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71.
在B3LYP/6-311+G(d,p)基组水平下采用密度泛函理论方法系统开展了以下工作:(1)优化得到1∶1、1∶2和1∶3铝-麦芽酚配合物10种可能构型的静态结构、NPA电荷以及能量参数,计算得到Al(ma)3配合物4种异构体的核磁共振、紫外和红外等光谱学数据并与文献实验值比较,证明本文采用的计算方法和模型适用于铝-麦芽酚体系的研究;(2)模拟1∶1和1∶2铝-麦芽酚配合物9种可能位点的水交换反应,其中3个位点计算得到的水交换反应速率对数log kex(s-1)分别为2.4(Al(ma)(H2O)2+4(cis to ma))、2.6(cis-Al(ma)2(H2O)+2(I))和3.0(trans-Al(ma)2(H2O)+2(I)),与实验值2.5(Al(ma)2+)和3.3(Al(ma)+2)相符,说明相应位点为反应活性位点;(3)探讨铝-麦芽酚配合物毒性与其形态结构之间的相关机制。  相似文献   
72.
Seas and oceans are confronted with a plethora of environmental problems, caused by land-based activities (agriculture, industries, and ports) and by maritime activities (such as shipping, fishing, oil and gas drilling, tourism, and navigational dredging). Environmental problems at sea challenge the efficacy of state sovereignty. Who is responsible, accountable, and regulates environmental and spatial problems at the level of regional seas, and what is the role of states in these processes of governance? In the regional seas and on the high seas, the environmental state is challenged by two developments: states become players at different levels, and states are confronted with the activities of big market players where they have no or little jurisdiction. The different forms of the environmental state in Europe’s regional seas and in the Arctic Ocean are examined.  相似文献   
73.
利用N,N’-双(水杨醛)缩邻苯二胺配体(L)与稀土金属离子合成了稀土水杨醛Salphen希夫碱配合物{[M(NO3)2]·2H2O;M=La,Nd,Sm},并利用红外光谱(IR)、紫外-可见光谱(UV)、元素分析、摩尔电导率和差热热重(TG—DTA)对配合物的结构做了表征。结果表明,配合物中稀土金属离子M(Ⅲ)的配位数为6,同时还有2个NO3-和配位中心配位。  相似文献   
74.
Chung K  Lee I  Han JI 《Chemosphere》2012,86(4):415-419
As an effort to better utilize the microbial fuel cell (MFC) technology, we previously proposed an innovative MFC system named M2FC consisting of ferric-based MFC part and ferrous-based fuel cell (FC) part. In this reactor, ferric ion, the catholyte in the MFC part, was efficiently regenerated by the FC part with the generation of additional electricity. When both units were operated separately, the ferric-based MFC part produced approximately 1360 mW m−2 of power density with FeCl3 as catholyte and Fe-citrate as anolyte. The ferrous-based FC part with FeCl3 as catholyte and Fe-EDTA as anolyte displayed the highest power density (1500 mW m−2), while that with ferricyanide as catholyte and Fe-noligand as anolyte had the lowest power density (380 mW m−2). The types of catholytes and chelating complexes as anolyte were found to play important roles in the reduction of ferric ions and oxidation of ferrous ion. Linear sweep voltammetry results supported that the cathode electrolytes were electrically active and these agreed well with the M2FC reactor performance. These results clearly showed that ligands played critical role in the efficiency and rate for recycling iron ion and thus the M2FC performance.  相似文献   
75.

Organic amendments are sometimes applied to agricultural soils to improve the physical, chemical, and microbiological properties of the soils. The organic fractions in these soil amendments also influence metal reaction, particularly the adsorption and desorption of metals, which, in turn, determine the bioavailability of the metals and hence their phytotoxicities. In this study, a Quincy fine sandy (mixed, mesic, Xeric Torripsamments) soil was treated with 0 to 160 g kg?1 rates of either manure, sewage sludge (SS), or incinerated sewage sludge (ISS) and equilibrated in a greenhouse at near field capacity moisture content for 100 days. Following the incubation period, the soil was dried and adsorption of copper (Cu) was evaluated in a batch equilibration study at either 0, 100, 200, or 400 mg L?1 Cu concentrations in a 0.01M CaCl2 solution. The desorption of adsorbed Cu was evaluated by three successive elutions in 0.01M CaCl2. Copper adsorption increased with an increase in manure rates. At the highest rate of manure addition (160 g kg?1 soil), Cu adsorption was two-fold greater than that by the unamended soil at all rates of Cu additions. With increasing rates of Cu additions, the adsorption of Cu decreased from 99.4 to 77.6% of Cu applied to the 160 g kg?1 manure amended soil. The desorption of Cu decreased with an increase in rate of manure amendment. Effects of sewage sludge amendments on Cu adsorption were somewhat similar to those as described for manure additions. Likewise, the desorption of Cu was the least at the high rate of SS addition (160 g kg?1), although at the lower rates there was not a clear indication of the rate effects. In contrast to the above two amendments, the ISS amendment had the least effect on Cu adsorption. At the highest rate of ISS amendment, the Cu adsorption was roughly 50% of that at the similar rate of either manure or SS amendments, across all Cu rates.  相似文献   
76.
黑土不同粒径有机-矿质复合体对镉的吸附特性   总被引:5,自引:1,他引:4  
采用振荡平衡法研究了黑土不同粒级有机-矿质复合体对Cd2+的吸附等温过程和吸附动力学过程,并采用常见数值模型进行了拟合. 结果表明,原土及各粒级复合体对Cd2+的吸附量随平衡液中ρ(Cd2+)的增加而增加. 各粒级组分对Cd2+的吸附量表现为黏粒>粉粒>原土>粗砂>细砂. Langmuir和Freundlich方程对Cd2+的等温吸附过程均有较好的拟合效果,线性方程拟合效果较差. 最大吸附量与吸附作用强度均呈随粒径增大而减小的趋势. 对影响最大吸附量和吸附作用强度的因子进行回归分析表明,w(有机质)、CEC(阳离子交换量)和比表面积的影响较大,其中w(有机质)是最主要因素,CEC和比表面积的影响次之. 各粒级复合体对土壤吸附Cd2+的贡献率为粉粒>细砂>黏粒>粗砂,99%的Cd2+吸附在<200 μm的组分上. 不同粒级组分对Cd2+的吸附动力学过程可分为0~20 min的快速反应阶段(吸附量均达到饱和吸附量的90%以上)和慢速反应阶段. 各组分对Cd2+的吸附符合二级动力学过程,表明吸附过程以化学吸附为主,并且吸附速率随颗粒粒径的增大而减小.   相似文献   
77.
金属络合吸收剂在湿法脱硝中的应用   总被引:3,自引:1,他引:3  
湿法络合脱硝是联合脱硫脱硝的重要研究方向.从金属络合吸收剂的结构出发,分析了铁、钴等金属中心离子和氨基羧酸类或巯基类配体的配位化学;归纳了金属络合吸收剂在不同条件下(如温度和pH值等)的动力学参数;总结了生物法、还原法和电解法再生吸收液的方法.提出了研究抗氧化能力强的吸收剂和吸收产物变废为宝的研究方向.  相似文献   
78.
A novel polycyclodextrin-modified magnetic cationic hydrogel(PCD-MCH) was developed and its performance,kinetics and mechanism for the removal of reactive brilliant red X-3B(X-3B) were studied.The results showed that the zeta-potential of PCD-MCH was 32.8 to16.7 mV at pH 3.0-10.5.The maximum X-3B adsorption capacity of PCD-MCH was2792.3 mg/g.The adsorption kinetics could be well-described by the Weber-Morris model and the homogeneous surface diffusion model(HSDM).Diffusion stages corresponding t...  相似文献   
79.
The incorporation of xenobiotics into soil, especially via covalent bonds or sequestration has a major influence on the environmental behavior including toxicity, mobility, and bioavailability. The incorporation mode of 4-chloro-2-methylphenoxyacetic acid (MCPA) into organo-clay complexes has been investigated under a low (8.5 mg MCPA/kg soil) and high (1000 mg MCPA/kg soil) applied concentration, during an incubation period of up to 120 days. Emphasis was laid on the elucidation of distinct covalent linkages between non-extractable MCPA residues and humic sub-fractions (humic acids, fulvic acids, and humin). The cleavage of compounds by a sequential chemical degradation procedure (OH?, BBr3, RuO4, TMAH thermochemolysis) revealed for both concentration levels ester/amide bonds as the predominate incorporation modes followed by ether linkages. A possible influence of the soil microbial activity on the mode of incorporation could be observed in case of the high level samples. Structure elucidation identified MCPA as the only nonextractable substance, whereas the metabolite 4-chloro-2-methylphenol was additionally found as bioavailable and bioaccessible compound.  相似文献   
80.
坝上高原生境脆弱与人为不合理活动的叠加影响,导致票钙土退化。表现为土壤代换量降低,养分含量减少,有机复合体破坏;松结合态、稳结合仓和紧结合态腐殖质下降,其下降率依序为21%~34%、44%~55.5%和5%~62%。  相似文献   
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