Table of Content

Volume 36 Issue 6
25 June 2020
Table of Contents
Table of Contents
2020, 36(6):  0-0. 
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Species Composition and Population Dynamics of Amphibians in Wuyi Mountain Observation Sample Region, Fujian Province
GENG Bao-rong, HE Yu-xiao, ZHANG Qiu-jin, XU Hai-gen
2020, 36(6):  689-696.  doi:10.19741/j.issn.1673-4831.2019.0726
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Amphibians are important indicators for biodiversity observation. During the period of 2012-2018, amphibian species composition and population dynamics in Wuyishan National Nature Reserve and its vicinity in Fujian Province were investigated by using the transect sampling method. In total, 24 species belonging to 8 families and two orders were recorded. Specifically, 12 species were only detected inside the nature reserve, where the dominant species were Limnonectes fujianensis and Odorrana huanggangensis, Amolops ricketti. 7 species were only recorded outside the nature reserve, where the dominant species were Fejervarya multistriata, Microhyla fissipes and Nidirana adenopleura. However, 5 species can be observed both in- and outside the nature reserve. In addition, the results also indicate that despite both total population dynamics and dominant species dynamics in the sampling region changed obviously, no significant difference was observed of their annual dynamics.
Spatial and Temporal Distribution of Amphibian Diversity at Baiyunshan Mountain Versus Jiulongshan Mountain in Lishui City, Zhejiang Province
ZHENG Wei-cheng, CAO Zhi-hao, ZHENG Zi-hong, WANG Yu, CHEN Zhi-qiang, DING Guo-hua
2020, 36(6):  697-705.  doi:10.19741/j.issn.1673-4831.2020.0080
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The decline of amphibian populations and their decreasing of biodiversity are attracting increasing research attention, and studies on amphibian diversity are helpful for species conservation and ecological environment monitoring. 12 sampling transects were used which covering three habitat types, i.e., stream, cropland and ditches, at Baiyunshan Mountain and Jiulongshan Mountain in Lishui, Zhejiang Province, China, to investigate and dynamically monitor amphibian diversity in April, June, and August of 2018. The following results were obtained:(1) A total of 20 amphibian species belonging to 7 families in 1 order were recorded in the two sampled areas. Species compositions differed between the two sampling areas, and the dominant species also differed between the sampling areas, between habitat types, and between three months of sampling. (2) Relative abundance of amphibians was negatively correlated with air temperature, and was positively correlated with elevation, as determined by using Pearson's correlation analysis. (3) Relative abundance was higher at Jiulongshan Mountain than at Baiyunshan Mountain, was higher on cropland than in ditches, and was higher in April than in August and species richness was higher in April and June than in August; and the interaction term of habitat type×month interaction showed a significantly effected on species richness, relative abundance, Simpson's diversity index and Shannon-Wiener index. In summary, spatial and temporal structure of amphibian diversity in Lishui of Zhejiang Province, differed significantly between Baiyunshan Mountain and Jiulongshan Mountain.
Spatial and Temporal Divergence of Amphibian Diversity in Yongfeng Sample Area of Jiangxi Province
CHEN Zhi-qiang, TANG Yun, CHEN Qiao-er, CHEN Jia-meng, DING Guo-hua, JI Xiang
2020, 36(6):  706-713.  doi:10.19741/j.issn.1673-4831.2020.0079
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Amphibians, as bioindicators in environmental monitoring, have a critical role in maintaining ecological balance. To reveal the spatial and temporal pattern of amphibian diversity, 15 sampling transects were employed in Yongfeng sample area (Jiangxi Province, China), which are located as stream, paddy field and artificial channel in April, June and August of 2018, to obtain the environmental data, the species and amounts of amphibians. The results showed that: (1) A total of 18 amphibian species were found in the survey which belong to two orders, seven families, and 16 genera, including one endangered and one vulnerable species. (2)Amolops wuyiensis, Fejervarya multistriata and Limnonectes fujianensis were the dominant species in stream, paddy field and artificial channel, respectively. (3) The Pearson correlation analysis show that the relative abundance was negatively related with the air temperature and the water temperature, respectively, and the species richness was negatively related with the water temperature in paddy field; but the relative abundance was positively related with air temperature in artificial channel. (4) The species richness, relative abundance, Simpson index and the Shannon-Wiener index of amphibians in paddy field and artificial channel were higher than those in stream; the relative abundance decreased with month, the interaction between habitat type and month induced the variation of the relative abundance. (5) Cody index in the paddy field vs. artificial channel was lower than that in the paddy field vs. stream and the stream vs. artificial channel. In conclusion, amphibian diversity has significant spatial and temporal variation in Yongfeng sample area of Jiangxi Province.
Amphibian Monitoring and Population Dynamics in Douba, Kangxian From 2014 to 2018
CAO Rui-dong, HE Yu-xiao, YU Peng, CHEN Zhuo, ZHAO Hao-chi, HUANG Qi-tong, GONG da-jie, XU Hai-gen
2020, 36(6):  714-719.  doi:10.19741/j.issn.1673-4831.2019.0791
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Currently, the survival situation of amphibians has already attracted more and more attention by ecologists and conservation biologists. Kangxian as experimental site in this study is located in the southeast of Longnan mountain area, which is just on the boundary of climate between north and south of China and the boundary between Indomalaya Ecozone and Palearctic Ecozone of the world animal geography division. This County is the key area of natural geography and animal geography division of China. From 2014 to 2018, the dynamic information of amphibian population in six representative sample sites in this County (Lijiagou, Douba, River of Luojiadi, Yingou, Mountain of Luojiadi and Yuanfeng) had been continuously monitored by using the method of line sampling and fence trap. Five species of amphibians, Feirana kangxianensis, Rana chensinensis, Bufo gargarizans, Hyla tsinlingensis, and Batrachuperus tibetanus were observed. Among them, only Batrachuperus tibetanus is a vulnerable species (VU), just four individuals were recorded in Lijiagou during 2015 to 2016, so no statistics were carried out for this species. The results show that the population of Feirana kangxianensis was increased, the population of Bufo chinensis remained stable, but the population of Rana chinensis and Hyla tsinlingensis were decreased. The population density of all species in each sample site was fluctuant in different trends, but bottom out at the lowest point in 2017. Except for 2014 and 2017, the density of amphibians in all sample plots was the highest in April, followed by a decrease in both June and August. The number of amphibians in the Yingou sampling transects was the largest, which was significantly largger than that in the Lijiagou and Mountian of Luojiadi sampling transects (P<0.05), and there was no significant difference between the other sampling transects (P>0.05). The main human interference for the decline of amphibian population and population density are quarrying activities and water pollution. Therefore, habitat protection should be strengthened.
Temporal and Spatial Patterns of Amphibian Species Richness in Lianyungang, Jiangsu
QIAN Ru-en, WANG Hao, HE Yu-xiao, CHEN Wan, LI Peng, HU Chao-chao, XU Hai-gen
2020, 36(6):  720-725.  doi:10.19741/j.issn.1673-4831.2020.0042
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The survey of amphibian communities plays an important role in formulating conservation strategies of biodiversity. In the past 20 years, rapid urbanization has occurred in Jiangsu Province, especially in Lianyungang City. Urbanization affects amphibian communities through habitat loss, fragmentation, and degradation of habitat quality, which are the main threats to amphibian populations. In order to understand the spatial and temporal patterns of amphibian communities in Lianyungang City, 14 sampling transect were established and surveys were conducted to investigated the richness and density of anurans in April, June and August of 2018. Five amphibian species were detected in the study area, which belong to 4 genera, 3 families, 1 order. The five species are Asiatic Toad (Bufogargarizans), Black-spotted Pond Frog (Pelophylaxnigromaculatus), Beijing Gold-stripe Pond Frog (P. plancyi), Zhenhai Brown Frog (Rana zhenhaiensis) and Hong Kong Rice-paddy Frog (Fejervarya multistriata). The species of F. multistriata was the most frequently detected, whereas R. zhenhaiensis was rare detected in the survey. The species diversity of amphibians varied significantly at the survey season, with the highest diversity index in June, followed by August, and the lowest in April. Based on the amphibian species richness and distribution pattern, it could be concluded that anurans in Lianyungang are affected both by environmental change in microhabitats and in temporal variables. Some protective suggestions are proposed.
An Observation on the Spatial and Temporal Pattern of Amphibian Diversity in Yulong Snow Mountain, Yunnan, China
YAO Chong-xue, WANG Zhi-hong, LIANG Liang, Lü Ting, HUANG Yuan, CHEN Ming-yong
2020, 36(6):  726-730.  doi:10.19741/j.issn.1673-4831.2019.0976
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In June and August 2018, the diversity of amphibians of Yulong Snow Mountain was observed by the application of sample line method. Total number of 1,143 amphibians which includes number of adults, sub-adults, and juveniles on 11 sampling transects were recorded. These individuals were identified as 8 species, which belong to 2 orders, 6 families and 8 genera. The numbers of individuals vary greatly in different seasons, 705 amphibians were recorded in June, and 438 in August. The numbers of species and individuals of amphibians recorded by each sampling transect were obvious and affected by several factors, such as average water temperature, average air temperature and human interference intensity. It demonstrates that the higher the average water temperature and the average air temperature and the weaker the human interference intensity on the sampling transects, the more the number of species and individuals recorded. The numbers of species and individuals of amphibians were different in each habitat. In artificial channel the number was the largest while in the river it was the smallest. From the results it could be concluded that the habitat type, water temperature, air temperature and human interference are important ecological factors affecting amphibian species diversity.
Path Analysis of Coordinated Development of Resource, Environment and Economy in Beijing-Tianjin-Hebei Region
DAI Tie-jun, AN Bai-chao, WANG Wan-jun
2020, 36(6):  731-740.  doi:10.19741/j.issn.1673-4831.2019.0958
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Promoting the coordinated development of resource, environment and economy in Beijing-Tianjin-Hebei Region is one of the goals of the coordinated development for this region. The economy-wide material flow analysis was combined with system dynamics in this study to set up a system dynamic model of resource-environment-economic system for exploring the path of coordinated development of resource-environment-economy in this region. Economic accelerated development model, inertia development model, resource-environmental protection model and coordinated development model were set up for comparison study. The results of the study show that under the coordinated development model, the development of social economy maintains relatively fast, and the pressure on resources and environment in the region will be reduced by adjusting the industrial structure, increasing investment in environment and technology, and improving the utilization and recycling rate of industrial solid wastes. The improvement of coordinated development of this region under this model is far higher than the other three models. In conclusion, the coordinated development model is the best one for coordinated development of resource-environment-economy in this region,however, Hebei Province still needs to pay attention to resolving the rising pressure on resources and environment in the process of urbanization.
Study on the Landscape Pattern of Southwest Transition Zone From Mountainous to Hilly Areas Under the Influence of Multi-Dimensional Terrain Factors: A Case Study of the Middle and Upper Reaches of Fujiang River Basin
HOU Lan-gong, LIU Tao
2020, 36(6):  741-751.  doi:10.19741/j.issn.1673-4831.2019.1004
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Due to its unique topography, the mountainous and hilly transition zone has a complex but regular landscape pattern. The analysis of terrain factors can not only make a reasonable explanation for the landscape pattern of complex geographical units, but also help further understand the distribution law of landscape pattern, laying a foundation for optimizing spatial allocation. Mainly based on Google Earth image, DEM and 30 m global surface coverage data in 2017 as data sources, applying methods of GIS technology, distribution index, landscape pattern index and moving window, this paper analyzes the spatial distribution characteristics of landscape types in the middle and upper reaches of Fujiang River Basin with the changes of elevation, slope, fluctuation and slope direction, the spatial difference of landscape pattern with the moving window method as well as exploring the influence degree of different terrain factors on landscape pattern change with Pearson correlation analysis method. The results show that: (1) With the increase of elevation, slope and fluctuation, the landscape type changes from man-made culticated and construction land to nature-driven grass and forest land; it is with the most obvious advantage and disadvantage changes of the construction land from sunny slope. (2) The most abundant landscape type in the basin is the impact plain, which is mainly distributed in the areas with altitude (>500-650 m), slope (0-5°) and fluctuation (>10-30 m); while the landscape pattern tends to be single and the fragmentation degree is weak in the areas with high altitude, slope and fluctuation. (3) The diversified landscape in mountainous areas is mainly distributed along the Fujiang River, while the landscape in hilly areas tends to be unitary along the Fujiang River. The landscape in the impact plain areas tends to be relatively unitary → diversified → relatively unitary from the outside to the inside, and the landscape in the urban-rural junctions is the most abundant. (4) The influence degree of different terrain factors on landscape pattern can be expressed as: elevation > slope > fluctuation > slope direction. Elevation, slope and fluctuation have strong correlation with landscape pattern, while slope direction shows weak correlation.
Synergic Use of Sentinel-1 and Sentinel-2 Images for Soil Moisture Retrieval in Vegetation Covered Agricultural Areas of Jingxian County of Heibei Province
LI Bo-xiang, CHEN Xiao-yong
2020, 36(6):  752-761.  doi:10.19741/j.issn.1673-4831.2019.0944
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Vegetation has significant effect on the retrieval of surface soil moisture by microwave remote sensing. A related study was carried out in Jingxian County of Hebei Province. The quantitative inversion research on the surface soil moisture in vegetation covered agricultural areas was based on the combination method of the modified water cloud model and the Oh model using Sentinel-1 SAR and Sentinel-2 optical remote sensing data. The results show that the combination method had good inversion accuracy in the VV polarization mode, with R2 of 0.653 0, RMSE of 0.040 1 cm3·cm-3, MAE of 0.032 7 cm3·cm-3. Compared with the VH polarization mode, the VV polarization mode had better ability for the detection of the change of surface soil water content. The proposed method can obtain the data of the surface soil moisture with high spatial resolution and high accuracy in the vegetation covered areas.
Research on the Release Potential of Ammonia in the Estuarine Wetland Sediments of Erhai Lake
YUAN Hai-ying, LIANG Qi-bin, HOU Lei, CHEN Xin
2020, 36(6):  762-769.  doi:10.19741/j.issn.1673-4831.2019.0917
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After running for ten years, the nitrogen content in the sediments of Luoshijiang Estuarine Wetland increased continuously, and there was great release risk. In order to explore the spatial-temporal distribution characteristics of nitrogen in the overlying water and sediment of the wetland, on-site investigation and monitoring were carried out. A 5-day laboratory simulation experiment was carried out by using the method of continuous flow culture of the original column samples to study the variation features and influencing factors of release flux of NH4+-N in wetland sediments. The results show that: (1)The concentrations of TN and NH4+-N were quite high and ranged from 3.11 to 5.13 and from 0.32 to 0.62 mg·L-1, respectively, which both showed a decreasing trend from inlet to outlet of the wetland. The contents of TN and NH4+-N in the surface sediments ranged from 1 264.83 to 2 554.48 and from 13.56 to 63.42 mg·kg-1, respectively, which showed that the contents in inlet were higher than those in other monitoring points. (2)The release fluxes of NH4+-N in the sediments of Luoshijiang Estuarine Wetland were in the range of 270.60 to 747.58 mg·m-2·d-1 with the average value of 482.95 mg·m-2·d-1, and the wetland sediments mainly acted as the release source of NH4+-N. During the experiment of 5-day continuous flow cultivation, the release flux of NH4+-N in wetland sediments showed a trend of first decreasing and then increasing, and reached the lowest value on the third day of the experiment. The results could provide scientific basis for the design and management of artificial wetland restoration in Erhai Lake Catchment.
Fluorescence Characteristics of DOM and Its Interaction With Mercury in Piliqing River Watershed in Xinjiang, China
MENG Yong-xia, CHENG Yan, LI Lin, WANG Yue, Berdybuk KUBUGAZA, SUN Yi
2020, 36(6):  770-777.  doi:10.19741/j.issn.1673-4831.2019.0886
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Taking the soil dissolved organic matter (DOM) in the typical small watershed of the Piliqinghe River as the research object, parallel factor technology was used combined with fluorescence quenching and titration technology to analyze and discuss fluorescence characteristics and soil DOM contents under different land use types (including woodland, farmland, grassland) in the watershed coordinated with Hg2+. The results show that different land use types had significant differences in soil DOM characteristics. The soil DOM contents were in the order of grassland > woodland > farmland, and the chromophoric dissolved organic matter (CDOM) contents were in the order of grassland > farmland > forest land. Under different land uses, soil DOM contains 3 kinds of fluorescence peaks: humus-like fluorescence peak A in the ultraviolet region, fulvic acid-like fluorescence peak C in the visible region, and marine or terrestrial humus-like fluorescence peak M. The parallel factors identified two components, C1 as humic acid and C2 as fulvic acid. In addition, the fluorescence intensity of the DOM components in the three different land-use types showed different degrees of fluorescence quenching with the increase of Hg2+ concentration. There were differences in the complexation constants of various fluorescent components and Hg2+ in DOM, which indicates that the type and number of functional groups participating in the reaction of DOM did affect the complexation ability of Hg2+ due to different land-use pollution sources, resulting in different complexation constants.
Ecological Network Construction and Spatial Conflict Identification Around Taihu Lake Area in Suzhou City
CHEN De-chao, SHI Zhu-kai, WANG Zu-jing, YU Cheng
2020, 36(6):  778-787.  doi:10.19741/j.issn.1673-4831.2020.0158
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Rapid urbanization led to serious habitat fragmentation, therefore, the construction of ecological network is of great significance to regional ecological security. Morphological spatial pattern analysis and minimum cumulative resistance model were applied to identify the ecological source, potential ecological corridor and ecological buffer zone based on the land use dataset and digital elevation model (DEM) in 2017, around Taihu Lake area. Then the urban construction land and the identified ecological network were spatially overlaid to explore the land use conflict. The area of the ecological network is 100 965.79 hm2, among which ecological source area, potential ecological corridor, and ecological buffer zone accounted for 35.72%, 5.82% and 58.46%, respectively. All the 16 ecological source areas are large-scale ecological land, including forest land, water bodies, and wetland. In terms of spatial distribution, the mountainous areas are mainly distributed in the west of the study area, and the water areas are mainly distributed in the east of the study area. However, the connectivity among the ecological source areas is weak and these ecological source areas are highly fragmented in the southeast. There are 105 potential ecological corridors, 12 of which are very important ones. The densities of the ecological corridors in the southeast are higher than that in the northwest, and the widths of the ecological corridors in the northwest are wider than that in the southeast. The area of ecological buffer zone is generally larger in the east than that in the west. From the main built-up area to the periphery of the city, the conflict between urban land and ecological network is gradually weakened, while the conflict between ancient city and ecological corridor is more striking. These conflicts are mainly resulted from the encroachment of ecological buffer zone by the urban fringe. Therefore, combining with urban renewal, multiple ecological protection measures should be carried out in the ancient city, for example, repairing the backbone water system and greening, linking the critical ecological corridors, regional coordinated governance in Chengnan residential district, restoring the green wedge in the southwest. This study is expected to provide technical support for ecological security and urban planning around Taihu Lake area.
Structure and Dynamic Characteristics of Pinus armandii Population in Karst Region, Northwest of Guizhou Province
HE Bin, LI Qing, CHEN Qun-li, XUE Xiao-hui, LI Wang-jun
2020, 36(6):  788-795.  doi:10.19741/j.issn.1673-4831.2019.0913
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An investigation was conducted on the population structure and dynamics of Pinus armandii in Caohai National Nature Reserve with the typical plot survey method. Diameter class was adopted to represent age class, the static life table and survival curves were compiled to analyze its current population structure and the survival analysis and time sequence analysis were used to predict its future quantitative dynamics. These can provide a scientific basis for the protection, resource management and restoration of karst forest ecosystems. The results show that: (1) The P. armandii population showed a spindle-shaped age structure, the survival curve tended to be Deevey-II type. The quantitative dynamic index (Vn) fluctuated greatly with the increase of age, the quantitative dynamic index neglecting (Vpi) and considering outside interference (Vpi')were both greater than 0, which showed that the P. armandii population belonged to the growing type. (2) Survival analysis show that the survival rate gradually decreased and the cumulative mortality gradually increased. The curve of death density decreased smoothly and that of risk rate increased gradually, which meant that the population of P. armandii was stable in the early stage, increased in the middle stage, and declined in the later stage. (3) The forecasting model of time sequence analysis indicated that after 2, 4, 6 and 8 age classes in the future, there will be a gradually decreasing trend from Ⅰ to Ⅲ age class, and a gradually increasing trend from Ⅴ to Ⅸ age class. Consequently,the regeneration of P. armandii population is mainly restricted by the built-up mechanism. It is suggested to strengthen tending, management and maintenance measures for seedlings and young trees.
Effect of Hematite on HAP Immobilization of Soil Copper and Cadmium Under Flooding Conditions
WU Qiu-gang, WANG Yan-jun, ZHAO Heng, YANG Liu, MENG Rui-yan, HE Jian-guo
2020, 36(6):  796-802.  doi:10.19741/j.issn.1673-4831.2019.0916
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Hydroxyapatite (HAP) is considered as an amendment for heavy metals contaminated soils, while The iron oxides in the soil have strong binding abilities with phosphate. However, it’s not clear about the effects of iron oxides on the immobilization of heavy metals in soil. The effect of hematite on the immobilization efficiency of copper and cadmium by HAP were investigated through flooding experiments in this study. Results show that the addition of HAP-only and hematite-only increased soil pH and soil solution pH compared with the control. Hematite with high content promoted the reduction of phosphate, dissolved Cu2+ and Cd2+ in the soil solution in the presence of HAP. Meanwhile, soil available phosphorus was reduced by 12.9%-41.0%, and CaCl2 extractable Cu and Cd were reduced by 24.9%-64.5% and 11.4%-39.3% respectively in HAP plus hematite treatments. Thus, hematite promoted the immobilization of Cu and Cd in the presence of HAP, and decreased the available P in soil under flooding conditions. The results of this study indicated that phosphorus-based materials can be applied to paddy soils in southern China for immobilizing heavy metals.
Degradation of Methyl Orange Wastewater by SA/GO@Fe3O4 Magnetic Particle Electrode
ZHANG Shu-ling, FENG Jin-cai, XU Bin, ZHANG Yi-min, YANG Fei, ZHANG Zhi-wei
2020, 36(6):  803-810.  doi:10.19741/j.issn.1673-4831.2019.0686
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In this research, SA/GO@Fe3O4 magnetic particle electrode was prepared and the structure was characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray powder diffraction. Methyl orange was selected as the target pollutant. The influence of four factors, including initial pH, particle electrode dosage, electrolysis time and current density, on TOC removal efficiency were investigated. The order influence degrees of the factors were as follows: current density > electrolysis time > particle electrode dosage > initial pH. In addition, the experimental results were evaluated by Box-Benhnken central composite response surface design. The optimum reaction conditions were predicted as particle electrode dosage 2.99 g·L-1, current density 29.58 mA·cm-2, reaction time 79.7 min and initial pH 4.31. On this condition, the TOC removal efficiency of methyl orange was 80.03%. The intermediate products and mechanism of the degradation process of methyl orange were analyzed by UV-Vis absorption spectroscopy and Fourier transform infrared spectroscopy, and the degradation pathway was speculated. Besides, particle electrode could be rapidly separated by magnetic field in five seconds. Meanwhile, the degradation efficiency decreased by only 4.3% after five reuses, which proves that SA/GO@Fe3O4 magnetic particle electrode has excellent recovery and reuse performance.
Preparation of C-Co Derived From Co Prussian Blue Analogues as an Activator of Peroxymonosulfate for the Degradation of Methylene Blue
TANG Rong, MAO Su-nan
2020, 36(6):  811-818.  doi:10.19741/j.issn.1673-4831.2019.0816
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A Prussian blue derived C-Co catalyst was synthesized and used to activate peroxymonosulfate (PMS) for the degradation of methylene blue. The C-Co catalyst exhibited higher catalytic performance than that of Co3O4, reaching degradation rate of 90.0% for 30 mg·L-1 methylene blue in 40 minutes. The reaction process was fitted by the pseudo-second order kinetic model, and the reaction rate constant was 1.57×103 L·mol-1·min-1. The effect of temperature, pH, PMS concentration and coexisting ions on methylene blue degradation rates were also investigated during the activation of PMS by C-Co. The reactive radicals in the reaction were further explored by free radical trapping experiments. The results demonstrate that the singlet oxygen produced by PMS activation played an important role in methylene blue degradation. Moreover, C-Co had a good reusability, keeping a high degradation rate after having been reused for three times.
Effect of Step Cooling on the Efficiency and Functional Flora Structure of a Half Partial Nitrification System
WANG Wei, LI Bo-lin, WANG Yue, WANG Heng, LI Ye, YAO Kai-fang, HUANG Xin
2020, 36(6):  819-824.  doi:10.19741/j.issn.1673-4831.2019.0405
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Partial nitritation was quickly begun by inoculating aerobic flocculent sludge and half partial nitritation was achieved. The changes in the microbial communities were studied during the process of step cooling. The results show that when controlling ρ(DO) to 1.2-1.5 mg·L-1, pH to 7.6-7.7, and temperature to (30±2) ℃, partial nitritation could be achieved on the 16th day. Subsequently, half partial nitritation was controlled to stabilize the effluent NO2--N/NH4+-N around 1.32. Then a stepwise cooling was set (28 ℃→25 ℃→20 ℃→15 ℃) simultaneously to an increase in ρ(DO) to 1.4-1.5 mg·L-1 and an increase of pH to 7.8-7.9 to keep the reactor stable at low temperatures. It showed that even at 15 ℃, the NH4+-N removal rate (NRR) and the NO2--N accumulation rate (NAR) averaged 59.7% and 80.2%, respectively. According to 16S rDNA high-throughput sequencing tests, the relative abundance of the ammonia oxidizing bacteria (AOB) Nitrosomonas increased from 0.09% in inoculated sludge to 5.20% at 15 ℃, about 58-fold increase. The relative abundance of the nitrite oxidizing bacteria (NOB) Nitrospira and Nitrobacter decreased from 0.90% and 0.98% in the inoculated sludge to 0.33% and 0.05% at 15 ℃, respectively. Thus the number of AOB increased significantly and NOB were effectively inhibited.