摘要：
Purpose Co-composting with agriculture waste and sediment is an effective method to passivate the heavy metal content of sediment, but it is still unclear whether this passivation will be effective in the long term, and the contribution of different components of humic substances (HS) to the passivation of heavy metals has not been investigated quantitatively.Methods A 256-day composting experiment was conducted in 165 L reactors. Sediment, vegetables, rice straw, and bran were used as raw materials. Two experiments were set up, with pile A as control and pile B inoculated with Phanerochaete chrysosporium.Results The results revealed that the residual fraction of Cd (Res-Cd) increased by 24.22% and 27.04% in pile A and pile B, respectively. During the first 60 days of composting, the contents of humic acids-bound Cd (HA-Cd) both increased in two piles and accounted for 16.54% and 17.69% of the total content of Cd (T-Cd) in pile A and pile B, respectively. The correlation analysis suggested that the Res-Cd exhibited a significantly positive correlation with humic acid (HA) (P < 0.01) and HA-Cd, but a negative correlation with fulvic acid (FA) in both piles. Fourier-transform infrared spectroscopy and excitation-emission matrix fluorescence spectroscopy analysis demonstrated that the inoculation could enhance the chelating capability of HA to Cd and improve the maturity of compost.Conclusions This study has demonstrated that composting had a persistent passivation on Cd for 256 days. The contribution of HS to Cd passivation largely depends on the amount of HA-Cd rather than FA-Cd. Moreover, the inoculation of Phanerochaete chrysosporium could enhance the binding ability of HA to Cd and improve the maturity of compost.
通讯机构：
[Yaoning Chen; Yuanping Li] C;College of Municipal and Mapping Engineering, Hunan City University, Yiyang, Hunan 413000, China<&wdkj&>College of Environmental Science and Engineering, Hunan University, Changsha 410082, China<&wdkj&>Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
摘要：
Humic substances (HSs) are key indicators of compost maturity and are important for the composting process. The application of additives is generally considered to be an efficient and easy-to-master strategy to promote the humification of composting and quickly caught the interest of researchers. This review summarizes the recent literature on humification promotion by additives in the composting process. Firstly, the organic, inorganic, biological, and compound additives are introduced emphatically, and the effects and mechanisms of various additives on composting humification are systematically discussed. Inorganic, organic, biological, and compound additives can promote 5.58-82.19%, 30.61-50.92%, 2.3-40%, and 28.09-104.51% of humification during composting, respectively. Subsequently, the advantages and disadvantages of various additives in promoting composting humification are discussed and indicated that compound additives are the most promising method in promoting composting humification. Finally, future research on humification promotion is also proposed such as long-term stability, environmental impact, and economic feasibility of additive in the large-scale application of composting. It is aiming to provide a reference for future research and the application of additives in composting.
作者机构：
[Sheng, Haiquan; Zhou, Lv; Chen, Yukai; Xian, Lingxiao; Ma, Shubian] Guilin Univ Technol, Coll Geomatics & Geoinformat, Guilin 541004, Peoples R China.;[Huang, Changjun] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Yang, Fei] China Univ Min & Technol Beijing, Geosci & Survey Engn Coll, Beijing 100083, Peoples R China.
通讯机构：
[Lv Zhou] C;College of Geomatics and Geoinformation, Guilin University of Technology, Guilin 541004, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
InSAR;persistent scatterer;Beijing;plain;Sentinel-1A;time series
摘要：
Surface subsidence is a serious threat to human life, buildings and traffic in Beijing. Surface subsidence is closely related to human activities, and human activities in Beijing area showed a decreasing trend during the Corona Virus Disease 2019 (COVID-19). To study surface subsidence in Beijing before and after the COVID-19 outbreak and its causes, a total of 51 Sentinel-1A SAR images covering Beijing from January 2018 to April 2022 were selected to derive subsidence information by Time Series Interferometry Synthetic Aperture Radar (TS-InSAR). The results of surface subsidence in Beijing demonstrate that Changping, Chaoyang, Tongzhou and Daxing Districts exhibited the most serious subsidence phenomenon before the COVID-19 outbreak. The four main subsidence areas form an anti-Beijing Bay that surrounds other important urban areas. The maximum subsidence rate reached −57.0 mm/year. After the COVID-19 outbreak, the main subsidence area was separated into three giant subsidence funnels and several small subsidence funnels. During this period, the maximum subsidence rate was reduced to −43.0 mm/year. Human activity decrease with the COVID-19 outbreak. This study effectively analysed the influence of natural factors on surface subsidence after excluding most of the human factors. The following conclusions are obtained from the analysis: (1) Groundwater level changes, Beijing’s geological structure and infrastructure construction are the main reasons for surface subsidence in Beijing. (2) Seasonal changes in rainfall and temperature indirectly affect groundwater level changes, thereby affecting surface subsidence in the area. (3) The COVID-19 outbreak in early 2020 reduced the payload of Beijing’s transportation facilities. It also slowed down the progress of various infrastructure construction projects in Beijing. These scenarios affected the pressure on the soft land base in Beijing and reduced the surface subsidence trend to some extent.
作者机构：
[Deng, Yumei; Deng, Jie; Zhang, Chun] Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Chun Zhang] S;School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
sponge city;waterlogging;water environment;sustainable development
摘要：
Urban waterlogging and urban water environment problems in Changde city caused by extreme weather have seriously hindered the sustainable development of cities. A sponge city not only involves the inheritance and development of foreign technology but also a new method for its use. The background of sponge city construction based on green infrastructures in China was introduced in this study. As one of the first pilot construction cities based on the sponge concept, Changde city possesses natural geographical advantages. The current urban situation, rainfall type and water environment in the sponge construction area were analyzed and the causes of urban waterlogging and deterioration of urban inland river water quality are presented. Based on the urban water environment and ecological status, the specific strategic objectives of the sponge city transformation are given. Meanwhile, the overall technical route and the concrete realization path of each index, such as the water environmental system, water ecological system and security system, are also presented. The annual net flow total control rate and the runoff pollution reduction reached 77.56% and 45.18%, respectively. The total runoff and peak flow were also reduced by 35.08% and 26.82%, respectively. Meanwhile, the peak flow of runoff pollution concentration was reduced by 31.99%. The pollutant load reduction rate of non-point source pollution in the area reached more than 45%. The project not only alleviated the problems of urban waterlogging and black and odorous water bodies but also ensured the sustainable development of the urban water environment.
摘要：
Sediment is the internal and external source of water environment pollution, so sediment remediation is the premise of water body purification. Sediment microbial fuel cell (SMFC) can remove the organic pollutants in sediment by electroactive microorganisms, compete with methanogens for electrons, and realize resource recycling, methane emission inhibiting and energy recovering. Due to these characteristics, SMFC have attracted wide attention for sediment remediation. In this paper, we comprehensively summarized the recent advances of SMFC in the following areas: (1) The advantages and disadvantages of current applied sediment remediation technologies; (2) The basic principles and influencing factors of SMFC; (3) The application of SMFC for pollutant removal, phosphorus transformation and remote monitoring and power supply; (4) Enhancement strategies for SMFC in sediments remediation such as SMFC coupled with constructed wetland, aquatic plant and iron-based reaction. Finally, we have summarized the drawback of SMFC and discuss the future development directions of applying SMFC for sediment bioremediation.
摘要：
The heterogeneous Fenton-like systems induced by Fe-containing minerals have been largely applied for the degradation of organic pollutants. However, few studies have been conducted on biochar (BC) as an additive to Fenton-like systems mediated by iron-containing minerals. In this study, the addition of BC prepared at different temperatures was found to significantly enhance the degradation of contaminants in the tourmaline-mediated Fenton-like system (TM/H(2)O(2)) using Rhodamine B (RhB) as the target contaminant. Furthermore, the hydrochloric acid-modified BC prepared at 700°C (BC700(HCl)) could achieve complete degradation of high concentrations of RhB in the BC700(HCl)/TM/H(2)O(2) system. Free radical quenching experiments showed that TM/H(2)O(2) system removed contaminants mainly mediated by the free radical pathway. After adding BC, the removal of contaminants is mainly mediated by the non-free radical pathway in BC700(HCl)/TM/H(2)O(2) system which was confirmed by the Electron paramagnetic resonance (EPR) experiments and electrochemical impedance spectroscopy (EIS). In addition, BC700(HCl) had broad feasibility in the degradation of other organic pollutants (Methylene Blue (MB) 100%, Methyl Orange (MO) 100%, and tetracycline (TC) 91.47%) in the tourmaline-mediated Fenton-like system. Possible pathways for the degradation of RhB by the BC700(HCl)/TM/H(2)O(2) system were also proposed.
期刊：
FRONTIERS IN EARTH SCIENCE,2023年11:1112772 ISSN：2296-6463
通讯作者：
Gao, H.
作者机构：
[Li, Ping] Tibet Agr & Anim Husb Univ, Coll Resources & Environm, Linzhi, Peoples R China.;[Gao, Hongshan; Yan, Tianqi] Lanzhou Univ, Coll Earth & Environm Sci, Key Lab Western Chinas Environm Syst, Minist Educ, Lanzhou, Peoples R China.;[Li, Zongmeng] Xinyang Normal Univ, Sch Geog Sci, Xinyang, Peoples R China.;[Wu, Yajie] Wuwei 1 Middle Sch, Wuwei, Peoples R China.;[Liu, Fenliang] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang, Peoples R China.
通讯机构：
[Gao, H.] K;Key Laboratory of Western China’s Environmental Systems (Ministry of Education), China
关键词：
downstream fining;gravel-sand transition;median grain size;river sediment;Shiyang River
摘要：
The grain size composition and distribution of river sediments are important for understanding regional geomorphological evolution, source-sink processes and drainage ecology. The Shiyang River basin, an inland river system in northwestern China, provides an environmental context within which to investigate the relationship between sediment particle size and environmental factors. Based on the analysis of the grain size characteristics of modern riverbed sediments, basin geomorphological parameters and lithology, it is found that the median grain size (Md) of river sediments shows a decrease trend from upstream to downstream in the basin. One of the tributaries named the Jinta River shows an obvious downstream fining trend (exponentially decreasing) of Md, which is related to the old geomorphological development stages and relatively homogeneous lithology in the basin. The downstream fining trend of Md along the Xiying River, another tributary, shows complex fluctuations, which might be affected by the tectonically active, young geomorphic development stage, complex lithology of the basin, and the sediment confluence of tributaries. The gravel-sand transition zone occurs in the plain section of the river about 28 km out of the mountain, which is related to the combination of regional geomorphological features, river morphology and hydraulic sorting.
期刊：
FRONTIERS IN EARTH SCIENCE,2023年11:1174017 ISSN：2296-6463
通讯作者：
Tang, M
作者机构：
[Tang, Miao; Chen, Jin; Deng, Hao; Mao, Xiancheng; Tang, M; Liu, Zhankun; Wang, Jinli] Cent South Univ, Sch Geosci & Info Phys, Key Lab Metallogen Predict Nonferrous Met & Geol E, Minist Educ, Changsha, Peoples R China.;[Chen, Jin; Deng, Hao; Mao, Xiancheng; Liu, Zhankun; Wang, Jinli] Hunan Key Lab Nonferrous Resources & Geol Hazards, Changsha, Peoples R China.;[Tang, Miao; Tang, M] Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang, Peoples R China.
通讯机构：
[Tang, M ] C;Cent South Univ, Sch Geosci & Info Phys, Key Lab Metallogen Predict Nonferrous Met & Geol E, Minist Educ, Changsha, Peoples R China.;Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang, Peoples R China.
关键词：
association rules analysis;favorable mineralization site;Jiaojia goldfield;metallogenic information extraction;spatial constraints
摘要：
Mesozoic orogenic gold deposits in the Jiaojia goldfield, Eastern China show the features of regular mineralization spatial distribution and have long been captivated the attention of geologists. This study integrates 3D modeling, model space analysis, and association rule analysis to extract the relationship between structural deformation and gold mineralization. The Apriori algorithm with spatial constraints is used to quantify the favorable mineralization sites in the Jiaojia gold field using different combinations of ore-controlling indicators. The first favorable mineralization site has a 44% probability of mineralization and is primarily located in segments of the fault footwall within 25 m of the fault buffer where the transition from steep to gentle occurs (similar to 1-24). Its uniform distribution indicates that the ore-bearing space near the main fault plane is relatively wide, and hydrothermal diffusion is relatively uniform. Site No. 2 has a 45% probability of mineralization and is located in convex segments (6-35 m) between 25 and 55 m of the fault footwall. The equidistant zonal distribution in this area indicates that secondary faults and fractures have facilitated the migration of hydrothermal fluids, resulting in the formation of extensive ore-bearing spaces. Site No. 3 sited in convex segments (similar to 0-6 m) distal to the fault footwall (similar to 55-515 m) of the fault buffer where the dip is gentle (similar to 30 degrees-35 degrees). The binary structure of differing dips formed by the intersection of steeply dipping orebodies and the slowly dipping orebodies in the central and southern parts of the Nanlu-Xinmu deposit exhibit the complex channel away from the main fault. In this study, the correlation between ore-controlling factors and mineralization in Jiaojia fold field is quantitatively expressed as favorable mineralization sites in the form of association rules, it would contribute to a deeper understanding of the underlying mechanisms governing the formation of structure-controlled orogenic gold deposits in the Jiaojia goldfield.
摘要：
The serial compound fluidized bed gasification process of HMSW (high moisture solid waste) is studied, and the semi-empirical kinetic model is established by combining hydrodynamics and reaction kinetics. The model include combustion sub-model and gasification sub-model, which are divided into dense phase and dilute phase for simulation. The dense phase is simulated by the three-phase bubble bed theory, and the dilute phase is simulated by Wen-Chen entrainment elutriation model combined with the ring-core model. The pyrolysis model is based on the empirical relationship. The effects of gasification temperature, S/HMSW (steam/high moisture solid waste) ratio, HMSW/C (high moisture solid waste/coal) ratio, and moisture on the gasification process are studied. The results show that the gasification temperature of 1000 degrees C, S/HMSW of 1.13, HMSW/C of 3, and moisture of 26% are the optimal gasification parameters. The study can guide the design, operation, and optimization of the serial compound gasification process.
摘要：
Tetracycline (TC) is an important antibiotic extensively used in livestock breeding and aquaculture, and so an effective removal strategy is urgently needed. This study explores the use of a series of hydroxyapatite calcinated at different temperatures (300, 400, 500, 600, and 700 degrees C) to activate peroxymonosulfate (PMS) for the removal of TC. The optimal conditions for the removal of 10 mg/L TC using hydroxyapatite calcinated at 600 degrees C (CHAP600) as a catalyst were determined to be: pH of 6.0, a catalyst dosage of 0.2 g/L and a PMS concentration of 0.3 mM. Under these conditions, the removal efficiency of TC reached 94 %. The potential degradation pathway of TC was proposed by identifying the intermediates using High Performance Liquid Chromatography/ Triple Quad mass spectrometry. The characterization analysis revealed that the presence of calcium carbonate on the surface of CHAP600 promoted the generation of singlet oxygen (1O2). Additionally, the phosphate group in CHAP600 served as a catalyst for the production of sulfate radicals (SO4 & BULL;-) from PMS, which subsequently react with hydroxyl or surface hydroxyl group to generate hydroxyl radicals (& BULL;OH). And the active species 1O2 is the most significant contributor to the catalytic degradation process of TC by CHAP600 activated PMS, followed by & BULL;OH, and then SO4 & BULL;-. This study provides new insight for the mechanism of removing organic contaminants using PMS activated with calcined hydroxyapatite.
期刊：
Journal of the Indian Society of Remote Sensing,2023年51(10):2041-2056 ISSN：0255-660X
通讯作者：
Huang, CJ
作者机构：
[Xue, Yun; Huang, Changjun; Cao, Yuanzhi; Liu, Fenliang] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Huang, Changjun] Key Lab Key Technol Digital Urban Rural Spatial Pl, Yiyang 413000, Peoples R China.;[Zhou, Lv] Guilin Univ Technol, Sch Geomat & Geoinformat, Guilin 541004, Peoples R China.
通讯机构：
[Huang, CJ ] H;Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;Key Lab Key Technol Digital Urban Rural Spatial Pl, Yiyang 413000, Peoples R China.
关键词：
Longmenshan fault zone;Wenchuan earthquake;SBAS-InSAR;Deformation characteristic;ENVISAT ASAR
摘要：
Fault activity property is one of the main reasons caused by the motion of crustal fault, and the research of fault activity characteristics has become an important direction in the study of earthquake prediction, which is an important source of new theory and new method in earthquake prediction science. The disastrous May 12, 2008, Mw7.9 Wenchuan earthquake in the Longmenshan fault zone (LFZ) took the local population as well as scientists by surprise. To analyze the temporal and spatial deformation characteristics of the Mao county-Wenchuan fault, the Beichuan-Yingxiu fault, and Jiangyou-Guan County in the central south segment of the LFZ after the Wenchuan earthquake, the SBAS-InSAR method was adopted to derive surface deformation rate with 20 Envisat SAR images acquired between August 6, 2007, and July 26, 2010. Our analysis shows that the overall movement speed of LFZ increased significantly, reaching about - 40 mm/year, which shows a dextral compression strike-slip. From west to east, the velocity changes of each section are different, and the movement of the front-range fault is dominant in the middle and south sections of Longmenshan, which is close to the epicenter. The reason may be related to the fact that the middle and south section of Longmenshan is the epicenter of the earthquake. The southern and mid-southern sections of the LFZ change from west to east, and the direction of profile movement increases gradually. In the middle and north segment of the fault zone between the two, the variation characteristics are not obvious. To a certain extent, it indicates that the fault is characterized by dextral strike-slip compression in the southern segment and the mid-southern segment. The difference in the profile movement direction in the LFZ may be related to the stress release of the southern segment of the LFZ after the earthquake while the movement of the northern segment of the LFZ was blocked. The research results will reveal the mechanism of earthquake pregnancy and earthquake generation of LFZ, enrich the knowledge of the impact on the aftershock distribution of the Wenchuan earthquake, and promote the development of earthquake prediction research.
期刊：
INTERNATIONAL JOURNAL OF EXERGY,2023年40(4):365-391 ISSN：1742-8297
通讯作者：
Xiang, XA
作者机构：
[Peng, Deyong; Zhou, Jun; Xiang, Xianan; Zhou, Xuehua; Deng, Zhiya; Li, Yongsuo] Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Hunan, Peoples R China.;[Wang, Chenhua] Univ Tianjin, Sch Civil Engn, Tianjin 300072, Peoples R China.
通讯机构：
[Xiang, XA ] H;Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
exergy;AHP-FCE;rural solid waste;gasification;fixed bed
摘要：
An analytic hierarchy process-fuzzy comprehensive evaluation method (AHP-FCE) based on exergy analysis is proposed to evaluate the rural solid waste fixed-bed gasification process. The influence of gasification temperature, equivalence ratio (ER) and gasification agent on the gasification evaluation score are studied. Firstly, the exergy efficiency of gasification system is calculated by exergy analysis. Secondly, the AHP method is used to establish the optimal gasification process model, and the weight of the selected evaluation indexes is determined. The evaluation indexes include exergy efficiency, gas production rate, lower heating value (LHV) of producer gas, greenhouse gas emissions and waste residue emissions. Finally, the priority ranking of different gasification processes is obtained by the FCE method. The results show that when the gasification temperature is 1,000°C and the ER is 0.35, the gasification score is the highest. The oxygen/steam gasification is better than steam gasification and air gasification.
作者机构：
[Xue, Yun; Huang, Changjun; Cao, Yuanzhi; Liu, Fenliang] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Zhou, Lv] Guilin Univ Technol, Sch Geomat & Geoinformat, Guilin 541004, Peoples R China.;[Liu, Zhong] Hunan Remote Sensing Geol Survey & Monitoring Inst, Changsha 411000, Peoples R China.
通讯机构：
[Changjun Huang] S;School of Municipal and Surveying Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Dam deformation monitoring data are generally characterized by non-smooth and no-saturated S-type fluctuation. The grey Verhulst model can get better results only when the data series is non-monotonic swing development and the saturated S-shaped sequence. Due to the limitations of the grey Verhulst model, the prediction accuracy will be limited to a certain extent. Aiming at the shortages in the prediction based on the traditional Verhulst model, the optimized grey Verhulst model is proposed to improve the prediction accuracy of the dam deformation monitoring. Compared with those of the traditional GM (1,1) model, the DGM (2,1) model, and the traditional Verhulst (1,1) model, the experimental results show that the new proposed optimized Verhulst model has higher prediction accuracy than the traditional gray model. This study offers an effective model for dealing with the non-saturated fluctuation sequence to predict dam deformation under uncertain conditions.
关键词：
fluvial process;climate change;Late Quaternary;upper Huaihe River
摘要：
Research into river processes in different climatic and geomorphic areas is vital for a clearer understanding of the non-linear responses of rivers to climate change. The Huaihe River (HHR) Basin, located in China's North-South Transition Zone (NSTZ), provides an ideal environment in which to explore river responses to climate change within a humid/semi-humid transitional area. Based on optically stimulated luminescence (OSL) and C-14 dating, combined with sedimentary stratigraphic analyses, we reconstructed the river processes of three sedimentary sequences in the upper HHR since the Late Quaternary. Our results showed that the upper HHR was characterized by aggrading meandering channels from the Last Glacial Maximum (LGM) to 0.5 ka, and an aggrading wandering channel from 0.2 ka to the present. Two periods of downcutting occurred during 5.8-3.0 and 0.5-0.2 ka, respectively. The river incision is potentially linked to changes in the climate during the Mid-Late Holocene transition and the Little Ice Age (LIA). However, there have been no marked changes in channel patterns in the upper HHR since the LGM. This phenomenon reflects the influence of vegetation on channel patterns during climate change. Our results showed that the fluvial processes in different climatic and geomorphic areas are controlled by the local hydroclimatic regime.
摘要：
Residential building space cooling and heating energy consumption account for approximately 15% of the total social energy consumption. Occupant behaviour is the primary factor influencing energy consumption for cooling and heating in residential buildings. This study used extensive face-to-face questionnaire surveys and actual measurements for typical households to study the cooling and heating energy consumption of high-rise residential buildings in Changsha. Statistical analysis was conducted on the influencing factors of participant information, architecture, occupant behaviour, and energy conservation awareness in the questionnaire survey. The household energy bills for cooling and heating were clustered, and PCA models were proposed between the influencing factors and the energy consumption, and were verified by measured data of typical households. The results demonstrated that the household energy bills could be divided into five categories. The PCA models show the mode of ventilation during the cooling period and the mode of air conditioner (AC) turning on/off during the heating period are the most important component, accounting for 46.7% and 35.9%, respectively. The statistical parameters provided a reference for the energy consumption simulation software, and the PCA models achieved energy consumption prediction through data of principal components, which are significant for building energy efficiency and carbon reduction.
期刊：
Transactions of the Indian Institute of Metals,2023年76(5):1221-1227 ISSN：0972-2815
通讯作者：
Bozhi Ren
作者机构：
[Ren, Bozhi; Wang, Xin] Hunan Univ Sci & Technol, Sch Civil Engn, Xiangtan 411201, Hunan, Peoples R China.;[Wang, Xin; Zhang, Chun] Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Hunan, Peoples R China.;[Ren, Bozhi] Hunan Prov Key Lab Shale Gas Resource Exploitat, Xiangtan 411201, Hunan, Peoples R China.;[Zhou, Yingying] ChongQing Univ, Coll Environm & Ecol, Chongqing 400044, Peoples R China.
通讯机构：
[Bozhi Ren] S;School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, People’s Republic of China<&wdkj&>Hunan Provincial Key Laboratory of Shale Gas Resource Exploitation, Xiangtan, People’s Republic of China
摘要：
Abandoned tailings are one of the important sources of heavy metal pollution in regions surrounding mining areas. In this study, the speciation and kinetic characteristics of Mn and Pb were analyzed in waste rocks from a manganese mining area. The results show that under different experimental conditions, Mn mainly occurs in the residual state and the iron-manganese oxide-bound state, accounting for more than 90%, and Pb mainly occurs in the residual state, accounting for more than 99%. The cumulative release data in the dynamic leaching experiment can be fitted with a quadratic function. This research aims to provide a scientific basis for relevant decision-making departments to formulate environmental governance and protection strategies in mining areas.
作者机构：
[Chi, Nianping; Yang, Zhenwen] Hunan City Univ, Hunan Prov Engn &Technol Res Ctr Rural Water Qual, Sch Municipal & Geomatics Engn, Yiyang 413000, Hunan, Peoples R China.;[Li, Xuhao; Feng, Li] Guangdong Univ Technol, Sch Civil & Transportat Engn, Guangzhou 510006, Peoples R China.;[Zhu, Junren] Chongqing City Management Coll, Chongqing 401331, Peoples R China.;[Jiang, Zhenzhen] Chongqing Vocat Inst Engn, Chongqing 402260, Peoples R China.;[Zheng, Huaili] Chongqing Univ, Key Lab Three Gorges Reservoir Reg Ecoenvironm, Minist Educ, Chongqing 400045, Peoples R China.
通讯机构：
[Li Feng] S;School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
关键词：
Biodegradability;Dyeing wastewater;Electro- Ce(III) process;Energy consumption;Medium oxidation;Reactive red 2
摘要：
Reactive red 2 (RR2) azo dye wastewater poses a serious hazard to the water environment health, so using a novel and efficient Electro- Ce(III) (E- Ce(III)) process takes on a critical significance in treating RR2 dye wastewater. In this study, the effects of a variety of single-factor conditions on RR2 removal efficiency were evaluated in depth. The results indicated that the optimal experimental conditions are as reaction temperature of 25°C, Na(2)SO(4) concentration of 25mM, Ce(III) concentration of 0.3mM, pH of 4.0, and current density of 40.0mA/cm(2). When the RR2 dye wastewater was treated for 40min under the optimal experimental conditions, a high removal rate of 99.8% for RR2 was obtained. It is suggested that the background ion PO(4)(3-) in the dye wastewater inhibits the E-Ce (III) process, whereas Cl- facilitates this process. Moreover, the yield of Ce(IV) increases with the increase of the current density. At the current density of 40.0mA/cm(2), a reasonable energy consumption of 3.85kW h/gTOC for the process was obtained after the 3-h treatment. The effects of different degradation processes (including Direct Electrooxidation (DEO), single Ce(III), and E-Ce (III)) on RR2 removal efficiency and TOC change were compared. The types of oxidizing substances in the E-Ce (III) process were detected, and the mechanism of RR2 oxidative degradation in the E-Ce (III) process was summarized. The result suggests that the E-Ce (III) process has low power consumption. Meanwhile, in the E-Ce (III) process, free reactive Ce(IV) with strong oxidation is continuously generated, RR2 can be efficiently degraded. And the continuous cycle transformation between Ce(III) and Ce(IV) maintains the strong oxidation of the process. The contribution of free reactive Ce(IV) and DEO to RR2 degradation was obtained as 58.8% and 39.8%, respectively. The combined effect of Ce(IV) and DEO played a major role in the E-Ce (III) process, while ·OH exhibited a relatively weak effect (nearly 1.4%). RR2 was comprised of 13 major intermediates, and the biodegradability of wastewater was improved significantly after treatment, thus facilitating the further mineralization and biodegradation of the products. The E- Ce(III) process is novel, efficient, and environment-friendly, and has a large market application space, suggesting that it can be applied as an efficient, economic, and sustainable water treatment process.
摘要：
The development of remote sensing technology has accumulated a large number of remote sensing image time series data for human monitoring of surface vegetation change, which provides a basis for vegetation change prediction. In order to improve the prediction accuracy of vegetation change, this paper uses discrete wavelet to decompose remote sensing image sequences at multiple scales, to explore the difference of influence of different temporal scale change characteristics on vegetation spatio-temporal change prediction, and find the best decomposition scale for vegetation change prediction. In this paper, the research object is the MODIS 13Q1 EVI image data of Hunan Province from 2001 to 2021. The discrete wavelet is adopted to obtain multi-scale vegetation trend components and detailed component sequences, and then complete the LSTM modeling prediction and comparison. The following are the experimental findings: the predictive ability of the discrete wavelet decomposition sequence group is better than that of the original EVI time series to varying degrees. The order of prediction accuracy is: monthly scale > seasonal scale > annual scale > original EVI time series. Thus, it is of reference significance to the research of application scenarios of change prediction of other regionalized variables with multi-scale characteristics.
作者机构：
[Xue, Yun; Xi, Zhen; Liu, Fenliang; Huang, Changjun] Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Peoples R China.;[Gao, Hongshan] Lanzhou Univ, Coll Earth & Environm Sci, Key Lab Western Chinas Environm Syst, Minist Educ, Lanzhou 730000, Peoples R China.;[Li, Zongmeng] Xinyang Normal Univ, Sch Geog Sci, Xinyang 464000, Peoples R China.
通讯机构：
[Liu, FL ] H;Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Peoples R China.
关键词：
lacustrine sediment;terrace;river evolution;Jinsha River
摘要：
The formation of the Jinsha River drainage is a significant subject of concern in the geological and geomorphological fields. Among them, one key question is whether there was a regional paleo lake into which Lower Jinsha River drainage drained during the late Pliocene to early Pleistocene, due to massive fluvio-lacustrine sediments widely distributed in the Lower Jinsha River. Nevertheless, there has yet to be a consensus on the genesis of those fluvio-lacustrine sediments due to poor sedimentological and chronological data. In this study, to unravel the origin of those fluvio-lacustrine sediments and the formation model of the Lower Jinsha River, sedimentary characteristics, including spatial distribution, lithological composition, and stratigraphic contact relationship of those fluvio-lacustrine sediments were analyzed, and chronological determination of the fluvio-lacustrine sediments using Electron Spin Resonance and Optically stimulated luminescence method was conducted. The results show that in the Lower Jinsha River, the lacustrine sediments are mainly composed of silt and clay, with apparent horizontal bedding, stacked with fluvial cobble-gravel and sand, and are in unconformable contact with the underlying bedrock strata or paleo soil. The lacustrine sediments are spatially discontinuous and mainly distributed in the Shigu, Taoyuan, Panzhihua, and Longjie reaches. Downstream of these reaches are deeply incised gorges with an average slope >30 degrees, and many landslide landforms and deposits can be identified here. In each reach, the lacustrine sediments were closely distributed along the trunk and tributary channels in the plane and were distributed at different altitudes, forming a sequence of lacustrine terraces. Chronological analysis shows that in different reaches, the deposition ages of lacustrine sediments are significantly different. In each reach, the deposition age of the lacustrine terraces of high altitude is older than that of low altitude. The above characteristics collectively indicate that the lacustrine sediments in the Lower Jinsha River were locally deposited by individual dammed lakes, probably induced by landslide rather than a regional paleo lake by tectonic activities. During the incision process of the river valley, landslides continuously block the river channel, forming dammed lakes, and then deposited lacustrine sediments at different elevations, forming lacustrine terraces. The lacustrine sediment of the topmost lacustrine terrace in Panzhihua reach was dated to be 1.78 Ma, combined with previous studies on the fluvial terraces, indicating the Lower Jinsha River existed and started to incise its valley before the early Pleistocene. The widespread dammed lake sediment indicates that the formation of the Jinsha River valley follows the pattern of "incision-landslide-damming-aggradation-incision".
摘要：
This paper examined the impacts of different pretreatments on the characteristics of biochar and its adsorption behavior for Pb(2+). Biochar with combined pretreatment of water-washing and freeze-drying (W-FD-PB) performed a maximum adsorption capacity for Pb(2+) of 406.99mg/g, higher than that of 266.02mg/g on water-washing pretreated biochar (W-PB) and 188.21mg/g on directly pyrolyzed biochar (PB). This is because the water-washing process partially removed the K and Na, resulting in the relatively enriched Ca and Mg on W-FD-PB. And the freeze-drying pretreatment broke the fiber structure of pomelo peel, favoring the development of a fluffy surface and large specific surface area during pyrolysis. Quantitative mechanism analysis implied that cation ion exchange and precipitation were the driving forces in Pb(2+) adsorption on biochar, and both mechanisms were enhanced during Pb(2+) adsorption on W-FD-PB. Furthermore, adding W-FD-PB to Pb-contaminated soil increased the soil pH and significantly reduced the availability of Pb.
