Column Studies

This paper will be limited to a discussion of our packed column studies in which we have addressed attention to questions regarding, (a) the role of ionic strength and surfactant effects on both HDC and porous packed column behavior, (b) the effects of pore size and pore size distribution on resolution, and (c) the effects of the light scattering characteristics of polystyrene on signal resolution and particle size distribution determination. 

Bunluesin, S., Kruatrachue, M., Pokethitiyook, P., Upatham, S., and Lanza, G.R., Batch and continuous packed column studies of cadmium biosorption by Hydrilla verticillata Biomass, Journal of Bioscience and Bioengineering, 103 (6), 509-513, 2007. 

Wagai R, Sollins P (2002) Biodegradation and regeneration of water-soluble carbon in a forest soil leaching column study. Biol Fertil Soils 35 18-26 Wardle DA, Ghani A (1995) A critique of the microbial metabolic quotient (qC02) as a bioindicator of disturbance and ecosystem development. Soil Biol Biochem 27 1601-1610... 

Biodegradation unacclimated aerobic aqueous biodegradation t,/2 = 48-192 h, based on a soil column study in which aerobic groundwater was continuously percolated through quartz sand (Kappeler Wuhrmann 1978 Howard et al. 1991) t,/2(aq. anaerobic) = 192-768 h, based on unacclimated aqueous aerobic biodegradation half-life (Howard et al. 1991). 

Kuhn, E.P, Coldberg, P.J., Schnoor, J.L., Waner, O., Zehnder, A.J.B. Schwarzenbach, R.P (1985) Microbial transformation of substituted benzenes during infiltration of river water to ground water laboratory column studies. Environ. Sci. Technol. 19, 961-968. 

Two types of bench-scale studies are common a flask (respirometer) study and a column study. For flask studies, samples of the aquifer matrix and contaminated... 

Column studies employ the same general techniques as flask studies, except glass tubes are packed with aquifer matrix, and groundwater, with or without amendments, is percolated through the column. Sterile and nutrient-amended columns are used as controls. Leachate is tested to determine the rate and type of chemical change that occurs in the column. While column studies do not accurately reflect the actual subsurface environment, they do provide an indication of the likely effects of sorption and precipitation within the aquifer. 

VI. Column Studies of the Relative Efficiencies of Various Complexing Agents for the Separation of Lighter Rare-Earths. J. Amer. chem. Soc. 75, 5647 (1953). 

Soil Based on data obtained from a 97-d soil column study, the estimated half-life of bis(2-chloroethyl) ether in soil is approximately 16.7 d (Kincannon and Lin, 1985). 

In a continuous-flow mixed-film methanogenic column study, tetrachloroethylene degraded to trichloroethylene with traces of vinyl chloride, dichloroethylene isomers, and carbon dioxide (Vogel and McCarty, 1985). In a static-culture-flask screening test, tetrachloroethylene (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. Significant degradation with gradual adaptation was observed after 28 d of incubation. The amount lost due to volatilization after 10 d was 16 to 23% (Tabak et al., 1981). 

Grisak, G.E., Pickens, J.F., and Cherry, J. A. Solute transport through fractured media. 2. Column study of fractured till. Water Resourc. Res., 16(4) 731-739, 1980. 

Since the limit of detection for small molecule ligands, with modern ESI-Tof mass spectrometers, is approximately 0.05 pM, the concentration of the protein-ligand complex prior to the GPC spin column treatment must be about 0.25 pM. For initial protein and ligand concentrations >5 pM, this corresponds to values <20 pM, as indicated in Fig. 2.3. This is a desirable region for the GPC spin column studies, since one wants to be certain to detect ligands from the stronger as well as the weakest ligand binders. 

Preliminary results of reactive ion exchange batch and column work will also be reported here. Column studies necessarily take more time to do and must rely on the wide range of data which can be obtained in solution. Values of k jg obtained in solution are necessary for correlation with and prediction of column conditions. The final objective of this research, the development and testing of a detoxification/fliter unit, will be pursued in the near future as soon as column conditions are sufficiently correlated with solution and batch RIEX results so as to permit optimization. 

Hodson, M. E., Valsami-Jones, E., Cotter-Howells, J. D., Dubbin, W. E., Kemp, A. J., Thornton, I. Warren, A. 2001. Effect of bone meal (calcium phosphate) amendments on metal release from contaminated soils - a leaching column study. Environmental Pollution, 112, 233-243. 

Laboratory batch and column studies to evaluate Apatite II removal of soluble uranium from contaminated groundwater. American Chemical Society National Meeting, American Chemical Society, Division of Environmental Chemistry, 41, 109-113. 

If the retention index for pyridine on squalane is 695, what is the McReynolds constant of this compound on the column studied, if it is known that under the conditions of the experiment, the retention time is 346 s ... 

Basic Procedures. The synthetic hard water used in all of the parfait column studies consisted of 0.070 g of NaHCC>3, 0.156 g of CaS04 2H20, and 0.047 g of CaCl2 per liter. This solution was prepared in 8-L batches just before use. The final pH was 7.2. 

For parfait column studies, standard solutions (400 /ug/mL) of each organic solute except phenanthrene were prepared in a suitable solvent (acetone, water, or methanol), and 1.00 mL of the standard was added to 8 L of the synthetic hard water with rapid stirring. This yielded a final organic solute concentration of 50 ng/L and a solvent concentration of less than 126 mg/L. In the runs simultaneously involving 16 compound four different mixtures of solutes were prepared so that the final solvent concentration was 500 mg/L. Phenanthrene was spiked to a final concentration of 1.0 /zg/L, rather than 50 /zg/L. Solutions were not degassed before application to a parfait column. No adjustments of pH were necessary after adding solutes to the synthetic hard water. 

Conditions favoring efficient separation of flocculent metal precipitates in a basin include a low surface overflow rate, adequate depth, and inlet and outlet designs for a uniform velocity field with minimal short circuiting or stagnation. Solids separation is likely to limit the overall efficiency of metals removal in treatment, so pilot studies include batch and continuous flow settling column studies.18... 

The studies carried out consist of the megascopic description of the master columns study of thin sections for maceral assessment, determination of maceral composition on polished blocks in reflected light, determination of mean maximum reflectance values on polished pellets, proximate analyses of selected petrographic zones, hot stage studies on vitrinoids to determine the thermal behavior at various temperatures, electron microprobe and spectrochemical studies of selected zones to determine the nature of ash forming elements, analyses of certain zones petrographically important to determine the variation of total carbon, and hydrogen and microhardness determinations on certain macerals. 

The authors have evaluated different C18 and C8 columns, studying the variation in capacity factors with the proportion of water in the mobile phase for all six acid derivatives. The detector was a fluorescence detector equipped with a 360-nm excitation and a 420-nm emission filter. They were unable to resolve derivatives of the six acids on three different C18, 5-/zm columns, despite using a wide range of solvent compositions. Table 3 shows capacity factor values for three critical acid derivatives on a number of columns. When a C8,5-/un column was used with an isocratic solvent system [acetonitrile/water (98 2)], they observed a marked improvement in the resolution of the six derivatives. However, it was not possible to achieve complete resolution of the six compounds under isocratic conditions, despite numerous experiments with a range of organic solvent mixtures consisting of acetonitrile, methanol, tetrahydrofuran, and water. 

Because nitrobenzene degradation is faster in batch experimental systems than in column studies, a mass-transfer limitation exists therefore, when determining the effectiveness of in situ groundwater treatment systems, hydraulics, mass transfer, and reaction kinetics should be taken into consideration (Burris et al., 1996). 

Column studies with the nanoparticle base polymer used solutions containing either lOOpg L 1 of As(III) or As(V) (Cumbal and Sengupta, 2005). Even after more than 10000 bed volumes of water had passed through the system, arsenic concentrations in the treated water still remained below 10 pg L 1. The nanoparticle system releases less than 5 pgL-1 of iron into treated water and can be regenerated with an aqueous mixture of 2 % NaOH and 3 % NaCl (Cumbal and Sengupta, 2005). 

KOber, R., Daus, B., Ebert, M. et al. (2005a) Compost-based permeable reactive barriers for the source treatment of arsenic contaminations in aquifers column studies and solid-phase investigations. Environmental Science and Technology, 39(19), 7650-55. 

Kundu, S., Kavalakatt, S.S., Pal, A. et al. (2004) Removal of arsenic using hardened paste of Portland cement batch adsorption and column study. Water Research, 38(17), 3780-90. 

Column studies more closely mimic the real soil environment and more readily allow the determination of kinetic information than batch methods. However, equipment costs are... 

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