Institute of Earth Environment
Institutional Repository of Institute of Earth Environment, CASNot a member yet
7120 research outputs found
Sort by
Influence of sulfamethazine (SMT) on the adsorption of antimony by the black soil: Implication for the complexation between SMT and antimony
No full textThis paper reported when sulfamethazine (SMT) and antimony (Sb(V)) coexisted in aqueous solution at pH of 3.0, 5.0 and 7.0, the complexation between SMT and Sb(V) occurred. Such a complexation impeded the adsorption of Sb(V) on the black soil. The higher the solution pH value was, the more the amount of Sb(V) was prevented from adsorbing on the black soil. The maximum adsorption capacity (qm) of Sb(V) at the presence of SMT under pH of 3.0, 5.0 and 7.0was 5.28, 3.45 and 1.95 mg/g, respectively. -NH2, N-H, S = O and C-\N of pyrimidine ring carried by SMT acted as the complexation sites with Sb(V). The complexation constant K were- 3.15,-3.26 and- 3.48 at pH of 7.0, 5.0 and 3.0, respectively, indicating that the complexation strength between SMT and Sb(V) followed the order of pH 7.0 > pH 5.0 > pH 3.0. The binding energy between Sb(V) and the C-N group of pyrimidine ring was the highest (1.42 eV), and then followed by the groups of -NH (1.37 eV), S = O (0.66 eV) and -NH2 (0.39 eV). Besides S = O and C-N, Sb(V) tends to complex with N-H via coordination bond at pH of 7.0 while -NH2 via cation-p interaction at pH 3.0 and 5.0. Compared to pH of 5.0, the strength of cation-p interaction at pH of 3.0 weakened according to the molecular electrostatic potentialmap. These results demonstrated that different from the situation where Sb(V) exists in aqueous solution alone, the coexistence of SMT with Sb(V) affected the adsorption behavior of Sb(V) in soil and solution pH was also an influence factor. These findings in this paperwould be helpful for further understanding themobility, bioavailability and other environmental behavior of Sb(V) in soil when Sb(V) coexists with antibiotics even other organic compounds. (C) 2020 Elsevier B.V. All rights reserved
Relative humidity variation derived from tree-ring delta O-18 and possible large-scale atmospheric circulations linkage over the Guanzhong Plain, central northern China, since 1760 CE
No full textChina is drastically influenced by the Asian monsoon. Based on the relationship (r = -.636, N = 62, p < .001) between tree-ring delta O-18 values from nine cores of Pinus tabulaeformis Carr. from Nanwutai and the Asia monsoon-related June-August relative humidity (RHJJA), we designed a transfer function reconstructing the RHJJA variation from 1760 to 2018 CE. Our RHJJA reconstruction captured some extreme climatic events that occurred in the past, such as the Ding-Wu disaster (1876-1878 CE), which was the most serious drought event of northern China in the 19th century, and the severe drought event of 1925-1930 CE. The spatial correlation analysis shows that our RHJJA reconstruction has not only local but also large-scale hydroclimate circulations. Our reconstruction compared well with other hydroclimate series from northern China, indicating the large-scale representativeness of our reconstruction. Both the ensemble empirical mode decomposition (EEMD) and the periodicity analyses revealed that the El Nino-South Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Arctic Oscillation (AO) and the solar activity strongly affected Asian monsoon-related RHJJA changes over Guanzhong Plain in the past. We believe this study is of great significance and provides an in-depth understanding of climate change in the Guanzhong Plain and in northern China
Provenance of sub-aerial surface sediments in the Tarim Basin, Western China
No full textProvenance of surface sediments in the Tarim Basin is important for understanding the aridification of the Asian interior and the interplay between the Westerlies and the Asian monsoon. Although the desert sands in the Taklamakan Desert have been studied intensively, there is no consensus regarding their provenance, namely, the dispute exists between various sand sources in different parts of the desert and homogenization of the sands in the entire desert. Moreover, other surface sediments in the basin are poorly investigated. Here we examine the particle-size-specific rare earth element (REE) and trace element characteristics of various surface sediments from different regions of the basin. The results reveal that the 63 mu m fraction are dominated by regional-derived materials, mainly from the adjacent mountains (e.g. Pamirs, Kunlun, Kuruktag, Altun, Tianshan Mountains), and the fluvial systems are an important additional transport mechanism. Our findings potentially provide an improved understanding of the dust cycle and atmospheric circulation patterns in Central Asia, and of the provenance of loess in North China
Water management and wheat yields in ancient China: Carbon isotope discrimination of archaeological wheat grains
No full textThe evaluation of ancient crop production and its response to climate change is key to exploring the ancient demographic and social changes. Wheat is currently the third most widely cultivated crop worldwide and was a major component across of the agricultural systems of the ancient Eurasia. In this study, the Delta C-13 values of 116 charred wheat grains from 28 archaeological sites, with direct AMS C-14 dating of 3952 +/- 66 to 389 +/- 73 cal yr BP, across northern China are reported. The result shows that the Delta C-13 values estimated wheat yields ranged from 0.5 to 2.5 Mg ha(-1), during the past 4000 years. The water supply and grain yield of wheat cultivation is the highest in China during the Bronze Age; however, the water supply and yield were significantly affected by climate fluctuation in the middle-late Holocene. No significant long-term trend of increasing wheat yield is observed over this interval, but a correlation between Delta C-13 values estimated wheat yield and cyclical climate changes can be noted
REPLY TO STUCHLI ' K ET AL.: The Younger Dryas onset at 12.87 ky BP is still justified if the Laacher See eruption is considered
No full textTiming and forcing mechanism of the final Neotethys seawater retreat from Central Iran in response to the Arabia-Asia collision in the late early Miocene
No full textThe Iranian Plateau lies in the middle of the Neotethys tectonic domain; to the east it connects with the Tibetan Plateau, and to the west with the Anatolian Plateau and the Alpine orogenic belts. In the Cenozoic it underwent land/sea changes and tectonic uplift in response to the Arabia-Asia plate collision. One of the most prominent geological consequences of the collision was the disappearance of an epicontinental sea in Central Iran, which was a northeastern branch of the Neotethys seaway in the Oligocene-early Miocene. The timing of the final seawater retreat from Central Iran and its forcing mechanism are important for understanding the effects of Arabia-Asia plate collision as well as global eustatic sea-level changes. In this paper we present new magnetostratigraphy, U-Pb ages of one tuffaceous bed, and stable isotopic records of carbonates. The results of this multidisciplinary study indicate that a shallow open sea in the Qom back-arc basin ended at 17 Ma, but the final seawater retreat from a restricted marine environment was at 16.8 Ma. The final regression was just before the Middle Miocene Optimum, implying that it was not related to a climatic factor, but driven by the Arabia-Asia plate collision. Moreover, the delta O-18 record of fine-grained lacustrine carbonates indicates an isotopic shift towards more positive isotopes after 13 Ma, suggesting an enhanced aridification in Central Iran. This climatic deterioration was a response to reduced transport of moisture by westerlies from a retreating Neotethys Sea driven by a global eustatic sea-level drop in response to the East Antarctica ice-sheet expansion after the middle Miocene Optimum
Decisive role of vacuum-assisted carbonization in valorization of lignin-enriched (Juglans regia-shell) biowaste
No full textBioenergy is considered a sustainable substitute to fossil-fuel resources and the development of a prudent combination of renewable and innovative conversion technologies are essential for the valorization and effective conversion of biowaste to value-added commodities. Here, a negative pressure-induced carbonization process was proposed for the valorization of lignin-enriched biowaste precursor to bio-oil and environmental materials (biochar) at various temperatures. The high heating values (HHV) of the as-prepared biochars from the lignin enriched precursor under negative pressure (low-medium vacuum) were within 25.9-31.5 MJ/kg, which matched satisfactorily to the commercial charcoal. Whereas, the bio-oils produced from the lignin enriched precursor under vacuum conditions was a blend of complex aromatic and straight-chain hydro-carbons, including aldehyde, ketone, phenol, and furans, exhibiting ability as potential heating-oil with HHV within 21.2-28.2 MJ/kg. Moreover, the biochars produced under vacuum environments at higher temperature showed greater stability (22.5-35.9%) than those produced under N-2 atmosphere
Responses of soil ammonia-oxidizing bacteria and archaea to short-term warming and nitrogen input in a semi-arid grassland on the Loess Plateau
No full textAmmonia-oxidizing archaea (AOA) and bacteria (AOB) predominantly control ammonia oxidation, the first and rate-limiting step of nitrification, and critically affect plant utilization and the fate of reactive nitrogen (N) input to soil. Both AOA and AOB are often sensitive to environmental changes, but their responses to the concurrent climate warming and N input remain poorly understood, particularly in semi-arid grassland ecosystems where nitrification dominates soil N transformations. We examined the interactive effects of short-term (2-yr) warming and N input (12 g N m(-2) y(-1)) on the abundance and community structure of AOA and AOB in a semi-arid grassland on China's Loess Plateau. Results showed that AOA abundance was significantly higher than AOB in all treatments. N input significantly increased the abundance of AOA and AOB by 32% and 521%, respectively, and induced a significant shift in the AOB community composition. Warming significantly increased the abundance of AOB by 94%, but had no impact on the AOA abundance. Warming (alone or combined with N input) did not significantly affect the community structure of AOA or AOB. These results indicated that AOB was more sensitive to N input and climate warming than AOA in semi-arid Loess grasslands. Our findings suggest that understanding the responses of AOB abundance and composition may be key to predict the N dynamics under future global change scenarios
Measurement report: quantifying source contribution of fossil fuels and biomass-burning black carbon aerosol in the southeastern margin of the Tibetan Plateau
No full textAnthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because there have been no high-time-resolution BC source apportionments. Intensive measurements were taken in a transport channel for pollutants from Southeast Asia to the southeastern margin of the TP during the premonsoon to investigate the influences of fossil fuels and biomass burning on BC. A receptor model that coupled multi-wavelength absorption with aerosol species concentrations was used to retrieve site-specific Angstrom exponents (AAEs) and mass absorption cross sections (MACS) for BC. An "aethalometer model" that used those values showed that biomass burning had a larger contribution to BC mass than fossil fuels (BCbiomass = 57 % versus BCfossil = 43 %). The potential source contribution function indicated that BCbiomass was transported to the site from northeastern India and northern Burma. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) indicated that 40 % of BCbiomass originated from Southeast Asia, while the high BCfossil was transported from the southwest of the sampling site. A radiative transfer model indicated that the average atmospheric direct radiative effect (DRE) of BC was +4.6 +/- 2.4 W m(-2), with +2.5 +/- 1.8 W m(-2) from BCbiomass and +2.1 +/- 0.9 W m(-2 )from BCfossil. The DRE of BCbiomass and BCfossil produced heating rates of 0.07 +/- 0.05 and 0.06 +/- 0.02 K d(-1), respectively. This study provides insights into sources of BC over a transport channel to the southeastern TP and the influence of the cross-border transportation of biomass-burning emissions from Southeast Asia during the pre-monsoon
Measurement report: quantifying source contribution of fossil fuels and biomass-burning black carbon aerosol in the southeastern margin of the Tibetan Plateau
No full textAnthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because there have been no high-time-resolution BC source apportionments. Intensive measurements were taken in a transport channel for pollutants from Southeast Asia to the southeastern margin of the TP during the premonsoon to investigate the influences of fossil fuels and biomass burning on BC. A receptor model that coupled multi-wavelength absorption with aerosol species concentrations was used to retrieve site-specific Angstrom exponents (AAEs) and mass absorption cross sections (MACS) for BC. An "aethalometer model" that used those values showed that biomass burning had a larger contribution to BC mass than fossil fuels (BCbiomass = 57 % versus BCfossil = 43 %). The potential source contribution function indicated that BCbiomass was transported to the site from northeastern India and northern Burma. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) indicated that 40 % of BCbiomass originated from Southeast Asia, while the high BCfossil was transported from the southwest of the sampling site. A radiative transfer model indicated that the average atmospheric direct radiative effect (DRE) of BC was +4.6 +/- 2.4 W m(-2), with +2.5 +/- 1.8 W m(-2) from BCbiomass and +2.1 +/- 0.9 W m(-2 )from BCfossil. The DRE of BCbiomass and BCfossil produced heating rates of 0.07 +/- 0.05 and 0.06 +/- 0.02 K d(-1), respectively. This study provides insights into sources of BC over a transport channel to the southeastern TP and the influence of the cross-border transportation of biomass-burning emissions from Southeast Asia during the pre-monsoon