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Scale prevention in sea water evaporators. Part III. Decarbonation, filtration, and acidificationCullen, John Darby January 1950 (has links)
The problem of supplying fresh water to meet the requirements for normal operation of ocean-going vessels has been of major importance for centuries in maritime circles. An early solution of this problem was the storing of fresh water on the vessel while in port for use white at sea. This solution was not satisfactory because it meant added tonnage and lost storage space. The present approach in the production of fresh water from salt water by distillation.
The distillation of sea water to produce fresh enter has been widely used in maritime circles throughout the world, but in spite of its wide adoption there are still matters existing that have not been settled. The most troublesome of these is the formation of scale on the heating surfaces of the distillation equipment. These scale deposits are caused by the precipitation of the solid matter in the sea water during the distillation process. As a result of the scale, the efficiency of the equipment is reduced and the production of fresh water is thereby diminished.
Much attention has been given to the elimination of scale deposits in sea water distilling apparatus. Chemical pretreatments, which had been successful in preventing scale in evaporators using ground waters, were tried on sea water equipment but no completely satisfactory processing has been found. Mechanical and chemical methods of scale removal are now being used, but these methods offer no solution to the scale formation problem.
A possible solution has been offered by the Armour Research Foundation of Chicago, Illinois. Basing their theory on the fact that the scale deposits formed are composed primarily of carbonates, the Armour Research Foundation has worked out, on a small laboratory scale, a heart-aeration process that eliminates the carbonates from the sea water before it enters the distilling plant. The process is divided into three separate steps. The first step, the removal of carbonates, is accomplished by heating the seat water to a temperature above 200 °F, holding the water at this condition for a period of time, and then aerating the water with compressed air. This step removes part of the carbonates present, but in the process magnesium hydroxide is precipitated. The second step, the removal of the precipitated magnesium hydroxide, is accomplished by filtering the decarbonated sea water. The third step, the neutralization of the high alkalinity resulting from decarbonation, is accomplished by injecting sulfuric acid into the sea water before it is fed to the evaporator. The sea water fed to the evaporator after this treatment is neutral and partially free of carbonates. The use of this treated sea water should greatly reduce the formation of scale in the evaporator.
A treatment and distillation plant has been erected at the Distillation Test Station, Fort Story, Virginia. Evaluation of the Armour Research Foundation process for the prevention of scale was made with the use of this equipment.
The specific purpose of this investigation is to evaluate the complete decarbonation-filtration-acidification process for scale prevention on sea water distillation equipment. / Master of Science
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The voltammetric determination of copper and lead in seawater : applications to Indian Arm and Burrard InletErickson, Paul Eric January 1973 (has links)
An anodic stripping voltammetric technique was developed
for the simultaneous determination of Cu and Pb in seawater. Mercuric ion added to the sample is plated out with the metals of interest onto a highly polished glassy carbon electrode. The thin mercury films obtained by this procedure gave excellent resolution and sensitivity although a non-linear response resulted in the case of Cu, presumably as a result of saturation of the mercury, at concentrations in excess of 4 μg/1.
The technique was applied to a short term study of the distribution of Cu and Pb in Indian Arm and Burrard Inlet. Large fluctuations in the concentrations of both metals were observed during the sampling period, July to October, 1972. Although dissolved Pb concentrations were lower than might be expected near a large urban area, there was, nevertheless, an overall enrichment of the subsurface waters of the inlets relative to Georgia Strait by as much as an order of magnitude. Dissolved Cu concentrations were not, however, significantly higher than those reported for other B.C. coastal waters.
Although study of metal speciation by the method employed here was limited by the excess of mercuric ions added to the samples and interferences from surface
active agents, evidence was obtained indicating that a portion of Cu in some British Columbia coastal seawater samples is complexed with dissolved organic matter. The experimental conditions indicate that these complexes are either inert to displacement by mercuric ions or have a high degree of specificity for Cu. / Science, Faculty of / Chemistry, Department of / Graduate
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Barium uptake by diatoms and the 226Ra-Ba-Si system in the oceans.Ng, Amy Chihang January 1976 (has links)
Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Includes bibliographical references. / M.S.
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The role of sulphate-reducing bacteria in mercury-contaminated estuarine sediments : a case study of Durban BaySimpson, Elizabeth Anne January 2003 (has links)
Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Durban Insititute of Technology, 2003. / Stimulated by the findings of international researchers, that the sulfate-reducing microorganism Desulfovibrio desulfuricans could be incriminated in the process of mercury bio-methylation, it was decided to test this hypothesis on sediments from selected areas of Durban Bay where elevated levels of the bio-hazardous heavy metal had previously been detected. The Environmentek Division of the Council for Scientific and Industrial Research (Durban) is involved in an ongoing chemical assessment of heavy metal contamination (including levels of mercury) in the sediments of this estuary, but nothing is currently understood about the form in which mercury exists or the biological processes that could be determining its fate. The purpose of this project was to attempt to answer some of these questions. The study involved attempting to isolate, identify and quantify microorganisms of the species Desulfovibrio desulfuricans, Escherichia coli and Clostridium perfringens in one hundred and eighty sediment samples taken from three designated sites in the bay. Each sample was additionally analysed for total and methyl mercury and sulfate content, as well as a number of physical parameters. Based on the outcome of the initial survey, it was envisaged that further laboratory experimentation would be conducted to determine whether or not isolates were responsible for the production of the highly toxic organic mercury and whether this process was occurring in situ in the sediments. The findings of this project were contrary to what had been expected. Total mercury concentrations (apart from one instance) did not appear to be appreciably elevated in the areas under study. Similarly, the levels of methyl mercury were fourrd to be either diminished or absent. Numbers of D. desulfuricans were low and not uniformly distributed throughout the sediments. Cl. perfringens was more in evidence, but counts were not perceptibly increased. Sulfate levels were consistently high, indicating significantly impaired rates of sulfate reduction. Difficulty experienced in sub-culturing / M
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The determination of molybdenum in seawater by ICP-AES after preconcentration by diethylenetriaminetetraacetic acid-functionalized polysiloxane.January 2002 (has links)
Chan Sze-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-73). / Abstracts in English and Chinese. / Acknowledgment --- p.i / Table of Contents --- p.ii / Abstract --- p.v / Abstract (Chinese Version) --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Molybdenum in the Environment --- p.1 / Chapter 1.1.1 --- General Chemistry of Molybdenum --- p.1 / Chapter 1.1.2 --- Molybdenum in Animals and Plants --- p.1 / Chapter 1.1.3 --- Uses of Molybdenum Compounds --- p.3 / Chapter 1.2 --- Inductively Coupled Plasma Atomic Emission Spectrometry --- p.4 / Chapter 1.2.1 --- Principle of ICP-AES --- p.4 / Chapter 1.2.2 --- Inductively Coupled Plasma Emission Source --- p.5 / Chapter 1.2.3 --- Optical System --- p.6 / Chapter 1.2.4 --- Advantages of ICP-AES --- p.7 / Chapter 1.2.5 --- Disadvantages of ICP-AES --- p.8 / Chapter 1.3 --- Preconcentration Method --- p.9 / Chapter 1.4 --- Polysiloxane --- p.11 / Chapter 1.4.1 --- Introduction of Silica-gel --- p.11 / Chapter 1.4.2 --- Introduction of Sol-gel Processes --- p.13 / Chapter 1.4.3 --- Hybrid Inorganic-organic Sol-gel Materials --- p.14 / Chapter 1.4.4 --- Advantages Using Sol-gel Preparation of Organomodified Silica --- p.16 / Chapter 1.5 --- Chelating Resin --- p.19 / Chapter 1.6 --- Scope of Work --- p.21 / Chapter Chapter 2 --- Experimental --- p.22 / Chapter 2.1 --- Apparatus and Instrument --- p.22 / Chapter 2.2 --- Chemicals --- p.24 / Chapter 2.3 --- Samples --- p.25 / Chapter 2.4 --- Procedures --- p.26 / Chapter 2.4.1 --- Preparation of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.26 / Chapter 2.4.1.1 --- Preparation of Silica Precursor --- p.26 / Chapter 2.4.1.2 --- Functionalization with Diethylenetriamine --- p.27 / Chapter 2.4.1.3 --- Carboxymethylation of the amine groups of the Polysiloxane --- p.28 / Chapter 2.4.2 --- Preconcentration and Determination of Molybdenum --- p.29 / Chapter 2.4.2.1 --- Optimum pH for Adsorption --- p.29 / Chapter 2.4.2.2 --- Amount of Polysiloxane Required for Sorption of Trace Amount of Molybdenum --- p.29 / Chapter 2.4.2.3 --- Equilibrium Time --- p.30 / Chapter 2.4.2.4 --- Total Adsorption Capacity --- p.30 / Chapter 2.4.2.5 --- Adsorption Isotherm of Molybdenum --- p.30 / Chapter 2.4.2.6 --- Desorption Studies --- p.31 / Chapter 2.4.2.7 --- Effect of Foreign Ions on Preconcentration --- p.31 / Chapter 2.4.2.8 --- Preparation of the Mini-column --- p.32 / Chapter 2.4.2.9 --- Effect of Flow Rate --- p.33 / Chapter 2.4.2.10 --- Reusability of the Mini-column --- p.33 / Chapter 2.4.2.11 --- Preconcentration Factor and Detection Limit --- p.33 / Chapter 2.4.2.12 --- Determination of Mo(VI) in Seawater by ICP-AES --- p.33 / Chapter Chapter 3 --- Results and Discussion --- p.35 / Chapter 3.1 --- Characterization of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.35 / Chapter 3.2 --- pH Dependence of Mo(VI) Ion Uptake --- p.44 / Chapter 3.3 --- Amount of Polysiloxane Required for Adsorption of Trace Amount of Mo(VI) --- p.45 / Chapter 3.4 --- Equilibrium Time --- p.46 / Chapter 3.5 --- Total Adsorption Capacity --- p.47 / Chapter 3.6 --- Adsorption Isotherm of Molybdenum --- p.48 / Chapter 3.7 --- Desorption Studies --- p.54 / Chapter 3.8 --- Effect of Foreign Ions on Preconcentration --- p.55 / Chapter 3.9 --- Effect of Flow Rate on the Recovery of Mo(VI) --- p.57 / Chapter 3.10 --- Reusability of the Column --- p.58 / Chapter 3.11 --- Preconcentration Factor --- p.59 / Chapter 3.12 --- Detection Limit --- p.59 / Chapter 3.13 --- Accuracy --- p.60 / Chapter 3.14 --- Determination of Mo(VI) in Seawater Samples --- p.61 / Chapter 3.15 --- Precision --- p.62 / Chapter Chapter 4 --- Conclusion --- p.63 / Chapter Chapter 5 --- References --- p.65
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Naturally-occurring chemical tracers in seawater and their application to verifying mid-ocean ballast water exchange.Murphy, Kathleen Ruth, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Recent regulation mandates that ships conduct mid ocean ballast water exchange (BWE) prior to discharging foreign ballast in territorial waters of Australia, the U.S. and elsewhere. The enforcement of ballast water exchange legislation is undermined, however, by a lack of sensitive and reliable methods for verifying compliance. One way to assess compliance is to compare the concentrations of chemical tracers in ballast tanks with their known distributions in the open ocean. In this work, dissolved organic matter and trace elements are investigated as potential tracers of mid-ocean ballast water exchange on commercial voyages in the North Pacific and Atlantic Oceans. The optical properties of chromophoric dissolved organic matter (CDOM) are frequently used as tracers of water masses in bays and estuaries. Characterization of the underlying fluorescence spectra in seawater dissolved organic matter was performed using parallel factor analysis, allowing the identification of at least nine independently varying fluorescent components present in varying concentrations in the ocean and in ballast water. Two of the humic components were terrestrial in origin and their signals could be traced in the open ocean (Pacific and Atlantic) at levels of approximately 1.5% of riverine concentrations. One humic terrestrial component was sufficient for predicting the coastal vs. oceanic source of most ballast water samples, suggesting that single and dual channel fluorometers could be optimized for verifying ballast water exchange. Barium, manganese and phosphorus were also investigated as potential tracers. Measurements of Ba and P obtained via engine-cooling pipes on commercial vessels were consistent with previous oceanographic measurements. While Ba behaved conservatively in ballast water, concentrations of phosphorus fluctuated and Mn was removed in ballast tanks over time. Ba and P demonstrated considerable promise as ballast water tracers, exhibiting predictable concentrations in exchanged ballast tanks, given a priori knowledge of the ocean (Atlantic versus Pacific) in which BWE was performed.
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Inorganic polyphosphate in the marine environment: field observations and new analytical techniquesDiaz, Julia M. 31 March 2011 (has links)
Phosphorus (P) is a requirement for biological growth, but this vital nutrient is present at low or limiting concentrations across vast areas of the global surface ocean. Inorganic polyphosphate (poly-P), a linear polymer of at least three orthophosphate units, is one component of the marine P cycle that has been relatively overlooked as compared to other P species, owing in part to a lack of routine analytical techniques that cleanly evaluate it within samples. This thesis demonstrates that inorganic poly-P is a quantitatively significant and dynamic component of the global marine P cycle while also establishing two new techniques for its analysis in biological and environmental samples. In Chapter 2, experiments using the freshwater algae Chlamydomonas sp. and Chlorella sp. illustrate X-ray fluorescence spectromicroscopy as a powerful tool for the sub-micron scale assessment of poly-P composition in organisms. This method enabled the discovery, detailed in Chapter 3, of a mechanism for the long-term sequestration of the vital nutrient P from marine systems via the initial formation of poly-P in surface waters and its eventual transformation into the mineral apatite within sediments. The importance of marine poly-P is furthermore established in Chapter 3 by observations showing that naturally-occurring poly-P represents 7-11% of total P in particles and dissolved matter in Effingham Inlet, a eutrophic fjord located on Vancouver Island, British Columbia. In Chapter 4, a new fluorometric protocol based on the interaction of inorganic poly-P with 4',6-diamidino-2-phenylindole (DAPI) is established as a technique for the direct quantification of poly-P in environmental samples. Chapter 5 presents work from Effingham Inlet utilizing this method that show that inorganic poly-P plays a significant role in the redox-sensitive cycling of P in natural systems.
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Application of the rate of nucleic acid synthesis to the study of microbial growth and production in seawaterWinn, Christopher David January 1984 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Includes bibliographical references. / Microfiche. / x, 216 leaves, bound ill. 29 cm
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Naturally-occurring chemical tracers in seawater and their application to verifying mid-ocean ballast water exchange.Murphy, Kathleen Ruth, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Recent regulation mandates that ships conduct mid ocean ballast water exchange (BWE) prior to discharging foreign ballast in territorial waters of Australia, the U.S. and elsewhere. The enforcement of ballast water exchange legislation is undermined, however, by a lack of sensitive and reliable methods for verifying compliance. One way to assess compliance is to compare the concentrations of chemical tracers in ballast tanks with their known distributions in the open ocean. In this work, dissolved organic matter and trace elements are investigated as potential tracers of mid-ocean ballast water exchange on commercial voyages in the North Pacific and Atlantic Oceans. The optical properties of chromophoric dissolved organic matter (CDOM) are frequently used as tracers of water masses in bays and estuaries. Characterization of the underlying fluorescence spectra in seawater dissolved organic matter was performed using parallel factor analysis, allowing the identification of at least nine independently varying fluorescent components present in varying concentrations in the ocean and in ballast water. Two of the humic components were terrestrial in origin and their signals could be traced in the open ocean (Pacific and Atlantic) at levels of approximately 1.5% of riverine concentrations. One humic terrestrial component was sufficient for predicting the coastal vs. oceanic source of most ballast water samples, suggesting that single and dual channel fluorometers could be optimized for verifying ballast water exchange. Barium, manganese and phosphorus were also investigated as potential tracers. Measurements of Ba and P obtained via engine-cooling pipes on commercial vessels were consistent with previous oceanographic measurements. While Ba behaved conservatively in ballast water, concentrations of phosphorus fluctuated and Mn was removed in ballast tanks over time. Ba and P demonstrated considerable promise as ballast water tracers, exhibiting predictable concentrations in exchanged ballast tanks, given a priori knowledge of the ocean (Atlantic versus Pacific) in which BWE was performed.
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An assessment of selected metal pollutants in Durban HarbourPaul, Vimla January 2001 (has links)
Submitted in partial fulfillment of the requirements for the Degree of Master of Technology in Chemistry, M.L. Sultan Technikon, 2001. / The purpose of this study was to determine the concentration of selected metals in Durban Harbour water and sediments. Four sites were selected for the investigation. The water and sediment samples were collected from July 1998 to July 1999 to accommodate seasonal changes / M
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