The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO c...The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).展开更多
The distribution of light fraction carbon （LF-C） in the various size classes of aggregates and its relationship to water- stable aggregates as well as the influence of cultivation on the organic components in virgin...The distribution of light fraction carbon （LF-C） in the various size classes of aggregates and its relationship to water- stable aggregates as well as the influence of cultivation on the organic components in virgin and cultivated black soils were studied by wet sieving and density separation methods. The total organic carbon （TOC） and LF-C were significantly higher （P≤ 0.05） in the virgin soils than in the cultivated soils. The LF-C in aggregates of different size classes varied from 0.9 to 2.5 g kg^-1 in the cultivated soils and from 2.5 to 7.1 g kg^-1 in the virgin soils, whereas the ratio of LF-C to TOC varied from 1.9% to 7.3% and from 5.0% to 12.2%, respectively. After being incubated under constant temperature and controlled humidity for three months, the contribution of LF-C to TOC sharply decreased to an amount （1.7%4.5%） close to the level in soils that had been cultivated for 20 to 25 years （1.3%-8.8%）. As a result, the larger water-stable macro-aggregates （especially 〉 1 mm） decreased sharply, indicating that the LF-C pool in virgin soils declined quickly after cultivation, which reduced the water stability of soil aggregates.展开更多
Using organic carbon density grouping method,the change trends of soil total organic carbon(SOC),light fraction content and light fraction organic carbon under 4 land use patterns of returning cultivated land to fores...Using organic carbon density grouping method,the change trends of soil total organic carbon(SOC),light fraction content and light fraction organic carbon under 4 land use patterns of returning cultivated land to forest(cropland,artificial forest,inter-cropping of forest and grassland and original sample plot)in alpine agricultural region of Qinghai were studied.The content of SOC was in order:intercropping of forest and grassland > original sample plot > artificial forest > cropland.There was signi...展开更多
Cropland(CP),native grassland(NG)and two shrub land treatments which were converted from cropland in 1985:seabuckthorn(Hippophae rhamnoides L.)(ST),and branchytamarisk(Tamarix ramosissima)(BT)were investigated to eval...Cropland(CP),native grassland(NG)and two shrub land treatments which were converted from cropland in 1985:seabuckthorn(Hippophae rhamnoides L.)(ST),and branchytamarisk(Tamarix ramosissima)(BT)were investigated to evaluate effects of land use conversion on soil organic carbon(SOC)and soil nutrients in the semi-arid region of the Loess Plateau of China.Total organic carbon(TOC),light fraction organic carbon(LFOC),heavy fraction organic carbon(HFOC),total N(TN),nitrate nitrogen(NO 3-N)and nitrite nitrogen(NO 2-N),ammonium nitrogen(NH+4-N),total P,and available P(AP)were measured.The results showed that SOC in NG,ST and BT were 12.7%,27.7%and 34.8%higher than that of the cropland,respectively.LFOC,light fraction(LF)dry matter,ratio of TOC to TN(C/N)and the ratio of TOC to AP(C/P)were higher in the shrub land or native grassland than in the cropland.Cropland had the highest TN,the sum of NO 3-N and NO 2-N,TP and AP due to the use of chemical fertilizers.TOC significantly correlated with LFOC,HFOC and C/N.LFOC significantly correlated with dry matter of the LF and C/N.TN,the sum of NO 3-N and NO 2-N and AP were significantly negatively correlated with TOC and LFOC.Therefore,land use conversion from cropland to shrub land,or maybe grassland,contributed to SOC sequestration and improved soil nutrients stabilization.展开更多
Gravel-sand mulch has been used for centuries to conserve water in the Loess Plateau of north- western China. In this study, we assessed the influence of long-term （1996-2012） gravel-sand mulching of cultiv- ated so...Gravel-sand mulch has been used for centuries to conserve water in the Loess Plateau of north- western China. In this study, we assessed the influence of long-term （1996-2012） gravel-sand mulching of cultiv- ated soils on total organic carbon （TOC）, light fraction organic carbon （LFOC）, microbial biomass carbon （MBC）, total organic nitrogen （TON）, particulate organic carbon （POC）, mineral-associated organic carbon （MOC）, perma- nganate-oxidizable carbon （KMnO4-C）, and non-KMnO4-C at 0-60 cm depths. Mulching durations were 7, 11 and 16 years, with a non-mulched control. Compared to the control, there was no significant and consistently positive effect of the mulch on TOC, POC, MOC, KMnO4-C and non-KMnO4-C before 11 years of mulching, and these organic C fractions generally decreased significantly by 16 years. LFOC, TON and MBC to at a 0-20 cm depth in- creased with increasing mulching duration until 11 years, and then these fractions decreased significantly between 11 and 16 years, reaching values comparable to or lower than those in the control. KMnO4-C was most strongly correlated with the labile soil C fractions. Our findings suggest that although gravel-sand mulch may conserve soil moisture, it may also lead to long-term decreases in labile soil organic C fractions and total organic N in the study area. The addition of manure or composted manure would be a good choice to reverse the soil deterioration that occurs after 11 years by increasing the inputs of organic matter.展开更多
Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab an...Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab analysis, we studied the seasonal variations, content differences, and interrelationships of total organic carbon （TOC）, light fraction organic carbon （LFOC）, and particulate organic carbon （POC） of the soil in the forest areas burned with different fire intensities in the Daxing＇anling Mountains. The mean TOC content in the low-intensity burned area was greater than that in the unburned area, moderate-intensity, and high-intensity burned areas in June and November （P 〈 0.05）. LFOC and POC in the low-intensity burned area were greater than that in either moderate-intensity or high-intensity burned areas, with significant differences in LFOC in September and November （P 〈 0.05）. A significant difference in LFOC between the unburned and burned areas was only found in July （P 〈 0.05）. However, the differences in POC between the unburned and burned areas were not significant in all the whole seasons （P 〉 0.05）. Soil LFOC and POC varied significantly with the seasons （P 〈 0.05） in the Daxing＇anling Mountains. Significant linear relationships were observed between soil TOC, LFOC, and POC, which were positively correlated with soil nitrogen and negatively correlated with soil temperature in the Daxing＇anling Mountains.展开更多
China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a ...China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon（LFOC） storage increased by 221 g C/m2（84%） and the total soil organic carbon（SOC） storage increased by 435 g C/m2（55%）.The light fraction dry matter content represented a small proportion of the total soil mass（ranging from 0.74% in 2005 to 1.39% in 2013）,but the proportion of total SOC storage accounted for by LFOC was remarkable（ranging from 33% to 40%）.The C sequestration averaged 28 g C/（m2·a） for LFOC and 54 g C/（m2·a） for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt＋clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land.展开更多
Labile organic carbon（LOC） is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the s...Labile organic carbon（LOC） is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sources and causes of LOC contamination are. In this study, soil organic carbon（SOC）, total nitrogen（TN）, microbial biomass carbon（MBC）, microbial biomass nitrogen（MBN） and LOC were analyzed based on different soil horizons and elevations using turnover time in an experimental site（3700 m to 4300 m area） in Sygera. SOC and LOC in higher-elevation vegetation types were higher than that of in lower-elevation vegetation types. Our results presented that the soil microbial biomass carbon（SMBC） and soil microbial biomass nitrogen（SMBN）were positively correlated with SOC. The content of easily oxidized carbon（EOC）, particulate organic carbon（POC） and light fraction organic carbon（LFOC） decreased with depth increasing and the content were the lowest in the 60 cm to 100 cm depth.The total SOC, ROC and POC contents decreased with increasing soil horizons. The SOC, TN, MBC and MBN contents increased with increasing altitude in the Sygera Mountains. The MBC and MBN contents weredifferent with the changes of SOC（p＆lt;0.05）,meanwhile, both LFOC and POC were related to total SOC（p＆lt;0.05）. The physical and chemical properties of soil, including temperature, humidity, and altitude,were involved in the regulation of SOC, TN, MBC,MBN and LFOC contents in the Sygera Mountains,Tibetan Plateau.展开更多
Afforestation is conducive to soil carbon（C） sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon（SOC） fractions...Afforestation is conducive to soil carbon（C） sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon（SOC） fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages（12-and 25-year-old） on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon（LFOC） and microbial biomass carbon（MBC）. The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios： under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12-and 25-year-old C. microphylla plantations than in moving sand dunes（i.e., control sites）, with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations（18.53 g C/（m^2·a）; 0–12 years） than in old C. microphylla plantations（16.24 g C/（m^2·a）; 12–25 years）, and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.展开更多
Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long...Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long-term C balance of terrestrial ecosystems. Different land use types can influence the distribution patterns of different SOC fractions. However, the underlying mechanisms are not well understood. In the present study, different fractions of SOC were determined in two land use types： a grazed grassland （established on previously cultivated cropland 25 years ago, GG） and a long-term cultivated millet cropland （MC）. The results showed that C concentration and C storage of light fractions （LF） and heavy fractions （HF） presented different patterns along the soil profiles in the two sites. More plant residues in GG resulted in 91.9% higher LF storage at the 0-10 cm soil depth, further contributed to 21.9% higher SOC storage at this soil depth; SOC storage at 20-60 cm soil depth in MC was 98.8% higher than that in GG, which could be mainly attributed to the HF storage 104.5% higher than in GG. This might be caused by the long-term application of organic manure, as well as the protection from plough pan and silt- and clay-sized particles. The study indicated that different soil management practices in this region can greatly influence the variations of different SOC fractions, while the conventional tillage can greatly improve the storage of SOC by in- creasing heavy fractions.展开更多
Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the op...Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO（fluorine-doped tin oxide）. The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.展开更多
We develop a dual porous （DP） TiO2 film for the electron transporting layer （ETL） in carbon cathode based perovskite solar cells （C-PSCs）. The DP TiO2 film was synthesized via a facile PS-templated method with t...We develop a dual porous （DP） TiO2 film for the electron transporting layer （ETL） in carbon cathode based perovskite solar cells （C-PSCs）. The DP TiO2 film was synthesized via a facile PS-templated method with the thickness being controlled by the spin-coating speed. It was found that there is an optimum DP TiO2 film thickness for achieving an effective ETL, a suitable perovskite]TiO2 interface, an efficient light harvester and thus a high performance C-PSC. In particular, such a DP TiO2 film can act as a scaffold for complete-filling of the pores with perovskite and for forming high-quality perovskite crystals that are seamlessly interfaced with Ti02 to enhance interracial charge injection. Leveraging the unique advantages of DP TiO2 ETL, together with a dense-packed and pinhole-free TiO2 compact layer, PCE of the C-PSCs has reached 9.81% with good stability.展开更多
Five 1,3diisopropoxyaloxanes,i.e.,(PriO)RO2AlOAlO2R(OPri)_C18H35(),_C9H16CH=CHC7H15(),_P(OCH2(C2H5)CHC4H9)2(),and_C12H23(),respectively]were synthesized by the hydrolysiscondensation of aluminium isopropoxide with wat...Five 1,3diisopropoxyaloxanes,i.e.,(PriO)RO2AlOAlO2R(OPri)_C18H35(),_C9H16CH=CHC7H15(),_P(OCH2(C2H5)CHC4H9)2(),and_C12H23(),respectively]were synthesized by the hydrolysiscondensation of aluminium isopropoxide with water and exchange reaction with relevant acids.They were characterized by elemental analysis,determination of molecular weight,IR,and 27Al NMR.The results show that the coordination number of Al atom in the compounds is 5 and they exist in monomers in benzene.The analyses of TG/DTG and DTA indicated that both the thermal hydrolysis stability and thermal stability of these compounds are in the following order:<<<.The viscosity determinations of light calcium carbonate(LCaCO3)/liquid paraffin suspension systems demonstrated that they had an excellent modification effect on the surface of LCaCO3 filler and the amount needed to form a monomolecular film on the surface of LCaCO3 particles is in the order.展开更多
A hybrid system combined with a non-contact membrane and bubbling absorption is proposed to capture CO_(2) from flue gas.The non-contact way of membrane and liquid absorbent effectively avoids the reduction of gas dif...A hybrid system combined with a non-contact membrane and bubbling absorption is proposed to capture CO_(2) from flue gas.The non-contact way of membrane and liquid absorbent effectively avoids the reduction of gas diffusion flux through the membrane.High-porosity ceramic membranes in hybrid systems are used for gas-solid separation in fuel gas treatment.Due to the high content of H_(2)O and cement dust in the flue gas of the cement plant,the membrane is hydrophobically modified by polytetrafluoroethylene(PTFE)to improve its anti-water,anti-fouling,and self-cleaning performances.The results show that the diffusion flux of CO_(2) through the membrane is still higher than 7.0×10^(−3) mol/m^(2)s(20%CO_(2) concentration)even under the influence of water and cement dust.In addition,slaked lime selected as the absorbent is cheap and the product after bubbling absorption is nano-scale light calcium carbonate.To sum up,the hybrid system combining non-contact membrane and bubbling absorption is expected to be used to capture carbon dioxide from the flue gas of the cement plant.展开更多
Band offset is a dominant factor affecting the photocatalytic performance of heterostructure photocatalysts. Therefore, controlling the band gap structure of semiconductors is a key challenge in the development of eff...Band offset is a dominant factor affecting the photocatalytic performance of heterostructure photocatalysts. Therefore, controlling the band gap structure of semiconductors is a key challenge in the development of efficient photocatalysts. We used a typical in situ-method to prepare diverse graphite-phase carbon nitride(g-C_3N_4)samples from melamine, thiourea, and a mixture thereof,and found that they exhibited band gaps between2.3–2.8 e V. From UV–Vis spectra and X-ray photoelectron spectroscopy measurements, we determined that the g-C_3N_4 samples exhibited different band gap values and valence band positions. On this basis, we constructed g-C_3N_4/m-La VO_4 heterojunctions with different band offsets. UV–Vis spectra and X-ray photoelectron spectroscopy measurements revealed that the valence band offsets(VBOs) of the different heterojunctions were similar, but their conduction band offsets(CBOs) were significantly different. Photocatalytic experiments revealed that the reaction rate was enhanced with an increase in the CBO value. Furthermore, the three-phase g-C_3N_4/g-C_3N_4/mLa VO_4 heterojunction composed of m-La VO_4 and mixed g-C_3N_4 showed the highest photocatalytic activity, which was mainly due to the construction of a multilevel structure. This work investigates the influence of the band offset on heterojunction photoelectrochemical properties and provides a new strategy to improve the photocatalytic activity by constructing multilevel structures.展开更多
The efficient utilization of natural lignin,which is the main by-product of the cellulose industry,is crucial for enhancing its economic value,alleviating the environmental burden,and improving ecological security.By ...The efficient utilization of natural lignin,which is the main by-product of the cellulose industry,is crucial for enhancing its economic value,alleviating the environmental burden,and improving ecological security.By taking advantage of the large sp2 hybrid domain of lignin and introducing amino functional groups,new lignin-derived carbon dots(SPN-CDs)with red fluorescence were successfully synthesized.Compared with green and blue fluorescent materials,red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability.The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite.Considering this feature,a portable,low-cost,and sensitive fluorescence sensing paper with a low limit of detection of 0.249μmol∙L^(–1) was fabricated using the SPN-CDs for hypochlorite detection.Furthermore,a new type of visible-light and fluorescence dual-channel information encryption platform was constructed.Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus,as well as an information“eraser”,facilitating a safe and diversified transmission and convenient decryption of information.This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.展开更多
基金the support from National Natural Science Foundation of China(22078208)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2020ZD0025)China Chengda Engineering Co.,Ltd.for its software support。
文摘The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).
基金Project supported by the State Key Basic Research Development Program (No. G1999011804) the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCXZ-SW-416).
文摘The distribution of light fraction carbon （LF-C） in the various size classes of aggregates and its relationship to water- stable aggregates as well as the influence of cultivation on the organic components in virgin and cultivated black soils were studied by wet sieving and density separation methods. The total organic carbon （TOC） and LF-C were significantly higher （P≤ 0.05） in the virgin soils than in the cultivated soils. The LF-C in aggregates of different size classes varied from 0.9 to 2.5 g kg^-1 in the cultivated soils and from 2.5 to 7.1 g kg^-1 in the virgin soils, whereas the ratio of LF-C to TOC varied from 1.9% to 7.3% and from 5.0% to 12.2%, respectively. After being incubated under constant temperature and controlled humidity for three months, the contribution of LF-C to TOC sharply decreased to an amount （1.7%4.5%） close to the level in soils that had been cultivated for 20 to 25 years （1.3%-8.8%）. As a result, the larger water-stable macro-aggregates （especially 〉 1 mm） decreased sharply, indicating that the LF-C pool in virgin soils declined quickly after cultivation, which reduced the water stability of soil aggregates.
基金Supported by Science and Technology Supporting Project of China during the Eleventh Five-Year Plan Period(2006BAD05B07)~~
文摘Using organic carbon density grouping method,the change trends of soil total organic carbon(SOC),light fraction content and light fraction organic carbon under 4 land use patterns of returning cultivated land to forest(cropland,artificial forest,inter-cropping of forest and grassland and original sample plot)in alpine agricultural region of Qinghai were studied.The content of SOC was in order:intercropping of forest and grassland > original sample plot > artificial forest > cropland.There was signi...
基金Project supported by the National Basic Research Program(973 Program)of China(No.2007CB106804)the International S&T Cooperation Program(ISTCP)of China(No.2006DFA31070)the International Foundation for Sciences(No.C/3313-2)
文摘Cropland(CP),native grassland(NG)and two shrub land treatments which were converted from cropland in 1985:seabuckthorn(Hippophae rhamnoides L.)(ST),and branchytamarisk(Tamarix ramosissima)(BT)were investigated to evaluate effects of land use conversion on soil organic carbon(SOC)and soil nutrients in the semi-arid region of the Loess Plateau of China.Total organic carbon(TOC),light fraction organic carbon(LFOC),heavy fraction organic carbon(HFOC),total N(TN),nitrate nitrogen(NO 3-N)and nitrite nitrogen(NO 2-N),ammonium nitrogen(NH+4-N),total P,and available P(AP)were measured.The results showed that SOC in NG,ST and BT were 12.7%,27.7%and 34.8%higher than that of the cropland,respectively.LFOC,light fraction(LF)dry matter,ratio of TOC to TN(C/N)and the ratio of TOC to AP(C/P)were higher in the shrub land or native grassland than in the cropland.Cropland had the highest TN,the sum of NO 3-N and NO 2-N,TP and AP due to the use of chemical fertilizers.TOC significantly correlated with LFOC,HFOC and C/N.LFOC significantly correlated with dry matter of the LF and C/N.TN,the sum of NO 3-N and NO 2-N and AP were significantly negatively correlated with TOC and LFOC.Therefore,land use conversion from cropland to shrub land,or maybe grassland,contributed to SOC sequestration and improved soil nutrients stabilization.
基金provided by the Office of Agricultural Program, Chinese Academy of Sciences (kscx2-ewb-1-8)the National Natural Science Foundation of China (41171027)
文摘Gravel-sand mulch has been used for centuries to conserve water in the Loess Plateau of north- western China. In this study, we assessed the influence of long-term （1996-2012） gravel-sand mulching of cultiv- ated soils on total organic carbon （TOC）, light fraction organic carbon （LFOC）, microbial biomass carbon （MBC）, total organic nitrogen （TON）, particulate organic carbon （POC）, mineral-associated organic carbon （MOC）, perma- nganate-oxidizable carbon （KMnO4-C）, and non-KMnO4-C at 0-60 cm depths. Mulching durations were 7, 11 and 16 years, with a non-mulched control. Compared to the control, there was no significant and consistently positive effect of the mulch on TOC, POC, MOC, KMnO4-C and non-KMnO4-C before 11 years of mulching, and these organic C fractions generally decreased significantly by 16 years. LFOC, TON and MBC to at a 0-20 cm depth in- creased with increasing mulching duration until 11 years, and then these fractions decreased significantly between 11 and 16 years, reaching values comparable to or lower than those in the control. KMnO4-C was most strongly correlated with the labile soil C fractions. Our findings suggest that although gravel-sand mulch may conserve soil moisture, it may also lead to long-term decreases in labile soil organic C fractions and total organic N in the study area. The addition of manure or composted manure would be a good choice to reverse the soil deterioration that occurs after 11 years by increasing the inputs of organic matter.
基金supported by the Ministry of Science and Technology project 973(2011CB403203)Youth science foundations in Heilongjiang province(QC2012C003)Youth science foundations in college of forest in Heilingjiang province(201415)
文摘Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab analysis, we studied the seasonal variations, content differences, and interrelationships of total organic carbon （TOC）, light fraction organic carbon （LFOC）, and particulate organic carbon （POC） of the soil in the forest areas burned with different fire intensities in the Daxing＇anling Mountains. The mean TOC content in the low-intensity burned area was greater than that in the unburned area, moderate-intensity, and high-intensity burned areas in June and November （P 〈 0.05）. LFOC and POC in the low-intensity burned area were greater than that in either moderate-intensity or high-intensity burned areas, with significant differences in LFOC in September and November （P 〈 0.05）. A significant difference in LFOC between the unburned and burned areas was only found in July （P 〈 0.05）. However, the differences in POC between the unburned and burned areas were not significant in all the whole seasons （P 〉 0.05）. Soil LFOC and POC varied significantly with the seasons （P 〈 0.05） in the Daxing＇anling Mountains. Significant linear relationships were observed between soil TOC, LFOC, and POC, which were positively correlated with soil nitrogen and negatively correlated with soil temperature in the Daxing＇anling Mountains.
基金supported by the National Natural Science Foundation of China (41271007,31170413)the National Science and Technology Support Program of China (2011BAC07B02)
文摘China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon（LFOC） storage increased by 221 g C/m2（84%） and the total soil organic carbon（SOC） storage increased by 435 g C/m2（55%）.The light fraction dry matter content represented a small proportion of the total soil mass（ranging from 0.74% in 2005 to 1.39% in 2013）,but the proportion of total SOC storage accounted for by LFOC was remarkable（ranging from 33% to 40%）.The C sequestration averaged 28 g C/（m2·a） for LFOC and 54 g C/（m2·a） for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt＋clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land.
基金supported by CFERN & GENE Award Funds on Ecological Paper
文摘Labile organic carbon（LOC） is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sources and causes of LOC contamination are. In this study, soil organic carbon（SOC）, total nitrogen（TN）, microbial biomass carbon（MBC）, microbial biomass nitrogen（MBN） and LOC were analyzed based on different soil horizons and elevations using turnover time in an experimental site（3700 m to 4300 m area） in Sygera. SOC and LOC in higher-elevation vegetation types were higher than that of in lower-elevation vegetation types. Our results presented that the soil microbial biomass carbon（SMBC） and soil microbial biomass nitrogen（SMBN）were positively correlated with SOC. The content of easily oxidized carbon（EOC）, particulate organic carbon（POC） and light fraction organic carbon（LFOC） decreased with depth increasing and the content were the lowest in the 60 cm to 100 cm depth.The total SOC, ROC and POC contents decreased with increasing soil horizons. The SOC, TN, MBC and MBN contents increased with increasing altitude in the Sygera Mountains. The MBC and MBN contents weredifferent with the changes of SOC（p＆lt;0.05）,meanwhile, both LFOC and POC were related to total SOC（p＆lt;0.05）. The physical and chemical properties of soil, including temperature, humidity, and altitude,were involved in the regulation of SOC, TN, MBC,MBN and LFOC contents in the Sygera Mountains,Tibetan Plateau.
基金funded by the National Natural Science Foundation of China (31640012, 41271007, 31660232)the One Hundred Person Project of the Chinese Academy of Sciences (Y551821)+1 种基金the Opening Foundation of the State Key Laboratory Breeding Base of DesertificationAeolian Sand Disaster Combating, Gansu Desert Control Research Institute (GSDC201505)
文摘Afforestation is conducive to soil carbon（C） sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon（SOC） fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages（12-and 25-year-old） on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon（LFOC） and microbial biomass carbon（MBC）. The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios： under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12-and 25-year-old C. microphylla plantations than in moving sand dunes（i.e., control sites）, with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations（18.53 g C/（m^2·a）; 0–12 years） than in old C. microphylla plantations（16.24 g C/（m^2·a）; 12–25 years）, and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.
基金supported by National Basic Research Program of China (2014CB138703)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050403)+3 种基金Changjiang Scholars and Innovative Research Team in University (IRT13019)Key Science and Technology Projects of Gansu Province (1203FKDA035)Fundamental Research Funds for the Central Universities (lzujbky-2014-78)the National Natural Science Foundation of China (31070412, 31201837)
文摘Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long-term C balance of terrestrial ecosystems. Different land use types can influence the distribution patterns of different SOC fractions. However, the underlying mechanisms are not well understood. In the present study, different fractions of SOC were determined in two land use types： a grazed grassland （established on previously cultivated cropland 25 years ago, GG） and a long-term cultivated millet cropland （MC）. The results showed that C concentration and C storage of light fractions （LF） and heavy fractions （HF） presented different patterns along the soil profiles in the two sites. More plant residues in GG resulted in 91.9% higher LF storage at the 0-10 cm soil depth, further contributed to 21.9% higher SOC storage at this soil depth; SOC storage at 20-60 cm soil depth in MC was 98.8% higher than that in GG, which could be mainly attributed to the HF storage 104.5% higher than in GG. This might be caused by the long-term application of organic manure, as well as the protection from plough pan and silt- and clay-sized particles. The study indicated that different soil management practices in this region can greatly influence the variations of different SOC fractions, while the conventional tillage can greatly improve the storage of SOC by in- creasing heavy fractions.
基金Project supported jointly by the Foundation of He'nan Educational Committee(15A150071)
文摘Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO（fluorine-doped tin oxide）. The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.
基金supported by the HK Innovation and Technology Fund (ITS/004/14)the HK-RGC General Research Funds (GRE No. HKUST 606511)
文摘We develop a dual porous （DP） TiO2 film for the electron transporting layer （ETL） in carbon cathode based perovskite solar cells （C-PSCs）. The DP TiO2 film was synthesized via a facile PS-templated method with the thickness being controlled by the spin-coating speed. It was found that there is an optimum DP TiO2 film thickness for achieving an effective ETL, a suitable perovskite]TiO2 interface, an efficient light harvester and thus a high performance C-PSC. In particular, such a DP TiO2 film can act as a scaffold for complete-filling of the pores with perovskite and for forming high-quality perovskite crystals that are seamlessly interfaced with Ti02 to enhance interracial charge injection. Leveraging the unique advantages of DP TiO2 ETL, together with a dense-packed and pinhole-free TiO2 compact layer, PCE of the C-PSCs has reached 9.81% with good stability.
文摘Five 1,3diisopropoxyaloxanes,i.e.,(PriO)RO2AlOAlO2R(OPri)_C18H35(),_C9H16CH=CHC7H15(),_P(OCH2(C2H5)CHC4H9)2(),and_C12H23(),respectively]were synthesized by the hydrolysiscondensation of aluminium isopropoxide with water and exchange reaction with relevant acids.They were characterized by elemental analysis,determination of molecular weight,IR,and 27Al NMR.The results show that the coordination number of Al atom in the compounds is 5 and they exist in monomers in benzene.The analyses of TG/DTG and DTA indicated that both the thermal hydrolysis stability and thermal stability of these compounds are in the following order:<<<.The viscosity determinations of light calcium carbonate(LCaCO3)/liquid paraffin suspension systems demonstrated that they had an excellent modification effect on the surface of LCaCO3 filler and the amount needed to form a monomolecular film on the surface of LCaCO3 particles is in the order.
文摘A hybrid system combined with a non-contact membrane and bubbling absorption is proposed to capture CO_(2) from flue gas.The non-contact way of membrane and liquid absorbent effectively avoids the reduction of gas diffusion flux through the membrane.High-porosity ceramic membranes in hybrid systems are used for gas-solid separation in fuel gas treatment.Due to the high content of H_(2)O and cement dust in the flue gas of the cement plant,the membrane is hydrophobically modified by polytetrafluoroethylene(PTFE)to improve its anti-water,anti-fouling,and self-cleaning performances.The results show that the diffusion flux of CO_(2) through the membrane is still higher than 7.0×10^(−3) mol/m^(2)s(20%CO_(2) concentration)even under the influence of water and cement dust.In addition,slaked lime selected as the absorbent is cheap and the product after bubbling absorption is nano-scale light calcium carbonate.To sum up,the hybrid system combining non-contact membrane and bubbling absorption is expected to be used to capture carbon dioxide from the flue gas of the cement plant.
基金supported by the National Natural Science Foundation of China(21173131)the Taishan Scholar Project of Shandong Province
文摘Band offset is a dominant factor affecting the photocatalytic performance of heterostructure photocatalysts. Therefore, controlling the band gap structure of semiconductors is a key challenge in the development of efficient photocatalysts. We used a typical in situ-method to prepare diverse graphite-phase carbon nitride(g-C_3N_4)samples from melamine, thiourea, and a mixture thereof,and found that they exhibited band gaps between2.3–2.8 e V. From UV–Vis spectra and X-ray photoelectron spectroscopy measurements, we determined that the g-C_3N_4 samples exhibited different band gap values and valence band positions. On this basis, we constructed g-C_3N_4/m-La VO_4 heterojunctions with different band offsets. UV–Vis spectra and X-ray photoelectron spectroscopy measurements revealed that the valence band offsets(VBOs) of the different heterojunctions were similar, but their conduction band offsets(CBOs) were significantly different. Photocatalytic experiments revealed that the reaction rate was enhanced with an increase in the CBO value. Furthermore, the three-phase g-C_3N_4/g-C_3N_4/mLa VO_4 heterojunction composed of m-La VO_4 and mixed g-C_3N_4 showed the highest photocatalytic activity, which was mainly due to the construction of a multilevel structure. This work investigates the influence of the band offset on heterojunction photoelectrochemical properties and provides a new strategy to improve the photocatalytic activity by constructing multilevel structures.
基金Yixuan Chang and Fanwei Kong contributed equally to the work.We are grateful for the financial support by the Undergraduate Training Programs for Innovations by NEFU(Grant No.202110225105)the National Natural Science Foundation of China(Grant No.51903031)+5 种基金Fundamental Research Funds for the Central Universities(Grant No.2572021CG05)Young Elite Scientists Sponsorship Program by CAST(Grant No.2019QNRC001)China Postdoctoral Science Foundation Funded Project(Grant Nos.2022T150102,2021M700735,2019T120249,2018M630331)Heilongjiang Postdoctoral Fund(Grant Nos.LBH-Z18010,LBH-TZ1001)the Key Program of the Natural Science Foundation of Heilongjiang Province(Grant No.ZD2021C001)the 111 Project(Grant No.B20088).
文摘The efficient utilization of natural lignin,which is the main by-product of the cellulose industry,is crucial for enhancing its economic value,alleviating the environmental burden,and improving ecological security.By taking advantage of the large sp2 hybrid domain of lignin and introducing amino functional groups,new lignin-derived carbon dots(SPN-CDs)with red fluorescence were successfully synthesized.Compared with green and blue fluorescent materials,red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability.The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite.Considering this feature,a portable,low-cost,and sensitive fluorescence sensing paper with a low limit of detection of 0.249μmol∙L^(–1) was fabricated using the SPN-CDs for hypochlorite detection.Furthermore,a new type of visible-light and fluorescence dual-channel information encryption platform was constructed.Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus,as well as an information“eraser”,facilitating a safe and diversified transmission and convenient decryption of information.This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.
