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11.
考察了粒状胺丙基硅(CUNAX00X)对水溶液中微囊藻毒素-LR(mLR)和微囊藻毒素-LA(mLA)的等温吸附行为,并通过对胺丙基硅结构中的微孔尺寸分布特征、表面官能团--胺丙基团(-CH2CH2CH2NH 3)和羟基自由基(·OH)的红外分析,对吸附机制进行了初步探讨.结果表明,胺丙基硅通过物理吸附和化学吸附对水溶液中的mLR和mLA进行吸附,即胺丙基硅结构中的有效吸附微孔对mLR/mLA的物理吸附,固体表面离子化的胺丙基团和·OH与mLR/mLA分子结构中离子化的羧基(-COO-)以及pH=4.33条件下mLR分子结构中离子化的胍基(-NHCNH·NH 2)之间的弱离子吸附. 相似文献
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我国海岸侵蚀灾害及对策 总被引:1,自引:0,他引:1
文章通过大量实际资料展现了我国海岸侵蚀灾害的严重性;从入海泥沙、人类活动、地面沉降、海岸特性、海平面上升等方面分析了造成海岸侵蚀的原因;提出了一系列防治海岸侵蚀灾害的对策。 相似文献
14.
Environment, Development and Sustainability - Sustainability assessing on agricultural production systems has developed rapidly over the last two decades, and various models are formulated from... 相似文献
15.
沟道土地是陕北黄土丘陵沟壑区重要的土地资源。然而,当前对黄土高原沟道土地的盐碱化问题关注不够,对盐碱化的现状、发生机制和防治措施也缺乏深入系统的认识,知识储备不能满足生产实际的需要。本文以陕北黄土丘陵沟壑区自然和人为形成的沟道土地为研究对象,分别是延安顾屯新造耕地(治沟造地)、延川马家湾淤地坝土地和子洲黄土洼天然古聚湫土地,在这些流域内沿沟道采集土壤样品,测定土壤的电导率(EC)、p H值、含水量及粒度,分析土壤盐碱化的现状和影响因子。结果表明:马家湾淤地坝土地盐碱化最为严重,流域中游至上游均出现不同程度的盐碱化;顾屯新造地上游出现盐碱化,盐碱化程度较马家湾轻,而黄土洼古聚湫全流域未出现盐碱化。地下水位较浅是沟道土地发生盐碱化的主要影响因素,因此陕北沟道土地盐碱化防治应着力控制地下水位,建设良好的排水系统,加强排水。 相似文献
16.
Influence of environmental factors on arsenic accumulation and biotransformation using the aquatic plant species Hydrilla verticillata 总被引:1,自引:0,他引:1
Hydrilla verticillata(waterthyme) has been successfully used for phytoremediation in arsenic(As) contaminated water.To evaluate the effects of environmental factors on phytoremediation,this study conducted a series of orthogonal design experiments to determine optimal conditions,including phosphorus(P),nitrogen(N),and arsenate(As(Ⅴ))concentrations and initial pH levels,for As accumulation and biotransformation using this aquatic plant species,while also analyzing As species transformation in culture media after 96-hr exposure.Analysis of variance and the signal-to-noise ratio were used to identify both the effects of these environmental factors and their optimal conditions for this purpose.Results indicated that both N and P significantly impacted accumulation,and N was essential in As species transformation.High N and intermediate P levels were critical to As accumulation and biotransformation by H.verticillata,while high N and low P levels were beneficial to As species transformation in culture media.The highest total arsenic accumulation was(197.2±17.4) μg/g dry weight when As(V) was at level 3(375μg/L),N at level 2(4 mg/L),P at level 1(0.02 mg/L),and pH at level 2(7).Although H.verticillata is highly efficient in removing As(Ⅴ) from aquatic environments,its use could be potentially harmful to both humans and the natural environment due to its release of highly toxic arsenite.For cost-effective and ecofriendly phytoremediation of As-contaminated water,both N and P are helpful in regulating As accumulation and transformation in plants. 相似文献
17.
Based on density functional theory (DFT) and basic structure models, the chemical reactions on the surface of vanadium-titanium based selective catalytic reduction (SCR) denitrification catalysts were summarized. Reasonable structural models (non-periodic and periodic structural models) are the basis of density functional calculations. A periodic structure model was more appropriate to represent the catalyst surface, and its theoretical calculation results were more comparable with the experimental results than a non-periodic model. It is generally believed that the SCR mechanism where NH3 and NO react to produce N2 and H2O follows an Eley-Rideal type mechanism. NH2NO was found to be an important intermediate in the SCR reaction, with multiple production routes. Simultaneously, the effects of H2O, SO2 and metal on SCR catalysts were also summarized. 相似文献
18.
Hao Yu Xueyan Zhao Jing Wang Baohui Yin Chunmei Geng Xinhua Wang Chao Gu Lihua Huang Wen Yang Zhipeng Bai 《环境科学学报(英文版)》2020,32(9):217-224
In order to understand the compositions characteristics of particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) fraction in road dust (RD2.5) of oasis cities on the edge of Tarim Basin, 30 road dust (RD) samples were collected in Kashi, Cele, and Yutian in the spring, 2018, and RD2.5 was collected using the resuspension approach. Eight water-soluble ions, 39 trace elements and 8 fractions of carbon-containing species in PM2.5 were analyzed. Ca2+ and Ca were the most abundant ions and elements in RD2.5 (7.1% and 9.5%). Cl- in RD2.5 was affected not only by attributed to saline-alkali soils in oasis cities of the Tarim Basin and dust from Taklimakan Desert but also by human activities. Moreover, the organic carbon/elemental carbon (OC/EC) ratio indicated that carbon components in RD2.5 in Cele town mainly come from fossil fuel combustion, while those in Yutian and Kashi mainly come from biomass combustion. It is noteworthy that high Ca in RD2.5 was seriously affected by anthropogenic emissions, and high Na and K contents in RD2.5 could be derived from soil and desert dust. It was estimated that Cd, Tl, Sn and Cr were emitted from anthropogenic emissions using the enrichment factor. The coefficients of divergence (COD) result indicated that the influence of local emission on road dust emission is greater than that of long-distance transmission. This study is the first time to comprehensively analyze the chemical characteristics of road dust in oasis cities, and the results provides the sources of road dust at the margin of Tarim Basin. 相似文献
20.
Zhao Zhibo Yuan Tian Shi Xunpeng Zhao Lingdi 《Mitigation and Adaptation Strategies for Global Change》2020,25(7):1363-1380
Mitigation and Adaptation Strategies for Global Change - Global change caused by carbon emissions alone has become a common challenge for all countries. However, current debates about urbanization... 相似文献