Removal of Pyridine from Aqueous Solution by Adsorption on an Activated Carbon Cloth     

Pedro Alonso‐Davila  Oliva L. Torres‐Rivera  Roberto Leyva‐Ramos  Raul Ocampo‐Perez 《洁净——土壤、空气、水》2012,40(1):45-53

Pyridine is a very toxic pollutant that has to be removed from wastewater. In this work, adsorption of pyridine on activated carbon cloth (ACC) is studied as a possible alternative for eliminating pyridine from aqueous solution. The ACC was produced from polyacrylonitrile. The adsorption equilibrium data of pyridine on ACC was obtained in a batch adsorber. The experimental data was interpreted with the isotherms of Langmuir, Freundlich, and Prausnitz‐Radke (PR), and the PR isotherm better represented the experimental data. The capacity of ACC for adsorbing pyridine was favored increasing the solution pH from 3 to 6, and this effect was due to the π–π dispersive and electrostatic interactions between the pyridine species in solution and the surface complexes of ACC. The modified Langmuir model fitted reasonably well the influence of pH on the adsorption capacity. In this model was assumed that both neutral pyridine and pyridinium were simultaneously adsorbed on ACC accordingly to the experimental results. The adsorption capacity was almost independent of temperature. The reversibility study revealed that 75% of the pyridine can be desorbed from ACC indicating that part of the pyridine was irreversibly adsorbed, and possibly chemisorbed.  相似文献   

雷州半岛红树林边缘效应及其对海岸有机碳库的影响   总被引：1，自引：0，他引：1  

杨娟  JAY Gao  刘宝林  ALAN Cheung  王铎  张苇 《海洋学报》2012,34(5):161-168

作为滨海湿地与邻近海区之间物质循环、能量和物种流动及其相互作用的重要界面,红树林的边缘效应对研究海陆生态系统相互作用,滨海湿地生物地貌形成过程以及海岸带有机碳库分布格局等方面的具有重要意义。文章以雷州半岛东岸红树林4种典型地貌分布区为重点,通过调查红树林前缘光滩,林缘及林内植被及土壤理化特征的变化,探讨红树林边缘效应的表现及其对土壤有机碳库的影响。结果表明,不同地貌类型红树林边界区的群落结构及土壤理化因子分布特征有所不同。边界区群落特征表现为林缘的冠层低于林内,叶面积指数低于林内,物种丰富度林内高于林缘(除河口区外),且林缘的植被盖度受风浪影响显著,表现出河口区>内湾区>岛屿区>前沿浪击区。土壤理化性质边缘效应表现为林缘的pH值、粒度低于光滩,氧化还原电位、盐度高于光滩(除内湾区外),而林内的土壤理化性质波动较大,可能受林缘植被演替及地貌双重影响。不同地貌单元红树林边界区的土壤表层有机碳含量,有机碳密度均表现为林内>林缘>光滩。综合影响表层土壤有机碳的主要生物及非生物因子进行主成分分析和相关分析,结果显示土壤表层有机碳密度与环境第一主成分呈显著负相关,即受植被盖度,叶面积指数和土壤pH因子影响密切。红树林土壤有机碳沉积虽然受到不同水文地貌的影响,但总体而言,红树林初级生产输入和土壤酸性环境对红树林林下土壤有机碳库的富存贡献显著。  相似文献   

2009-2010年冬季南海东北部中尺度过程观测   总被引：2，自引：1，他引：1  

刘长建  庄伟  夏华永  杜岩 《海洋学报》2012,34(1):8-16

根据南海北部陆架陆坡海域2009-2010年冬季航次的CTD调查资料,发现西北太平洋水在上层通过吕宋海峡入侵南海,其对南海东北部上层水体温盐性质的影响自东向西呈减弱趋势,影响范围可达114°E附近。入侵过程中受东北部海域反 气旋式涡旋(观测期间,其中心位于20.75°N,118°E附近) 的影响,海水的垂向和水平结构发生了很大变化,特别是涡旋中心区域,上层暖水深厚,混合层和盐度极大值层显著深于周边海域。该暖涡在地转流场、航载ADCP观测海流及卫星高度计资料中均得到了证实。暖涡的存在还显著影响了海水化学要素的空间分布,暖涡引起的海水辐聚将上层溶解氧含量较高的水体向下输运,使次表层的暖涡中心呈现高溶解氧的分布特征。  相似文献   

Habitat heterogeneity influences cold‐seep macrofaunal communities within and among seeps along the Norwegian margin – Part 2: contribution of chemosynthesis and nutritional patterns     

Carole Decker  Karine Olu 《Marine Ecology》2012,33(2):231-245

The relative contribution of chemosynthesis in heterotrophic fauna at seeps is known to be influenced by depth and by habitat. Using stable isotopes of carbon and nitrogen, we investigated macro‐ and megafaunal nutritional patterns in Norwegian margin cold seeps by comparing food webs both among habitats within a seep site and between different sites. The very active Håkon Mosby mud volcano (HMMV) is characterized by geochemical gradients, microbial activity and faunal zonation from the centre to the periphery. The Storegga Slide (600–900 m depth) has pockmarks with patchy less active seeps, and also shows concentric zonation of habitats but at much smaller spatial scale. The dominant carbon source for macrofaunal nutrition in both areas was chemosynthetically fixed and the bulk of organic carbon was derived from sulphur‐oxidizing bacteria. In HMMV, food chains were clearly separated according to habitats, with significantly lighter δ¹³C signatures on microbial mats and adjacent sediment (?33.06 to ?50.62‰) than in siboglinid fields (?19.83 to ?35.03‰). Mixing model outputs revealed that the contribution of methane‐derived carbon was small in siboglinid fields (0–17%) but significant (39–61%) in the microbial mats. Moreover, the variability of macrofauna signatures within this later habitat suggests the co‐occurrence of two food chains, one based on primary production via methanotrophy and the other via sulphide oxidation. The length of the food chains also varied among habitats, with at least one more trophic level in the siboglinid fields located at the periphery of the volcano. Conversely, in Storrega pockmarks, faunal δ¹³C signatures did not vary among habitats but among species, although separate food chains seem to co‐occur. The small size of the seepage areas and their lower fluxes compared to HMMV allow more background species to penetrate the seep area, increasing the range of δ¹⁵N and the trophic level number. Probably due to the higher flux of photosynthetic particulate organic carbon, the overall chemosynthesis‐based carbon contribution in invertebrate nutrition was lower than that in HMMV.  相似文献   

中太平洋富钴结壳中生物标志物、有机碳同位素地球化学及其古海洋环境意义     

李雪富  武光海  刘捷红  张宏 《海洋学研究》2012,30(4):29-36

利用2003年大洋DY105-12,14航次在中太平洋海山获取的KXD28富钴结壳样品,采用气相色谱(GC)内标法对该结壳样品的分层样进行了可溶有机质(氯仿沥青“A”)及其族组成(饱和烃、芳烃、非烃)、正构烷烃、类异戊二烯烃的定量分析,并结合总有机碳(TOC)及有机碳同位素(δ¹³C)分析,探讨了结壳样品有机质来源及富钴结壳组成与生长环境之间的关系。结果表明:(1)富钴结壳中有机质生物母源主要为海洋生物和菌藻类,并混有少量陆源物质;有机碳同位素同样也指示了海洋水生生物碳同位素特征;(2)KXD28结壳从底层到最外层有机碳同位素发生了很大变化,结壳中有机碳同位素组成变化与结壳生长过程中的海洋环境气候相符合:富钴结壳生长前期δ¹³C组成由正变负,对应全球气候变冷,南极底层流向太平洋挺进;而富钴结壳生长后期δ¹³C逐渐偏正,与全球气候变暖和南极底层流萎缩相关联。  相似文献   

Organic carbon deposition flux on the North Chukchi Sea shelf based on 210pb radioactivity dating     

LI Yiliang  YU Wen  HE Jianhua  SU Jian 《极地研究(英文版)》2012,23(4):231-236

Deposition of organic carbon forms the final net effect of the ocean carbon sink at a certain time scale. Organic carbon deposition on the Arctic shelves plays a particularly important role in the global carbon cycle because of the broad shelf area and rich nutrient concentration. To determine the organic carbon deposition flux at the northern margin of the Chukchi Sea shelf, the 210pb dating method was used to analyze the age and deposition rate of sediment samples from station R17 of the third Chinese National Arctic Research Expedition. The results showed that the deposition rate was 0.6 mm＇aI, the apparent deposition mass flux was 0.72 kg.m2a1, and the organic carbon deposition flux was 517 mmol C.m2.al. It was estimated that at least 16% of the export organic carbon flux out of the euphoric zone was transferred and chronically buried into the sediment, a value which was much higher than the average ratio （-10%） for low- to mid-latitude regions, indicating a highly effective carbon sink at the northern mar- gin of the Chukchi Sea shelf. With the decrease of sea ice coverage caused by warming in the Arctic Ocean, it could be inferred that the Arctic shelves will play an increasingly important role in the global carbon cycle.  相似文献   

More than Carbon Stocks： A Case Study of Ecosystem-based Benefits of REDD＋ in Indonesia   总被引：3，自引：0，他引：3  

LU Heli  YAN Weiyang  QINYaochen  LIU Guifang 《中国地理科学(英文版)》2012,22(4):390-401

During the 15th Conference of the Parties(COP 15),Parties agreed that reducing emissions from deforestation and forest degradation and enhancing ’removals of greenhouse gas emission by forests’(REDD+) in developing countries through positive incentives under the United Nations Framework Convention on Climate Change(UNFCCC) was capable of dealing with global emissions.As REDD+ seeks to lower emissions by stopping deforestation and forest degradation with an international payment tier according to baseline scenarios,opportunities for ecosystem benefits such as slowing habitat fragmentation,conservation of forest biodiversity,soil conservation may be also part of this effort.The primary objective of this study is to evaluate ecosystem-based benefits of REDD+,and to identify the relationships with carbon stock changes.To achieve this goal,high resolution satellite images are combined with Normalized Difference Vegetation Index(NDVI) to identify historical deforestation in study area of Central Kalimantan,Indonesia.The carbon emissions for the period of 2000-2005 and 2005-2009 are 2.73 × 10 5 t CO 2 and 1.47 × 10 6 t CO 2 respectively,showing an increasing trend in recent years.Dring 2005-2009,number of patches(NP),patch density(PD),mean shape index distribution(SHAPE_MN) increased 30.8%,30.7% and 7.6%.Meanwhile,largest patch index(LPI),mean area(AREA_MN),area-weighted mean of shape index distribution(SHAPE_AM),neighbor distance(ENN_MN) and interspersion and juxtaposition index(IJI) decreased by 55.3%,29.7%,15.8%,53.4% and 21.5% respectively.The area regarding as positive correlation between carbon emissions and soil erosion was approximately 8.9 × 10 3 ha corresponding to 96.0% of the changing forest.These results support the view that there are strong synergies among carbon loss,forest fragmentation and soil erosion in tropical forests.Such mechanism of REDD+ is likely to present opportunities for multiple benefits that fall outside the scope of carbon stocks.  相似文献   

大气二氧化碳遥感反演精度检验及时空特征分析（可下载全文）     

何茜  余涛  程天海  顾行发  谢东海  吴俣 《地球信息科学学报》2012,14(2):250-257

 利用卫星遥感探测大气二氧化碳(CO₂)浓度,相比传统的地面观测方法,具有稳定、连续、大尺度观测等诸多优点,能更好地获得全球CO₂的时空分布与变化特征。随着卫星遥感技术的发展,一系列具备大气CO₂探测能力的卫星相继发射升空,大气制图扫描成像吸收光谱仪(SCIAMACHY)、温室气体观测卫星(GOSAT)、大气红外探测仪(AIRS)等卫星传感器,已经获得了多年的全球CO₂浓度分布产品。对这些卫星资料进行对比分析,并与本底观测数据进行全球范围的长时间序列的对比验证。研究显示,3种CO₂卫星遥感产品中,SCIAMACHY数据系统性略高于本底数据,且观测范围局限性较大;GOSAT数据稳定性较好,但系统误差较大,平均低于本底数据近9ppmv;AIRS数据产品相比前两者优势突出,单月全球覆盖率达到90%左右,与本底观测数据平均误差小于2ppmv(0.5%),相关系数达到0.9以上,能够较好地反映全球大气CO₂浓度的时空特征。卫星遥感产品与本底观测资料显示,全球CO₂浓度空间分布呈现出明显的纬度分布规律与海陆分布规律,时间变化规律方面则表现出明显的季节性周期变化。  相似文献   

钼催化作用下的煤成烷烃气碳同位素演化     

秦勇  吴艳艳  刘金钟  申建 《地球科学与环境学报》2012,(3):1-7

为了阐释钼催化作用下的煤成气碳同位素演化特征和机理,采用在原煤中添加单质钼的方式,开展催化生气模拟试验,测定模拟系列气样的单体烷烃气碳同位素组成,并对其演化规律和模式进行探讨.结果表明:无论加钼与否,模拟气甲烷碳同位素组成(δ(13C1))均以镜质组反射率1.1%为界分为演化趋势截然相反的2个阶段,乙烷碳同位素组成(δ(13C2))不存在明显的演化阶段性,但加钼煤样δ(13C2)由在较低成熟度阶段重于原煤样变为在较高成熟度阶段轻于原煤样;加钼条件下,模拟烷烃气呈现出正碳同位素系列,δ(13C1)为(-25~-45)×10-3,δ(13C2)重于-29×10-3,表明钼催化成因气属于有机热成因气范畴.对比模拟烷烃气碳同位素组成与镜质组反射率之间的关系,发现模拟烷烃气碳同位素组成演化规律与前人模式有所不同.加钼煤样的不同单体烷烃气碳同位素组成随有机质成熟度变化速率的不同而不同,指示生气作用在钼催化作用下得到增强,这一效应在裂解气生成过程中更为显著;加钼煤样δ(13C2)在较高成熟度条件下轻于原煤样δ(13C2)的原因可能在于钼催化效应促进了煤中壳质组裂解生气.  相似文献   

土壤中氮碳间相互作用对全球碳循环的影响(英文)     

Siegfried FLEISCHER 《资源与生态学报(英文版)》2012,3(1):16-19

氮循环中的能量产生过程构成与全球碳循环间的重要关联。例如,氮投入土壤,一开始导致CO2排放降低。这一众所周知的效应被理解为土壤呼吸作用受到阻碍或延缓。然而,当把冗余考虑在内便知,氮投入并不使最初得到的CO2最低排放量保持不变,而是逐渐导致排放增加。土壤中硝化作用对CO2消耗过程的特异性抑制,加上铵冗余投入或乙炔作用,往往导致额外的CO2排放量。这种总自养性呼吸(GHR)与CO2净排放(NHR)之间的差就是土壤内CO2汇。土壤呼吸作用单纯由NHR产生的CO2排放量(通常情况)来决定会导致对土壤系统的曲解,特别是在氮沉降量高的地区。因此,必须重新考虑温暖区域土壤呼吸作用的"适应环境"问题。可能也需要质疑氮投入带来的"呼吸抑制"概念。无视这些过程,包括上述氮驱动下的土壤内CO2汇过程,也许会有碍于采取足够的措施来对抗气候变化。  相似文献