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A micro-packed bed reactor has been developed to demonstrate aerobic oxidation of alcohols to aldehydes, utilizing green oxidant O2 and effective Cu/TEMPO-catalyzed system.

In recent years, self-optimization strategies have been gradually utilized for the determination of optimal reaction conditions owing to their high convenience and independence from researchers' experience. However, most self-optimization algorithms still focus on homogeneous reactions or simple heterogeneous reactions. Investigations on complex heterogeneous gas–liquid–solid reactions are rare. Based on the Nelder–Mead simplex method and Bayesian optimization, this work proposes a reaction optimization framework for optimizing complex gas–liquid–solid reactions. Three gas–liquid–solid reactions including the hydrogenations of nitrobenzene, 3,4-dichloronitrobenzene, and 5-nitroisoquinoline are investigated, respectively. Reaction parameters (temperature, hydrogen pressure, liquid flow rate, and gas flow rate) are optimized. Compared with the traditional OVAT method, the proposed Bayesian based optimization algorithm exhibits remarkable performance with higher yields (0.998, 0.991 and 0.995, respectively) and computational efficiency.

Methods of coating Al2O3 on nickel micro-foam were compared and screened, aiming to overcome the capillary force and prepare the micro-foam monolithic catalyst coatings. The surface of micro-foam substrate was pretreated by a chemical etching method to improve the adhesion of the coatings on the substrate. The results showed that the slurry circulation at 162 ml·min-1 was evaluated as the optimal method. The pore size on the substrate surface can be controlled by changing the pretreatment conditions. An empirical correlation was also proposed, showing an excellent practicality for predicting the pore size. The adhesion of the coatings with substrate pretreatment was significantly better than that without substrate pretreatment. The minimum value of weight loss after ultrasonic vibration was 3.9%. This mainly attributes to the squeezing of Al2O3 particles in the pores of substrate surface. The coatings on nickel micro-foam are hopefully used in micropacked beds for catalytic reactions.

The selective hydrogenation of halogenated nitroaromatic compounds is of great importance in the fine chemical industry. However, the hydrogenation reactions in commonly utilized batch reactors suffer from the undesired dehalogenation, resulting in higher requirement for subsequent separation processes and severe corrosion to industrial fatalities. In this work, a H-flow system with the micropacked bed reactor was developed for the selective hydrogenation of halogenated nitroaromatic compounds and the reduction of 3,4-dichloronitrobenzene was selected as the model reaction. With the optimal hydrogenation conditions, the yield of 3,4-dichloroaniline was obtained as high as 99.8% under mild conditions. With this strategy this flow system was successfully employed to the reduction of other chlorinated nitroaromatics also demonstrating low dehalogenation. The H-flow system enables negligible dehalogenation and remarkable yield of target product with higher efficiency and lower energy cost compared with the batch reactor.

The hydrogenation of heterocyclic nitroaromatics is of great importance in the pharmaceutical industry for the synthesis of key intermediates. However, high selectivity is difficult to achieve in c...

Sulfur dioxide (SO2) measured by satellites is widely used to estimate anthropogenic emissions. The Sentinel-5 Precursor (S-5P) operational SO2 product is overestimated compared to the ground-based multiaxis differential optical absorption spectroscopy (MAX-DOAS) measurements in China and shows an opposite variation to the surface measurements, which limits the application of TROPOspheric monitoring instrument (TROPOMI) products in emissions research. Radiometric calibration, a priori profiles, and fitting windows might cause the overestimation of S-5P operational SO2 product. Here, we improve the optimal-estimation-based algorithm through several calibration methods. The improved retrieval agrees reasonably well with the ground-based measurements (R > 0.70, bias

OBJECTIVE This study aimed to examine the developmental pattern of diurnal cortisol rhythm during pubertal transition and its prospective association with psychopathological symptoms. METHODS A cohort of 1158 children consisting of 608 boys and 550 girls aged 7 to 9 years (mean [standard deviation] age = 8.04 [0.61] years) were recruited in the Anhui Province of China in 2015 (wave 1). A single awakening sample was collected at baseline, and three additional samples were collected at one weekday in wave 2 to wave 4. Four indices of cortisol activity were evaluated and calculated across the day: awakening cortisol level, cortisol awakening response, the area under the curve with respect to ground (AUC), and the diurnal cortisol slope. In each wave, pubertal development was assessed by testicular size in boys and Tanner scales in girls. Psychopathological symptoms were ascertained in waves 2 to 4. RESULTS Multilevel mixed models revealed no significant pubertal changes in diurnal cortisol activity in girls. In boys, awakening cortisol (β = -0.005, p = .004) and total cortisol output (lnAUC, β = -0.005, p = .040) significantly decreased across pubertal transition. Higher awakening cortisol and total cortisol output (lnAUC) were associated with higher scores on internalizing symptoms in girls (β = 0.82, p < .001; β = 0.62, p = .012) and externalizing symptoms in boys (β = 0.73, p = .001; β = 0.55, p = .019) during the 3-year follow-up. In contrast, no associations were found between cortisol awakening response and diurnal cortisol slope with psychopathological symptom scores in boys or girls. CONCLUSIONS Development of diurnal cortisol activity during pubertal transition occurs in a sex-specific manner. Awakening cortisol level and daily total cortisol output may serve as markers for psychopathology during pubertal transition.

The Sentinel-5 Precursor (S-5P) was launched into low earth orbit with a single payload TROPOspheric Monitoring Instrument (TROPOMI) on 13 October, 2017. TROPOMI is able to provide atmospheric composition observations including sulfur dioxide (SO2) daily and globally. It has a higher spatial resolution, specifically with a ground resolution of 7 km ×3.5 km in the nadir, than previous satellite instruments such as Ozone Monitoring Instrument (OMI, 13 km ×24 km) and Ozone Mapping and Profiler Suite (OMPS, 50 km ×50 km). The three types of S-5P operational SO2 products (offline (OFFL), Reprocessing (RPRO) and Near Real Time (NRTI)) are on basis of the differential optical absorption spectroscopy (DOAS) algorithm, and available from the S-5P Pre-Operations Data Hub. To evaluate these data, the results of OFFL are compared to the measurements obtained by ground-based Multi-Axis DOAS (MAX-DOAS) and China National Environmental Monitoring Center (CNEMC). We find that the S-5P operational SO2 products significantly overestimate SO2 concentrations over Northern China. Compared with four ground-based MAX-DOAS measurements in terms of the weekly average SO2 vertical column densities (VCDs), the S-5P operational SO2 products exhibit an overestimation of 61%−140%, with the correlation coefficient less than 0.5. The a priori SO2 profiles in S-5P operational products are from daily Tracer Model (TM5) simulations. SO2 surface concentrations are converted by the S-5P operational SO2 products and a priori SO2 profiles used in the retrievals. The correlation coefficient between the SO2 surface concentrations measured by CNEMC over Northern China and those from the S-5P operational products is higher than 0.5, and the S-5P operational products at these CNEMC sites show an overestimation of about 54.6% on average. In this study, the SO2 products (TROPOMI USTC SO2 products) are retrieved by the University of Science and Technology of China (USTC) with the optimal estimation algorithm (OE) from TROPOMI measurements, with the a priori SO2 profiles from monthly average GEOS-Chem simulations. The mean biases between the TROPOMI USTC SO2 products and the ground-based MAX-DOAS measurements are reduced significantly (−4.8%−22%), together with an improvement in the correlation coefficients (0.72−0.89). TROPOMI USTC SO2 surface concentrations are transformed by the TROPOMI USTC SO2 products and a priori SO2 profiles in the retrievals. Based on the evaluation statistics of the S-5P operational SO2 products, a smaller mean bias of −25.8% is found between the TROPOMI USTC SO2 surface concentrations and CNEMC measurements over Northern China. Compared to the TROPOMI USTC SO2 products in the heavily polluted area (33°−45°N, 110°−122°E), the S-5P operational SO2 products have an overestimation of around 41.3%, with a correlation coefficient of 0.73. In addition, S-5P operational SO2 products show a larger area of heavy pollution than TROPOMI USTC SO2 products. Additionally, the sensitivity analysis indicates many influential factors of the SO2 retrievals using OE algorithm, such as radiative calibration, fitting window and a priori SO2 profiles. In the fitting window of 310.5−326.0 nm, the SO2 columns retrieved by the a priori profiles from monthly GEOS-Chem simulations show better agreement with the MAX-DOAS measurements than those from daily TM5 simulations. A possible reason is that the emission inventory used in GEOS-Chem is based on a Chinese power sector database for 31 provinces supported by CMEP (Chinese Ministry of Environmental Protection), resulting in a better performance of GEOS-Chem than that of TM5 over China in simulations. And the overestimation of the S-5P operational SO2 products over Northern China may be attributed to the fitting window used.

An automated flow platform based on a tube-in-tube contactor and micro-packed bed reactor is developed to measure the kinetics of gas–liquid–solid hydrogenation reactions. The liquid flowing in the inner tube of the tube-in-tube contactor is rapidly saturated to ensure a constant H2 concentration before entering the micro-packed bed, which transforms the gas–liquid–solid system into a liquid–solid system. A ramping strategy is adopted in which the continuously varied residence time and the corresponding conversion data are obtained in a single experiment. Two reactions including hydrogenation of α-methylstyrene and nitrobenzene are chosen to demonstrate the accuracy and efficiency of this automated platform. Varying the flow rate ramping shows that accurate kinetic determination requires a specific range of flow rate ramps. A kinetic curve of conversion versus residence time (more than ten thousand data points) can be obtained in a single experiment within 50 min. The kinetic parameters obtained with this strategy agree well with literature values. The automated flow platform with flow rate ramping enables accurate determination of gas–liquid–solid reaction kinetics with higher efficiency and lower reagent cost compared with other methods.

Sulfur dioxide (SO

The hydrogenation of m-dinitrobenzene to m-phenylenediamine is a significant transformation for the synthesis of dyes and pigments in the fine chemical industry. Owing to the complexity of this reaction mechanism and negative effect of the first amino group on the reduction of the second nitro group, it is difficult to inhibit eminently the generation of side products and obtain m-phenylenediamine efficiently. Hence it is imperative to establish kinetic network and investigate the intrinsic kinetic parameters of this reaction for further optimization. In this study, a continuous flow system based on micro-packed bed reactor was developed and a kinetic model of the hydrogenation of m-dinitrobenzene was established successfully. The activation energies and pre-exponential factors were acquired using the kinetic network and the kinetic model exhibited reasonable fit for the transformation of each substance. Moreover, the influence of pressure was investigated, and the accuracy of kinetic model was validated by the comparison with the values in literature. This kinetic model enabled the accurate determination of kinetic parameters with Pt/C and Ni/SiO2 catalysts, and provided the rate determining steps and characteristics of different catalysts for the process optimization.

Controllable integration of metal nanoparticles (NPs) and metal–organic frameworks (MOFs) is of significant importance in many applications owing to their unique properties. In situ efficient synthesis of metal NPs with different structures into MOFs is a great challenge. Herein, we report the nanostructures of octahedron and flower Pt–Cu frame@HKUST-1, which is successfully synthesized under a microwave irradiation method in only 30 min. In this study, Pt–Cu alloys, serving as the self-template, are synthesized first, followed by the HKUST-1 shell growing in situ via the consumption of Cu0. As multifunctional catalysts, the core–shell structures exhibit excellent performance for the hydrogenation of 1-hexene. Notably, octahedron Pt–Cu frame@HKUST-1 displays high turnover number (TON) and turnover frequency (TOF) of 1004 and 2008 h–1, respectively. Thanks to the protective effect of HKUST-1, the octahedron Pt–Cu frame@HKUST-1 can be recycled for at least four runs without serious loss of activity and obvi...

Pubertal timing has been suggested as biological factors implicated in the onset of depression in girls. This study aims to examine the prospective association between accelerated pubertal progression with depressive symptoms, and to further explore the possible role of individual reactivity to social stress in this association. A total of 56 girls with early puberty timing (assessed through breast Tanner stage) and 56 age-matched normal breast development girls were recruited at Wave 1 (grade 3) and followed for 4 years biennially. Hypothalamic-pituitary-adrenal axis stress reactivity was indexed by four cortisol samples collected before, during and after the Groningen Social Stress Test (GSST) at Wave 1. Depressive symptoms were interviewed through Mood & Feeling Questionnaire (MFQ) at each wave. About 42.9% (24/56) from early pubertal timing group and 19.6% (11/56) from normal control group were found accelerated breast development during 4-year follow-up. Mixed effects linear models illustrated that among accelerated breast development girls, those with heightened stress reactivity is likely to have a 6.62 (95% CI, 1.14-12.11)-point higher MFQ scores, and 41.9% (95%CI: 25.2 to 58.6%) higher probability for depressive symptoms, compared with girls with persistent normal breast development and moderate stress reactivity. However, no similar effects were found in girls with accelerated breast development but attenuated stress reactivity. The finding suggests that heightened cortisol reactivity to social stress may represent a useful biomarker in identifying girls at greatest risk of development of depressive symptoms following accelerated pubertal progression.

The green credentials of hydroelectricity in terms of greenhouse-gas (GHG) emissions have been tarnished with the finding of the researches on GHG emissions from hydroelectric reservoirs in the last two decades. Substantial amounts of GHGs release from the tropical reservoirs, especially methane (CH4) from Brazil’s Amazonian areas. CH4 contributes strongly to climate change because it has a global warming potential (GWP) 24 times higher than carbon dioxide (CO2) on a per molecule basis over a 100-year time horizon. GHGs may emit from reservoirs through four different pathways to the atmosphere: (1) diffusive flux at the reservoir surface, (2) gas bubble flux in the shallow zones of a reservoir, (3) water degassing flux at the outlet of the powerhouse downstream of turbines and spillways, and (4) flux across the air–water interface in the rivers downstream of the dams. This paper reviewed the productions and emissions of CH4, CO2, and N2O in reservoirs, and the environmental variables influencing CH4 and CO2 emissions were also summarized. Moreover, the paper combined with the progress of GHG emissions from Three Gorges Reservoir and proposed three crucial problems to be resolved on GHG emissions from reservoirs at present, which would be benefit to estimate the total GHG emissions from Three Gorges Reservoir accurately.

This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g

Diffusive carbon dioxide (CO2) emissions from the water surface of the Three Gorges Reservoir, currently the largest hydroelectric reservoir in the world, were measured using floating static chambers over the course of a yearlong survey. The results showed that the average annual CO2 flux was (163.3 +/- 117.4) mg CO2/(m2.hr) at the reservoir surface, which was larger than the CO2 flux in most boreal and temperate reservoirs but lower than that in tropical reservoirs. Significant spatial variations in CO2 flux were observed at four measured sites, with the largest flux measured at Wushan (221.9 mg CO2/(m2.hr)) and the smallest flux measured at Zigui (88.6 mg CO2/(m(2).hr)); these differences were probably related to the average water velocities at different sites. Seasonal variations in CO2 flux were also observed at four sites, starting to increase in January, continuously rising until peaking in the summer (June-August) and gradually decreasing thereafter. Seasonal variations in CO2 flux could reflect seasonal dynamics in pH, water velocity, and temperature. Since the spatial and temporal variations in CO2 flux were significant and dependent on multiple physical, chemical, and hydrological factors, it is suggested that long-term measurements should be made on a large spatial scale to assess the climatic influence of hydropower in China, as well as the rest of the world.

[1] To investigate temporal and spatial variations in diffusive CH4 emission from the surface of the Three Gorges Reservoir, CH4 emissions were measured using the static chamber technique along the mainstream of the reservoir from January to December 2010. The overall average CH4 flux is 7.93 mg CH4 m−2 d−1, which is comparable to those from other temperate reservoirs but significantly lower than those from tropical reservoirs. Seasonal variations showed that CH4 emission reached the maximum in the summer and turned to the low levels in the other seasons; such variations reflected the seasonal dynamics of temperature, dissolved oxygen, and water velocity. Moreover, the yearly average CH4 flux decreased from upstream to downstream before the Three Gorges Dam, but CH4 emission from the surface of the downstream river was higher than that from the surface at Zigui, the upstream water before the Three Gorges Dam. The differences in water velocity and allochthonous input of organic matter probably caused the spatial variations in CH4 emission. These results indicate that systematic sampling is needed to better estimate CH4 emission through coverage of the temporal and spatial scales and to better assess the influence of CH4 emission from the Three Gorges Reservoir on climate change in China, as well as the rest of the world.

Bio-nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self-assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs affect the formation of the BNCs, and ultimately control the activity of the bound enzymes. Smaller MNPs form small clusters with a low affinity for the HRP. While the turnover for the bound fraction is drastically increased, there is no difference in the H2O2 inhibitory concentration. Larger MNPs with a higher magnetization aggregate in larger clusters and have a higher affinity for the enzyme and a lower substrate inhibition. All of the BNCs are more active than the free enzyme or the MNPs (BNCs > HRP ≫ MNPs). Since the BNCs show surprising resilience in various reaction conditions, they may pave the way towards new hybrid biocatalysts with increased activities and unique catalytic properties for magnetosensitive enzymatic reactions.

Recently reported summertime methane (CH4) emissions (6.7 +/- 13.3 mg CH4/(m2 x hr)) from newly created marshes in the drawdown area of the Three Gorges Reservoir (TGR), China have triggered broad concern in academic circles and among the public. The CH4 emissions from TGR water surfaces and drawdown areas were monitored from 3rd June to 16th October 2010 with floating and static chambers and gas chromatography. The average CH4 emission flux from permanently flooded areas in Zigui, Wushan and Yunyang Counties was (0.33 +/- 0.09) mg CH4/(m2 x hr). In half of these hottest months of the year, the wilderness, cropland and deforested drawdown sites were aerobic and located above water level, and the CH4 emissions were very small, ranging from a sink at 0.12 mg CH4/(m2 x hr) to a source at 0.08 mg CH4/(m2 x hr) except for one mud-covered site after flood. Mean CH4 emission in flooded drawdown sites was 0.34 mg CH4/(m2 x hr). The emissions from the rice paddy sites in the drawdown area were averaged at (4.86 +/- 2.31) mg CH4/(m2 x hr). Excepting the rice-paddy sites, these results show much lower emission levels than previously reported. Our results indicated considerable spatial and temporal variation in CH4 emissions from the TGR. Human activities and occasional events, such as flood, may also affect emission levels. Long-term CH4 measurements and modeling in a large region are necessary to accurately estimate greenhouse gas emissions from the TGR.

Few investigations have been made on the impact of elevated ozone (O3) concentration on methane (CH4) emission from rice paddies. Using open-top chambers in situ with different O3 treatments, CH4 emissions were measured in a rice paddy in Yangtze River Delta, China in 2007 and 2008. There were four treatments applied: charcoal-filtered air (CF), nonfiltered air (NF), and charcoal-filtered air with different O3 additions (O3-1 and O3-2). The mean O3 concentrations during the O3 fumigation were 19.7, 22.6, 69.6 and 118.6ppb in 2007 and 7.0, 17.4, 82.2 and 138.3ppb in 2008 for treatments CF, NF, O3-1 and O3-2, respectively. The rice yields, as compared with CF, were reduced by 32.8% and 37.1%, 58.3% and 52.1% in treatments O3-1 and O3-2 in 2007 and 2008, respectively. The diurnal patterns of CH4 emission varied temporally with treatments and there was inconsistence in diurnal variations in CH4 emissions from the paddy field. The daily mean CH4 emissions were significantly lower in treatments O3-1 and O3-2 than those in treatments CF and NF. Compared with CF treatment, CH4 emissions from the paddy field were decreased to 46.5% and 38.3%, 50.6% and 46.8% under treatments O3-1 and O3-2 in the whole growing seasons of 2007 and 2008, respectively. The seasonal mean CH4 emissions were negatively related with AOT40 (accumulative O3 concentration above 40ppb; Po0.01 in both years), but positively related to the relative rice yield (reference to CF; Po0.01 in 2007 and Po0.001 in 2008), aboveground biomass (Po0.01 in both years) and underground biomass (Po0.01 in 2007 and Po0.05 in 2008). The decreased CH4 emission from the rice paddy due to an increased O3 exposure might partially mitigate the global warming potential induced by soil carbon loss under elevated O3 concentrations.

Th is publication was based on work supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). Experimental details of the synthesis and characterization of the sorbent. Adsorption and desorption of the sorbent.

Methane emissions from hydroelectric reservoirs can comprise a considerable portion of anthropogenic methane. However, lack of data on CH(4) emissions in different geographical regions and high spatial-temporal variability in the emission rates of reservoirs has led to uncertainties regarding regional emission estimates of CH(4). In the subtropical plateau climate region, we used the Ertan hydroelectric reservoir as a study area. The CH(4) flux at the air-water interface was assessed by floating chambers and factors influencing emissions, including the distance from the dam, water depth, seasonal variation in wet and dry season, air-water temperature gradient and wind speed, and was also studied through a year-long systematic sampling and monitoring experiment. The results showed that the surface of the reservoir was a source of CH(4) during the sampling period and the annual average CH(4) flux was 2.80 +/- 1.52 mg m(-2) d(-1). CH(4) flux (and its variation) was higher in the shallow water areas than in the deep-water areas. CH(4) flux near the dam was significantly higher than that of other locations farther from the dam in the dry season. The seasonal variations of CH(4) emission in wet and dry seasons were minor and significant diurnal variations were observed in wet and dry seasons. Exponential relationships between the CH(4) flux and air-water temperature gradient were found. Air-water temperature gradient was an important factor influencing diurnal variations of CH(4) flux in the Ertan hydroelectric reservoir. These results indicate that systematic sampling is needed to better estimate CH(4) flux through coverage of the spatial variation of different water depths, measuring-point distance from the dam, seasonal variation in wet and dry seasons and changes in climate factors (such as air-water temperature gradient). Our results also provide a fundamental parameter for CH(4) emission estimation of global reservoirs. Copyright (C) 2010 John Wiley a Sons, Ltd.

Based on the carbon-nitrogen cycles and greenhouse gas (GHG) mitigation and emission processes related to straw return and burning, a compound greenhouse gas budget model, the "Straw Return and Burning Model" (SRBM), was constructed to estimate the net mitigation potential of straw return to the soil in China. As a full GHG budget model, the SRBM addressed the following five processes: (1) soil carbon sequestration, (2) mitigation of synthetic N fertilizer substitution, (3) methane emission from rice paddies, (4) additional fossil fuel use for straw return, and (5) CH4 and N2O emissions from straw burning in the fields. Two comparable scenarios were created to reflect different degrees of implementation for straw return and straw burning. With GHG emissions and mitigation effects of the five processes converted into global warming potential (GWP), the net GHG mitigation was estimated. We concluded that (1) when the full greenhouse gas budget is considered, the net mitigation potential of straw return differs from that when soil carbon sequestration is considered alone; (2) implementation of straw return across a larger area of cropland in 10 provinces (i.e., Shanghai, Jiangsu, Zhejiang, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, and Hainan) will increase net GHG emission; (3) if straw return is promoted as a feasible mitigation measure in the remaining provinces, the total net mitigation potential before soil organic carbon (SOC) saturation will be 71.89 Tg CO2 equivalent (eqv)/yr, which is equivalent to 1.733% of the annual carbon emission from fossil fuel use in China in 2003; (4) after SOC saturation, only 13 of 21 provinces retain a relatively small but permanent net mitigation potential, while in the others the net GHG mitigation potential will gradually diminish; and (5) the major obstacle to the feasibility or permanence of straw return as a mitigation measure is the increased CH4 emission from rice paddies. The paper also suggests that comparable scenarios in which all the related carbon-nitrogen cycles are taken into account be created to estimate the mitigation potentials of organic wastes in different utilizations and treatments.

This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2 concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2 concentrations. That a system rooted in “cumulative emissions per capita,” the best conception of the “common but differentiated responsibilities” principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries’ cumulative emissions per capita, estimates of their cumulative emissions from 1900 to 2005, and their annual emissions allowances into the future (2006–2050), a 470 ppmv atmospheric CO2 concentration target was set. According to the following four objective indicators-total emissions allowance from 1900 to 2050, actual emissions from 1900 to 2005, emissions levels in 2005, and the average growth rate of emissions from 1996 to 2005-all countries and regions whose population was more than 300000 in 2005 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this proposal, most G8 countries by 2005 had already expended their 2050 emissions allowances. The accumulated financial value based on emissions has reached more than 5.5 trillion US dollars (20 dollars per ton of CO2). Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2006 to 2050 would still be much higher than those of developing countries; under such circumstance, these future emissions would create more than 6.3 trillion US dollars in emissions deficits. Because of their low cumulative emissions per capita, most developing countries fall within one of the latter two groups, which means that they have leeway for making emissions decisions in the future. Although China accounts for more than 30% of the total global emissions allowance from 2006 to 2050, its total emissions can be controlled within that allowance by no other way than reducing its future emissions growth rates. In the end, nine key issues related to international climate negotiations were briefly addressed.

Soil as the largest global carbon pool has played a great role in sequestering the atmospheric carbon dioxide (CO(2)). Although global carbon sequestration potentials have been assessed since the 1980s, few investigations have been made on soil carbon sequestration (SCS) in China's cropland. China is a developing country and has a long history of agricultural activities. Estimation of SCS potentials in China's cropland is very important for assessing the potential measures to prevent the atmospheric carbon rise and predicting the atmospheric CO(2) concentration in future. After review of the available results of the field experiments in China, relationships between SCS and nitrogen fertilizer application, straw return and no-tillage (NT) practices were established for each of the four agricultural regions. According to the current agricultural practices and their future development, estimations were made on SCS by nitrogen fertilizer application, straw return and NT in China's cropland. In the current situation, nitrogen fertilizer application, straw return and zero tillage can sequester 5.96, 9.76 and 0.800 Tg C each year. Carbon sequestration potential will increase to 12.1 Tg C yr(-1) if nitrogen is fertilized on experts' recommendations. The carbon sequestration potentials of straw return and NT can reach 34.4 and 4.60 Tg C yr(-1) when these two techniques are further popularized. In these measures, straw return is the most promising one. Full popularization of straw return can reduce 5.3% of the CO(2) emission from fossil fuel combustion in China in 1990, which meets the global mean CO(2) reduction requested by the Kyoto Protocol (5.2%). In general, if more incentive policies can be elaborated and implemented, the SCS in China's cropland will be increased by about two times. So, popularization of the above-mentioned agricultural measures for carbon sequestration can be considered as an effective tool to prevent the rapid rise of the atmospheric CO(2) in China.

This study was initiated to explore the effects of ozone (O-3) exposure on potted wheat roots and soil microbial community function. Three treatments were performed: (1) Air with daily averaged O-3 concentration of 4-10 ppb (control situation, CK), (2) Air plus 8 h averaged O-3 concentration of 76.1 ppb (O-3-1), and (3) Air plus 8 h averaged O-3 concentration of 118.8 ppb (O-3-2). In treatments with elevated O-3 concentration (O-3-1 and O-3-2), the root and shoot biomass were reduced by 25% and 18%, respectively, compared to the control treatment (CK). On the other hand, root activity was significantly reduced by 58% and 90.8% in the O-3-1 and O-3-2 treatments, respectively, compared to CK. The soil microbial biomass was significantly reduced only in the highest O-3 concentration (O-3-2 treatment) in the rhizosphere soil. Soil microbial community composition was assessed under O-3 stress based on the changes in the sole carbon source utilization profiles of soil microbial communities using the Biolog (TM) system. Principal component analysis showed that there was significant discrimination in the sole-carbon source utilization pattern of soil microbial communities among the O-3 treatments in rhizosphere soil; however, there was none in the bulk soil. In rhizosphere soil, the functional richness of the soil microbial community was reduced by 27% and 38% in O-3-1 and O-3-2 treatments, respectively, compared to CK. O-3-2 treatment remarkably decreased the Shannon diversity index of soil microbial community function in rhizosphere soil, but the O-3-1 treatment did not. In the dominant microorganisms using carbon sources of carbohydrates and amino acids groups were significantly reduced by an elevated O-3 concentration in the rhizosphere soil. Our study shows that the elevated ozone levels may alter microbial community function in rhizosphere soil but not in the bulk soil. Hence, this suggests that O-3 effects on soil microbes are caused by O-3 detriments on the plant, but not by the O-3 direct effects on the soil microbes.

Laboratory culture experiments were conducted with common reed (Phragmites australis) to elucidate the role of root exudates on CH4 production in wetland soils as well as the importance of different plant organs as routes of CH4 to the atmosphere. In the 50 d experiment period, root exudates ranged from 0.03 to 1.53 µmolg−1d−1, which increased with reed growth. CH4 production rate of soil was stimulated as root exudates collected was added. CH4 transport capacity rate also increased with plant growth and influenced by light intensity. Root tips were the most important part of controlling diffusion of CH4 into reed shoots, and leave transport accounted for 45.34% of total emissions into the atmosphere.

With rapid industrialization and urbanization in the Yangtze Delta, China, the tropospheric ozone concentration has increased to levels that induce crop yield loss. Rice, a widely grown crop in China, was investigated in field-established, open-top chambers. Four treatments were used: charcoal-filtered air (CF), non-charcoal-filtered air (NF), and charcoal-filtered air with two levels of additional ozone (O(3)-1 and O(3)-2). The AOT40s (accumulated hourly mean ozone concentration above 40 ppbv) were 0, 0.91, 23.24, and 39.28 ppmv.h for treatment of CF, NF, O(3)-1, and O(3)-2, respectively. The rice height and biomass were reduced in the elevated ozone concentration. Less organic matter partitioning to roots under the elevated ozone significantly decreased rice root activity. The yield loss was 14.3% and 20.2% under O(3)-1 and O(3)-2 exposure, respectively. This was largely caused by a reduction in grain weight per panicle.

We investigated the effects of vascular plants on methane emissions from Wuliangsu Lake, a wetland in an arid region of northwestern China. Under natural conditions in early June and late July, average CH4 fluxes were respectively 16.3±4.3 and 19.3±6.0 mg m−2 h−1. Whereas, shading treatments, which eliminated direct sunlight to plants, resulted in lower CH4 emission (8.2±1.9 and 10.2±2.6 mg m−2h−1 for the two periods). When the culms were cut below the water surface, the fraction of CH4 emissions was about 18% and 15% of that of natural control systems in early June and late July, respectively. Our findings indicated that the photosynthesis of reed had a positive influence on the process of methane emission; however, effects on production and transport outweighed oxidation. Of the carbon fixed by photosynthesis, only 4.7% was returned to the atmosphere as CH4.

CH4 emissions have been widely studied in various wetlands, such as boreal peatlands, rice paddies, and tropical swamps. However, little investigation has been carried out for CH4 emissions from lakes or wetlands in arid regions where these freshwaters play a vital role in providing ecosystem services for local people. To quantify the spatial and temporal variations of CH4 flux and understand its key controlling factors in shallow lakes in arid regions of Western China, CH4 fluxes from Wuliangsu Lake were measured at different vegetation zones and water depths with a static chamber technique during a growing season from April to October in 2003. Results showed that the average emission flux of CH4 from submerged plant (Potamogeton pectinatus) growing zones was 2.16 mg CH4 m−2 h−1, which was 85.8% lower than that from emergent macrophyte (Phragmites australis) growing zones. CH4 emissions increased with increasing water depth in Phragmites Community. Significant seasonal and diurnal variations of CH4 emission were observed for P. australis during the plant growth stage, for P. pectinatus growing zones, however, the variations were minor. In addition to vegetation cover and water depth, bottom silt temperature and light intensity were also important factors influencing seasonal and diurnal variations of CH4 flux from Phargmites growing zone.

Monodispersed hollow spherical mesoporous particles with tunable particle size and shell thickness were readily synthesized using latex templates and a silica precursor in a weakly basic ethanol−water mixture.

We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)-magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2 O2 , producing free radicals. The phenoxy radicals react with each other in a non-enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP-magnetic nanoparticle hybrids are supported on micron-scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes.

Methane (CH4) emissions from the drawdown area of the Three Gorges Reservoir (TGR) have not been thoroughly investigated even though the drawdown area encompasses one third of the reservoir surface. In this study, CH4 emissions from different land uses were measured in the TGR drawdown area. The average diffusive CH4 emissions were 2.61, 0.19, 0.18, and 0.12 mg CH4 m(-2) h(-1) in rice paddies, fallow lands, deforested lands, and croplands, respectively, and were positively related to the duration of the inundated season among the latter three land uses. On average the drawdown areas studied here (except rice paddies) were sources in the inundated season (0.22 +/- 0.26 mg CH4 m(-2) h(-1)) and a sink in the drained season (-0.008 +/- 0.035 mg CH4 m(-2) h(-1)). The water level was the dominant factor that controlled whether the drawdown area was either inundated or drained, which in turn determined whether the drawdown area was a source or sink of CH4 emissions. The average diffusive CH4 emissions from the fallow lands, croplands, and deforested lands increased as the distance from the dam increased from Zigui (0.10 +/- 0.15 mg CH4 m(-2) h(-1)) to Wushan (0.15 +/- 0.29 mg CH4 m(-2) h(-1)) to Yunyang (0.24 +/- 0.27 mg CH4 m(-2) h(-1)), which could reflect different sediment characteristics and water velocities. The total CH4 emission from the drawdown area was estimated to range from 1033.5 to 1333.9 Mg CH4 yr(-1), which would account for 42-54% of the total CH4 emissions from the water surface of TGR.

We report an interesting approach for efficient synthesis of SnO2 hollow spheres inside mesoporous silica “nanoreactors”. The as-prepared products are shown to have a uniform size distribution and good structural stability. When evaluated for their lithium storage properties, these SnO2 hollow spheres manifest improved capacity retention. Accepted version

A novel high efficiency nanocomposite sorbent for CO2 capture has been developed based on oligomeric amine (polyethylenimine, PEI, and tetraethylenepentamine, TEPA) functionalized mesoporous silica capsules. The newly synthesized sorbents exhibit extraordinary capture capacity up to 7.9 mmol g−1 under simulated flue gas conditions (pre-humidified 10% CO2). The CO2 capture kinetics were found to be fast and reached 90% of the total capacities within the first few minutes. The effects of the mesoporous capsule features such as particle size and shell thickness on CO2 capture capacity were investigated. Larger particle size, higher interior void volume and thinner mesoporous shell thickness all improved the CO2 capacity of the sorbents. PEI impregnated sorbents showed good reversibility and stability during cyclic adsorption–regeneration tests (50 cycles).