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1.
本文研究了在Pb~(2+),Cd~(2+)和Cu~(2+)等离子共存的条件下,羟基磷灰石对溶液中Zn~(2+)离子的吸附行为,讨论了Pb~(2+),Cd~(2+)和Cu~(2+)离子对Zn~(2+)吸附行为的影响;比较了羟基磷灰石对上述离子的吸附能力。实验结果表明:随着Cd~(2+)离子浓度增大,对Zn~(2+)的去除率逐渐增高,羟基磷灰石对Cd~(2+)和Zn~(2+)离子无吸附选择性。而随着Cu~(2+)离子浓度增大,对Zn~(2+)的去除率急剧下降,表现出明显的吸附选择性。另一方面,对Zn~(2+)的去除率几乎不随Pb~(2+)离子浓度的变化而改变,这是由于羟基磷灰石对这两种离子的吸附行为与机理不同。上… 相似文献
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为了研究不同煤级煤对H2S气体的吸附差异及吸附模型,采集新疆气煤,山西潞安瘦煤、晋城无烟煤3个煤样进行了工业分析、煤岩分析和平衡水条件下的等温吸附实验。采用Langmuir,BET,D-R和D-A吸附模型,利用拟合软件对等温吸附实验数据进行了非线性回归拟合,并检验拟合程度。结果表明:煤对H2S的吸附量随着煤化程度的加深而增加,为第Ⅰ类等温吸附线;其中Langmuir模型的拟合效果最好,n=1的D-A模型的拟合效果次之,BET模型的拟合效果较差,模型对实验数据的拟合效果与吸附模型中参数个数无明显关系;煤吸附H2S可用单分子层吸附理论来解释。 相似文献
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为揭示深部煤层超临界CO2（ScCO2）吸附特征及其控制机理,以沁水盆地南部余吾矿、寺河矿、成庄矿的3号煤为研究对象,通过自制等温吸附仪进行了不同温度（45℃,62.5℃,80℃）、最高压力达到CO2超临界压力以上时的等温吸附实验。研究结果表明:高温高压条件下ScCO2吸附曲线不同于常温常压下CO2吸附曲线,随压力升高ScCO2过剩吸附量和绝对吸附量分别呈4段式和3段式变化,ScCO2达到过剩吸附量峰值出现的压力点具有随温度升高向高压增高的特征;ScCO2过剩吸附量远低于绝对吸附量,无法采用Langmuir吸附模型进行解释;温度对ScCO2吸附抑制明显,水分对ScCO2吸附没有起到抑制作用,灰分含量较高对ScCO2吸附量有明显抑制作用,煤中高镜质组含量和高Rmax对ScCO2吸附具有较明显的促进作用;超临界状态下煤对ScCO2的吸附量大小由微孔和过渡孔所控制,且与微孔比表面积大小有关,高变质煤对ScCO2的吸附能力降低可能是因微孔中矿物充填所致。 相似文献
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施威特曼石普遍存在于含大量SO42-的酸矿水中,其表面吸附的SO42-使得该矿物具有强吸附重金属离子的能力,可用于处理重金属离子污染。实验通过在不同浓度Cu2＋溶液中合成施威特曼石时发现,Cu2＋与施威特曼石的共沉淀量较低,FTIR分析表明Cu2＋与施威特曼石的羟基发生反应。开展施威特曼石吸附Pb2＋的实验,结果表明施威特曼石对Pb2＋的吸附符合Langmuir模型,施威特曼石吸附Cu2＋和Pb2＋后出现1545.4 cm-1和1435.0 cm-1（Cu2＋）两个吸收峰,可能是施威特曼石孔道表面形成了三元配合物。在241×10-6的初始浓度（与尾矿孔隙水的Pb2＋含量相近）下有61.4%的Pb2＋去除率,显示了较好的环境修复价值。 相似文献
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坡缕石对Zn^2＋的吸附性能及吸附工艺条件优化研究 总被引：1，自引：2，他引：1
从坡缕石粘土提纯人手，进行了坡缕石吸附Zn^2 的实验研究，结果表明坡缕石对水中Zn^2 的吸附性能主要受振荡速度、吸附时间、溶液pH值、吸附剂用量等因素影响，30℃时坡缕石对Zn^2 的等温吸附曲线同时符合Langmuir方程和BET方程。在本实验条件下，坡缕石对水中的Zn^2 (20mL，Zn^2 浓度均为50mg／L)的最佳吸附工艺条件为：振荡速度150r／min，吸附时间120min，吸附剂用量0．120g，溶液pH为6．2，此条件下去除率达到T95．5％。 相似文献
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注CO2提高煤层气采收率的模拟实验研究 总被引：1，自引：1，他引：0
根据煤储层的吸附/解吸机理,模拟煤层气井"排采-注气-排采"的生产过程,进行CH4、CO2的单相气体吸附/解吸和CO2注入置换煤层CH4的实验,得到了CH4和CO2二元气体相组分变化数据和CH4和CO2混合气体的相分离图解.结果表明,在CH4和CO2二元气体的竞争吸附中,CO2组分的吸附速率是先快后慢,而CH4组分的吸附速率先慢后快,解吸时则相反.反映了CO2组分在与CH4组分的竞争吸附中占据优势,优先被吸附;同时发现注入气体数量越大,注入气体中CO2组分浓度越高,单位压降下的CH4解吸率和CO2吸附率越高.实验结论对工业规模的煤层气开发试验具有一定的指导意义. 相似文献
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注入CO2提高煤层气产能的可行性研究 总被引：15，自引：0，他引：15
根据煤储层吸附一解吸机理,首次采用“解吸一注气一解吸”的实验方法,分别进行CH4,CO2的吸附一解吸和CO2注入置换煤层CH4实验,模拟了煤层气井“排采一注气一排采”的增产途径和效果。结果表明：在CH4和CO2二元体系的竞争吸附中,CO2组分的吸附速率是先快后慢,而CH4组分的吸附速率先慢后快,解吸时则相反,反映出CO2在竞争吸附中占据优势;注入CO2气体的数量越大和相对浓度越高,单位压降CH4解吸率和CO2吸附率就越高。实验结论对工业规模的煤层气开发试验具有指导意义。 相似文献
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火山岩的脱气实验和对昌德东CO2气藏气源的分析结果表明:加热火山岩到250℃时,脱出挥发分总量为0.0299～0.0790mL/g,其中CO2脱出量为0.0218～0.0706mL/g(0.429～1.387wt%);挥发组分以CO2为主,还含有H2、CO、CH4等还原性气体,以及少量低碳烷烃,CO2含量和总烃呈现反比关系;基性岩的CO2脱出量、脱出率高于中、酸性岩;CO2脱出量与岩石碱质含量正相关。松辽盆地北部昌德东CO2气藏成藏模式为“自生自储”,成藏CO2气主要来自深部被火山岩吸附的气。随岩浆上升,在岩浆冷凝成火山岩的过程中被吸附于火山岩的节理、劈理和晶体位错之中的CO2气,连同火山岩包体中的残留气,成为高纯CO2气藏的主要补给源,并非地幔气体沿大断裂上来直接充注成藏。 相似文献
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火山岩的脱气实验和对昌德东CO2气藏气源的分析结果表明:加热火山岩到250℃时,脱出挥发分总量为0.0299～0.0790mL/g,其中CO2脱出量为0.0218～0.0706mL/g(0.429～1.387wt%);挥发组分以CO2为主,还含有H2、CO、CH4等还原性气体,以及少量低碳烷烃,CO2含量和总烃呈现反比关系;基性岩的CO2脱出量、脱出率高于中、酸性岩;CO2脱出量与岩石碱质含量正相关.松辽盆地北部昌德东CO2气藏成藏模式为“自生自储“,成藏CO2气主要来自深部被火山岩吸附的气.随岩浆上升,在岩浆冷凝成火山岩的过程中被吸附于火山岩的节理、劈理和晶体位错之中的CO2气,连同火山岩包体中的残留气,成为高纯CO2气藏的主要补给源,并非地幔气体沿大断裂上来直接充注成藏. 相似文献
11.
Fractal-like adsorption kinetics of Pb^2＋ in rocks 总被引：1，自引：0，他引：1
The adsorption kinetics of Pb^2＋ in rocks has been studied using ion selective electrodes and atomic absorption spectrophotometer. The results showed that the adsorption process is a fractal-like reaction. The adsorption rate was relatively high before 30 minutes, and then dropped. The saturated adsorption capacity （a） of Pb^2＋ and kinetic parameters （b, a, D and k） increased with increasing initial concentrations of Pb^2＋. These parameters （except a） decreased while Na^＋ was present in the solution. Furthermore, the smaller the rocks were in grain size, the bigger these kinetic parameters would be, though the parameter a was almost constant. 相似文献
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The problem associated with multi-metals contaminated soils has generated increasingly more attention. Thus, it is necessary within the field to study the mutual influence of environmental factors on competitive adsorption. The majority of studies carried out to date have concentrated on the variation of adsorption capacity or the removal efficiency, with only a single factor changed (including pH, ionic strength, and metal concentration). However, the interaction effect among various environmental factors was ignored in these studies. The purpose of this study was mainly aimed toward the investigation of the interaction of two influential factors, as well as the influential degree of each factor (such as the initial pH, ionic strength, initial metal concentration, and the competitive metal concentration) on competitive adsorption using the response surface method. These results demonstrated that the influential degree of each factor studied on the competitive adsorption of Zn2+ and Cd2+ followed the trend of having the initial concentration of the target metal?>?initial pH?>?concentration of competitive metal?>?ionic strength. When the metal concentration was held constant, we found that the competitive adsorption of Zn2+ initially increased, followed by a decrease with increasing initial pH. However, this was found to change minimally with increasing ionic strength. When the initial pH or ionic strength was held constant, the competitive ability was observed to increase with increasing Zn2+ concentration. However, with increasing Zn2+ or Cd2+ concentrations, the variation degree of the competitive adsorption was found to become smaller. These results provide novel information toward a better understanding of the effect of multifactors on the competitive adsorption of Zn2+ and Cd2+. 相似文献
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We present results from low-temperature heat capacity measurements of spinels along the solid solution between MgAl2O4 and MgCr2O4. The data also include new low-temperature heat capacity measurements for MgAl2O4 spinel. Heat capacities were measured between 1.5 and 300 K, and thermochemical functions were derived from the results.
No heat capacity anomaly was observed for MgAl2O4 spinel; however, we observe a low-temperature heat capacity anomaly for Cr-bearing spinels at temperatures below 15 K. From
our data we calculate standard entropies (298.15 K) for Mg(Cr,Al)2O4 spinels. We suggest a standard entropy for MgAl2O4 of 80.9 ± 0.6 J mol−1 K−1. For the solid solution between MgAl2O4 and MgCr2O4, we observe a linear increase of the standard entropies from 80.9 J mol−1 K−1 for MgAl2O4 to 118.3 J mol−1 K−1 for MgCr2O4. 相似文献
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N. V. Chukanov I. V. Pekov S. Möckel A. E. Zadov V. T. Dubinchuk 《Geology of Ore Deposits》2007,49(7):509-513
Zinclipscombite, a new mineral species, has been found together with apophyllite, quartz, barite, jarosite, plumbojarosite, turquoise, and calcite at the Silver Coin mine, Edna Mountains, Valmy, Humboldt County, Nevada, United States. The new mineral forms spheroidal, fibrous segregations; the thickness of the fibers, which extend along the c axis, reaches 20 μm, and the diameter of spherulites is up to 2.5 mm. The color is dark green to brown with a light green to beige streak and a vitreous luster. The mineral is translucent. The Mohs hardness is 5. Zinclipscombite is brittle; cleavage is not observed; fracture is uneven. The density is 3.65(4) g/cm3 measured by hydrostatic weighing and 3.727 g/cm3 calculated from X-ray powder data. The frequencies of absorption bands in the infrared spectrum of zinclipscombite are (cm?1; the frequencies of the strongest bands are underlined; sh, shoulder; w, weak band) 3535, 3330sh, 3260, 1625w, 1530w, 1068, 1047, 1022, 970sh, 768w, 684w, 609, 502, and 460. The Mössbauer spectrum of zinclipscombite contains only a doublet corresponding to Fe3+ with sixfold coordination and a quadrupole splitting of 0.562 mm/s; Fe2+ is absent. The mineral is optically uniaxial and positive, ω = 1.755(5), ? = 1.795(5). Zinclipscombite is pleochroic, from bright green to blue-green on X and light greenish brown on Z (X > Z). Chemical composition (electron microprobe, average of five point analyses, wt %): CaO 0.30, ZnO 15.90, Al2O3 4.77, Fe2O3 35.14, P2O5 33.86, As2O5 4.05, H2O (determined by the Penfield method) 4.94, total 98.96. The empirical formula calculated on the basis of (PO4,AsO4)2 is (Zn0.76Ca0.02)Σ0.78(Fe 1.72 3+ Al0.36)Σ2.08[(PO4)1.86(AsO4)0.14]Σ2.00(OH)1. 80 · 0.17H2O. The simplified formula is ZnFe 2 3+ (PO4)2(OH)2. Zinclipscombite is tetragonal, space group P43212 or P41212; a = 7.242(2) Å, c = 13.125(5) Å, V = 688.4(5) Å3, Z = 4. The strongest reflections in the X-ray powder diffraction pattern (d, (I, %) ((hkl)) are 4.79(80)(111), 3.32(100)(113), 3.21(60)(210), 2.602(45)(213), 2.299(40)(214), 2.049(40)(106), 1.663(45)(226), 1.605(50)(421, 108). Zinclipscombite is an analogue of lipscombite, Fe2+Fe 2 3+ (PO4)2(OH)2 (tetragonal), with Zn instead of Fe2+. The mineral is named for its chemical composition, the Zn-dominant analogue of lipscombite. The type material of zinclipscombite is deposited in the Mineralogical Collection of the Technische Universität Bergakademie Freiberg, Germany. 相似文献
15.
The position of hydrogen in the structure of topaz-OH was determined by means of ab-initio quantum-mechanic calculations. Static lattice energy calculations predict the existence of four non-equivalent positions of protons, which are characterized by O4–H1... O1, O4–H2... O2, O4–H3... O3 and O4–H4... O4 hydrogen bonds. The distribution of the protons between positions of local equilibrium is controlled by the proton–proton avoidance rule and the strength of the hydrogen bonds. The most favourable configuration of hydrogen atoms is achieved for adjacent protons, which form O4–H3... O3 and O4–H4... O4 hydrogen bonds, respectively. The thermal excitation of atoms at a temperature of 55 K is large enough for the hydrogen atoms occasionally to change their positions to form O4–H1... O1 and O4–H2... O2 bonds. At ambient pressures and higher temperatures the protons are in a dynamic exchange between the allowed positions of local minima. As a consequence, for nearly room-temperature conditions, the dynamic change between different structural configurations leads to the violation of all possible symmetry elements and with that to space group #E5/E5#1. The flipping of the protons between different sites is achieved by simple rotation of the OH-dipole and does not produce any significant distortion of the framework of topaz, whose symmetry remains that of the space group Pbnm. Therefore, no reduction of symmetry has been observed in former X-ray studies on topaz-OH. Calculated IR absorption spectra of topaz-OH were found to be in good agreement with measured spectra. According to the calculations, the two favourable configurations of protons might correspond to the measured peak splitting within the OH-stretching range. An experimentally observed low-frequency band at 3520 cm–1 was assigned to the OH-stretching of the O4–H3... O3 bond, while the band at 3600 cm–1 was attributed to OH-stretching of the O4–H4... O4 hydrogen bond. The broad peak in FAR-IR frequency range at 100–150 cm–1 is attributed to the stretching of H3... O3 and H4... O4 contacts. The rate of proton exchange at 670 K among different sites was estimated by ab-inito molecular dynamic simulations. The calculations predict that flipping of adjacent protons between O4–H3... O3 and O4–H4... O4 bonds at 670 K occur at a rate of about 1.96 THz. 相似文献
16.
Tamiris Chahm Bruna Aparecida Martins Clovis Antonio Rodrigues 《Environmental Earth Sciences》2018,77(13):508
This study assesses the ability of two low-cost adsorbents made from waste of Rapanea ferruginea treated with ethanol (WRf) and its H2SO4-treated analog (WRf/H2SO4) for the removal of two cationic dyes methylene blue (MB) and crystal violet (CV) from aqueous solutions. The adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectrometry, thermogravimetric analysis, point of zero charge (pHpzc), specific surface, and functional groups. The adsorption of dye onto the adsorbents was studied as a function of pH solution (2–12), contact time (up to 120 min) and initial concentration (20–120 mg/L), and temperature (25, 35, and 55 °C). The influence of these parameters on adsorption capacity was studied using the batch process. The response surface methodology (RSM) was used in the experimental design, modeling of the process, and optimizing of the variables and was optimized by the response involving Box–Behnken factorial design (15 runs). The results show that the data correlated well with the Sips isotherm. The maximum adsorption capacities of MB and CV onto WRf were found to be 69 and 106 mg/g, and onto WRf/H2SO4, the adsorption capacities were 33 and 125 mg/g, respectively. The kinetic data revealed that adsorption of cationic dyes onto the adsorbents closely follows the pseudo-second-order kinetic model. Regression analysis showed good fit of the experimental data to the second-order polynomial model, with coefficient of determination (R2) values for MB (R2?=?0.9685) and MB (R2?=?0.9832) for WRf and CV (R2?=?0.9685) and CV (R2?=?0.9832) for WRf/H2SO4 indicated that regression analysis is able to give a good prediction of response for the adsorption process in the range studied. The results revealed that waste from R. ferruginea is potentially an efficient and low-cost adsorbent for adsorption of MB and CV. 相似文献
17.
Taku Okada Takehiko Yagi Daisuke Nishio-Hamane 《Physics and Chemistry of Minerals》2011,38(4):251-258
The phase relations and compression behavior of MnTiO3 perovskite were examined using a laser-heated diamond-anvil cell, X-ray diffraction, and analytical transmission electron
microscopy. The results show that MnTiO3 perovskite becomes unstable and decomposes into MnO and orthorhombic MnTi2O5 phases at above 38 GPa and high temperature. This is the first example of ABO3 perovskite decomposing into AO + AB2O5 phases at high pressure. The compression behavior of volume, axes, and the tilting angle of TiO6 octahedron of MnTiO3 perovskite are consistent with those of other A2+B4+O3 perovskites, although no such decomposition was observed in other perovskites. FeTiO3 is also known to decompose into two phases, instead of transforming into the CaIrO3-type post-perovskite phase and we argue that one of the reasons for the peculiar behavior of titanate is the weak covalency
of the Ti–O chemical bonds. 相似文献
18.
E. Molyanyan S. Aghamiri M. R. Talaie N. Iraji 《International Journal of Environmental Science and Technology》2016,13(8):2001-2010
In this work 3-[2-(2-aminoethylamino)ethylamino]propyl trimethoxysilane (TRI) was employed to functionalize MWCNT containing hydroxyl groups (OH-MWCNT), and the XRD, FTIR, TGA and CHNS elemental analysis techniques were used to characterize the resulted adsorbents. The characterization results for amine-MWCNT showed amine groups effectively attached to the surface of the MWCNT. The equilibrium adsorption capacity of pure CO2 and CH4 and their binary mixture on the pristine MWCNT, OH-MWCNT and amine-MWCNT was measured through a set of equilibrium adsorption experiments at 303.2 and 318.2 K. Capacities of all three types of adsorbents for CO2 adsorption were higher than those for methane adsorption. Also, amine-MWCNT demonstrated better performance on CO2 adsorption than the other two adsorbents, especially at low partial pressures. The capacity of amine-MWCNT for pure CO2 adsorption was 2.5 and 4 times as much as those for pristine MWCNT and OH-MWCNT, respectively, at the temperature of 303.2 K and the pressure of 0.2 bar. The binary adsorption experiment revealed that CO2/CH4 selectivity for pristine MWCNT and amine-MWCNT in all molar fractions of CO2 is about 1.77 and 7, respectively. 相似文献
19.
Adsorption of H2O, NH3 and C6H6 on H- and alkali metal-exchanged structures of mordenite and on corresponding cations on the smectite layer is investigated
by ab initio density-functional calculations. Proton or an alkali metal cation compensates one Al/Si framework substitution
and resides in the extra-framework position of zeolite or above flat smectite layer close to the Al/Si substitution. Pronounced
similarities between zeolite and smectite are observed in changes of the adsorption energies and location of the external
cation with changing character of the external cation. Calculated adsorption energies exhibit the following trend: E(NH3) > E(H2O) > E(C6H6). Because of looser contact with the framework, zeolitic cations are stronger adsorption centers and calculated adsorption
energies of zeolites are by ~20–30% larger than cations of smectites. The highest adsorption energy is calculated for H-exchanged
structures and down the group of alkali metal cations a decrease of the adsorption energy is observed. Deviations from the
smooth variation of the adsorption energy are caused by: (1) formation of strong hydrogen bonds in H-exchanged structures,
(2) adsorption induced migration of the external Li+ cation, and (3) steric hindrances of the flat C6H6 molecule adsorbed on the cation in the cage of zeolite. 相似文献
20.
The effect of CaO, Na2O, and K2O on ferric/ferrous ratio in model multicomponent silicate melts was investigated in the temperature range 1450–1550?°C at 1-atm total pressure in air. It is demonstrated that the addition of these network modifier cations results in an increase of Fe3+/Fe2+ ratio. The influence of network modifier cations on the ferric/ferrous ratio increases in the order Ca?<?Na?<?K. Some old controversial conceptions concerning the effect of potassium on Fe3+/Fe2+ ratio in simple model liquids are critically evaluated. An empirical equation is proposed to predict the ferric/ferrous ratio in SiO2–TiO2–Al2O3–FeO–Fe2O3–MgO–CaO–Na2O–K2O–P2O5 melts at air conditions. 相似文献