depths where UVR at λ = 320 nm is reduced to ten percent of surface intensity (Z10 %) decreased 15 cm (about 24 %) in Beznar, 17 cm (about 27 %) in Cubillas, and 43 cm (about 39 %) in Quéntar due to dust inputs.

scholarly journals Changes in PM<sub>2.5</sub> Peat Combustion Source Profiles with Atmospheric Aging in an Oxidation Flow Reactor

2019 ◽  
Author(s):  
Judith C. Chow ◽  
Junji Cao ◽  
L.-W Antony Chen ◽  
Xiaoliang Wang ◽  
Qiyuan Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Organic Carbon ◽  
Source Apportionment ◽  
Aging Time ◽  
Organic Compounds ◽  
Flow Reactor ◽  
Atmospheric Modeling ◽  
Water Soluble ◽  
Atmospheric Aging ◽  
Source Profiles

Abstract. Smoke from laboratory chamber burning of peat fuels from Russia, Siberia, U.S.A. (Alaska and Florida), and Malaysia representing boreal, temperate, subtropical, and tropical regions was sampled before and after passing through a potential aerosol mass-oxidation flow reactor (PAM-OFR) to simulate ∼2- and 7-day atmospheric aging. Species abundances in PM2.5 between aged and fresh profiles varied by >5 orders of magnitude with two distinguishable clusters: around 0.1 % for reactive and ionic species and mostly >10 % for carbon. Organic carbon (OC) accounted for 58–85 % of PM2.5 mass in fresh profiles with low EC abundance (0.67–4.4 %). After a 7-day aging time, degradation was 20–33 % for OC, with apparent reductions (4–12 %) in low temperature OC1 and OC2 (thermally evolved at 140 and 280 °C), implying evaporation of higher vapor pressure semi-volatile organic compounds (SVOCs). Additional losses of OC from 2- to 7-days aging is somewhat offset by the formation of oxygenated organic compounds, as evidenced by the 12–19 % increase in organic mass (OM) to OC ratios. However, the reduction of OM abundances in PM2.5 by 3–18 % after 7 days, reconfirms that volatilization is the main loss mechanism of SVOCs. Although the ammonia (NH3) to PM2.5 ratio rapidly diminished with a 2-day aging time, it represents an intermediate profile – not sufficient for completed OC evaporation, levoglucosan degradation, organic acid oxidation, or secondary inorganic aerosol formation. Week-long aging resulted in an increase to ∼7–8 % of NH4+ and NO3− abundances, but with enhanced degradation of NH3, low temperature OC, and levoglucosan for Siberia, Alaska, and Everglasdes (FL) peats. Elevated levoglucosan was found for Russian peats, accounting for 35–39 % and 20–25 % of PM2.5 mass for fresh and aged profiles, respectively. Abundances of water-soluble organic carbon (WSOC) in PM2.5 was >2-fold higher in fresh Russian (37.0 ± 2.7 %) than Malaysian (14.6 ± 0.9 %) peats. While Russian peat OC emissions are largely water-soluble, Malaysian peat emissions are mostly water-insoluble, with WSOC/OC ratios of 0.59–0.71 and 0.18–0.40, respectively. Source profiles can change with aging during transport from source to receptor. This study shows significant differences between fresh and aged peat combustion profiles among the four biomes that can be used to establish speciated emission inventories for atmospheric modeling and receptor model source apportionment. A sufficient aging time (∼one week) is needed to allow gas-to-particle partitioning of semi-volatilized species, gas-phase oxidation, and particle volatilization to achieve representative source profiles for regional-scale source apportionment.

scholarly journals On the implications of aerosol liquid water and phase separation for organic aerosol mass

2016 ◽  
Author(s):  
Havala O. T. Pye ◽  
Benjamin N. Murphy ◽  
Lu Xu ◽  
Ng L. Ng ◽  
Annmarie G. Carlton ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Water Uptake ◽  
Liquid Water ◽  
Transport Model ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Organic Nitrates ◽  
Monitoring Networks ◽  
Chemical Transport Model

Abstract. Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM/OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM/OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH > SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM/OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically-derived semivolatile species in the CMAQ model were highly water soluble, and expected to contribute to water soluble organic carbon (WSOC). Organic aerosol and SOA precursors were abundant at night; but, additional improvements in daytime organic aerosol are needed to close the model-measurement gap. By taking into account deviations from ideality, including both inorganic (when RH > SRH) and organic water in the organic partitioning medium reduced the mean bias in SOA for routine monitoring networks and improved model performance compared to observations from SOAS. Property updates from this work will be released in CMAQ v5.2.

Water-soluble organic compounds (WSOCs) in PM2.5and PM10at a subtropical site of India

Tellus B ◽  
2011 ◽  
Vol 63 (5) ◽  
Author(s):  
Puja Khare ◽  
B. P. Baruah ◽  
P. G. Rao
Keyword(s):  
Organic Compounds ◽  
Water Soluble
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