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In present study the pool boiling process for the model system of refrigerant R11(trichlorofluoromethane or CCl3F)/mineral compressor oil solution has been examined. The experiments performed at various boiling temperatures (40, 50, 60 °C) and initial mass fractions (3.485, 7.456, 14.000 mass.%) of compressor oil in the range of the heat fluxes 5–63 kW/m2. The solutions were sampled 10 mm above, 10 mm below and at the level of the heater simultaneously with measurements of the heat transfer coefficient (HTC). We found that the oil concentration does not change with the level. However, the oil concentration considerably varies with the heat flux density and was always higher than the initial concentration value. The visual observations for the pool boiling process reveal that the concentration of solution depends on superposition between convective and diffusive components of the mass transfer. The data analysis indicates to significant underestimation of the HTC caused by change in the oil concentration. Finally, an influence of oil concentration change was examined for the refrigerant/oil solutions pool boiling with oleic acid surfactant and TiO2 nanoparticles additives.

The atmospheric concentration of trichlorofluoromethane (CFC-11) has been in decline since the production of ozone-depleting substances was phased out under the Montreal Protocol1,2. Since 2013, the concentration decline of CFC-11 slowed unexpectedly owing to increasing emissions, probably from unreported production, which, if sustained, would delay the recovery of the stratospheric ozone layer1–12. Here we report an accelerated decline in the global mean CFC-11 concentration during 2019 and 2020, derived from atmospheric concentration measurements at remote sites around the world. We find that global CFC-11 emissions decreased by 18 ± 6 gigagrams per year (26 ± 9 per cent; one standard deviation) from 2018 to 2019, to a 2019 value (52 ± 10 gigagrams per year) that is similar to the 2008−2012 mean. The decline in global emissions suggests a substantial decrease in unreported CFC-11 production. If the sharp decline in unexpected global emissions and unreported production is sustained, any associated future ozone depletion is likely to be limited, despite an increase in the CFC-11 bank (the amount of CFC-11 produced, but not yet emitted) by 90 to 725 gigagrams by the beginning of 2020. Atmospheric concentration measurements at remote sites around the world reveal an accelerated decline in the global mean CFC-11 concentration during 2018 and 2019, reversing recent trends and building confidence in the timely recovery of the stratospheric ozone layer.

The recovery of the stratospheric ozone layer relies on the continued decline in the atmospheric concentrations of ozone-depleting gases such as chlorofluorocarbons1. The atmospheric concentration of trichlorofluoromethane (CFC-11), the second-most abundant chlorofluorocarbon, has declined substantially since the mid-1990s2. A recently reported slowdown in the decline of the atmospheric concentration of CFC-11 after 2012, however, suggests that global emissions have increased3,4. A concurrent increase in CFC-11 emissions from eastern Asia contributes to the global emission increase, but the location and magnitude of this regional source are unknown3. Here, using high-frequency atmospheric observations from Gosan, South Korea, and Hateruma, Japan, together with global monitoring data and atmospheric chemical transport model simulations, we investigate regional CFC-11 emissions from eastern Asia. We show that emissions from eastern mainland China are 7.0 ± 3.0 (±1 standard deviation) gigagrams per year higher in 2014–2017 than in 2008–2012, and that the increase in emissions arises primarily around the northeastern provinces of Shandong and Hebei. This increase accounts for a substantial fraction (at least 40 to 60 per cent) of the global rise in CFC-11 emissions. We find no evidence for a significant increase in CFC-11 emissions from any other eastern Asian countries or other regions of the world where there are available data for the detection of regional emissions. The attribution of any remaining fraction of the global CFC-11 emission rise to other regions is limited by the sparsity of long-term measurements of sufficient frequency near potentially emissive regions. Several considerations suggest that the increase in CFC-11 emissions from eastern mainland China is likely to be the result of new production and use, which is inconsistent with the Montreal Protocol agreement to phase out global chlorofluorocarbon production by 2010. Emissions from eastern China account for approximately 40 to 60 per cent of the global rise in emissions of trichlorofluoromethane (CFC-11), which may be a result of new production and use.

The oceans are becoming a significant source of trichlorofluoromethane (CFC-11) emissions, a finding that must be accounted for when enforcing the ban on this chemical in coming years, according to...

Recent studies have indicated that Eastern China might be a potential source region of increased atmospheric chlorofluorocarbons (CFCs). To investigate this possibility, a field measurement was carried out from October to December 2017 for identifying the ambient concentration levels of representative trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trifluorotrichloroethane (CFC-113), and tetrafluorodichloroethane (CFC-114) at the residential and municipal solid waste (MSW) landfills and industrial sites in Eastern China. The ambient mixing ratios of CFCs at residential sites were almost within 20% enhancements of the global background sites. The highest levels of CFCs were observed at the MSW landfill sites. Moreover, CFC-11 and CFC-113 concentrations at MSW landfill, which was in service, were two times higher than that at completed MSW landfill. Mean concentrations of 322 pptv for CFC-11, 791 pptv for CFC-12, 91 pptv for CFC-113, and 16 pptv for CFC-114 at various industrial sites were higher than those at residential sites, but they were obviously lower than that at MSW landfill in use. A poor intercorrelation between the CFCs indicated that they did not come from the same source. Higher concentrations measured in this study compared with background sites indicates that MSW landfills could be an unintentional emission source and there are still substantial amounts of CFCs being stored in banks that may discharge CFCs into the atmosphere in Eastern China.

Power generation using Organic Rankine Cycle (ORC) was studied in this paper. A thermodynamic model was achieved in Aspen Plus environment and the highest output power and efficiency were obtained for on variance working fluids. The Organic Rankine Cycle (ORC) is analysed using commonly used working fluids for cycle use, they are R245fa (1,1,1,3,3-Pentafluoropropane), R11 (Trichlorofluoromethane), and R123 (2,2-Dichloro-1,1,1-trifluoroethane) . The results show that some of the effects of the pressure on the inlet turbine, and working fluids variances on the performance of the cycle. The output power turbine and efficiency of the system were simulated and discussed.

Porous materials are widely used in industry for applications that include chemical separations and gas scrubbing. These materials are typically porous solids, although the liquid state can be easier to manipulate in industrial settings. The idea of combining the size and shape selectivity of porous domains with the fluidity of liquids is a promising one and porous liquids composed of functionalized organic cages have recently attracted attention. Here we describe an ionic-liquid, porous, tetrahedral coordination cage. Complementing the gas binding observed in other porous liquids, this material also encapsulates non-gaseous guests-shape and size selectivity was observed for a series of isomeric alcohols. Three gaseous chlorofluorocarbon guests, trichlorofluoromethane, dichlorodifluoromethane and chlorotrifluoromethane, were also shown to be taken up by the liquid coordination cage with an affinity that increased with their size. We hope that these findings will lead to the synthesis of other porous liquids whose guest-uptake properties may be tailored to fulfil specific functions.

The Montreal Protocol was designed to protect the stratospheric ozone layer by enabling reductions in the abundance of ozone-depleting substances such as chlorofluorocarbons (CFCs) in the atmosphere1–3. The reduction in the atmospheric concentration of trichlorofluoromethane (CFC-11) has made the second-largest contribution to the decline in the total atmospheric concentration of ozone-depleting chlorine since the 1990s 1 . However, CFC-11 still contributes one-quarter of all chlorine reaching the stratosphere, and a timely recovery of the stratospheric ozone layer depends on a sustained decline in CFC-11 concentrations 1 . Here we show that the rate of decline of atmospheric CFC-11 concentrations observed at remote measurement sites was constant from 2002 to 2012, and then slowed by about 50 per cent after 2012. The observed slowdown in the decline of CFC-11 concentration was concurrent with a 50 per cent increase in the mean concentration difference observed between the Northern and Southern Hemispheres, and also with the emergence of strong correlations at the Mauna Loa Observatory between concentrations of CFC-11 and other chemicals associated with anthropogenic emissions. A simple model analysis of our findings suggests an increase in CFC-11 emissions of 13 ± 5 gigagrams per year (25 ± 13 per cent) since 2012, despite reported production being close to zero 4 since 2006. Our three-dimensional model simulations confirm the increase in CFC-11 emissions, but indicate that this increase may have been as much as 50 per cent smaller as a result of changes in stratospheric processes or dynamics. The increase in emission of CFC-11 appears unrelated to past production; this suggests unreported new production, which is inconsistent with the Montreal Protocol agreement to phase out global CFC production by 2010.

We demonstrate the fabrication of a highly sensitive opto-chemical sensor system based on cyclodextrin derivative functionalized planar Bragg gratings for an online in-situ detection and measurement of the environmentally harmful propellant trichlorofluoromethane in real-time.

Chromatographic monitoring of chlorofluorocarbons in air requires the preconcentration of these highly volatile species. In this paper, we present functionalized multiwalled carbon nanotubes as effective sorbents for a microtrap designed for chlorofluorocarbons preconcentration. Among the commercial carbons and carbon nanotubes studied, functionalization via carboxylation and propyl amine was most effective for dichlorofluoromethane and trichlorofluoromethane (Freon 11), which were selected as representative chlorofluorocarbons. The results show that carbon nanotubes functionalized with a polar groups led to as much as a 300% increase in breakthrough volume and the desorption bandwidth was reduced by 2.5 times.

The outdoor atmospheric distributions of chlorinated volatile organic compounds (VOCs) from locations receiving the emissions of a chlor-alkali plant have been studied. Trichloroethylene and tetrachloroethylene (medians 2.4 μg/m3 and 1.7 μg/m3, respectively) were the most abundant compounds, which was in accordance with the production processes from these installations. The concentrations of trichlorofluoromethane, median 1.6 μg/m3, are rather similar to the average levels described in general in the troposphere and cannot be attributed to this specific source. Several by-products involving dichloroacetylene, carbon tetrachloride, hexachloroethane, hexachlorobutadiene, trans-1H-pentachloro-1,3-butadiene, 2H-pentachloro-1,3-butadiene, cis-1H-pentachloro-1,3-butadiene, tetrachloro- and trichloro-butadienes and hexachlorobenzene were also identified. Some of these compounds, e.g. carbon tetrachloride, chloroform and tetrachloroethane, could also have been manufactured during some periods. The occurrence of these manufactured compounds and by-products in the atmosphere could also reflect, at least in part, volatilization during the extraction of previously discharged chlor-alkali residues developed within the environmental restoration program of the Flix water reservoir. In this respect, the tri-, tetra- and pentachloro-1,3-butadienes could also originate from microbial transformation in the solid deposits accumulated in the water reservoir which were volatilized after extraction. Among all identified VOCs, trichloroethylene showed the highest health risks considering the measured airborne concentrations and the WHO and USEPA recommendations.

The ex situ treatment of N-nitrosodimethylamine (NDMA) and N-nitrodimethylamine (NTDMA) in groundwater was evaluated in a field-scale fluidized bed bioreactor (FBR). Both of these compounds, which originally entered groundwater at the test site from the use of liquid rocket propellant, are suspected human carcinogens. The objective of this research was to examine the application of a novel field-scale propane-fed fluidized bed bioreactor as an alternative to ultraviolet irradiation (UV) for treating NDMA and NTDMA to low part-per-trillion (ng/L) concentrations. Previous laboratory studies have shown that the bacterium Rhodococcus ruber ENV425 can biodegrade NDMA and NTDMA during growth on propane as a primary substrate and that the strain can effectively reduce NDMA concentrations in propane-fed bench-scale bioreactors of different design. R. ruber ENV425 was used as a seed culture for the FBR, which operated at a fluidization flow of ∼19 L-per-min (LPM) and received propane, oxygen, and inorganic nutrients in the feed. The reactor effectively treated ∼1 μg/L of influent NDMA to effluent concentrations of less than 10 ng/L at a hydraulic residence time (HRT) of only 10 min. At a 20 min HRT, the FBR reduced NDMA to 3 of expanded bed/hr of operation and 1.1 mg NTDMA treated/m 3 of expanded bed/hr of operation, respectively. The FBR system was highly resilient to upsets including power outages. Treatment of NDMA, but not NTDMA, was marginally affected when trace co-contaminants including trichloroethene (TCE) and trichlorofluoromethane (Freon 11) were initially added to feed groundwater, but performance recovered over a few weeks in the continued presence of these compounds. Strain ENV425 appeared to be replaced by native propanotrophs over time based on qPCR analysis, but contaminant treatment was not diminished. The results suggest that a FBR can be a viable alternative to UV treatment for removing NDMA from groundwater.

Volatilization causes changes in the isotopic composition of organic compounds as a result of different vapor pressures of molecules containing heavy and light isotopes. Both normal and inverse vapor pressure isotope effects (VPIE) have been observed, depending on molecular interactions in the liquid phase and the investigated element. Previous studies have focused mostly on pure compound volatilization or on compounds dissolved in organic liquids. Environmentally relevant scenarios, such as isotope fractionation during volatilization of organics from open water surfaces, have largely been neglected. In the current study, open-system volatilization experiments (focusing thereby on kinetic/-nonequilibrium effects) were carried out at ambient temperatures for trichloromethane, trichloroethene, trichlorofluoromethane, trichlorotrifluoroethane, methanol, and ethanol dissolved in water and, if not previously reported in the literature for these compounds, for volatilization from pure liquids. Stable carbon isotopic signatures were measured using continuous flow isotope ratio mass spectrometry. The results demonstrate that volatilization of the four halogenated compounds from water does not cause a measurable change in the carbon isotopic composition, whereas for pure-phase evaporation, significant inverse isotope effects are consistently observed (+0.3 ‰ε+ 1.7 ‰). In contrast, methanol and ethanol showed normal isotope effects for evaporation of pure organic liquids (-3.9 ‰ and -1.9 ‰) and for volatilization of compounds dissolved in water (-4.4 ‰ and -2.9 ‰), respectively. This absence of measurable carbon isotope fractionation considerably facilitates the application of isotopic techniques for extraction of field samples and preconcentration of organohalogens-known to be important pollutants in groundwater and in the atmosphere.

Field chemical analysis (FCA) of volatile halogenated hydrocarbons is a highly debated topic of widespread interest due to the significant negative impact of these compounds on public health, on ecosystems and in the environment (e.g. destruction of stratospheric ozone). This article reports, for the first time, the use of a unique, lightweight (11 kg), man-portable membrane inlet mass spectrometer (MIMS) in the qualitative determination (for both detection and screening) and quantitative analysis of organohalogen chemical analytes in the gaseous phase. Representative compounds examined include: (a) volatile organochlorine compounds (e.g. trichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,1,2-tetrachloroethane), (b) volatile organobromine and chlorobromocarbon compounds (e.g. bromomethane, dibromomethane, chlorobromomethane, bromodichloromethane), and (c) volatile chlorofluorocarbon and organoiodine compounds (e.g. chlorodifluoromethane, trichlorofluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, methyl iodide). Gas phase experiments were undertaken at concentration levels from low ppb to low ppm. The results obtained exhibited excellent linearity within the concentration range examined, high sensitivity (limit of detection < 10 ppb), good repeatability (relative standard deviation, RSD < 5%) and membrane response times in real time (analysis within few seconds). Chemical investigations of mixture effects are also presented. Our method was successfully validated in laboratory based experiments within a test chamber.

Hourly atmospheric measurements of halocarbons and chlorofluorocarbon (CFC) replacements were conducted at an urban site of Lukang, Changhua, in central Taiwan from May to August, 2013. The temporal distribution of different groups of halocarbons in the Lukang urban atmosphere, including chlorofluorocarbons (CFCs), Chlorodifluoromethane (HCFC-22), Bromochlorodifluoromethane (Halon-1211), and other chlorinated compounds, is presented and discussed. The concentrations (mixing ratios) of HCFC-22, Dichlorodifluoromethane (CFC-12), Halon-1211, Trichlorofluoromethane (CFC-11), Dichloromethane (CH 2 Cl 2 ), and Trichloroethylene (TCE) were enhanced with respect to the local background levels; the atmospheric mixing ratio of carbon tetrachloride (CCl 4 ) was slightly higher than its local background level; on the other hand, 1,1,2-Trichlorotrifluoroethane (CFC-113) was relatively uniform and not very different from background atmospheric level in non-urban areas. Among these compounds, HCFC-22, Halon-1211 and the halogenated compounds, CH 2 Cl 2 and TCE, used as solvents were strongly enhanced. The average mixing ratio of Halon-1211 was higher than the local background of ∼4.5 ppt by ∼60% although Halon-1211 production had been phased out by 1996. Hourly average mixing ratios of halocarbons (HCFC-22, CFC-12, Halon-1211, CFC-11, CH 2 Cl 2 , and TCE) illustrated a distinct diurnal cycle characterized with a pattern of elevated mixing ratio and large mixing ratio variability amplitude at night relative to that in daytime. Although emission sources of these halocarbons were complex, hourly average mixing ratios for most of these high variability halocarbons peaked at ∼5:00 AM when the hourly average wind speed reached the minimum value of the day; by contrast, the hourly average mixing ratio of CO peaked at ∼8:30 AM when the ambient atmospheric wind condition was strongly influenced by sea breezes during the traffic rush hours. This phenomenon revealed that meteorological factors predominated the distribution of halocarbon mixing ratio in the urban atmosphere and the traffic emission of CFC-12 derived from old vehicles manufactured before 1994 was insignificant to the CFC-12 mixing ratio in the urban atmosphere. The meteorological condition of nighttime atmospheric temperature inversion and low wind speed facilitated the accumulation of terrestrial airborne pollutants near the ground; consequently the hourly average mixing ratios at night were higher than those in daytime by up to ∼2% (CFC-11), ∼7% (CFC-12), ∼75% (HCFC-22), ∼72% (Halon-1211), ∼280% (CH 2 Cl 2 ), and ∼155% (TCE).

The temporal variation of trace component emissions from the working surface of a landfill in Beijing was investigated. Specific days in a year were selected as representatives for all four seasons. Different chemical species were quantified in all four seasons with the following average concentrations: spring: 41 compounds, 2482.6 μg m −3 ; summer: 59 compounds, 4512.6 μg m −3 ; fall: 66 compounds, 2438.4 μg m −3 ; and winter: 54 compounds, 2901 μg m −3 . The detected compounds included sulfur compounds, oxygenated compounds, aromatics, hydrocarbons, halogenated compounds, and terpenes. Oxygenated compounds were the most abundant compound in most samples. Isobutane, ethyl alcohol, limonene, butane, toluene, and trichlorofluoromethane were recognized as the most abundant compounds on the working surface throughout the year. This study would bring new light in assessing the particle pollution in urban areas and the effect of trace components on landfill odor.

Although many studies have been conducted in recent years on the emissions of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) at the large regional (such as East Asia) and national scales, relatively few studies have been conducted for cities or metropolitan areas. In this study, 192 air samples were collected in the Pearl River Delta (PRD) region of China in November 2010. The atmospheric mixing ratios of six halocarbons were analyzed, including trichlorofluoromethane (CFC-11, CCl3F), dichlorodifluoromethane (CFC-12, CCl2F2), monochlorodifluoromethane (HCFC-22, CHClF2), 1,1-dichloro-1-fluoroethane (HCFC-141b, CH3CCl2F), 1-dichloro-1,1-fluoroethane (HCFC-142b, CH3CClF2), and 1,1,1,2-tetrafluoroethane (HFC-134a, CH2FCF3), and their emissions were estimated based on an interspecies correlation method using HCFC-22 as the reference species. The results showed no significant change in the regional concentration and emission of CFC in the past 10years, suggesting that the continuous regional emission of CFC has had no significant effect on the CFC regional concentration in the PRD region. Concentrations and emissions of HCFCs and HFCs are significantly higher compared to previous research in the PRD region (P

The concentrations of trichlorofluoromethane (CFC-11), methyl iodide (CH3I), dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl), and bromoform (CHBr3) were determined in the marine atmosphere and surface seawater of the East China Sea (ECS) and the South Yellow Sea (SYS) between March and April 2017. Mean mixing ratios (range) of CFC-11, CH3I, CH2Br2, CHBrCl2, CHBr2Cl, and CHBr3 were 192.6 (179.4–226.9), 2.0 (0.7–4.5), 1.0 (0.3–8.0), 0.8 (0.2–5.0), 0.7 (0.2–3.0), and 5.6 (1.1–25.3) pptv, respectively. Anthropogenic activities contributed to elevated atmospheric concentrations of CFC-11, while a combination of biological processes in the seawater and terrestrial sources contributed to elevated atmospheric concentrations of CH3I and bromoalkanes. Mean (range) concentrations of CFC-11, CH3I, CH2Br2, CHBrCl2, CHBr2Cl, and CHBr3 in the surface seawater were 9.47 (4.43–21.28), 4.65 (3.70–6.05), 12.07 (9.63–31.07), 5.45 (1.06–30.04), 13.51 (4.36–54.29), and 15.80 (1.21–34.51) pmol L−1, respectively. Productions of CH3I and bromoalkanes in the surface seawater might be influenced by phytoplankton, picophytoplankton, heterotrophic bacteria, dissolved organic carbon, and nutrients. CFC-11 in the atmosphere and seawater showed little diurnal variation. Compared with weak variation in the seawater, CH3I in the atmosphere showed a significant diurnal variation with a range of 1.2–5.6 pptv. The variation of bromoalkanes concentrations in the atmosphere corresponded to the water concentrations, with the highest value occurring at mid-day. In the current study, the emissions of CH3I, CH2Br2, and CHBr3 from the ECS and the SYS accounted for about 1.1%, 1.8%, and 0.01% of the annual global ocean emissions, respectively, highlighting the importance of the coastal areas to the reactive bromine and iodine in the atmosphere.

Atmospheric monitoring has tracked rogue emissions of ozone-destroying chlorofluorocarbons to northeast China (Nature 2019, DOI: 10.1038/s41586-019-1193-4). Trichlorofluoromethane, or CFC-11, is controlled under the Montreal protocol, and its production was meant to cease by 2010. Before then, CFC-11 was widely used for blowing foams, and it is still leaking from insulating foam in buildings, refrigerators, and other products. Although that reservoir should decline over time, researchers reported last year that global CFC-11 emissions had actually risen between 2014 and 2016, potentially delaying ozone-layer recovery by a decade. Atmospheric modeling suggested that new production and use of the chemical in east Asia was responsible. Members of the same team have now gathered additional data from monitoring stations in South Korea and Japan that show that emissions from eastern mainland China—particularly the provinces of Shandong and Hebei—more than doubled from 2008–12 to 2014–17, an increase of 7,000 me...

Trichlorofluoromethane was once a promising and versatile applicable chlorofluorocarbon. Unaware of its ozone-depleting character, for a long time it was globally applied as propellant and refrigerant and thus led to significant thinning of the ozone layer and contributed to the formation of the so-called ozone hole. Although production and application of this substance were gradually reduced at an early stage, we still face the consequences of its former careless use. Today, trichlorofluoromethane is released during recycling processes of waste cooling devices, traded on the black market, and according to recent findings still illegally manufactured. Here, we present an optical sensor device for real-time in-situ detection and measurement of this environmentally harmful chlorofluorocarbon. The described sensor is based on a planar Bragg grating that is functionalized with cyclodextrin derivatives and operates on the principle of a chemical sensor. In our study, the sensor is sensitized using per-methyl-, per-ethyl-, and per-allyl-substituted &alpha, &beta, and &gamma, cyclodextrins as affinity materials for airborne trichlorofluoromethane. These functional coatings have been proven to be highly efficient, as an up to 400-times stronger signal deflection could be achieved compared to an identical but uncoated sensor. The presented sensor device shows instantaneous response to trichlorofluoromethane exposure, and features a limit-of-detection of less than 25 ppm, depending on the applied affinity material.

Comparing the data sets of chemical transient tracers (trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), sulfur hexafluoride (SF6)) among three reobservations from 1993 to 2006 in the Okhotsk Sea, we found the remarkable change in the efficiency of oceanic absorption of anthropogenic carbon (EF) based on the observed change of apparent tracer age. EF above 27.0 sigma(theta) increased by 16 % while EF below 27.0 sigma(theta) declined by 27 % during the period from 1993 to 2006. Consequently, EF in the entire water column decreased by 14 %. We concluded that the recent reinforcement of ocean stratification derived from the ocean warming caused the weakening of water ventilation in this region, indicating that the penetration of atmospheric anthropogenic carbon to the deep ocean interior is becoming difficult. Citation: Watanabe, Y. W., J. Nishioka, and T. Nakatsuka (2013), Decadal time evolution of oceanic uptake of anthropogenic carbon in the Okhotsk Sea, Geophys. Res. Lett., 40, 322-326, doi:10.1002/grl.50113.

Field sampling and testing were used to investigate the relationship between baseline geochemical and microbial community data and in situ reductive dechlorination rates at a site contaminated with trichloroethene (TCE) and carbon tetrachloride (CTET). Ten monitoring wells were selected to represent conditions along groundwater flow paths from the contaminant source zone to a wetlands groundwater discharge zone. Groundwater samples were analyzed for a suite of geochemical and microbial parameters; then push-pull tests with fluorinated reactive tracers were conducted in each well to measure in situ reductive dechlorination rates. No exogenous electron donors were added in these tests, as the goal was to assess in situ reductive dechlorination rates under natural attenuation conditions. Geochemical data provided preliminary evidence that reductive dechlorination of TCE and CTET was occurring at the site, and microbial data confirmed the presence of known dechlorinating organisms in groundwater. Push-pull tests were conducted using trichlorofluoroethene (TCFE) as a reactive tracer for TCE and, in one well, trichlorofluoromethane (TCFM) as a reactive tracer for CTET. Injected TCFE was transformed to cis- and trans-dichlorofluoroethene and chlorofluoroethene, and, in one test, injected TCFE was completely dechlorinated to fluoroethene (FE). In situ TCFE transformation rates ranged from less than 0.005 to 0.004/day. In the single well tested, injected TCFM was transformed in situ to dichlorofluoromethane and chlorofluoromethane; the TCFM transformation rate was estimated as 0.001/day. The results indicate that it is possible to use push-pull tests with reactive tracers to directly detect and quantify reductive dechlorination of chlorinated ethenes and ethanes under monitored natural attenuation conditions, which has not previously been demonstrated. Transformation rate estimates obtained with these techniques should improve the accuracy of contaminant transport modeling. © 2012 Wiley Periodicals, Inc.

Periodic illumination and changes in the interfacial aqueous-CFC surface area reveal interesting features of the propagation process occurring during the photoinitiated chain reduction of trichlorofluoromethane (CFC 11) to CHCl2F and Cl– in TiO2 suspensions containing HCO2– ions. Formate ions serve as hole scavengers on the TiO2 surface and react with •CCl2F radicals to form HCCl2F and •CO2–. Carboxyl radicals are capable of propagating the chain reaction in the solution phase by reducing CCl3F. Chain reduction of CCl3F continues after illumination has ceased, and the postirradiation reactions constitute 10% or more of the total Cl– yield. The dark reduction of CFC 11 provides further support to the proposed mechanism in which •CCl2F and •CO2– ions function as chain carriers. The reaction rate measured during a period of illumination is affected by the length of the preceding dark period. In addition, the rate of CCl3F reduction is significantly enhanced by the presence of excess CFC 11, which forms a sec...

Hazardous volatile organic compounds (HVOCs) have been increasingly getting concern in urban air chemistry due to photochemical smog as well as its toxicity or potential hazards. In this study, we investigated their concentrations and the properties in tunnel, urban roadside and residential area. As a result, among 36HVOCs measured in this study, BTEX (benzene, toluene, ethylbenzene, xylene) and dichlorodifluoromethane, 1,2,4-trimethylbenzene, trichlorofluoromethane were detected above the concentration of in every sampling site and the most abundant compound was toluene. The other compounds were detected at trace level or below the detection limit. In addition, we found that three CFCs (chlorofluorocarbons), such as CFC-12, CFC-11, CFC-113, were persistently detected because of the emission in the past. Toluene to benzene ratio (T/B) at tunnel and roadside were calculated to be 4.3~5.3 and at residential area 15.4, suggesting that the residential area had several emission sources other than car exhaust. The ratio of X/E (m,p-xylene to ethylbenzene) ratio was calculated to be 1.8~2.1 at tunnel, 1.7 at roadside and 1.2 at residential area, which means this ratio reflected well the relative photochemical reactivity between these compounds. Good correlation between m,p-xylene and ethylbenzene ( > 0.85) were shown in every study sites. This indicated that correlation between -alkylbenzenes were not severely affected by 3-way catalytic converter. In this study, it was demonstrated that the concentration of benzene was very low, compared with national air quality standard (annual average of ). Its concentration were in roadside and in residential area. We thought this was the result of persistent policy implementation including the reduction of benzene content in gasoline enforced on January 1, 2009.

The severely ozone‐depleting trichlorofluoromethane is still appearing in several recycling processes or industrial applications. A simple and selective supramolecular complex formation of per‐methylated α‐cyclodextrin (1) with the highly volatile trichlorofluoromethane (2) is reported. This interaction moreover leads to thermally stable crystals. Per‐methylated α‐cyclodextrin is successfully exploited as a reversible and selective adsorption material for liquid and airborne trichlorofluoromethane as well as an affinity material for the chemical sensing and detection of this particular volatile organic component.

The cover image depicts the hazard caused by chlorofluorocarbons such as CFC‐11, which are used, for example, as blowing agents for polyurethane foams, and the protective effect of the oligosaccharide, hexakis‐(2,3,6‐tri‐O‐methyl)‐α‐cyclodextrin, which is capable of binding CFC‐11 by supramolecular complexation and thus protecting the stratospheric ozone layer from the harmful trichlorofluoromethane. Further details can be found in article number 1800057 by Ralf Hellmann, Siegfried R. Waldvogel, and co‐workers.

In a feat of atmospheric detective work, researchers have uncovered evidence that thousands of metric tons of an ozone-destroying chemical are still being released into the air every year, despite a global ban on production (Nature 2018, DOI: 10.1038/s41586-018-0106-2). Their investigation traced trichlorofluoromethane (a chlorofluorocarbon, CFC-11) back to east Asia, and concluded that it was probably emitted by new, unreported production facilities. “If it continues at this rate, it will delay ozone recovery by about a decade,” says Stephen A. Montzka of the National Oceanic and Atmospheric Administration, who led the research. CFC-11 is one of a suite of halocarbons that are controlled under the Montreal Protocol on Substances That Deplete the Ozone Layer, widely hailed as being the most effective environmental treaty in history. When the protocol came into force in 1989, it set a timetable to phase out various industrial halocarbons used as refrigerants, solvents, and propellants. In

Trichlorofluoromethane (CCl3F) and water form clathrate hydrate which melts at 8.5 °C under atmospheric pressure. By DSC and X rays analysis we could distinguish between hydrate and ice formed in emulsion containing NaCl and show that quantity of hydrate formed and its dissociation temperature are dependent on solution concentration. The equilibrium curve hydrate-NaCl solution is displaced towards higher temperatures with respect to corresponding ice curve. Consequently solid–liquid equilibrium can not be established in presence of both solids. Growth of hydrate crystals at the expense of ice was evidenced. Role of salt in hydrate growth and ice melting is examined.