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1.
为研究黑臭河道沉积物资源化利用方式,评估沉积物资源化以后对营养盐去除效果和研究其去除机制,以北京市某黑臭河道沉积物（S）为供试样品,对其进行氧化并负载金属离子改性,最终得到氧化-载钠改性沉积物（MS）.选取S和MS两种材料,评估其对氮和磷的去除效果,通过采用动力学、热力学等手段,进一步阐明改性材料对氮、磷去除机制.结果表明,在环境温度为35℃,固液比1：50（g：ml）的条件下,经氧化-载钠联合改性材料对氮（初始浓度20 mg/L）的去除效果均达到90%以上,其中对磷（初始浓度10 mg/L）的去除率最高可达98%;准二级动力学模型能更好的描述改性材料的吸附动力学行为（R2>0.93）,且动力学和吸附等温分析结果显示,Langmuir模型可以更好地描述两种材料的吸附等温线,改性材料对氮和磷的最大吸附量分别达到0.891和0.474 mg/g;热力学研究结果表明,吸附过程中,标准反应焓变（ΔH0）、标准反应熵变（ΔS0）均为正值,标准吉布斯自由能变（ΔG0）为负值,且随着温度的升高,ΔG0呈下降趋势.研究显示,MS具有更高的吸附性能,对氮、磷的吸附主要是材料表面活性吸附点位起主导作用,并且吸附过程是个吸热、自发进行的过程,更高的温度更有利于吸附.在同一温度下,随着氮、磷初始浓度的增加,MS对氮、磷的解吸比吸附过程更容易发生. 相似文献
2.
北京市北运河沉积物对氮、磷的吸附/解吸动力学特征 总被引：3，自引：0，他引：3
选取北运河土沟、榆林庄及和合站3个典型河道断面,进行河道0~60 cm深度沉积物对氨氮、磷酸盐的吸附/解吸批平衡静态试验研究,采用多种动力学模型分析北运河沉积物对氮、磷的吸附/解吸动力学特性,提出适用于北运河沉积物吸附/解吸特性的动力学模型,并对模型参数的主要影响因素进行探讨.结果表明:1)北运河典型断面各深度的沉积物对氨氮和磷酸盐的吸附/解吸过程总体呈现3个阶段:快反应阶段—慢反应阶段—平衡阶段;在0~0.5 h的快反应阶段可完成吸附或解吸总量的60%,且对氮、磷的吸附速率大于解吸速率.2)北运河各断面对氨氮与磷酸盐的平衡吸附量表现为S(榆林庄)S(土沟)S(和合站);对氨氮的平衡解吸量表现为S(土沟)S(榆林庄)S(和合站),对磷酸盐的平衡解吸量表现为S(和合站)S(土沟)S(榆林庄),沉积物对氨氮和磷酸盐的吸附以化学吸附为主,平衡吸附与解吸量随断面深度的增加而减小,0~20 cm表层沉积物对氮、磷的吸附能力较强.3)Lagergren二级动力学模型对各深度沉积物的吸附/解吸过程拟合最优,模型参数公式为k2=S-0.369max+0.163;qe=0.022 Smax+18.077 Kf+41.947.通过模拟得出在400 mg/L氮、磷浓度下吸附于沉积物中的氮、磷污染物会随着解吸过程释放52%~80%的氨氮和6%~42%的磷酸盐,可能不仅二次污染上覆水体,还随河水下渗从而对地下水质形成潜在污染风险. 相似文献
3.
模拟扰动条件下太湖表层沉积物磷行为的研究 总被引：83，自引：8，他引：75
利用恒温震荡器构筑的模拟扰动环境,研究了太湖水－沉积物界的磷释放和吸附行为。结果表明：表层沉积物的磷酸盐释放作用在模拟扰动条件下并不十分明显,在低强度的扰动条件下未观察到释放现象,模拟高强度扰动后,出现一个相对较强的释放过程,最大释放时沉积物上覆水浓度约为低强度扰动时的3倍,最大释放时间（Tmax)可能受磷酸盐形态分布的不同而有所差异,相比较而言,磷酸盐的吸附作用表现得十分明显迅速,沉积物上覆水磷酸盐浓度在0．5h后分别0229mg/L和l0.215mg／L下降为0．05mg/L和0.013mg/L,可以看出当上覆水磷酸盐浓度较高时,吸附作用的强度远大于释放作用,在25℃,模拟中等强度（100rpm)的模拟扰动条件下,当初始磷酸盐浓度为1．01mg/L时,梅梁湾和五里湖的表层沉积物吸附容量分别为每克千重吸附0．04mg和0.050mg磷酸盐,这种较高的吸附能力对浅水湖泊的磷酸盐缓冲作用能起到积极作用。 相似文献
4.
过氧化钙在处理厌氧底泥中的应用初探 总被引：1，自引：0，他引：1
为改善河道厌氧底质及内源氮、磷等营养盐释放问题,考察对沉水植被恢复的影响,研发可同步解决沉积物供氧和削减内源氮、磷释放的氧缓释材料.实验通过向沉积物-水界面处散点注射不同剂量的过氧化钙(Ca O2),研究界面处溶解氧的动态变化特征及表层沉积物与底层水体之间溶解态氮、磷的交换过程.结果表明:添加Ca O2显著提高了界面处底层上覆水溶解氧浓度,随着Ca O2浓度的增加溶解氧浓度增加,不同处理组之间具有显著差异;Ca O2对沉积物中PO3-4-P释放具有明显的抑制作用,且随Ca O2浓度的增加抑制效果愈加明显,上覆水中可溶性活性磷浓度最大可削减98%.实验开始时,磷释放速率可降至-241.916±22.501 mg/(m2·d),降幅最高可达到144%;Ca O2对沉积物NH+4-N释放的抑制效果不佳,上覆水中NH+4-N浓度随着时间的变化波动性较大,且有逐渐增大的趋势.另外,添加Ca O2会显著提高底层上覆水p H值,不同处理组之间差异显著,但当Ca O2投加量小于0.529 kg/m2时,不会对苦草种子的萌发生长有显著影响,p H值波动在可接受范围内(7.62~10.87).因此,结合污染沉积物的状况,适当地投加Ca O2有望同步解决底质厌氧、内源磷释放及后期沉水植被定植底质生境改善的问题,可推荐为一种黑臭污染底泥治理技术在实际的河道生态工程中应用,其适宜浓度为0.176 kg/m2左右. 相似文献
5.
6.
人工湿地复合基质深度净水除磷实验 总被引：4，自引：0，他引：4
通过垂直上升流人工湿地模拟柱实验,研究了泥炭、蛭石、砾石以不同体积比(柱1比例1:1:3,柱2比例1:1:2, 柱3比例1:1:1,柱4全为砾石)组成的复合基质对人工湿地出水的深度除磷效果．结果表明,填充复合基质的柱1-3对总磷和正磷酸盐的处理效果较好,去除率分别达到了77％和90％以上,明显优于填充单一基质砾石的柱4(27％和 21％);蛭石、泥炭价格远高于砾石,从经济、有效的原则出发,用蛭石、泥炭、砾石以1:1:3的体积比例混合作为复合填料比较合理;该复合基质适合于水质深度净化,在进水总磷浓度不超过0．1 mg／L的情况下,除磷效果相当稳定,可以保证 0．02mg／L以下的出水浓度(地表Ⅲ类水质标准),并达到80％左右的去除率;遇到高浓度磷污染负荷冲击时,磷去除率会降低;该复合基质的除磷机制主要为吸附净化,单独使用易吸附饱和,而与人工湿地中与湿地植物的吸收净化衔接起来,就能形成稳定持久的除磷效果． 相似文献
7.
湖泊沉积物中磷酸盐氧同位素前处理方法对比 总被引：2，自引：1，他引：1
磷酸盐氧同位素(δ~(18)OP)是一种有效的磷源示踪方式.由于湖泊沉积物的组成十分复杂,必须对样品进行除碳处理和纯化处理.本文对目前应用较为广泛的几种前处理方法进行比较,包括NaClO处理和H_2O_2处理等除有机碳方法,以及Blake法和Mc Laughlin法等纯化方法,以期获得适用于湖泊沉积物磷酸盐氧同位素的前处理方法.结果表明:(1)NaClO处理可以保证较高的无机磷提取效率,同时能有效地减少无机磷提取液中有机质含量,且对不同形态磷的破坏较小;H2O2对有机质的去除效果不稳定,且处理后样品磷形态之间发生转化,显著增加了提取的无机磷浓度.(2)Blake法和Mc Laughlin法分别采用磷钼酸铵(APM)+磷酸铵镁(MAP)沉淀和Ce PO4沉淀对样品进行纯化.在纯化处理湖泊沉积物过程中,Blake法优于Mc Laughlin法,主要体现为有机质去除率高,并且磷的回收率较为稳定.(3)经Blake法纯化丹麦Nordborg湖沉积物样品得到的Ag_3PO_4中C、N含量低于Mc Laughlin法且重现性好.本文结合NaClO法与Blake法的优点,建立了一种适合湖泊沉积物的磷酸盐氧同位素前处理方法:首先用2.5%NaClO对沉积物样品进行除碳预处理,然后对磷酸盐提取液依次通过氢氧化镁共沉淀(MAGIC)、APM+MAP沉淀、阳离子交换树脂处理,最后生成Ag3PO4沉淀. 相似文献
8.
鄱阳湖沉积物和水界面磷的交换通量 总被引：6，自引：0，他引：6
采用扩散模型法与实验培养法对鄱阳湖沉积物和水界面间可溶性总磷和可溶性磷酸盐的界面交换过程进行研究,并探讨了其影响因素.结果表明,利用2种方法得到鄱阳湖各站点可溶性总磷和可溶性磷酸盐在沉积物与水界面间的交换方向不完全相同,大部分站点沉积物是磷的源,其中,利用扩散模型法估算的可溶性总磷和可溶性磷酸盐平均扩散通量分别为0.052和0.047 mg/(m~2·d),而实验培养法测得可溶性总磷和可溶性磷酸盐的平均交换通量则分别为0.25和0.24 mg/(m~2·d),且各站点利用扩散模型法测得磷的交换通量均小于实验培养法的计算结果.此外,上覆水溶解氧浓度及水体温度对可溶性总磷和可溶性磷酸盐的交换过程均具有一定的影响,表现为温度越高,溶解氧浓度越小,可溶性总磷和可溶性磷酸盐的交换越强烈. 相似文献
9.
浅水湖泊沉积物磷释放的波浪水槽试验研究 总被引：15，自引：1，他引：15
为探索浅水湖泊水动力扰动作用对沉积物内源营养盐释放的规律,采用波浪水槽试验研究了波浪扰动对太湖和巢湖沉积物悬浮和磷释放的作用.试验结果显示在强波浪扰动下,底泥大规模悬浮,使得水体中悬浮固体(SS)、总磷(TP)和溶解性总磷(DTP)含量显著升高,太湖和巢湖底泥水槽试验中上覆水体TP含量分别升高了6倍和3倍,DTP分别升高了1倍和70％,太湖底泥试验中溶解性活性磷(SRP)含量亦升高了25％.掀沙过程中,不但表层底泥间隙水中的溶解性磷释放到上覆水体当中,沉积物颗粒所吸附的磷也大量转化为SRP而解吸释放.然而,强波浪掀沙一段时间后,溶解态磷的释放逐渐受到限制.随着波浪扰动作用的持续,悬浮物的中值粒径减小,细颗粒组分的百分含量明显增加,使得悬浮物对溶解态磷的吸附能力增强;波浪扰动显著提高了水体的溶解氧浓度,也会促进水体铁锰物质的氧化,增大其对磷酸根离子的吸附能力.这些变化可能是波浪掀沙后期限制水体SRP浓度进一步升高的主要原因.太湖底泥波浪水槽试验的结果与太湖梅梁湾中心区域常见风浪扰动下底泥的悬浮起动情况相吻合,底泥起动的临界切应力也基本相同,强波浪掀沙的切应力条件及水体SS,TP及SRP浓度变化的特点也一致,表明本实验的结果接近太湖的实际状况.本研究说明太湖的水动力扰动能显著提高水体TP及SRP浓度,大波掀沙初期对底泥磷释放的影响最大,后期的影响强度则有所下降. 相似文献
10.
氧化还原条件对红枫湖沉积物磷释放影响的微尺度分析 总被引：7，自引：0，他引：7
选取贵州红枫湖为研究对象,在实验室条件下模拟了自然、好氧和厌氧条件下沉积物内源磷的释放过程,联合应用微电极技术和沉积物磷形态分析对沉积物—水界面开展了微尺度观测与研究.结果表明,厌氧条件下红枫湖沉积物总磷含量显著降低,且主要是NaOH提取态磷(NaOH-P)和残渣态磷(rest-P)含量降低所致,厌氧条件下沉积物孔隙水中磷酸盐浓度明显升高,而好氧条件下沉积物孔隙水磷酸盐浓度显著降低,反映厌氧条件显著促进了红枫湖沉积物磷释放.厌氧条件下沉积物内部溶解氧浓度下降、硫还原活动增强可能是导致NaOH-P释放的主要原因.O_2浓度的降低加速了沉积物还原作用并产生大量H2S,进而与二价铁离子形成硫化亚铁沉淀,最终导致NaOH-P(Fe-P)释放到孔隙水中.好氧条件向厌氧条件的转换可通过改变沉积物内部pH值分布和微生物活动促使rest-P释放:厌氧条件下,厌氧微生物不仅可以消耗硫酸根产生H_2S,导致pH值降低,还可消耗有机质,将有机磷转变为无机磷.上述研究结果表明,沉积物—水界面氧化还原环境可影响沉积物氧渗透深度、pH值分布、微生物活动、硫循环以及有机质降解过程,进而控制沉积物磷的形态转化与释放.联合应用微电极技术和沉积物磷形态分析对湖泊沉积物—水界面开展微尺度观测研究是揭示沉积物内源磷释放机制与控制因素的有效途径. 相似文献
11.
Edoardo Daly A. Christopher Oishi Amilcare Porporato Gabriel G. Katul 《Advances in water resources》2008
Near-surface soil CO2 gas-phase concentration (C) and concomitant incident rainfall (Pi) and through-fall (Pt) depths were collected at different locations in a temperate pine forest every 30 min during the 2005 and 2006 growing seasons (and then averaged to the daily timescale). At the daily scale, C temporal variations were well described by a sequence of monotonically decreasing functions interrupted by large positive jumps induced by rainfall events. A stochastic model was developed to link rainfall statistics responsible for these jumps to near-surface C dynamics. The model accounted for the effect of daily rainfall variability, both in terms of timing and amount of water, and permitted an analytical derivation of the C probability density function (pdf) using the parameters of the rainfall pdf. Given the observed positive correlation between daily C and soil CO2 fluxes to the atmosphere (Fs), the effects of various rainfall regimes on the statistics of Fs can be deduced from the behavior of C under different climatic conditions. The predictions from this analytical model are consistent with flux measurements reported in manipulative experiments that varied rainfall amount and frequency. 相似文献
12.
Ying-Ya Hsu Tung-Li Hsiung H. Paul Wang Yasuhiro Fukushima Yu-Ling Wei Juu-En Chang 《Marine pollution bulletin》2008,57(6-12):873
The nitrogen-doped TiO2 nanotube (N-TNT) thin films were synthesized using ZnO nanorods as the template and doped with urea at 623 K. Under ultraviolet (UV) and visible light irradiation, the efficiencies for photocatalytic degradation of methylene blue is as high as 30%. About 10% of toluene (representing aromatics in the spill oils) in sea water can be photocatalytically degraded under visible light radiation for 120 min. The aliphatic model compound (1-hexadecene) has, on the contrary, a less efficiency (8%) on the N-TNT photocatalyst. On the average, under visible light radiation, the effectnesses of the N-TNT for photocatalytic degradation of model compounds in the spill oils in sea water are 0.38 mg toluene/gN-TNT h and 0.25 mg 1-hexadecene/gN-TNT h. It is expected that spill oils in the harbors or seashores can be adsorbed and photocatalytically degraded on the N-TNT thin films that are coated onto levee at the sea water surface level. 相似文献
13.
A numerical simulation was conducted to predict the change of pCO2 in the ocean caused by CO2 leaked from an underground aquifer, in which CO2 is purposefully stored. The target space of the present model was the ocean above the seafloor. The behavior of CO2 bubbles, their dissolution, and the advection-diffusion of dissolved CO2 were numerically simulated. Here, two cases for the leakage rate were studied: an extreme case, 94,600 t/y, which assumed that a large fault accidentally connects the CO2 reservoir and the seafloor; and a reasonable case, 3800 t/y, based on the seepage rate of an existing EOR site. In the extreme case, the calculated increase in ΔpCO2 experienced by floating organisms was less than 300 ppm, while that for immobile organisms directly over the fault surface periodically exceeded 1000 ppm, if momentarily. In the reasonable case, the calculated ΔpCO2 and pH were within the range of natural fluctuation. 相似文献
14.
A. V. Pavlov 《Pure and Applied Geophysics》1988,127(2-3):529-544
Theoretical and experimental aspects of the production, transformation, diffusion and loss of N2 in the upper atmosphere are considered. The N2-CO2 near-resonant system in theD andE regions is taken into account. We describe our understanding of the methods necessary to find the vibrational populations of N2 and CO2 (asymmetric mode of CO2). The calculations of the vibrational temperatures in theD, E, andF regions for the mid-latitude ionosphere and an aurora are presented. The connection between the excited species and the 4.26-m radiation intensities is considered. The models for the rate coefficient of the reaction of O+ with N2 and the electron density decrease resulting from N2 in the F region are discussed. 相似文献
15.
Turhan Dogan Toshiya Mori Fumiaki Tsunomori Kenji Notsu 《Pure and Applied Geophysics》2007,164(12):2449-2463
Soil H2 and CO2 surveys were carried out along seven active faults and around the aftershock region of the 2000 Tottori-ken Seibu earthquake
in Japan. Diffuse CO2 effluxes were also measured along one fault and around the 2000 aftershock region. The results show highly variable H2 concentration in space and time and it seems that the maximum H2 concentration at each active fault correlates with fault activity as exemplified by the time of the latest big earthquakes.
Even though observed H2 concentrations in four faults were markedly lower than those collected previously in the latter half of the 1970s, it is
evident that the higher H2 concentrations in this study are due to the addition of the fault gases. Comparing the chemical composition of trapped gases
(H2: 5–20% and CO2/H2: 0.5–12) in fractured rocks of drill cores bored at the Nojima fault, a soil gas sample with the highest H2 concentration showed large amounts of the trapped fault gas, diluted with atmospheric component. The profile experiment across
a fracture zone at the Yamasaki fault showed higher H2 concentrations and lower CO2/H2 ratios as was observed in soil gas from the fracture zone. A few days after the 2000 Tottori-kei Seibu earthquake, no CO2 effluxes related to the occurrence of earthquakes were observed at the aftershock region. However, only above the epicenter
zone, relatively high H2 concentrations in soil gases were observed. 相似文献
16.
On the basis of the study of volcanic products during 1199–1200AD eruption of Baitou Mountain (Baitoushan), the released volatile
content was estimated by comparing Cl, F, S, H2O concentrations of undegassed glass inclusions with those of degassed matrix glasses. The calculations show that volatile
yields, released from the melt, are 109.88 × 106 ton of HCl, 196.80 × 106 ton of HF, 1477.84 × 106 ton of H2O, 23.14 × 106 ton of SO2, which could have formed 35.43 x106 ton of H2SO4 aerosol in the atmosphere. They could have substantial effect on paleoclimate and paleo-environment. 相似文献
17.
M. L. Carapezza B. Badalamenti L. Cavarra A. Scalzo 《Journal of Volcanology and Geothermal Research》2003,123(1-2):81
The northwestern flank of the Colli Albani, a Quaternary volcanic complex near Rome, is characterised by high pCO2 values and Rn activities in the groundwater and by the presence of zones with strong emission of gas from the soil. The most significant of these zones is Cava dei Selci where many houses are located very near to the gas emission site. The emitted gas consists mainly of CO2 (up to 98 vol%) with an appreciable content of H2S (0.8–2%). The He and C isotopic composition indicates, as for all fluids associated with the Quaternary Roman and Tuscany volcanic provinces, the presence of an upper mantle component contaminated by crustal fluids associated with subducted sediments and carbonates. An advective CO2 flux of 37 tons/day has been estimated from the gas bubbles rising to the surface in a small drainage ditch and through a stagnant water pool, present in the rainy season in a topographically low central part of the area. A CO2 soil flux survey with an accumulation chamber, carried out in February–March 2000 over a 12 000 m2 surface with 242 measurement points, gave a total (mostly conductive) flux of 61 tons/day. CO2 soil flux values vary by four orders of magnitude over a 160-m distance and by one order of magnitude over several metres. A fixed network of 114 points over 6350 m2 has been installed in order to investigate temporal flux variations. Six surveys carried out from May 2000 to June 2001 have shown large variations of the total CO2 soil flux (8–25 tons/day). The strong emission of CO2 and H2S, which are gases denser than air, produces dangerous accumulations in low areas which have caused a series of lethal accidents to animals and one to a man. The gas hazard near the houses has been assessed by continuously monitoring the CO2 and H2S concentration in the air at 75 cm from the ground by means of two automatic stations. Certain environmental parameters (wind direction and speed; atm P, T, humidity and rainfall) were also continuously recorded. At both stations, H2S and CO2 exceeded by several times the recommended concentration thresholds. The highest CO2 and H2S values were recorded always with wind speeds less than 1.5 m/s, mostly in the night hours. Our results indicate that there is a severe gas hazard for people living near the gas emission site of Cava dei Selci, and appropriate precautionary and prevention measures have been recommended both to residents and local authorities. 相似文献
18.
藏北高原恶劣的自然地理条件使扎仓茶－卡珍贵的锂资源的开发极为困难,必须采用尽可能简化的提取工艺才能降低成本,本文提出了一种经ＣａＯ,（ＮＨ４）２Ｃ２Ｏ４和Ｎａ２ＣＯ３三步沉积得到粗Ｌｉ２ＣＯ３的简化工艺,其产品纯度可达８５．６２％,总回收率约２０％,卤旦回收率约为７６％。 相似文献
19.
三峡水库澎溪河消落区土-气界面CO2和CH4通量初探 总被引：1，自引：0，他引：1
水库近岸湿地(消落区)温室气体(CO2、CH4)产汇是水库温室气体效应问题的重要组成部分.本文以三峡水库支流澎溪河的白家溪、养鹿两处大面积消落区为研究对象,于2010年6 9月水库低水位运行期间,对近岸消落区土-气界面CO2、CH4通量进行监测.白家溪消落区土-气界面CO2通量均值为12.38±2.42 mmol/(m2·h);CH4通量均值为0.0112±0.0064 mmol/(m2·h).养鹿消落区CO2、CH4通量均值分别为10.54±5.17、0.14±0.16 mmol/(m2·h).总体上,6 9月土-气界面CO2通量呈增加趋势,而CH4通量水平呈现显著的递减趋势.消落区土地出露后植被恢复,在一定程度上促进了土壤有机质含量的增加,使得6 9月CO2释放通量的总体趋势有所增加.消落区退耕后,其甲烷氧化菌的活性得到恢复,加之在土地出露曝晒过程中土壤透气性增强,使得消落区土壤对大气中CH4吸收氧化潜势增强.尽管如此,仍需进一步的研究以明晰消落区土-气界面CO2、CH4产汇的主要影响因素. 相似文献
20.
Hiroshi Ishida Lars G. Golmen Julia West Martin Krüger Patricia Coombs John Arthur Berge Tastuo Fukuhara Michimasa Magi Jun Kita 《Marine pollution bulletin》2013
Carbon capture and storage (CCS) methods, either sub-seabed or in ocean depths, introduces risk of CO2 leakage and subsequent interaction with the ecosystem. It is therefore important to obtain information on possible effects of CO2. In situ CO2 exposure experiments were carried out twice for 10 days during 2005 using a Benthic Chamber system at 400 m depth in Storfjorden, Norway. pCO2 in the water above the sediment in the chambers was controlled at approximately 500, 5000 and 20,000 μatm, respectively. This article describes the experiment and the results from measured the biological responses within the chamber sediments. The results show effects of elevated CO2 concentrations on biological processes such as increased nanobenthos density. Methane production and sulphate reduction was enhanced in the approximately 5000 μatm chamber. 相似文献