Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water

Lutes, Chris; Henderson, Trent; Liles, David; Garcia, Daniel J.; Clayton, Renee; Patterson, Judodine; Parette, Robert; Cannon, Frederick S.; Goltz, Mark N.; Craig, Daniel A.

doi:10.21236/ada579136

Cited by 2 publications

(1 citation statement)

References 55 publications

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“…The pilot-scale system consisted of two vessels in series (refer to Lutes et al, 2010 for details). Each contained 16.8 gallons (62 L) of surfactant-tailored GAC in the lead region (on top), and 8.4 gallons (32 L) of conventional GAC in the lower region (on bottom), which corresponds to a diameter of 14 inches (36 cm) and a height of 47 in (120 cm).…”

Section: Methodsmentioning

confidence: 99%

Competition of Anions with Perchlorate for Exchange Sites on Cationic Surfactant-Tailored GAC

Patterson

Parette

Cannon

et al. 2011

Environmental Engineering Science

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Removal of perchlorate (ClO 4 À ) while using granular-activated carbon (GAC) that had been preloaded with cetylpyridinium chloride was appraised using Rapid Small-Scale Column tests (RSSCT) and pilot-scale demonstration. ClO 4 À competed with nitrate, sulfate, chloride, and other anions for ion exchange sites on the preloaded carbon. Tests used native groundwater from Fontana, CA, which contained nitrate of 32 mg/L as NO 3 À , 7 mg/L as ClO 4 À , and 1.9 mg/L (as U) of uranyl carbonate species (predominantly UO 2 (CO 3 ) 3 4À ) species. RSSCT with Fontana groundwater exhibited ClO 4 À breakthrough at 25,000 bed volumes. When the same groundwater was spiked to three times the native NO 3 À concentration, ClO 4 À breakthrough occurred at 12,000 bed volumes. When the total dissolved solids (TDS) increased from the native 250 mg/L up to 660-810 mg/L TDS, by adding magnesium sulfate, sodium bicarbonate, or sodium chloride, the bed-life for removing ClO 4 À increased by 10%-30%. This result was attributed to perchlorate's competition with native UO 2 (CO 3 ) 3 4À , which limited the bed-life for ClO 4 À breakthrough. Specifically, at higher TDS the computed activity coefficient of UO 2 (CO 3 ) 3 4À decreased relative to that of single-charged ClO 4 À , and this effectively yielded more favorable ionexchange competition by the ClO 4 À . Pilot-scale studies that used elevated nitrate levels in the water exhibited similar trends to the RSSCTs. These effects further emphasized the compounded competition that the uranyl carbonate posed on cetylpyridinium chloride-tailored GAC where this surfactant had been loaded in compactmicellar configuration. This represents an important consideration for a number of groundwater sources where uranium appears in trace concentrations.

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Section: Methodsmentioning

confidence: 99%

Competition of Anions with Perchlorate for Exchange Sites on Cationic Surfactant-Tailored GAC

Patterson

Parette

Cannon

et al. 2011

Environmental Engineering Science

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Applications of Chemically Modified Clay Minerals and Clays to Water Purification and Slow Release Formulations of Herbicides

et al. 2020

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This review deals with modification of montmorillonite and other clay-minerals and clays by interacting them with organic cations, for producing slow release formulations of herbicides, and efficient removal of pollutants from water by filtration. Elaboration is on incorporating initially the organic cations in micelles and liposomes, then producing complexes denoted micelle- or liposome-clay nano-particles. The material characteristics (XRD, Freeze-fracture electron microscopy, adsorption) of the micelle– or liposome–clay complexes are different from those of a complex of the same composition (organo-clay), which is formed by interaction of monomers of the surfactant with the clay-mineral, or clay. The resulting complexes have a large surface area per weight; they include large hydrophobic parts and (in many cases) have excess of a positive charge. The organo-clays formed by preadsorbing organic cations with long alkyl chains were also addressed for adsorption and slow release of herbicides. Another examined approach includes “adsorptive” clays modified by small quaternary cations, in which the adsorbed organic cation may open the clay layers, and consequently yield a high exposure of the siloxane surface for adsorption of organic compounds. Small scale and field experiments demonstrated that slow release formulations of herbicides prepared by the new complexes enabled reduced contamination of ground water due to leaching, and exhibited enhanced herbicidal activity. Pollutants removed efficiently from water by the new complexes include (i) hydrophobic and anionic organic molecules, such as herbicides, dissolved organic matter; pharmaceuticals, such as antibiotics and non-steroidal drugs; (ii) inorganic anions, e.g., perchlorate and (iii) microorganisms, such as bacteria, including cyanobacteria (and their toxins). Model calculations of adsorption and kinetics of filtration, and estimation of capacities accompany the survey of results and their discussion.

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Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water

Cited by 2 publications

References 55 publications

Competition of Anions with Perchlorate for Exchange Sites on Cationic Surfactant-Tailored GAC

Competition of Anions with Perchlorate for Exchange Sites on Cationic Surfactant-Tailored GAC

Applications of Chemically Modified Clay Minerals and Clays to Water Purification and Slow Release Formulations of Herbicides

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