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1.
辽宁大石桥菱镁矿床的碳氧同位素组成和成因 总被引：13，自引：8，他引：5
在2.33~2.06Ga期间,δ13Ccarb发生了地质历史上最强烈的正异常事件,被称为Lomagundi事件。辽河群形成于2.3~1.85Ga期间,其大石桥组蕴涵超大型的大石桥菱镁矿矿床,在矿区厚约1144m。为检验华北克拉通对Lomagundi事件响应,揭示大石桥菱镁矿的成因,本文报道我们最新获得的地球化学研究结果。大石桥菱镁矿6件下伏白云岩地层样品的CaO/MgO摩尔比为0.87~0.94,δ13Ccarb和δ18Ocarb值分别为0.6‰~1.4‰（平均1.2‰,V-PDB标准）和16.4‰~19.5‰（平均18.2‰,SMOW标准）;与世界正常海相碳酸盐岩地层相比,δ13Ccarb较高,而δ18Ocarb较低,表明原始沉积物具有类似于Lomagundi事件的δ13Ccarb正异常,δ13Ccarb可能高达4.2‰,但δ13Ccarb和δ18Ocarb值均在沉积之后的成岩或/和变质过程中显著降低。研究剖面大石桥菱镁矿含矿地层厚逾550m,6件样品的CaO/Mg0摩尔比为0.005~0.23,δ13Ccarb和δ18Ocarb值分别为0.1‰~0.6‰（平均0.4‰）,9.2‰~12.7‰（平均10.9‰）,均低于下伏围岩白云岩;推测与区域变质有关的流体交代作用导致岩石发生重结晶作用和同位素交换,使δ13CV-PDB和δ18OV-SMOW值降低。而对菱镁矿顶板白云岩和网脉状菱镁矿矿石的研究进一步证明了上述解释的合理性。总之,大石桥菱镁矿的形成经历了初始沉积、成岩作用、区域变质和流体交代作用以及成矿后的局部蚀变作用。 相似文献
2.
J. K. W. Lee 《Contributions to Mineralogy and Petrology》2000,139(5):526-540
The elucidation of thermal histories by geochronological and isotopic means is based fundamentally on solid-state diffusion
and the concept of closure temperatures. Because diffusion is thermally activated, an analytical solution of the closure temperature
(T
c
*) can only be obtained if the diffusion coefficient D of the diffusion process is measured at two or more different temperatures. If the diffusion coefficient is known at only
one temperature, however, the true closure temperature (T
c
*) cannot be calculated analytically because there exist an infinite number of possible (apparent) closure temperatures (Tˉ
c
) which can be generated by this single datum. By introducing further empirical constraints to limit the range of possible
closure temperatures, however, mathematical analysis of a modified form of the closure temperature equation shows that it
is possible to make both qualitative and quantitative estimates of T
c
* given knowledge of only one diffusion coefficient D
M
measured at one temperature T
M
. Qualitative constraints of the true closure temperature T
c
* are obtained from the shapes of curves on a graph of the apparent T
c
(Tˉ
c
) vs. activation energy E, in which each curve is based on a single diffusion coefficient measurement D
M
at temperature T
M
. Using a realistic range of E, the concavity of the curve shows whether T
M
is less than, approximately equal to, or greater than T
c
*. Quantitative estimates are obtained by considering two dimensionless parameters [ln
êRT^
c
vs. T
c
*/T
M
] derived from these curves. When these parameters are plotted for known argon diffusion data and for a given diffusion size
and cooling rate, it is found that the resultant curves are almost identical for all of the commonly dated K–Ar minerals –
biotite, phlogopite, muscovite, hornblende and orthoclase – in spite of differences in their diffusion parameters. A common
curve for Ar diffusion can be derived by least-squares fitting of all the Ar diffusion data and provides a way of predicting
a “model” closure temperature T
cm
from a single diffusion coefficient D
M
at temperature T
M
. Preliminary diffusion data for a labradorite lead to a T
cm
of 507 ± 17 °C and a corresponding activation energy of about 65 kcal/mol, given a grain size of 200 μm and a cooling rate
of 5 °C/Ma. Curves for He diffusion in silicates (augite, quartz and sanidine) also overlap to a significant degree, both
among themselves and with the Ar model curve, suggesting that a single model curve may be a good representation of noble gas
closure temperatures in silicates. An analogous model curve for a selection of 18O data can also be constructed, but this curve differs from the Ar model curve. A single model curve for cationic species
does not appear to exist, however, suggesting that chemical bonding relationships between the ionic size/charge and crystal
structure may influence the closure temperatures of diffusing cations. An indication of the degree of overlap among the various
curves for Ar, He, 18O and cations is also obtained by considering the dimensionless parameter E/RT
c
*; for the noble gases and 18O, E/RT
c
* values for the respective minerals are very similar, whereas for cations, there is significant dispersion. Given these constraints,
this may be a potential method of estimating closure temperatures for certain diffusing species when there are limited diffusion
data.
Received: 1 July 1999 / Accepted: 24 March 2000 相似文献
3.
4.
大氧化事件在山西滹沱群中的记录:碳酸盐岩碳同位素资料分析 总被引：1，自引：1，他引：0
古元古代早期爆发了全球性大氧化事件（GOE）,诱发了休伦冰川事件（Huronian Glaciation Event,HGE）和2.3~2.06Ga的拉玛岗地-瓦图里碳酸盐碳同位素正漂移事件（Lomagundi-Jatuli Event,LJE）。滹沱群是华北克拉通最具代表性的古元古代沉积地层,变质程度最低,地层学研究程度高,是探索GOE以及HGE和LJE的理想研究对象。通过总结和分析滹沱群碳酸盐岩碳同位素研究结果,我们发现：（1）滹沱群主体未显示δ13Ccarb正漂移现象,但下部大石岭组有高达3.5‰的δ13Ccarb正异常;（2）显示δ13Ccarb正异常的大石岭组可能形成于2.08Ga之前,未显示δ13Ccarb正异常的东冶亚群可能形成于2.06Ga之后;（3）五台地区记录休伦冰川事件的冰碛岩应发育在大石岭组之下,即四集庄组砾岩。总之,滹沱群形成于2.3Ga之后,下部豆村亚群沉积于HGE或LJE期间,可能保留了更显著的δ13Ccarb正漂移信息及冰川沉积记录,中部的东冶亚群沉积于LJE之后,不存在δ13Ccarb正漂移。 相似文献
5.
伊海生 《沉积与特提斯地质》2021,41(4):505-511
藏北双湖县巴岭乡地区出露一套深水相黑色页岩地层,包括下侏罗统曲色组和中侏罗统色哇组二个组地层单元。根据菊石化石控制的生物地层时代,下伏曲色组划归Pliensbachian-Toarcian 阶,上覆色哇组级代表Aalenian-Bajocian 期沉积,二者之间为连续沉积,是目前西藏特提斯域菊石化石控制程度最高的中下侏罗统地层。野外实测了索布查J2/J1界线剖面,按2m间距采集了148件样品,室内开展了无机碳(δ13Ccarb)和有机碳(δ13Ckero)分析,目的是揭示早侏罗世末期到中侏罗世初期这一时段的古海洋演化过程。研究结果表明,曲色组沉积期古海水δ13CDIC偏正,而色哇组δ13CDIC偏负,J2/J1界线上下δ13Ccarb值显示阶步式负向偏移的特点。根据相关分馏方程计算,Toarcian期海洋浮游植物繁盛,δ13CDIC偏正,海水营养盐NO3浓度偏低,而Aalenian期海洋浮游植物衰减,δ13CDIC偏低,NO3浓度升高。沉积有机质或干酪根碳同位素δ13Ckero在J2/J1界线上下与δ13Ccarb变化趋势一致,也具有由高值逐渐偏低的特点,但δ13Ccarb和δ13Ckero变化曲线的波峰和波谷并不同步,这是因为海源和陆源有机质相对含量高低变化所致。文中根据碳同位素质量平衡方程,定量的描述了索布查界线剖面陆源和海源有机质比例的变化过程,讨论了曲色组和色哇组烃源岩在油气勘探中的意义。 相似文献
6.
闪叶石族矿物是富含Sr、Na、Ca和Ba等的钛硅酸盐矿物的总称,迄今共有19个矿物种,其中的氟闪叶石矿物首次发现于巴西Serrote山碱性岩中。本文利用电子探针和X射线衍射仪等分析测试手段,从化学成分和晶体结构等方面对产出于中国辽宁赛马碱性岩体中的闪叶石族矿物进行了详细的矿物学特征研究,发现其中常呈柱状、针状和纤维状集合体产出的闪叶石的晶体化学式为(Sr1.00Na1.00)Σ2.00Ti2(Na1.98Sr0.33Mn0.26K0.12Mg0.10Ca0.09Ba0.05)Σ2.93(Ti0.69Fe3+0.33Al0.02)Σ1.04(Si3.80O14) O2(F1.16OH0.84)Σ2.00,属于单斜晶系,空间群为C2/m,晶胞参数a=19.271 9(8) Å,b=7.077 9(3) Å, c=5.388 2(2) Å, β=96.780(2)°, V=729.84(5) Å3, Z=2。上述矿物学特征均与巴西发现的新矿物氟闪叶石的矿物学特征一致,表明赛马碱性岩体产出的氟闪叶石堪称该矿物种在中国的首次发现。不仅如此,赛马碱性岩体也有闪叶石产出,而且,迄今已发现多个新矿物,寓示该岩体仍有良好的新矿物发现前景。 相似文献
7.
登埂温泉与玛布温泉位于云南泸水市,出露于怒江深切峡谷西岸。研究区分布的主要地层为第四系（Q42）砂土、砾土,石炭系上统卧牛寺组（C3w）玄武岩和三叠系河湾街组下段（T2h1）灰岩。温泉水温为48.9~69.6℃,矿化度为0.493~0.782 g/L,水化学类型分别为HCO3·Ca-Mg型和HCO3·Ca-Na型,为中低温、弱酸性温泉。热水中F-含量为0.78~2.13 mg/L,H2SO3为41.0~70.2 mg/L,含有锂、锶、铷、铯、钡等微量元素。氢氧稳定同位素组成表明研究区温泉补给来源为大气降水,用同位素方法估算温泉的补给区高程为1260~1435 m,补给区温度为6.18~9.02℃,计算的热储温度为100~127.5℃。研究区温泉Ca2+与HCO3-含量较高,占阴、阳离子的毫克当量浓度百分比分别达到60%、82%以上,水中方解石、文石矿物都处于饱和状态,水中CO2含量较高且pCO2远高于大气中pCO2,具有有利于CaCO3沉积的水化学和水动力条件,导致登埂温泉YLS3-1、YLS3-3及YLS3-4和玛布温泉YLS4-1的沉积钙华。登埂温泉与玛布温泉是地下水在怒江西部山区补给区获得大气降水入渗补给,在经历深循环过程中获得深部热流加热后上升在怒江河谷西岸流出地面形成的温泉,是渗入深循环型上升的的中低温温泉。热水在上升过程中与浅部冷水相遇,冷水混入比例为60%~73%,热水循环深度为2375.2~3161.7 m。 相似文献
8.
矿山环境土壤重金属污染潜在生态风险评价模型探讨 总被引：9，自引：0，他引：9
Weeks(2005)提出有关土壤污染的生态风险“层叠式 (Tiered approach)”评价框架,有关各层次的评价技术是当前环境科学研究的热点。针对矿山环境土壤重金属污染生态风险特征,提出矿山环境土壤重金属污染潜在生态风险评价模型,属于Tire 1层次评价模型。根据矿山环境土壤重金属污染生态风险特征,遵循生态风险评价中的熵原理和证据权重原则,用土壤中重金属的浓度风险表征污染指数（Cif）;以其环境生物可利用性表征毒性响应系数（Tib）,以对污染指数进行修正;以重金属元素的生物毒性响应因子（Tie）为权重,提出矿山环境土壤重金属污染潜在生态风险评价模型：RI=∑mi=1Eri其中,Eri= Tie×Tib×Cif;RI表示土壤中多种重金属潜在生态风险指数;Eri为元素i的潜在风险因子;Cif=Ci/Cio ,Ci为土壤中重金属浓度实测值,Cio为计算所需要的参照值。Tib=（Rib/ Pib）1/2,Rib为样品中某元素生物可利用相态占总含量的百分比,Pib为参照土壤的相应比值。 相似文献
9.
Frederick A. Ochs III. Rebecca A. Lange 《Contributions to Mineralogy and Petrology》1997,129(2-3):155-165
The molar volumes of 19 hydrous albitic liquids (1.9 to 6.1 wt% H2Ototal) were determined at one bar and 505–765 K. These volume data were derived from density measurements on hydrous glasses at
298 K, followed by measurements of the thermal expansion of each glass from 298 K to its respective glass transition temperature.
The technique exploits the fact that the volume of a glass is equal to that of the corresponding liquid at the limiting fictive
temperature (T
f′), and that T
f′ can be approximated as the temperature near the onset of the rapid increase in thermal expansion that occurs in the glass
transition interval. The volume data of this study were combined with available volume data for anhydrous, Na2O-Al2O3-SiO2 liquids to derive the partial molar volume (±1) of the H2O component in an albitic melt at ∼565 K and one bar. To extend the determination of to higher temperatures and pressures, the molar volumes of the hydrous albitic liquids determined in this study were combined
with those measured by previous authors at 1023–1223 K and 480–840 MPa, leading to the following fitted values (±1) at 1673
K and one bar: (±0.46)×10−3 cm−3/mol-K, and dVˉ
H
2
O
total
/dP=−3.82 (±0.36)×10−4 cm3/mol-bar. The measured molar volumes of this study and those of previous authors can be recovered with a standard deviation
of 0.5%, which is within the respective experimental errors. There is a significant difference between the values for derived in this study as a function of temperature and pressure and those obtained from an existing polynomial, primarily
caused by the previous absence of accurate density measurements on anhydrous silicate liquids. The coefficients of thermal
expansion (=4.72×10−4/K) and isothermal compressibility (
T
=1.66×10−5/bar) for the H2O component at 1273 K and 100 MPa, indicate that H2Ototal is the single most expansive and compressible component in silicate liquids. For example, at 1473 K and 70 MPa (conditions
of a mid-ocean ridge crustal magma chamber), the presence of just 0.4 wt% H2O will decrease the density of a basaltic liquid by more than one percent. An equivalent decrease in melt density could be
achieved by increasing the temperature by 175 degrees or the decreasing pressure by 230 MPa. Therefore, even minor quantities
of dissolved water will have a marked effect on the dynamic properties of silicate liquids in the crustal environment.
Received: 20 August 1996 / Accepted: 15 March 1997 相似文献
10.
【研究目的】川滇黔地区铅锌矿成因具有多样性,特别是与峨眉山玄武岩的关系存在较大的争议,本文从前人关注较少的二叠系碳酸盐岩中的铅锌矿入手,研究成矿物质来源。【研究方法】以云南寻甸县太平子铅锌矿为研究对象,运用S、Pb、C、H、O同位素实验数据及流体包裹体测温等方法,对成矿物质来源及成矿流体特征进行探讨。【研究结果】矿石铅同位素组成比较均一,分布集中,206Pb/204Pb、207Pb/204Pb、208Pb/204Pb的变化范围分别为18.543～18.584、15.646～15.694、38.799～38.958,属于正常普通铅,具壳源特征,主要来源于基底岩石,水岩反应可能使赋矿围岩贡献少量的成矿物质。矿石硫化物δ34S变化范围为-13.6‰～-7.3‰,方铅矿的δ34S高于闪锌矿,硫同位素分馏并未达到平衡,生物成因硫酸盐还原作用（BSR）是还原硫的主要来源。热液方解石δ13CV-PDB范围为3.8‰～4.7‰,δ18OV-SMOW范围为12.0‰～16.7‰,相较于滇东北其他重要的铅锌矿床,具有明显的低δD、高δ18Ofluid特点,成矿流体中的水主要来源于岩浆水和有机水的混合,具有中—高温、低盐度特征。【结论】太平子铅锌矿在成矿物质、流体、成矿温度等均与区域上其他典型铅锌矿有较明显差别,具有典型的岩浆-热液成因特点。 相似文献
11.
The ability of ion-exchange resin for ammonia removal from aqueous solution was studied. The results showed that Amberlite ion-exchange resin was effective in removing ammonia from aqueous solution. Factorial design and response surface methodology were applied to evaluate and optimize the effects of pH, resin dose, contact time, temperature and initial ammonia concentration. Low pH condition was preferred with the optimum pH found to be 6. High resin dose generated high removal rate and low exchange capacity. Results of factorial design and response surface methodology showed that temperature was not a significant parameter. The model prediction was in good agreement with observed data (R 2 = 0.957). The optimum Q e was 28.78 mg/g achieved at pH = 6 and initial TAN concentration of 3000 mg/L. The kinetics followed the pseudo-second-order kinetic model (R 2 = 0.999). Equilibrium data were fitted to Langmuir and Freundlich isotherm models with Langmuir model providing a slightly better predication (R 2 = 0.996). The resin was completely regenerated by 2 N H2SO4. 相似文献
12.
Phosphorus dynamics and corn growth under applications of corn stalks biochar in a clay soil 总被引：1，自引：0，他引：1
Abu El-Eyuoon Abu Zied Amin 《Arabian Journal of Geosciences》2018,11(14):379
Biochar prepared from corn stalks is used as a source of phosphorus in this study. The hypotheses were to investigate effects of biochar applications in clay soil on availability, changes of phosphorus pools and maximum adsorption of phosphorus as well as corn growth. The soil was placed in plastic pots with each contains 3 kg of this soil. Biochar was added at levels of 0 (control), 6.5 (B1), 19 (B2), and 38 (B3) g pot?1. In this experiment, the pot was planted with corn (Zea mays). The results of this study revealed that the biochar application enhanced available phosphorus (Olsen-P) from 11.51 to 17.10 mg kg?1. Adding biochar significantly increased the amount of NH4Cl-P, NaHCO3-Po, and NaOH I-Po fractions (p?≤?0.05), but it significantly decreased HCl-Pi fraction (p?≤?0.05). Addition of biochar at the highest level increased the fresh and dry matter productions by up to about 75 and 48.7%, respectively, compared to the control. The phosphorus uptake by corn plants significantly increased with increasing levels of biochar. The removal efficiency (% sorption) and maximum adsorption (b) of phosphorus increased with increasing level of biochar addition compared to control. Consequently, it is recommended to add biochar produced from corn stalks to the soil in order to substitute phosphate fertilizers. 相似文献
13.
Previously studied thermosequences of wood (chestnut) and grass (rice straw) biochar were subjected to hydrogen pyrolysis (hypy) to evaluate the efficacy of the technique for determining pyrogenic carbon (CP) abundance. As expected, biochar from both wood and grass produced at higher temperature had higher CP amount. However, the trend was not linear, but more sigmoidal. CP/CT ratio values (CT = total organic carbon) for the wood thermosequence were ⩽0.03 at biochar production temperature (TCHAR) ⩽ 300 °C. They increased dramatically until 600 °C and remained relatively constant and near unity at higher biochar production temperature. Grass biochar was similar in profile, but CP/CT values rose dramatically after 400 °C. The findings are consistent with the hypothesis that hypy residues contain polycyclic aromatic hydrocarbons (PAHs) with a degree of condensation above at least 7–14 fused rings, with labile organic matter and pyrogenic PAHs below this degree of condensation removed by hypy.Both wood and grass thermosequences displayed δ13CP values that decreased with increased TCHAR, indicating that recalcitrant carbon compounds (pyrogenic aromatic PAHs with a relatively high degree of condensation) were first formed from structural components with relatively high δ13C values (e.g. cellulose). Relatively constant δ13C values at TCHAR ⩾ 500 °C suggested the dominant pyrolysis reaction was condensation of PAHs with no additional fractionation. Comparison of hypy with benzene polycarboxylic acid (BPCA), ‘ring current’ NMR and pyrolysis gas chromatography–mass spectrometry (GC–MS) results from the same suite of samples indicated a consistent overview of the structure of CP, but provided unique and complimentary information. 相似文献
14.
Robert H Byrne 《Geochemical transactions》2002,3(1):11-6
Assessments of inorganic elemental speciation in seawater span the past four decades. Experimentation, compilation and critical review of equilibrium data over the past forty years have, in particular, considerably improved our understanding of cation hydrolysis and the complexation of cations by carbonate ions in solution. Through experimental investigations and critical evaluation it is now known that more than forty elements have seawater speciation schemes that are strongly influenced by pH. In the present work, the speciation of the elements in seawater is summarized in a manner that highlights the significance of pH variations. For elements that have pH-dependent species concentration ratios, this work summarizes equilibrium data (S = 35, t = 25°C) that can be used to assess regions of dominance and relative species concentrations. Concentration ratios of complex species are expressed in the form log[A]/[B] = pH - C where brackets denote species concentrations in solution, A and B are species important at higher (A) and lower (B) solution pH, and C is a constant dependent on salinity, temperature and pressure. In the case of equilibria involving complex oxy-anions (MO x (OH) y ) or hydroxy complexes (M(OH) n ), C is written as pK n = -log K n or pK n * = -log K n * respectively, where K n and K n * are equilibrium constants. For equilibria involving carbonate complexation, the constant C is written as pQ = -log(K 2 l K n [HCO3 -]) where K 2 l is the HCO3 - dissociation constant, K n is a cation complexation constant and [HCO3 -] is approximated as 1.9 × 10-3 molar. Equilibrium data expressed in this manner clearly show dominant species transitions, ranges of dominance, and relative concentrations at any pH. 相似文献
15.
Two anhydrous equilibria can be written among the components of stilpnomelane, chlorite, white mica and quartz, namely 89 daphnite+131 Fe-celadonite+190 quartz=96 stilpnomelane+71 muscovite, and amesite+Mg-celadonite=muscovite+clinochlore. We assume that the free energy change of reaction, ΔG=ΔGo+ΣRT lnaij, is approximated by ΔG=A?BT +C(P?1)+ΣRT lnaij, where ΔGo is the free energy change of the end-member components at temperature T and pressure P, ai is the activity of component i whose coefficient in the equilibrium is j, and A, B and C are constants to be determined. Values of C can be approximated by the change in volume on reaction, namely C=406.517 J/bar for the first reaction and C=0.613 J/bar for the second reaction. Constants A and B were determined by using six occurrences of the assemblage stilpnomelane–chlorite–white mica for which P–T have been otherwise estimated. Using solution models from the literature, linear regression gives for the first equation A=?6118.269 kJ, B=?4584.09 J/K, and for the second equation A=19.397 kJ, B=66.72 J/K. These values predict P–T within 0.5 kbar and 25 K for all occurrences, and appear reasonably robust relative to probable analytical errors. P–T are determined by intersection of the curves generated by given compositions in P–T space. Fine-grained and/or zoned chlorite and white mica make application of the geothermobarometer difficult in some instances, but our work in the Bathurst region of New Brunswick suggests that, with patience and care, useful analyses can be obtained, and the database for the geothermobarometer greatly expanded. 相似文献
16.
氟碳钡铈矿(Cordylite)BaCe2(CO3)3 F2本世纪初首先发现于格陵兰纳尔萨尔苏克(Narssarssuk)的碱性正长伟晶岩脉中,与霓石、氟碳铈钙矿、柱星叶石和碳锶铈矿共生。1965年该矿物又发现于我国白云鄂博西矿区热液交代的元古代白云岩中。1975年,加拿大魁北克省圣赫莱山(Mont st. Hilaire,Quebec)的霞石正长岩中的伟晶岩脉中也发现了这一矿物,它与方沸石、霓石和钠闪石共生。 相似文献
17.
This study describes the development of scallop shell synthesized ceramic biomaterial for phosphorus removal from water. The synthesized biomaterial was characterized by scanning electron microscope, Brunauer–Emmett–Teller and X-ray diffractometer methods. The influences of contact time, initial phosphate concentration, initial solution pH, co-existing ions and temperature for phosphorus removal were investigated by batch experiments. The results indicated that the equilibrium data can be fitted by the Langmuir isotherm model at temperatures ranging from 15 to 55 °C, with the maximum sorption capacity of 13.6 mg/g. Sorption kinetics followed a pseudo-second-order kinetic equation model. The sorption process was optimal at a wide range of solution pH (above 2.4), with a relatively high sorption capacity level. Phosphorus sorption was slightly impeded by the presence of F?, HCO3 ? and NH4 + ions, and significantly inhibited by Cl?, SO4 2? and NO3 ? ions. Sorption process appeared to be controlled by a chemical precipitation processes. The mechanism may be attributed to ion complexation during subsequent sorption of phosphorus on scallop shell synthesized ceramic biomaterial. 相似文献
18.
采用液相还原法成功制备纳米零价铁,并组装出生物质炭负载纳米零价铁复合材料(NZVI/BC)。XRD图谱显示,NZVI/BC由生物质炭(BC)和纳米零价铁(NZVI)两种成分复合而成;SEM图像显示,加入生物质炭之后,NZVI颗粒在炭表面分散良好。研究考察溶液p H值、还原剂投加量、铁/炭比和NO-3初始浓度等因素对NZVI/BC还原性能的影响。结果表明,NZVI/BC显示出优良的还原性能。在相同条件下,反应2 h,NZVI对NO-3的去除率为75%,而NZVI/BC对NO-3的去除率为96%。NZVI/BC是一种具有应用前景的硝态氮净化材料。 相似文献
19.
Muhammad Riaz Mumtaz Khan Shafaqat Ali Muhammad Daud Khan Rehan Ahmad Muhammad Jamil Khan Muhammad Rizwan 《Arabian Journal of Geosciences》2018,11(23):752
Biochar has been considered a safe soil additive to enhance soil fertility and agronomic traits of different crops. This study was conducted to explore the impacts of sugarcane waste straw biochar on soil characteristics and some agronomic traits of okra. The experiment was carried out with four treatments, i.e., control, sugarcane waste straw biochar (10 ton ha?1), farmyard manure (FYM, 10 ton ha?1), and chemical fertilizers (NPK; 120:100:80 kg ha?1) having three replications of each treatment. Soil samples were tested for texture, bulk density, particle density, pH, electrical conductivity (EC), organic matter content, nitrate nitrogen (NO3-N), and extractable-P. The sugarcane waste straw biochar was characterized for plant major nutrient elements. The impact of various treatments was observed on soils and agronomic traits of okra like plant height, fruit size, fruit length, and yield of okra. Results revealed that sugarcane waste straw biochar expressed higher EC value and noticeable amounts of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and magnesium (Mg). The sugarcane waste straw biochar, in comparison with FYM and NPK, significantly improved the NO3-N, extractable-P, OM and EC of the calcareous soil, and reduced the soil bulk density. Furthermore, plant growth and yield parameters were significantly improved under biochar application over the control, FYM and NPK. Overall, sugarcane waste straw biochar proved to be a good alternative to conventional organic and inorganic fertilizers under calcareous soil conditions. 相似文献
20.
Hydraulic Conductivity and Coefficient of Consolidation of Two Sulphide Clays in Sweden 总被引：1，自引：0，他引：1
The variation and anisotropy in hydraulic conductivity and the coefficient of consolidation was investigated for two Swedish
sulphide clays. A series of constant rate of strain oedometer tests was performed on samples trimmed in the vertical and horizontal
direction. A methodology to evaluate the horizontal coefficients of consolidation c
h
via the horizontal hydraulic conductivity k
h
and the vertical compression modulus M
v
is proposed. Laboratory evaluations of c
h
are also compared with determinations of c
h
from in situ piezometer measurements in vertically drained sulphide clay. Furthermore, the validity of the empirical correlation
between hydraulic conductivity change index C
k
and initial void ratio e
0, C
k
= 0.5e
0 (Tavenas et al. in Can Geotech J 20(4):645–660, 1983b), was investigated for the sulphide clays. The results from the investigation show large ranges in measured hydraulic conductivities
and coefficients of consolidation. However, the results indicate that the correlation C
k
= 0.5e
0 is valid. The anisotropy in hydraulic conductivity and the coefficient of consolidation of the sulphide clays tested seems
to be small. For design purposes, multiple tests for assessment of hydraulic conductivity and the coefficient of consolidation
should be made, and a partial factor of safety, depending on the requisite level of safety and the spatial variability of
the parameters, should be introduced. For design purposes in this type of clay, k
h
= k
v
and c
h
= c
v
are suggested. 相似文献