Phytoremediation as a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants is becoming an increasingly important objective in plant research. In this study, biologic...Phytoremediation as a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants is becoming an increasingly important objective in plant research. In this study, biological cycles of five nutrient elements （N, P, K, Ca, and Mg） and eight heavy metal elements （Fe, Cu, Zn, Mn, Cd, Ni, Pb and Co） were examined in young paniculed goldraintree （Koelreuteria paniculata Laxm） and common elaeocarpus （Elaeocarpus decipens） mixed stands in an abandoned mining area. We found that after vegetation restoration in abandoned mining areas, the organic matter and concentrations of nutrient elements were significantly increased and the heavy metal elements were significantly decreased, the annual retention, uptake and return were 75.0, 115.4, and 40.3 kg/hm^2 for nutrient elements, and 1 878.0, 3 231.0 and 1 353.0 g/hm^2 for heavy metal elements, respectively, with the utilization coefficient, cycling coefficient and turnover rate of 0.92, 0.35 and 0.32 for nutrient elements, and 1.24, 0.42 and 1.92 for heavy metal elements, respectively. Our results suggested that the vegetation restoration in abandoned mining areas had significant effects in improving environmental conditions, enhancing soil available nutrients, and ensuring human health.展开更多
An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitatio...An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitation. The present study examines the roles of persistent low-level jets(LLJs) in maintaining the precipitation using surface station observations and reanalysis datasets. The LLJs triggered strong ascending motions and carried moisture mainly from the outflow of Typhoon In-fa(2021). The varying directions of the LLJs well corresponded to the meridional shifts of the rainfall. The precipitation rate reached a maximum during 20-21 July as the LLJs strengthened and expanded vertically into double LLJs, including synoptic-weather-system-related LLJs(SLLJs) at 850–700 hPa and boundary-layer jets(BLJs)at ~950 hPa. The coupling of the SLLJ and BLJ provided strong mid-and low-level convergence on 20 July, whereas the SLLJ produced mid-level divergence at its entrance that coupled with low-level convergence at the terminus of the BLJ on21 July. The formation mechanisms of the two types of LLJs are further examined. The SLLJs and the low-pressure vortex(or inverted trough) varied synchronously as a whole and were affected by the southwestward movement of the WPSH in the rainiest period. The persistent large total pressure gradient force at low levels also maintained the strength of low-level geostrophic winds, thus sustaining the BLJs on the synoptic scale. The results based on a Du-Rotunno 1D model show that the Blackadar and Holton mechanisms jointly governed the BLJ dynamics on the diurnal scale.展开更多
Absorption,accumulation and distribution of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S elements in loblolly pine plantation in the hilly regions of southern Jiangsu province were studied.The results show that the storage of nine el...Absorption,accumulation and distribution of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S elements in loblolly pine plantation in the hilly regions of southern Jiangsu province were studied.The results show that the storage of nine elements in the soil of the forest is in order of S>P>Mn>Zn>Cr>Cu>Pb>Ni>Cd,their contents in different organs of trees are quite different,being Pb 0 96～5 81,Cd 0 266～0 720,Cr 8 55～9 49,Cu 4 36～9 44,Mn 18 98～61 07,Ni 1 74～9 03,Zn 13 44～32 69,P 168～987,and S 446～1770(mg·kg -1 ).Their accumulation ratios of elements in plants are in order of Cd >P>S>Cu>Zn>Cr>Pb>Ni> Mn.The accumulation amounts of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S in the biomass of the community are 36 30 ,5 47,85 58,74 54,248 1,26 81,236 5,3268,and 8158 (mg·m -2 ),respectively,of which the overground part accounted for 5 37%,10 60%,23 77%,15 99%,16 61%,12 38%,12 34%,24 85%,and 4712%,higher than underground part.The biological cycles of the elements in the community are described as follows:annual uptake is Pb 23 75,Cd 1 97,Cr 24 07,Cu 27 44,Mn 170 17,Ni 19 51,Zn 109 29,P 1721 69,and S 2843 14 (mg·m -2 ).Annual return is Pb 12 70,Cd 0 68,Cr 1 66,Cu 10 49,Mn 70 72,Ni 6 46,Zn 40 60,P 257 61,and S 486 56 (mg·m -2 ).The turnover periods of nine elements are 3,8,52,7,4,4,6,57 and 17 years respectively.展开更多
A greenhouse experiment was carried out to compare differences in potential activities of ammonification, nitrification and denitrification in rhizosphere and bulk soil in a heavy-metal-stressed system. Exchangeable f...A greenhouse experiment was carried out to compare differences in potential activities of ammonification, nitrification and denitrification in rhizosphere and bulk soil in a heavy-metal-stressed system. Exchangeable fractions of Cd, Cu and Cr were all higher in the rhizosphere of maize than in bulk soil. Results showed that the mineralization of N in soil was stimulated by low concentration of Cd. Addition of Cd at low levels stimulated the ammonifying and nitrifying activity in soil, while inhibitory influences were shown at high levels. Nitrifying bacteria was proved to be the most sensitive one, whilst the effect on denitrifying bacteria was very limited. Comparing Cd, Cu and Cr(VI) at 20 mg/kg soil, Cd was the most effective inhibitor of ammonification and denitrification, while Cr(VI) had the strongest inhibitory influence on nitrifying activity. Root exudates played important roles on the different exchangeable metal fractions and bacterial activities between rhizosphere and non-rhizosphere. Nitrate was the main form of mineral N in soil, as well as the main form of N absorbed by plants, but the formation and relative absorption of ammonium were promoted in response to high Cd exposure.展开更多
Heavy water-moderated molten salt reactors(HWMSRs)are novel molten salt reactors that adopt heavy water rather than graphite as the moderator while employing liquid fuel.Owing to the high moderating ratio of the heavy...Heavy water-moderated molten salt reactors(HWMSRs)are novel molten salt reactors that adopt heavy water rather than graphite as the moderator while employing liquid fuel.Owing to the high moderating ratio of the heavy water moderator and the utilization of liquid fuel,HWMSRs can achieve a high neutron economy.In this study,a large-scale small modular HWMSR with a thermal power of 500 MWth was proposed and studied.The criticality of the core was evaluated using an in-house critical search calculation code(CSCC),which was developed based on Standardized Computer Analyses for Licensing Evaluation,version 6.1.The preliminary fuel cycle performances(initial conversion ratio(CR),initialfissile fuel loading mass,and temperature coefficient)were investigated by varying the lattice pitch(P)and the molten salt volume fraction(VF).The results demonstrate that the temperature coefficient can be negative over the range of investigated Ps and VFs for both 233U-Th and LEU-Th fuels.A core with a P of 20 cm and a VF of 20%is recommended for 233U-Th and LEU-Th fuels to achieve a high performance of initial CR and fuel loading.Regarding TRU-Th fuel,a core with a smaller P(~5 cm)and larger VF(~24%)is recommended to obtain a negative temperature coefficient.展开更多
After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catal...After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catalytic cracking called RICP which does not further recycles the FCC heavy cycle oil (HCO) inside the FCC unit and delivers HCO to the residue hydrotreating unit as a diluting oil for the residue that is concurrently subjected to hydrotreating prior to being used as the FCC feed oil. The RICP technology can stimulate residue hydrotreating reactions through utilization of HCO along with an in- creased yield of FCC light distillate, resulting in enhanced petroleum utilization and economic benefits of the refinery.展开更多
Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanis...Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanisms,and pollution control,their relationship remains a mystery.Researchers generally focused on one topic independently without comprehensive considerations due to the knowledge gap between environmental science and human health.Indeed,the full life cycle control of HMs is crucial and should be reconsidered with the combination of the occurrence,transport,and fate of HMs in the environment.Therefore,we started by reviewing the environmental behaviors of HMs which are affected by a variety of natural factors as well as their physicochemical properties.Furthermore,the related toxicity mechanisms were discussed according to exposure route,toxicity mechanism,and adverse consequences.In addition,the current state-of-the-art of available technologies for pollution control of HMs wastewater and solid wastes were summarized.Finally,based on the research trend,we proposed that advanced in-operando characterizations will help us better understand the fundamental reaction mechanisms,and big data analysis approaches will aid in establishing the prediction model for risk management.展开更多
This paper reports the absorption, accumulation, distribution and cycle of Cu, Pb, Zn, Cr and Ni in S. apetala + S. caseolaris, mangrove community at Futian Mangrove Nature Reserve of Shenzhen. The Cu, Pb, Zn, Cr and...This paper reports the absorption, accumulation, distribution and cycle of Cu, Pb, Zn, Cr and Ni in S. apetala + S. caseolaris, mangrove community at Futian Mangrove Nature Reserve of Shenzhen. The Cu, Pb, Zn, Cr and Ni contents in forest soil increase from bottom to surface layers, and the storage of the five heavy metals in the surface layer (depth 0 ~ 30 cm) is Zn > Pb > Ni > Cr > Cu. The concentration ability is S. caseolaris > S. apetala > K. candel. The existing accumulation of Cu, Pb, Zn, Cr and Ni in the community μis 23 019.63g/m2μ, 23 429.66g/m2μ, 117 870.42g/m2μ, 6 835.80g/m2μ, and 12 995.22g/m2μ, respectively. The annual absorption is 6 592.57g/m2μ, 2 664.80g/m2μ, 23 123.56g/m2μ, 853.24g/m2μ, and 1 990.95g/m2, respectively. The annual return is μ3 179.50g/m2μ, 1 300.65g/m2μ, 7 401.31g/m2μ, 398.99g/m2μ, and 646.20g/m2, respectively. The annual net retention accumulation of Cu, Pb, Zn, Cr and Ni in the community is 3 413.07μg/m2, 1 364.15μ g/m2, 15 722.25μg/m2, 454.25μg/m2, and μ1 344.75g/m2, respectively. The turn over periods of Cu, Pb, Zn, Cr and Ni are 8,19,15,18 and 21 years, respectively.展开更多
基金Supported by the National Natural Science Foundation of China （No. 30571487the Key project of State Forestry Administration（2006-11, 2006-17）+1 种基金the Urban Forest Ecological Key Laboratory of Hunan Province（No. 06FJ3083）and the Platform Construction Project of the Ministry of Science and Technology of China（No. 20021220）.
文摘Phytoremediation as a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants is becoming an increasingly important objective in plant research. In this study, biological cycles of five nutrient elements （N, P, K, Ca, and Mg） and eight heavy metal elements （Fe, Cu, Zn, Mn, Cd, Ni, Pb and Co） were examined in young paniculed goldraintree （Koelreuteria paniculata Laxm） and common elaeocarpus （Elaeocarpus decipens） mixed stands in an abandoned mining area. We found that after vegetation restoration in abandoned mining areas, the organic matter and concentrations of nutrient elements were significantly increased and the heavy metal elements were significantly decreased, the annual retention, uptake and return were 75.0, 115.4, and 40.3 kg/hm^2 for nutrient elements, and 1 878.0, 3 231.0 and 1 353.0 g/hm^2 for heavy metal elements, respectively, with the utilization coefficient, cycling coefficient and turnover rate of 0.92, 0.35 and 0.32 for nutrient elements, and 1.24, 0.42 and 1.92 for heavy metal elements, respectively. Our results suggested that the vegetation restoration in abandoned mining areas had significant effects in improving environmental conditions, enhancing soil available nutrients, and ensuring human health.
基金supported by Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)the National Natural Science Foundation of China(Grant Nos.42122033,41875055,and 42075006)Guangzhou Science and Technology Plan Projects(202002030346 and 202002030196).
文摘An extremely heavy rainfall event lasting from 17 to 22 July 2021 occurred in Henan Province of China, with accumulated precipitation of more than 1000 mm over a 6-day period that exceeded its mean annual precipitation. The present study examines the roles of persistent low-level jets(LLJs) in maintaining the precipitation using surface station observations and reanalysis datasets. The LLJs triggered strong ascending motions and carried moisture mainly from the outflow of Typhoon In-fa(2021). The varying directions of the LLJs well corresponded to the meridional shifts of the rainfall. The precipitation rate reached a maximum during 20-21 July as the LLJs strengthened and expanded vertically into double LLJs, including synoptic-weather-system-related LLJs(SLLJs) at 850–700 hPa and boundary-layer jets(BLJs)at ~950 hPa. The coupling of the SLLJ and BLJ provided strong mid-and low-level convergence on 20 July, whereas the SLLJ produced mid-level divergence at its entrance that coupled with low-level convergence at the terminus of the BLJ on21 July. The formation mechanisms of the two types of LLJs are further examined. The SLLJs and the low-pressure vortex(or inverted trough) varied synchronously as a whole and were affected by the southwestward movement of the WPSH in the rainiest period. The persistent large total pressure gradient force at low levels also maintained the strength of low-level geostrophic winds, thus sustaining the BLJs on the synoptic scale. The results based on a Du-Rotunno 1D model show that the Blackadar and Holton mechanisms jointly governed the BLJ dynamics on the diurnal scale.
文摘Absorption,accumulation and distribution of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S elements in loblolly pine plantation in the hilly regions of southern Jiangsu province were studied.The results show that the storage of nine elements in the soil of the forest is in order of S>P>Mn>Zn>Cr>Cu>Pb>Ni>Cd,their contents in different organs of trees are quite different,being Pb 0 96～5 81,Cd 0 266～0 720,Cr 8 55～9 49,Cu 4 36～9 44,Mn 18 98～61 07,Ni 1 74～9 03,Zn 13 44～32 69,P 168～987,and S 446～1770(mg·kg -1 ).Their accumulation ratios of elements in plants are in order of Cd >P>S>Cu>Zn>Cr>Pb>Ni> Mn.The accumulation amounts of Pb,Cd,Cr,Cu,Mn,Ni,Zn,P and S in the biomass of the community are 36 30 ,5 47,85 58,74 54,248 1,26 81,236 5,3268,and 8158 (mg·m -2 ),respectively,of which the overground part accounted for 5 37%,10 60%,23 77%,15 99%,16 61%,12 38%,12 34%,24 85%,and 4712%,higher than underground part.The biological cycles of the elements in the community are described as follows:annual uptake is Pb 23 75,Cd 1 97,Cr 24 07,Cu 27 44,Mn 170 17,Ni 19 51,Zn 109 29,P 1721 69,and S 2843 14 (mg·m -2 ).Annual return is Pb 12 70,Cd 0 68,Cr 1 66,Cu 10 49,Mn 70 72,Ni 6 46,Zn 40 60,P 257 61,and S 486 56 (mg·m -2 ).The turnover periods of nine elements are 3,8,52,7,4,4,6,57 and 17 years respectively.
基金The National Basic Research and Development Program(No. 2002CB410807) and the Key Project of National Natural Science Foundation of China(40432004)
文摘A greenhouse experiment was carried out to compare differences in potential activities of ammonification, nitrification and denitrification in rhizosphere and bulk soil in a heavy-metal-stressed system. Exchangeable fractions of Cd, Cu and Cr were all higher in the rhizosphere of maize than in bulk soil. Results showed that the mineralization of N in soil was stimulated by low concentration of Cd. Addition of Cd at low levels stimulated the ammonifying and nitrifying activity in soil, while inhibitory influences were shown at high levels. Nitrifying bacteria was proved to be the most sensitive one, whilst the effect on denitrifying bacteria was very limited. Comparing Cd, Cu and Cr(VI) at 20 mg/kg soil, Cd was the most effective inhibitor of ammonification and denitrification, while Cr(VI) had the strongest inhibitory influence on nitrifying activity. Root exudates played important roles on the different exchangeable metal fractions and bacterial activities between rhizosphere and non-rhizosphere. Nitrate was the main form of mineral N in soil, as well as the main form of N absorbed by plants, but the formation and relative absorption of ammonium were promoted in response to high Cd exposure.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)the National Natural Science Foundation of China(No.11905285)+1 种基金the National Natural Science Foundation of China(No.11790321)the Frontier Science Key Program of the Chinese Academy of Sciences(No.QYZDY-SSW-JSC016)。
文摘Heavy water-moderated molten salt reactors(HWMSRs)are novel molten salt reactors that adopt heavy water rather than graphite as the moderator while employing liquid fuel.Owing to the high moderating ratio of the heavy water moderator and the utilization of liquid fuel,HWMSRs can achieve a high neutron economy.In this study,a large-scale small modular HWMSR with a thermal power of 500 MWth was proposed and studied.The criticality of the core was evaluated using an in-house critical search calculation code(CSCC),which was developed based on Standardized Computer Analyses for Licensing Evaluation,version 6.1.The preliminary fuel cycle performances(initial conversion ratio(CR),initialfissile fuel loading mass,and temperature coefficient)were investigated by varying the lattice pitch(P)and the molten salt volume fraction(VF).The results demonstrate that the temperature coefficient can be negative over the range of investigated Ps and VFs for both 233U-Th and LEU-Th fuels.A core with a P of 20 cm and a VF of 20%is recommended for 233U-Th and LEU-Th fuels to achieve a high performance of initial CR and fuel loading.Regarding TRU-Th fuel,a core with a smaller P(~5 cm)and larger VF(~24%)is recommended to obtain a negative temperature coefficient.
文摘After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catalytic cracking called RICP which does not further recycles the FCC heavy cycle oil (HCO) inside the FCC unit and delivers HCO to the residue hydrotreating unit as a diluting oil for the residue that is concurrently subjected to hydrotreating prior to being used as the FCC feed oil. The RICP technology can stimulate residue hydrotreating reactions through utilization of HCO along with an in- creased yield of FCC light distillate, resulting in enhanced petroleum utilization and economic benefits of the refinery.
基金supported by the National Key Research and Devel-opment Program of China(Grant No.2019YFA0210400)the National Natural Science Foundation of China(Grant Nos.21836002 and 52104315)+1 种基金the Foundation for Innovative Research Groups of the Na-tional Natural Science Foundation of China(Grant No.52121004)the Major program Natural Science Foundation of Hunan Province of China(No.2021JC0001).
文摘Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanisms,and pollution control,their relationship remains a mystery.Researchers generally focused on one topic independently without comprehensive considerations due to the knowledge gap between environmental science and human health.Indeed,the full life cycle control of HMs is crucial and should be reconsidered with the combination of the occurrence,transport,and fate of HMs in the environment.Therefore,we started by reviewing the environmental behaviors of HMs which are affected by a variety of natural factors as well as their physicochemical properties.Furthermore,the related toxicity mechanisms were discussed according to exposure route,toxicity mechanism,and adverse consequences.In addition,the current state-of-the-art of available technologies for pollution control of HMs wastewater and solid wastes were summarized.Finally,based on the research trend,we proposed that advanced in-operando characterizations will help us better understand the fundamental reaction mechanisms,and big data analysis approaches will aid in establishing the prediction model for risk management.
文摘This paper reports the absorption, accumulation, distribution and cycle of Cu, Pb, Zn, Cr and Ni in S. apetala + S. caseolaris, mangrove community at Futian Mangrove Nature Reserve of Shenzhen. The Cu, Pb, Zn, Cr and Ni contents in forest soil increase from bottom to surface layers, and the storage of the five heavy metals in the surface layer (depth 0 ~ 30 cm) is Zn > Pb > Ni > Cr > Cu. The concentration ability is S. caseolaris > S. apetala > K. candel. The existing accumulation of Cu, Pb, Zn, Cr and Ni in the community μis 23 019.63g/m2μ, 23 429.66g/m2μ, 117 870.42g/m2μ, 6 835.80g/m2μ, and 12 995.22g/m2μ, respectively. The annual absorption is 6 592.57g/m2μ, 2 664.80g/m2μ, 23 123.56g/m2μ, 853.24g/m2μ, and 1 990.95g/m2, respectively. The annual return is μ3 179.50g/m2μ, 1 300.65g/m2μ, 7 401.31g/m2μ, 398.99g/m2μ, and 646.20g/m2, respectively. The annual net retention accumulation of Cu, Pb, Zn, Cr and Ni in the community is 3 413.07μg/m2, 1 364.15μ g/m2, 15 722.25μg/m2, 454.25μg/m2, and μ1 344.75g/m2, respectively. The turn over periods of Cu, Pb, Zn, Cr and Ni are 8,19,15,18 and 21 years, respectively.
