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1.
Vegetation patterns and nature reserve construction in an extremely-arid desert in Anxi,NW China's Gansu Province 总被引:2,自引:0,他引:2
Anxi County is located in the northwestern part of the Hexi Corridor in gansu Province and has the sole national level nature reserve of extremely-arid desert in China.Phytosociological methods (Braun-Blanquet,1964) are used to classify plant community types in this area.Eleven are disting uished,including six of deserts,four of oases and one transitional type between deserts and oases.Direct gradient analysis (DCA) is employed to correlate the distribution of plant communities to physiogeographic conditions.This study makes clear that water is the most important ecological factor for the distribution of plant species and communities in this area.The effects of water have been demonstrated in different ways.A vegetation gradient from lower altitude to higher altitude in the southern part of the reserve is driven by a precipitation gradient.The effects of the depth of ground water table contribute to the differentiation of vegetation from desert to oasis in the flat area.In a finer scale,the washed gullies have obviously higher species richness and also higher vegetation cover than the surround gobi surfaces,possibly caused by the effects of floods.The vegetation patterns demonstrate that the area of Anxi County is a complete landscape unit.The range of the current nature reserve is not large enough for the purpose of conserving the unique biodiversity in this area. 相似文献
2.
Wang Hong-Yan Chen Peng Zhu Yong-Guan Cen Kuang Sun Guo-Xin 《Environmental science and pollution research international》2019,26(9):8575-8584
Environmental Science and Pollution Research - A novel biochar was prepared by loading birnessite to improve its capability to simultaneously adsorb As(III), As(V), and Cd(II) in water and soil.... 相似文献
3.
采用厌氧颗粒污泥处理低浓度废水来启动实验规模的沼气提升厌氧反应器,以啤酒废水为例,厌氧反应器在温度(35±1)℃和进水COD浓度在2100~2400mg/L条件下,通过提高进水量方式,来缩短水力停留时间HRT和提高有机负荷OLR.用First-order、Monod and Contois、Grau second-order和Modified Stover–Kincannon动力学模型,考察在不同的HRT和进水浓度Si条件下,出水浓度Se与前两者的关系,确定动力学参数.实验结果表明:First-order和Monod and Contois模型不适用本实验,Grau second-order和Modified Stover–Kincannon模型适用,通过后两个模型公式分别比较实验值Se与计算值Se的差别,Grau second-order模型比Modified Stover–Kincannon模型更接近实验值. 相似文献
4.
采用斑马鱼胚胎发育技术和传统毒理学方法, 研究了氟吡菌胺对斑马鱼胚胎、成鱼及仔鱼的毒性效应.结果发现,氟吡菌胺对3个阶段斑马鱼均具有致死能力,对仔鱼LC50(48h)值为0.204mg/L,成鱼LC50(96h)为0.286mg/L,幼鱼LC50(96h)为1.489mg/L.研究表明,0.0596mg/L以上浓度的氟吡菌胺对斑马鱼胚胎均有一定程度的致死效应,高浓度处理组胚胎出现心包囊肿、卵黄囊不吸收、黑色素沉积少及鱼体弯曲等症状;氟吡菌胺对斑马鱼成鱼进行14d暴露后,处理组成鱼体重下降,产卵量减少,有效卵量降低; 0.0298mg/L处理组144h子代仔鱼存活率虽然比较高,但存活鱼大部分出现心包囊肿、体弯曲等畸形.上述结果说明,水体中残留的氟吡菌胺对于斑马鱼各生命阶段的生长发育均具有潜在的危害. 相似文献
5.
Peng Chen Jin Li Hong-Yan Wang Rui-Lun Zheng Guo-Xin Sun 《Environmental science and pollution research international》2017,24(27):21739-21749
Arsenic (As) removal through microbially driven biovolatilization can be explored as a potential method for As bioremediation. However, its effectiveness needs to be improved. Biostimulation with organic matter amendment and bioaugmentation with the inoculation of genetic engineered bacteria could be potential strategies for As removal and site remediation. Here, the experiments were conducted to evaluate the impacts of rice straw and biochar amendment, inoculation of genetic engineered Pseudomonas putida KT2440 (GE P. putida) with high As volatilization activity, on microbial mediated As volatilization and removal from three different arseniferous soils. In general, the addition of rice straw (5%) significantly enhanced As methylation and volatilization in comparison with corresponding non-amended soils. Biochar amendments and inoculation of the GE P. putida increased As methylation and volatilization, respectively, but less than that of rice straw addition. The effectiveness of As volatilizations are quite different in the various paddy soils. The combined amendments of rice straw and GE P. putida exhibited the highest As removal efficiency (483.2 μg/kg/year) in Dayu soil, with 1.2% volatilization of the total As annually. The highest water-soluble As concentration (0.73 mg/kg) in this soil could be responsible for highest As volatilization besides the rice straw and bacteria in this soil. 相似文献
6.
Lu Xiao-Lin Wu Hao Song Shi-Li Bai Hong-Yan Tang Meng-Jun Xu Fang-Ji Ma Yan Dai Chuan-Chao Jia Yong 《Environmental science and pollution research international》2021,28(22):27998-28013
Environmental Science and Pollution Research - Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent... 相似文献
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8.
通过室内添加Cd2+培养中肋骨条藻(Skeletonema costatum),开展了Cd2+胁迫对中肋骨条藻生长的影响及藻细胞内超氧化物歧化酶(SOD)、二胺氧化酶(DAO)、多胺氧化酶(PAO)的活性以及丙二醛(MDA)和各形态多胺含量变化的实验,以探究多胺对于海洋微藻在重金属胁迫下的响应及生理作用.结果显示,Cd2+对中肋骨条藻的生长产生胁迫作用,且Cd2+浓度越大对藻细胞生长的抑制作用越强.Cd2+胁迫下中肋骨条藻细胞内MDA含量略有升高,SOD活性显著降低,DAO和PAO活性分别增强.随着Cd2+胁迫作用的增强,藻细胞内游离态腐胺(Put)、亚精胺(Spd)、精胺(Spm)含量先降低后升高;结合态Put、Spd和Spm含量先升高后降低;束缚态Put、Spm和Spd含量及Put总量和Spm总量升高.表明Cd2+胁迫会导致中肋骨条藻细胞产生氧化损害,同时细胞内DAO和PAO活性的增强以及游离态Put、束缚态Spd和Spm、Put总量和Spm总量的升高可能会增强藻细胞抵抗Cd2+胁迫的能力. 相似文献
9.
Hong-Yan Zeng He Jiang Kui Xia Ya-Ju Wang Yan Huang 《Environmental science and pollution research international》2010,17(5):1035-1044
Background, aim, and scope
Two new high phenol-degrading strains, Micrococcus sp. and Alcaligenes faecalis JH 1013, were isolated. The two isolates could grow aerobically in mineral salts medium containing phenol as a sole carbon source at concentration of 3,000 mg L−1. It was found that the binary mixed culture of the two isolates possessed good potential for phenol removal. 相似文献10.
Background, aim, and scope Dye pollutants are a major class of environmental contaminants. Over 100,000 dyes have been synthesized worldwide and more
than 700,000 tons are produced annually and over 5% are discharged into aquatic environments. The adsorption or sorption is
one of the most efficient methods to remove dye and heavy metal pollutants from wastewater. However, most of the present sorbents
often bear some disadvantages, e.g. low sorption capacity, difficult separation of spoil, complex reproduction, or secondary
pollution. Development of novel sorbents that can overcome these limitations is desirable.
Materials and methods On the basis of the chemical coprecipitation of calcium oxalate (CaC2O4), bromopyrogallol red (BPR) was embedded during the growing of CaC2O4 particles. The ternary C2O4
2––BPR–Ca2+ sorbent was yielded by the centrifugation. Its composition was determined by spectrophotometry and AAS, and its structure
and morphology were characterized by powder X-ray diffraction (XRD), laser particle-size analysis, and scanning electron microscopy
(SEM). The adsorption of ethyl violet (EV) and heavy metals, e.g. Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) were carried
out and their removal rate determined by spectrophotometry and ICP-OES. The adsorption performance of the sorbent was compared
with powder activated carbon. The Langmuir isothermal model was applied to fit the embedment of BPR and adsorption of EV.
Results The saturation number of BPR binding to CaC2O4 reached 0.0105 mol/mol and the adsorption constant of the complex was 4.70 × 105 M–1. Over 80% of the sorbent particles are between 0.7 and 1.02 μm, formed by the aggregation of the global CaC2O4/BPR inclusion grains of 30–50 nm size. Such a material was found to adsorb cationic dyes selectively and sensitively. Ethyl
violet (EV) was used to investigate the adsorption mechanism of the material. One BPR molecule may just bind with one EV molecule.
The CaC2O4/BPR inclusion material adsorbed EV over two times more efficiently than the activated carbon. The adsorption of EV on the
CaC2O4/BPR inclusion sorbent was complete in only 5 min and the sedimentation complete in 1 h. However, those of EV onto activated
carbon took more than 1.5 and 5 h, respectively. The treatment of methylene blue and malachite green dye wastewaters indicated
that only 0.4% of the sorbent adsorbed over 80% of color substances. Besides, the material can also adsorb heavy metals by
complexation with BPR. Over 90% of Pb2+, and approximately 50% of Cd2+ and Cu2+, were removed in a high Zn2+-electroplating wastewater when 3% of the material was added. Eighty-six percent of Cu2+, and 60% of Ni2+ and Cd2+, were removed in a high Cd2+-electroplating wastewater.
Discussion The embedment of BPR into CaC2O4 particles responded to the Langmuir isothermal adsorption. As the affinity ligand of Ca2+, BPR with sulfonic groups may be adsorbed into the temporary electric double layer during the growing of CaC2O4 particles. Immediately, C2O4
2– captured the Ca2+ to form the CaC2O4 outer enclosed sphere. Thus, BPR may be released and embedded as a sandwich between CaC2O4 layers. The adsorption of EV on the sorbent obeyed the Langmuir isothermal equation and adsorption is mainly due to the ion-pair
attraction between EV and BPR. Different from the inclusion sorbent, the activated carbon depended on the specific surface
area to adsorb organic substances. Therefore, the adsorption capacity, equilibrium, and sedimentation time of the sorbent
are much better than activated carbon. The interaction of heavy metals with the inclusion sorbent responded to their coordination.
Conclusions By characterizing the C2O4
2––BPR–Ca2+ inclusion material using various modern instruments, the ternary in situ embedment particle, [(CaC2O4)95(BPR)]
n
2n–, an electronegative, micron-sized adsorbent was synthesized. It is selective, rapid, and highly effective for adsorbing cationic
dyes and heavy metals. Moreover, the adsorption is hardly subject to the impact of electrolytes.
Recommendations and perspectives The present work provides a simple and valuable method for preparing the highly effective adsorbent. If a concentrated BPR
wastewater was reused as the inclusion reactant, the sorbent will be low cost. By selecting the inclusion ligand with a special
structure, we may prepare some particular functional materials to recover the valuable substances from seriously polluted
wastewaters. The recommended method will play a significant role in development of advanced adsorption materials.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献