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改进了用于水中硫化物测定的酸化-吹取-吸收预处理方法,对样样预处理条件及校准曲线的制作 进行了详细试验。该方法具有吹取完全,吸收安全、操作简单、准确度高的优点,适用于水和废水中微量硫化物的测定。 相似文献
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监测规范规定,使用原子吸收分光光度法进行试样测定时,每次均必须制作校准曲线.进行铅试样分析时,由于测定的频次较高,并且铅标准溶液多为一次性使用,从而导致监测成本的增加.本试验从试样保存方法和保存时间两个方面,通过相关性试验、对比试验和准确度试验,对铅中间标准溶液进行了贮存试验.试验结果表明在低温冷藏和密闭贮存的条件下,配置好的铅中间标准溶液性质比较稳定,可至少有效保存2个月.试验达到了降低试剂消耗和提高工作效率的目的,在实际工作中有一定的推广应用价值,效果令人满意. 相似文献
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应用新的差分吸收光谱烟气浓度反演算法对SO2、NO、NO2混合气体浓度反演进行了试验研究。与常规反演算法相比,该算法充分考虑了被测对象在不同波段上的差分吸收结构差异,避免了多组分同时反演时使用同一频率进行数字滤波引入的误差。结果表明,该算法能对多组分气体浓度进行快速、准确的反演,误差小于5%。 相似文献
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A numerical model BAEROSOL for solving the general dynamic equation (GDE) of aerosols is presented. The goal was to model the capture of volatilized metals by sorbents under incinerator-like conditions. The model is based on algorithms presented by Jacobson and Turco [Aerosol Science and Technology 22 (1995) 73]. A hybrid size bin was used to model growth and formation of particles from the continuum phase and the coagulation of existing particles. Condensation and evaporation growth were calculated in a moving size bin approach, where coagulation and nucleation was modeled in the fixed size bin model of the hybrid grid. To account for the thermodynamic equilibrium in the gas phase, a thermodynamic equilibrium code CET89 was implemented. The particle size distribution (PSD) calculated with the model was then compared to analytical solutions provided for growth, coagulation and both combined. Finally, experimental findings by Rodriguez and Hall [Waste Management 21 (2001) 589-607] were compared to the PSD predicted by the developed model and the applicability of the model under incineration conditions is discussed. 相似文献
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采用气相置换法制备了Zn-Cu-BTC双金属有机骨架化合物,运用XRD,SEM-EDS,BET等技术对材料进行了分析表征,并以二苯并噻吩-正辛烷为模拟油(硫含量450 μg/g),通过吸附脱除二苯并噻吩评价了材料的吸附脱硫性能。表征结果显示,Zn的引入改变了Cu-BTC特有的八面体结构。实验结果表明:在模拟油与吸附剂的质量比100∶1、吸附温度30 ℃的条件下,吸附90 min后Zn-Cu-BTC对硫的吸附达到平衡,吸附量可达38.8 mg/g,脱硫率为94.20%,而Cu-BTC吸附120 min后达到平衡,吸附量仅为26.6 mg/g;Langmuir等温吸附模型可有效描述Zn-Cu-BTC对硫的吸附过程。 相似文献
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A comparative adsorption/biosorption study of mono-chlorinated phenols onto various sorbents 总被引:9,自引:0,他引:9
The potential use of dried activated sludge and fly ash as a substitute for granular activated carbon for removing mono-chlorinated phenols (o-chlorophenol and p-chlorophenol) was examined. The pollutant binding capacity of the adsorbent/biosorbent was shown to be a function of substituted group, initial pH and initial mono-chlorinated phenol concentration. The working sorption pH value was determined as 1.0 and the equilibrium uptake increased with increasing initial mono-chlorinated phenol concentration up to 500 mg dm(-3) for all the mono-chlorinated phenol-sorbent systems. The suitability of the Freundlich, Langmuir and Redlich-Peterson adsorption models to the equilibrium data were investigated for each mono-chlorinated phenol-sorbent system. The results showed that the equilibrium data for all the mono-chlorinated phenol-sorbent systems fitted the Redlich-Peterson model best within the concentration range studied. 相似文献
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将粉煤灰进行碱激发改性,运用XRD和SEM技术对碱激发粉煤灰进行了表征,通过静态平衡吸附实验研究了碱激发粉煤灰对Cs+的吸附动力学和热力学特性,并对吸附前后的碱激发粉煤灰进行了FTIR分析。表征结果显示,碱激发处理后,粉煤灰的晶相发生了改变,且粉煤灰表面密实的硬壳层被破坏。实验结果表明:在初始Cs+质量浓度为200 mg/L、吸附温度为25℃、溶液pH为10、碱激发粉煤灰投加量为12.0 g/L的条件下,碱激发粉煤灰对Cs+的平衡吸附率可达80%以上,其吸附能力比碱激发前提高了3倍以上;吸附过程可用准二阶动力学方程来描述,并较好地符合Langmuir等温吸附模型;碱激发粉煤灰对Cs+的吸附是吸热过程,且能自发进行;该过程以物理吸附为主,并伴随化学吸附。 相似文献
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Modeling of mercury sorption by activated carbon in a confined,a semi-fluidized,and a fluidized bed 总被引:5,自引:0,他引:5
A process model was developed to simulate elemental mercury sorption by activated carbon in three distinct beds, namely a confined, a semi-fluidized, and a fluidized bed. The model involved the coupling of a kinetic model based on the mechanisms of surface equilibrium and external mass transfer, and a material balance model based on the tank-in-series approach. For surface equilibrium, three different equilibrium laws were used in the model, namely the Henry's Law, the Langmuir isotherm and the Freundlich isotherm. Literature mercury sorption data were used to determine the best-fit values of parameters for these equilibrium expressions. The parameter-fitted model was then used to simulate mercury sorption processes in the three distinct beds. The simulation parameters were mercury concentration, gas flow rate, adsorption temperature and the degree of semi-fluidization. The simulation results have indicated that the model is capable of describing the literature available mercury sorption data. All the three surface equilibrium laws appear to simulate the adsorption profiles equally well mainly because the sorption process occurs in an extremely low concentration range. The simulation results for the three distinct beds have suggested that the confined bed has the best mercury control performance; however, it generates the highest pressure-drop across the bed. A fluidized bed creates the least pressure drop; however, its sorption performance is poor. A semi-fluidized bed offers acceptable performance with affordable pressure-drops and can be a practical candidate for the process. 相似文献
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This work investigates the colloid-facilitated migration of radionuclides with radioactive decay in porous media. The sorption processes for radionuclides with both the solid matrix and colloids are treated as equilibrium or nonequilibrium. An analytical solution is obtained from a simplified linear equilibrium interaction mechanism. In addition, the adsorption processes for radionuclides with colloids and porous rock can be assumed as nonequilibrium and modeled by the linear kinetic adsorption. The numerical method is employed to solve the coupled colloid and radionuclide transport equations under nonequilibrium sorption assumption. Moreover, the reaction rates of the adsorption processes for radionuclides with the solid matrix and colloids affect the transport characteristics of radionuclides. The fast reaction rate of radionuclides with colloids causes a higher concentration of radionuclides adsorbed on colloids in a dispersed phase and enlarges acceleration caused by colloids. However, the fast reaction rate for radionuclides with solid matrix increases the retardation effect caused by the solid matrix. This work developed a predictive model for the transport of colloid-facilitated radionuclides in porous medium and to assess the importance of various phenomenological coefficients, particularly parameters for the adsorption interactions. 相似文献
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This paper describes the finite difference algorithm that has been developed for the flow sub-model of the University of Southampton landfill degradation and transport model LDAT. The liquid and gas phase flow components are first decoupled from the solid phase of the full multi-phase, multi-component landfill process constitutive equations and are then rearranged into a format that can be applied as a calculation procedure within the framework of a three dimensional array of finite difference rectangular elements.The algorithm contains a source term which accommodates the non-flow landfill processes of degradation, gas solubility, and leachate chemical equilibrium, sub-models that have been described in White and Beaven (2013).The paper includes an illustration of the application of the flow sub-model in the context of the leachate recirculation tests carried out at the Beddington landfill project. This illustration demonstrates the ability of the sub-model to track movement in the gas phase as well as the liquid phase, and to simulate multi-directional flow patterns that are different in each of the phases. 相似文献
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In this study, a synthetic filter material with nutrients (PVA/peat/KNO3 composite bead) was developed for biofilteration. The optimal preparing condition was each of the peat and PVA aqueous solutions mixed with 6.4 g KNO3, and the minimum nitrogen content in the boric and phosphate aqueous solutions was 3.94 and 1.52 g-N/l, respectively. The equilibrium amount of inorganic nitrogen extracted by leaching from the prepared composite bead was between 7.95 and 8.21 mg N/g dry solid. The path of inorganic nitrogen extracted by leaching was the inorganic nitrogen dispersed in the peat phase firstly diffused into the outer PVA phase and then it diffused out of the bead surface for the A-type bead; and that was the inorganic nitrogen dispersed in both the peat and PVA phases simultaneously diffuses into the outer PVA phase and out of the bead surface, respectively, for the H-type bead. The microbial growth rate k
g of the H-type composite bead was higher than that of the A-type composite bead about 1.09–1.58 times, and the maximum value of k
g was at the H-type composite bead immersed in 0.384 M KNO3 aqueous solution. The percentage of removed VOCs retained at more than 98% during the biofilter operating 230 days as the composite bead immersed in KNO3 aqueous solution before packing. This composite bead bed was without the further addition of nutrients during the operating period. 相似文献
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The 1970s oil spill model described the infiltration of oil (light nonaqueous phase liquid or LNAPL) into the subsurface, resulting in an oil pancake depressing the water table within the capillary fringe. An update to the 1970s model is needed because, according to the discussion by Lenhard et al. on the work of Lenhard and Parker and Farr et al., “A key concept of their efforts was that LNAPL-saturated ‘pancakes’ do not exist.” Lenhard and Parker and Farr et al. showed that the distribution of water, LNAPL, and air in the subsurface was a function of the LNAPL, water, and air pressures; fluid properties; and the pore-size distribution of the porous medium, and that the fluid saturations can be calculated from fluid levels in a monitoring well. The 1970s oil spill infiltration model described that spilled LNAPL migrates downward through the vadose zone under the force of gravity with some lateral spreading. The vadose zone, where all of the liquid pressures are less than atmospheric pressure, becomes a three-fluid zone consisting of variable saturations of air, water, and LNAPL, which together fully saturate the pore spaces. One important update to the 1970s model is that instead of the infiltrating LNAPL stopping at and depressing the water table, LNAPL penetrates the water table to a depth consistent with the gravitational and capillary forces experienced during LNAPL infiltration and creates a two-fluid zone below the water table where LNAPL and water pressures are greater than atmospheric pressure. After the LNAPL release stops, LNAPL infiltration and migration will cease after reaching equilibrium. The updated LNAPL infiltration conceptual model, like the 1970s model, describes the situation where the LNAPL release has stopped and LNAPL infiltration and migration have ceased after reaching equilibrium. The volume of LNAPL released is also assumed to be sufficient to pass through the vadose zone and enter the saturated zone. 相似文献
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Harry Amuguni Chanzu John Mmari Onyari Paul Mwanza Shiundu 《Journal of Polymers and the Environment》2012,20(3):665-672
Batch experiments were conducted to study the biosorption of Malachite Green (MG) onto polylactide (PLA)/spent brewery grains (SBGs) films. Films were prepared by solvent-casting method using dichloromethane. Effects of contact time, pH, salt concentration, and optimal experimental condition was evaluated. At pH 6.89 and low salt concentration, Malachite Green was removed effectively. The isotherm data fitted the Freundlich model with 0.969 R2 value and 0.738 slope implying chemisorptions process. The biosorption process followed pseudo-second order kinetics with calculated adsorption capacity at equilibrium (qe) of 0.572?mg/g at 23?°C. The investigation showed that PLA/SBGs films are effective in dye removal from textile, paper and leather industries effluents. 相似文献