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121.
炉渣处理含磷废水的实验研究   总被引:9,自引:0,他引:9       下载免费PDF全文
以炉渣作为吸附剂,用静态吸附实验方法研究了炉渣对模拟含磷废水脱磷的一般规律,结果表明,炉渣是一种有效的吸附剂,对废水中的磷有较强的吸附去除性能。影响炉渣除磷的主要因素有吸附时间、炉渣用量、pH值和原水含磷浓度。在含磷浓度2~13mg/L、炉渣用量5g/L、中性、吸附时间为2h的实验条件下,磷的去除率可高达99%以上。  相似文献   
122.
Sewage sludge ash (SSA), the waste generated in sewage sludge incineration, was obtained from Wuhan Sewage Treatment Plant and used as a low-cost sorbent for removing Cu (Ⅱ) from wastewaters. The sorbent was first modified with 5 % sulfuric acid to increase its sorption capacity. The specific surface area, porosity, cation-exchange capacity (CEC) and pHzzc of the sorbent were measured. Batch experiments were made to study the effect of contact time, solution pH value and temperature on sorption. Both Langmuir and Freundlich models well described the Cu (Ⅱ) sorption process,with correlation coefficient (R2 ) values of 0. 993 4 and 0.9899 respectively. And the sorption process follows the Lagergren first order kinetic model. The equilibrium sorption capacity of acidified SSA to Cu(Ⅱ) is estimated to be 7.78 mg/g under optimal conditions.  相似文献   
123.
铬在土壤及地下水中迁移转化研究综述   总被引:10,自引:0,他引:10  
评述了铬在土壤及地下水中迁移转化的主要方式,着重讨论了吸附作用、氧化还原作用和生物作用对铬迁移转化的影响.并对目前研究中存在的问题进行了总结,对今后的发展方向进行了展望.  相似文献   
124.
125.
Fourier-Transform Infrared (FT-IR) spectroscopy has been used extensively to characterize natural organic matter (NOM). Absorption bands at 1100-1000 cm^-1 in the FT-IR spectra of NOM have been frequently assigned to alcoholic and polysaccharide C-O stretching or to vibrations of SiO2-related impurities. However, these interpretations do not consider that a strong band associated with P-O bonds of phosphate also appears in the same region. We evaluated the correlation between absorbance in this region and P content of 19 NOM samples from terrestrial, aquatic and plant shoot sources. In the spectra of 10 humic and fulvic acid samples, shoulder to minor bands appeared around 1050 cm^-1. Absorbance intensity at 1050 cm^-1 (Y) was linearly related to P content (X) by the following: Y=4.38X+0.3 l, with R2=0.90. We did not observe such a close correlation between absorbance and P content in two aquatic NOM samples. Apparently, this is because the aquatic NOM samples were concentrated by reverse osmosis, which would have concentrated not only humic and fulvic acids but also other soluble organic solutes present in natural waters. In the FT-IR spectra of seven dissolved organic matter (DOM) samples obtained from dried plant shoots, broad and/or multiple bands around 1075 cm^-1 were observed with a shoulder at 977 cm^-1. These characteristics were more like those of organic phosphate compounds (such as inositol hexaphosphate). However, solution 31P nuclear magnetic resonance spectroscopic analysis showed no significant amount of organic phosphate present in these samples.  相似文献   
126.
We investigated in more detail the adsorption phenomenon which was described earlier. It was clearly established that the hydroxyl apatite was not participated in P adsorption. This phenomenon takes place because of ferric hydroxide film. Modem sediments from the Southem Basin of Lake Baikal were taken and stirred with Baikal water. Carrier-free [^32p]-orthophosphate was added in this system. Similar experiments were made with carrier-free [^35S]-sulphate. Sulphate stayed in supematant completely. The influence of pH on the system with inorganic phosphate was also studied. In low alkali conditions phosphate migrated in supematant, in low acid, in sediments. Baikal sediment was stripped of iron-hydroxous film by treatment with 1% oxalic acid. Investigation of striped sediment shown that phosphate stays in supematant only. Hence, hydroxyl apatite cannot be the phase of the sediments of Lake Baikal which binds phosphate. This all showed by our group before. Now we have found the limit of phosphate sorption in Lake Baikal sediments and the stehiometry of the sorption. The sorption limit of Lake Baikal sediments was studied. An experiment with inorganic ^31P phosphate was made. 0.025% K2HPO4 solution with adding ^32P radioactive mark into it was prepared. 100 μL of mixture of ^31PO4^3- and ^32PO4^3- seven times were added in a "Baikal water-Baikal sediment" system and blank (100 ml BW only). Concentrations of inorganic ^31PO4^3- were very low so the bend dot on the diagram was found and sorption limit of sediment was estimated. Baikal sediment stopped assimilating phosphate in the bend dot. The stehiometry of sorption was estimated by supematant-sediment radioactive ratio, which equals 3, that is, three Fe (Ⅲ) atoms associate one PO4^3- anion. The only Fe (Ⅲ) substance which could associate P is -Fe-O-Fe- polymer film. It also dissolves in acid conditions.  相似文献   
127.
Sorption of geosorbents including soils and sediments is a key process controlling the fate and transport of hydrophobic organic compounds (HOCs) in the environment. HOC sorption has been generally correlated to the nature and content of organic matter present in the geosorbents. However, several environments can have organic matter contents low enough so that clay mineral surfaces are the dominant sorbents, including low-organic carbon soils, some ground water aquifers, atmospheric water droplets (e.g. clouds, fogs, and raindrops), and engineered environmental systems (e.g. clay barriers). Furthermore, several previous studies demonstrated that clays or clay components in soils sorb HOCs higher than expected, especially those compounds containing strong polar functionalities. Because many environmentally related HOCs including a significant portion of pesticides and herbicides contain polar functional groups, studying the interactions of these compounds with mineral surface at the molecular level is of great theoretical and practical importance. In the present study, we studied sorption of a series of nonionic pesticides (e.g. dichlobenil, carbaryl, alachlor, metolachlor, monuron, diuron, cyanazine) containing polar functional groups and a polycyclic aromatic hydrocarbon, naphthalene, as a control on a reference smectite (SWy-2) saturated with K^+ using combined batch sorption and FTIR methodologies.  相似文献   
128.
银和金的选择吸附实验研究及意义   总被引:4,自引:1,他引:3  
吸附作用被认为是低温表生矿床的一种重要的成矿机制。文章内多种矿物对银和金的吸附实验表明,呈纳米粒级的银和金的单质对自然界矿物的吸附有明显的选择性,尤其是银对方铅矿和金对黄铁矿的强选择吸附,与自然界的实际情况符合得很好。这一实验结果为解释许多矿床中方铅矿常作为银的载体矿物及黄铁矿常作为金的载体矿物提供了科学依据。实验还证明了粘土、有机质和黑色页岩对银和金的吸附作用。  相似文献   
129.
Heavy Metal Removal from Water by Adsorption Using Pillared Montmorillonite   总被引:1,自引:0,他引:1  
Removal of Cu^2+, Cr^3+ and Cd^2+ from aqueous solutions by adsorption on montmorillonite modified by sodium dodecylsulfate (SDS) and hydroxy-alumino-silicate (HAS) was investigated. Experiments were carried out as a function of solution pH, solute concentration, and time. The Langmuir model was adopted to describe the single-solute adsorption isotherm, in which the Langmuir parameters were directly taken from those obtained in single-solute systems. The kinetics of metal ions adsorption was examined and the pseudo-first-order rate constant was finally evaluated.  相似文献   
130.
The adsorption kinetics of methylene blue from aqueous solutions on purified palygorskite was investigated. The kinetics data related to the adsorption of methylene blue from aqueous solutions are in good agreement with the pseudo-second order equation in ranges of initial concentration of 120-210 mg/L, oscillation speed of 100-200 r/min and temperature of 298-328K. The experimental results show that methylene blue is only adsorbed onto the external surface of purified palygorskite, and the apparent adsorption activation energy is 13.92 kJ/mol. The relatively low apparent adsorption activation energy suggests that the adsorption of methylene blue involves in not only a chemical, but also a physical adsorption process, and it is controlled by the combination of chemical adsorption and liquid-film diffusion.  相似文献   
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