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Isolation of Organic Materials from in Situ Oil Shale Retort Water Using Macroeticular Resins, Ion Exchange Resins, and Activated Carbons

“Isolation of Organic Materials from in Situ Oil Shale Retort Water Using Macroreticular Resins, Ion Exchange Resins, and Activated Carbons” Measurement of Organic Pollutants in Water and Wastewater, ASTM STP 686. Ed. C. E. Van Hall. Philadelphia: American Standard Testing Materials, 1979.l 275-290.

Huffman, E. W. D., Jr.

ABSTRACT: Organic materials in an oil shale retort water produced in situ were fractionated using macroreticular resins, ion exchange resins, and activated carbon. Approximately 50 percent of the material was adsorbed on the macroreticular resin. Of the materials adsorbed on the macroreticular resin, 26 percent were basic, 36 percent were acidic, and 38 percent were of neutral character. Of materials passing through the resine, 21 percent were adsorbed on a cation exchange resin (basic), 58 percent were adsorbed on anion exchange resins (acidic, and 20 percent were not adsorbed (neutral). Activated carbon adsorbed quantities of material similar to those adsorbed by the ion exchangers if the sample was acidified before adsorption. Based on these fractionation experiments, a procedure to perform a preparative scale fractionation of an oil shale retort water produced in situ into representative organic compound classes has been developed. The four primary fractions isolated include hydrophobic bases, hydrophobic neutrals, carbon adsorbables, and nonadsorbables.

KEY WORDS: organic carbon, dissolved organic fractionation, oil shale retort water

As the petroleum reserves of the United States decrease in abundance, development of alternative fuels such as shale oil is essential. In situ oil shale processing is an attractive technology. A major consequence of in situ processing technologies developed to date is the production of copious quantities of by-product water. The possibility of obtaining as much as one barrel of retort water for every barrel of product oil poses serious environmental and technological problems [1].

ORGANIC POLLUTANT IN WATER AND WASTEWATER

A large quantity (47 128 litres) of an oil shale retort water produced in situ has been collected and preserved [2, 3]. The composition of the retort water produced in situ used in this study represents an approximate average of changing compositions observed during the course of the experimental burn. [1]. This sample has been collected to allow for use by a number of investigators and thus provide an opportunity for an interdisciplinary evaluation of a single sample type. The experiments reported in this study are exclusively concerned with this reserve of retort water.

As a result of the diversity and complexity of the dissolved organic constituents, specific methods for individual compound analysis and techniques such as gas chromatography-mass spectroscopy have limited application to the overall characterization of the organic materials in oil shale retort waters. There exists as need for general characterization methods that will provide insight into the overall organic composition of such waters. One method that shows promise in this direction is the recently reported high-performance liquid chromatographic technique for fingerprinting or profiling dissolved organics [4[. Rubin et al [5] have developed a liquid-liquid extraction procedure for the fractionation of organic compounds in coal gasification and oil shale retorting by-product waters. Leenheer and Huffman [6] have recently developed a physical separation scheme utilizing macroreticular and ion exchange resins to reproducibly separate organic compounds into groups that are quantitated on the basis of their relative contribution to the total dissolved organic carbon (DOC) in the water sample. This scheme referred to as the DOC fractionation scheme, is generally superior to fractionation schemes involving liquid-liquid partitioning and carbon adsorption.

Whereas, the DOC fractionation provides an analytical means of characterizing the nature of organic materials in retort water, a preparative fractionation scheme provides a means of determining the effects of related types of compounds in various systems. Preparative fractionation will allow studies to delineate biologically active materials, studies of the fates of various types of materials in the environment, and more detailed chemical and physical characterization.

A preparative fractionation procedure designed to obtain fractions from oil shale retort water for subsequent biological and environmental studies should have the following characteristics:

  1. The quantity and quality of material recovered in each fraction must be reproducible between each batch of material fractionated.
  2. Recoveries of materials in each fraction should be maximized and any incomplete recoveries documented.
  3. The fractions should represent a cohesive group of materials suitable for additional subfractionation with minimal overlaps between fractions.
  4. A limited number of fractions should be produced at each level of fractionation. This provides great cost savings in certain expensive biological experiments.
  5. The procedure should be adaptable to producing at least several gram quantities of products in major fractions.

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