共查询到20条相似文献，搜索用时 343 毫秒
1.
The conditional stability constant of HSO4? has been determined at 25°C, 1 atm and a formal ionic strength of 0.7 M in solutions containing sodium, magnesium, chloride and sulphate. This was done spectrophotometrically (UV), using diphenylamine as indicator. The value obtained was 17.0 ± 0.1 (molar scale). Single ion activity coefficients for Na2SO4, K2SO4 and MgSO4 have been calculated according to the Bates et al. (1970) model, assuming that the sulphate ion is not hydrated. It was found that the single ion activity coefficient of sulphate changes very little between Na2SO4, K2SO4 and MgSO4 when the formal ionic strength is kept constant.These results have been used to obtain relations between the stability constants of NaSO4? and MgSO4 valid for seawater. 相似文献
2.
The stability constants of the ion pairs NaSO4?, KSO4?, MgSO4?, CaSO4, MgCl+ and CaCl+ were determined at 25°C and 0.7 M formal ionic strength, by measuring the solubility of gypsum (CaSO4 · 2H2O) in different media. The media used contained one or two of the following electrolytes: NaCl, KCl, MgCl2, NaClO4, Mg(ClO4)2, Na2SO4. Values for the stability constants are 1.22, 1.84, 12.3, 30.6, 0.48 and 1.20 M?1, respectively, and the solubility product for gypsum is 2.87 · 10?4M2. The distribution of the main constituents of seawater was calculated using these results and the values of the carbonate and bicarbonate constants given by Dyrssen and Hansson (1972–1973). The solubility of gypsum in seawater as calculated and determined experimentally was 21.43 mM and 21.10 mM, respectively. 相似文献
3.
This paper discusses the geochemical characteristics of the interstitial water of the Bohai Gulf, where the main salt contents (K+, Na+, Ca++ Mg+ + , C1-, HCO3-, SO4-) in 55 sedimentary layers of 13 cores (3-4 m in length) and those of bottom seawater have been determined and the exchange capacity and exchange cations (K+, Na+, Ca++, Mg++) of the layers analysed (see Fig. 1)Fig. J. The stations of core samplings in the Bohai Gult. 相似文献
4.
Self-diffusion coefficients of five major ions have been determined by a radioactive tracer method (capillary tube method) in seawater of salinity 34.86 at 25°C. Data are presented for Na+, Ca2+, Cl−, SO42, and HCO3−, which constitute about 95% by weight of sea salt. The influence of temperature and salinity on these coefficients has been studied for Na+ and Cl− which are the major components of sea salt: self-diffusion coefficients of these two ions have been measured in seawater, at different temperatures for a salinity of 34.86 and at different salinities for a temperature of 25°C. Diffusion coefficients of the same ions have been determined at 25°C by using another radioactive tracer method (quasi-steady cell method). In this experiment, seawater ions were allowed to diffuse from natural seawater into dilute seawater. Data have been obtained at 25°C for Na+, Ca 2+, Cl−, SO42− and HCO3−, corresponding to different salinity gradients. 相似文献
5.
D. J. Forsyth 《新西兰海洋与淡水研究杂志》2013,47(3):525-539
Abstract The water chemistry, flora, and fauna of Lake Rotokawa (38° 37.8’ S, 176° 11.2'E) was studied in 1975–76. The mean pH is 2.1 and thermal inflows may elevate the mean summer temperature of the surface waters 4.2°c above that of nearby cold water Lake Rotongaio (18.9°c). The temperature range of surface water was from 10.1 °c in winter to 23.1°c in summer. The major anions were SO4 2? 679 g.m?3, and Cl‐ 314 g.m?3. Mean concentrations of major cations were Na+ 224 g.m?3, K+ 28.9 g.m?3, Ca2+ 13.3 g.m?3, and Mg2+ 2.6 g.m?3. Two species of flagellate algae were recorded, of which Euglena anabaena was predominant. Only two benthic macroinvertebrates were found, larvae of Chironomus zealandicus, mean density 253 per square metre, and Helobdella sp., 1.3 per square metre. The Parariki Stream was influenced by thermal springs in its upper and lower reaches, being cooler (24–25°c) about halfway along its length than near its source (27.8–39.0°c) or confluence (26.5°‐28.0°c) with the Waikato River. In the cooler stretch of the stream where unidentified benthic algae were not limited by high temperature, chlorophyll and total pigment increased from 3.9 to 377.9 mg.m?3 and from 17.5 to 534.4 mg.m?3 respectively, and nutrient levels fell (NO3‐N, 22–10.5 mg.m?3; NH4‐N, 6440–230 mg.m?3; and PO4‐P, 51–19 mg.m?3). 相似文献
6.
C.M.G Van Den Berg 《Marine Chemistry》1982,11(4):323-342
The MnO2 adsorption method combined with voltammetry is proposed for the direct determination of metal complexation in seawater of various salinities as a more satisfactory alternative to direct voltammetric measurements and bioassay methods. A small quantity of MnO2 is equilibrated with copper ions in filtered seawater. Natural organic ligands in the seawater compete for copper with the MnO2. Total dissolved copper is measured by differential pulse anodic stripping voltammetry after filtration and acidification of the sample. Preconcentration of natural water samples is unnecessary and measurement is performed at the natural equilibrium pH of the aerated sample. The analytical limit of detection of the method depends on contamination from the filtration step, and for copper complexation a ligand concentration of 5 × 10?8 M was obtained. The sensitivity can be increased by use of radioisotopes as tracers. The method is very versatile in that complexation of various metals may be determined by any analytical method that measures total dissolved metal concentrations. Neither organic ligands nor their complexes with copper adsorb on the MnO2 at pH8, but at pH 1.8 MnO2 is an efficient scavenger for electroactive organic material.Samples of surface water from the Irish Sea and the Atlantic Ocean were found to contain ligand concentrations of 1.7 × 10?7 and 1.1 × 10?7 M, with conditional stability constants (log values) of 9.84 ± 0.13 and 9.86 ± 0.23, respectively, at pH 8.0. 相似文献
7.
The distribution of Al, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb in seawater was investigated in the Chukchi and Beaufort Seas of the western Arctic Ocean in September 2000. The unfiltered and filtered seawater samples were used for determination of total dissolvable metal (TDM) and dissolved metal (DM), respectively. The concentration of labile particulate metal (LPM) was estimated with the difference between that of TDM and DM. The concentrations of TDAl, TDMn, TDFe, TDCo and TDPb varied substantially in the study area. The high concentrations occurred at stations near the Bering Strait, in the Mackenzie delta, and above reductive sediments on the shelf and slope. These elements were mostly dominated by labile particulate species, such as Fe?CMn oxides and species adsorbed on terrestrial clay. DCo was correlated with DMn over the study area (r?=?0.78, n?=?135), and the slope of the regression line was 27 times higher at a pelagic station than at a shelf station. TDNi, TDCu, TDZn and TDCd showed relatively small variations and were generally dominated by dissolved species. There was a moderate correlation between DCd and phosphate for all samples (r?=?0.79), whereas there were no significant correlation between the other DMs and nutrients. TDNi and TDCu showed a remarkable linearity for most stations except those near the Bering Strait (R 2?=?0.95, n?=?126). These results suggest that biogeochemical cycling including uptake by phytoplankton and remineralization from settling particles has only minor control over the distribution of trace metals in this area. Using the present data, the annual input of bioactive trace metals form the Bering Strait and the Mackenzie River was estimated. Also, the trace metal compositions of major water masses were evaluated. The dissolved elemental ratio was P:Al:Mn:Fe:Co:Ni:Cu:Zn:Cd?=?1:1.2?×?10?2:4.4?×?10?4:1.4?×?10?3:3.7?×?10?5:3.7?×?10?3:1.4?×?10?3:4.5?×?10?3:2.2?×?10?4 for Canada Basin deep water (CBDW). This ratio was significantly different from that for Pacific deep water and Bering Sea water, suggesting substantial modification of the trace metal compositions of seawater in the study area. 相似文献
8.
Monosaccharides were determined in waters and sediment pore waters from a wide variety of environments and locations. Desalting was performed by electrodialysis and concentrated extracts were analyzed by two forms of liquid chromatography. At least 12 sugars were identified. Glucose and fructose were the dominant monosaccharides in nearly all samples examined. Analyses of over 150 seawater and sediment pore water samples showed that fructose is highly significantly correlated (>0.99) with glucose concentrations. Laboratory kinetic experiments on the epimerization reaction, glucose ? fructose, in sterilized natural seawater in the dark, yielded a forward rate constant, k1, of 1.2 × 10?5 h?1 at 25°C and 1.6 × 10?7 h?1 at 2°C. The approximate time required to attain equilibrium at 25°C was 1.1 y and at 2°C, 15.4 y; the measured equilibrium constant was in the range 0.3–0.4. The actual ratio of fructose to glucose in natural water samples was usually in the range 1.0–1.4/l, independent of the total monosaccharide concentrations, which varied in the samples by a factor of ～100. Several possible explanations for the apparent discrepancy in the determined and found ratios are discussed: the presence of universal, as yet, undiscovered major biological sources for fructose in marine environments; preferential utilization of glucose; preferential incorporation of fructose into or onto inorganic colloids; and preferential formation of fructose-transition metal ion associations. 相似文献
9.
用磁力浮沉子法溶液密度测量装置,在15—25℃之间的三个温度下测定了黄河口渤海湾36个站位海水样品(于1989年7月和1990年7月采集)的密度,发现所有实验测定值与根据其盐度和温度由1980年国际海水状态方程的计算值比较,均有明显的正偏差,此正偏差随海水盐度降低而增大。在黄河口渤海湾海水样品全部盐度范围内,已发现其海水密度正偏差与海水[Ca~(2+)]/s,[Mg~(2+)]/s,[SO_4~(2-)]/s之间呈指数曲线相关,而与碱度之间呈S形曲线相关,但在盐度25.72—31.57范围内都可近似看作直线相关。黄河口渤海湾海水的高碱度、高[Ca~(2+)]/s为其特征,这也是其密度正偏差的主要影响因素。本文还给出了计算黄河口及渤海湾海水密度的公式。 相似文献
10.
Shinichiro Noriki 《Journal of Oceanography》1983,39(6):324-326
An improved Strickland and Parsons' method, in which silicate correction is made, is described for the colorimetric determination of phosphate in seawater. Silicate correction is made by subtracting the value of 0.025 (C/100)2, whereC is silicate concentration (µg atoms 1?1), from the observed phosphate concentration. The relative standard deviations are 2 % at the 1 µg atom PO 4 3? ?Pl?1 level and less than 1 % at the 3 µg atoms PO 4 3? ?Pl?1 level in seawater. 相似文献
11.
L. P. Golobokova V. E. Pavlov I. V. Khvostov T. V. Khodjer 《Izvestiya Atmospheric and Oceanic Physics》2011,47(3):329-335
We consider the resemblance between the ion composition of the fraction of soluble aerosols and gaseous admixtures in the atmospheric surface layer at the high-level Mondy station (East Sayan), those in the Listvyanka settlement south of Lake Baikal, in the city of Irkutsk, and at the Primorskaya station near the city of Ussuriysk (Primorskii krai). We use measurement data on the concentrations of the following ions: HCO 3 ? , SO 4 2? , NO 3 ? , Cl?, H+, Na+, K+, Mg2+, Ca2+ in the soluble fraction of aerosols and gases HNO3, HCl, NH3, and SO2 in air samples over a 10-year period conducted in the mode of online monitoring. We found the lognormal form of distributions of concentrations of each of the abovementioned components according to the number of samples. A versatile scheme of the distribution of mean geometric concentrations of atmospheric components was proposed for all four groups. 相似文献
12.
Association constants of orthophosphate ion with Na+, Ca2+, and Mg2+ were measured at μ = 0.68 and 20°C. The results were used to calculate phosphate speciation in seawater. Free HPO42? ion and MgHPO4o are found to be the predominant species. 相似文献
13.
The activity of NaCl in artificial seawater was measured potentiometrically with Na+- and Cl? -sensitive electrodes. The salinity of the solutions, examined at 25°C, ranged from 10–40‰ salinity. The change in the activity from 5–25°C was measured at 35‰ salinity.The molal mean activity coefficient of NaCl in 35‰ seawater at 25°C is 0.667. The relative partial molal enthalpy of NaCl in 35‰ seawater is ?130 ±50 cal mol?1. This value is in good agreement with the value measured in pure 0.72 M NaCl.The results were compared with activity coefficients predicted by a specific interaction model and by an ion association model. Good agreement was found in both cases. 相似文献
14.
A theoretical evaluation of basic thermodynamic relationships reveals that variation of activity coefficients, ion pairing and electrical interactions must be considered when modelling ionic diffusion in seawater. The contributions of ion-pair formation and change in activity coefficient along the diffusion path were studied experimentally by conducting diffusion experiments in which solutions of KCl, NaCl, MgCl2, Li2SO4, K2SO4, Na2SO4 and MgSO4, at an ionic strength of 0.7, were allowed to diffuse into distilled water. The study reveals that the thermodynamic factor, required to correct for changes in the activity coefficient along the diffusion path, is significant for all the salts studied. Agreement between a simple diffusion model, which does not include ion pairing, and observed data was good for completely dissociated salts, but poor for salts which are known to form ion pairs at the concentration levels studied. The diffusion of MgSO4, 0.425 of which is associated at I = 0.7, was successfully modelled by assuming that the diffusion coefficient of the MgSO40 ion pair is different from the diffusion coefficient of the dissociated salt. The diffusion coefficient of this ion pair is estimated to be 1.9 × 10−5 cm2 s−1 at 30°C, as compared to 0.49 × 10−5 cm2 s−1 for the dissociated salt. It is suggested that the high mobility of this ion pair could cause magnesium enrichment in pore water of sulfate depleted sediments. 相似文献
15.
基于海南省东部和南部海岸带地区地下水现场监测数据和室内水化学测定数据,研究了各水化学指标间的相关性,分析了区域海水入侵现状。研究结果表明地下水中Cl~–与Na~+的变异系数较高,与矿化度(TDS)具有强的相关性;以m(Cl~–)(m表示质量浓度)和TDS分别作为评价因子开展了海水入侵现状评价,结果表明研究区域内地下水未受到海水入侵的影响;m(Na~+)/m(Cl~–)、 m(Cl~–)/m(HCO_3~–)、m(Cl~–)/m(SO_4~(2–))、m(Ca~(2+))/m(Na~+)、m(Ca~(2+))/m(Mg~(2+))、钠吸附比(SAR)与m(Cl~–)的相关性分析结果表明m(Na~+)/m(Cl~–)、m(Ca~(2+))/m(Na~+)、m(Ca~(2+))/m(Mg~(2+))以及SAR4个参数可以作为海南省海水入侵判定的评价因子。研究结果对建设海南省"国际旅游岛"战略目标,指导当地合理利用地下水具有参考价值。 相似文献
16.
Stoichiometric association constants, which have been measured for the ion pairs of Cl? and SO4?2 with Na+, K+, Mg2+, and Ca2+, were used to determine the speciation in an artificial sea water containing only these ions. The resulting distribution is quite different to that found in earlier models in which chloride ion association was ignored. The concentrations of chloride ion pairs with the cations are 4 to 5 times larger than the concentrations of the sulphate ion pairs with the same cations. The total activity coefficients of the neutral salts in sea water calculated from the model are in good agreement with the experimentally measured values. The concentration of MgSO40 calculated to be present agrees with the amount determined from ultrasonic absorption data. The calculated solubility of gypsum is also in good agreement with the measured values. 相似文献
17.
Influence of Salinity on pH and Aluminum Concentration on the Interaction of Acidic Red Soil with Seawater 总被引：1，自引：0，他引：1
Contamination of acidic red soil in the coastal areas of Okinawa Islands is a serious environmental problem. This study was conducted to examine the effects of the salinity on pH and aluminum concentration when the acidic red soil interacts with seawater. Acidic red soil from Gushikawa recreation center was fractionated into bulk soil, coarse sand and silt + clay. Different weights of each fraction were equilibrated with seawater solutions. The pH and concentrations of Al3+, Na+, K+, Ca2+ and Mg2+ were then analyzed in the extracts. The results showed a decreasing trend of pH with increasing soil to solution ratio while the extracted Al3+ revealed an increasing trend. The lowest pH values were 3.85, 4.06, 4.41, 4.66 and their corresponding highest Al3+ concentrations were 2.50, 1.01, 0.062 and 0.036 mmolL−1 in the seawater extracts, one-tenth seawater extracts, one-hundredth seawater extracts and one-thousandth seawater solution extracts, respectively. Mostly, the concentrations of Na+, Ca2+, Mg2+ and especially K+ decreased with increasing soil weight in the high salinities but showed the opposite trend in the low salinity samples. Potassium concentration decreased by 39%, 53% and 40% in the seawater extracts, one-tenth and one-hundredth seawater extracts but increased by 200% in one-thousandth seawater extracts. The coincidence of the increase in Al3+ and H+ concentrations, and the decrease of Na+, K+, Ca2+ and Mg2+ concentrations in the solutions suggests ion exchange/adsorption, while the increased patterns, particularly at low salinity could be attributed to the dissolution of the species from the soils. 相似文献
18.
黄河三角洲浅层地下水化学特征与演化 总被引：1，自引：0，他引：1
2009年4月~2010年3月连续2年对黄河三角洲19口地下水监测井进行观测并对地下水离子化学成分分析,探讨了该区域浅层地下水化学成分、水化学类型及演化规律,为揭示区域地下水环境特征和演化具有现实意义。结果表明,黄河三角洲地区地下水p H值变化较小,地下水埋深较浅且年内变化幅度为1.0~3.0 m,但矿化度和各离子差异明显,地下水以Na+、Cl–占绝对优势;矿化度较低的测井的离子浓度变幅较小,反之,矿化度高的测井离子浓度变幅较大;地下水化学类型分为氯化物型、重碳酸盐氯化物型、重碳酸盐氯化物硫酸盐型和硫酸盐重碳酸盐型四大类型,主要包括Na+-Cl–、Na+-Cl–.3HCO?、Na+-Cl–.3HCO?、Na+-Cl–.3HCO?.24SO?、Na+-3HCO?.Cl–.24SO?和Na+-24SO?.3HCO?六种子类型,氯化物型主要分布于广饶县咸水入侵区和滨海区域,重碳酸盐氯化物型主要分布于黄河三角洲保护区内,重碳酸盐氯化物硫酸盐型分布在广饶县咸水入侵区,硫酸盐重碳酸盐型主要分布在靠近黄河流路附近;根据黄河三角洲流路变迁和Gibbs模型,黄河三角洲地区水样化学组成均落在Gibbs提出的Boomerang Envelope模型右上翼,表明研究区水样化学组成主要受蒸发和沉淀作用,海水控制起次要作用,土地利用变化、灌溉、施肥等人为活动的影响亦不能忽视。 相似文献
19.
M. f. Fitzsimons P. R. Dando J. A. Hughes F. Thiermann I. Akoumianaki S. M. Pratt 《Marine Chemistry》1997,57(3-4)
A shallow hydrothermal brine seep located off the Greek island of Milos in the Aegean Sea was studied. The brine fluid outcropped as a pool of water in a seabed depression and was detected in the surrounding pore-waters of sediments colonised by the sulphur bacterium Achromatium volutans. The seep fluid was highly saline and sulphidic, depleted in Mg2+ and SO42−, but enriched over seawater in Na+, Ca2+, K+, Cl−, SiO2, reduced species and dissolved gases. The high concentrations of Na+, Ca2+ and K+ were consistent with the Milos tectonic setting. Na-K and Na-K-Ca geothermometers predicted a reservoir temperature of 300–325 °C for the most concentrated seep samples. The deep geothermal reservoir within the metamorphic basement of Milos island has already been located and studied and may represent the source of the seep fluid. Faunal diversity was lowest in seep-influenced sediments, but a sulphide-intolerant species was found in areas of the bacterial mat where salinity and temperature were much lower. Pressure-induced variations in the vertical depth of the brine interface may be occurring in the sediment. 相似文献
20.
Two-year-old New Zealand geoducks (Panopea zelandica) were conditioned within combinations of three water temperatures (7–8, 11–12 and 16–17 °C) and three feeding rations (10,000, 50,000 and 100,000 cells mL?1 of Chaetoceros mulleri and Isochrysis galbana) for 73 days. Similar percent matured and dry condition index values were observed among temperatures. However, significantly higher dry gonadosomatic indices (GSIdw) were recorded at 8 and 12 °C. Although no difference was detected in percentage of spawned individuals and connective tissue occupation indices, a higher percent matured were recorded when fed 10,000 and 50,000 cells mL?1. A reference group conditioned in pond water became matured 2 months later than the other nine experimental groups, but GSIdw were similar. To maximise reproductive output, we suggest that 2-year-old P. zelandica may be conditioned in pond water for a month and then in 8 or 12 °C seawater with 50,000 cells mL?1. 相似文献